Manufacturer: School of Medicine and Public Health University of Wisconsin-Madison 610 Walnut Street Madison, WI 53726

CT Protocols for Revolution™ Discovery™ CT /

Discovery™ CT750 HD

Copyright © 2017

Manufactured in USA

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University of Wisconsin-Madison CT Protocols for

Revolution™ Discovery™ CT / Discovery™ CT750 HD

Table of Contents

Page No. Changes from Revision 2 to Revision 3 .......................................................................... 1

CT Protocol Scanner Compatibility Information ............................................................... 6

Direct Multi-Planar Reformat (DMPR) Protocols ............................................................. 7

Introduction to University of Wisconsin-Madison CT Protocols ....................................... 9

Design Philosophy of UW Protocols: Abdominal ................................................................................................................ 14 Chest ........................................................................................................................ 16 Cardiovascular ......................................................................................................... 17 Musculoskeletal ....................................................................................................... 18 Neuroradiology ......................................................................................................... 19 Pediatrics (including Higher Image Quality) ............................................................. 20

Protocols

Abdominal Protocols: Abd/Pelvis: # 6.1/6.2/6.3 ......................................................................................... 23 High Image Quality Cancer Follow-up Abd/Pelvis: # 6.7/6.8/6.9 ............................. 26 Abd/Pelvis - R/O Hernia ........................................................................................... 29 Abd/Pelvis - Flank Pain: # 6.10/6.11/6.12 ............................................................... 31 Abd/Pelvis - Pre-IVC Filter Removal: # 6.73/6.74/6.75 ........................................... 33 Low Dose Renal Stone (including limited follow-up): # 6.13/6.14/6.15 ................... 35 Abd/Pelvis - Colonography: # 6.16/6.17/6.18 .......................................................... 38 Chest/Abd/Pelvis with IV Contrast: # 5.4/5.5/5.6 ..................................................... 43 Chest/Abd/Pelvis without IV Contrast: # 5.7/5.8/5.9 ................................................ 47 Abd/Pelvis - Urography: # 6.22/6.23/6.24 ............................................................... 51 Urothelial Tumor Follow-Up: # 6.70/6.71/6.72 ......................................................... 55 Abd-Liver - Biphasic: # 6.25/6.26/6.27 .................................................................... 59 Abd-Liver - Triphasic: # 6.28/6.29/6.30 ................................................................... 63 Abd-Liver - Hepatocellular Carcinoma (HCC): # 6.82/6.83/6.84 ............................. 72 Abd-Adrenal Gland - Adenoma: # 6.31/6.32/6.33 ................................................... 76 Abd-Pancreas – Pancreas Cancer (Neoplasm Screening): # 6.40/6.41/6.42 ......... 80

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Abdominal Protocols (cont.): Abd/Pelvis - Kidney Tumor: # 6.49/6.50/6.51 .......................................................... 84 CTA Abd - Renal Donor: # 6.52/6.53/6.54 .............................................................. 88 Abd-Small Bowel - Enterography: # 6.55/6.56/6.57 ................................................ 92 CTA Abd - Obscure GI Bleed: # 6.58/6.59/6.60 ...................................................... 94 CTA Abd - Mesenteric Ischemia: # 6.61/6.62/6.63 .................................................. 98 Trauma - Chest: # 5.22/5.23/5.24 ......................................................................... 101 Trauma - Chest/Abd/Pelvis: # 5.25/5.26/5.27 ....................................................... 105 Trauma - Abd/Pelvis: # 6.4/6.5/6.6 ........................................................................ 112 Cystogram: # 8.10/8.11/8.12 ................................................................................. 117 Body Pelvis: # 8.16/8.17/8.18 ............................................................................... 121

Chest Protocols: Chest - Standard (Routine & High-Resolution): # 5.1/5.2/5.3 ................................ 124 Chest - Low Dose Follow-up: # 5.10/5.11/5.12 ..................................................... 129 Chest - Low Dose Screening: # 5.13/5.14/5.15 ..................................................... 132 Chest - CTA for PE: # 5.16/5.17/5.18 ................................................................... 135 Chest - Dynamic 3D Airway: # 5.70/5.71/5.72 ...................................................... 138

Cardiovascular (CV) Protocols*: Non-Gated CTA (Chest/Abd/Pelvis): # 5.28/5.29/5.30 .......................................... 142 Retrospectively-Gated CTA Chest: # 5.31/5.32/5.33 ............................................ 147 -Gated Chest and Non-Gated Abd/Pelvis CTA: # 5.34/5.35/5.36 ......................... 152 Prospectively-Gated Coronary CTA: # 5.37/5.38/5.39 .......................................... 157 Retrospectively-Gated Coronary CTA: # 5.40/5.41/5.42 ....................................... 161 TAVI CTA: # 5.43/5.44/5.45 .................................................................................. 165 Prospectively-Gated CTA Chest (Non-Coronary): # 5.46/5.47/5.48 ...................... 169 Upper Extremity CTA: # 5.49/5.50/5.51 ................................................................ 173 Lower Extremity CTA: # 5.52/5.53/5.54 ................................................................ 177 Post-Endostent Non-Con Volume Change (Abd/Pelvis only): #5.58/5.59/5.60 ..... 182 Prospectively-Gated Left Atrial Appendage: # 5.73/5.74/5.75 ............................... 184 * NOTE: All non-cardiovascular chest protocols are in the Chest Protocols section.

Musculoskeletal (MSK) Protocols: Bony Pelvis/Hips/SI/Femur/FAI (Without Metal): # 8.1/8.2/8.3 .............................. 188 Bony Pelvis/Hips/SI/Femur/FAI (With Metal): # 8.4/8.5/8.6 ................................... 193 Knee/Tibia (Without Metal): # 9.3 .......................................................................... 198 Knee/Tibia (With Metal): # 9.4 ............................................................................... 202 Ankle/Foot/Distal Tibia (Without Metal): # 9.1 ....................................................... 206 Ankle/Foot/Distal Tibia (With Metal): # 9.2 ............................................................ 211 Femoral Anteversion: #9.8/9.9/9.10 ...................................................................... 216 Shoulder/Humerus (With or Without Metal): # 4.1/4.2/4.3 ..................................... 222

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Musculoskeletal (MSK) Protocols (cont.): Elbow/Forearm (Without Metal): # 4.6................................................................... 229 Elbow/Forearm (With Metal): # 4.7 ....................................................................... 235 Wrist (Without Metal): # 4.8 ................................................................................... 241 Wrist (With Metal): # 4.9 ........................................................................................ 247 Chest Wall/Clavicle/AC Joint/SC Joint/Sternum/Ribs: # 4.11/4.12/4.13 ................ 253 Soft Tissue Extremity with IV Contrast: # 9.13/9.14/9.15 ...................................... 256

Neuroradiology (Neuro) Protocols: Brain - Routine and Pediatric NAT/Trauma (Helical Mode): # 1.1/11.1/11.2 ......... 259 Brain - Helical Scan with Angled Axial Reformations: # 1.2/11.3/11.4 .................. 264 Brain (Axial Mode): # 1.3/11.5/11.6 ....................................................................... 269 Stealth - Stereotactic Head (Whole Brain Treatment Planning): # 1.10/11.11/11.12 .... 274 Orbit - Routine: # 2.1/12.1/12.2 ............................................................................. 277 Facial Trauma - Routine: # 2.5/12.9/12.10 ............................................................ 282 Sinuses - Diagnostic: # 2.7/12.13/12.14................................................................ 287 Temporal Bone (without Contrast): # 2.10/12.18/12.19......................................... 292 Temporal Bone (with Contrast Only or with & without Contrast): # 2.11/12.20/12.21 .... 295 Adult Neck - Routine: # 3.1/3.2/3.3 ....................................................................... 301 Neck (Parathyroid Adenoma): # 3.5/3.6/3.7 ........................................................... 306 Pediatric Neck - Routine: # 13.1.1,13.2.1,13.4.1,13.6.1,13.8.1 ............................. 314 Adult Cervical Spine (without Metal): # 3.16/3.17/3.18 ......................................... 319 Adult Cervical Spine (with Metal): # 3.19/3.20/3.21 .............................................. 324 Adult Thoracic Spine (without Metal): # 7.4/7.5/7.6 ............................................... 329 Adult Thoracic Spine (with Metal): # 7.19/7.20/7.21 .............................................. 333 Adult Lumbar Spine (without Metal): # 7.1/7.2/7.3 ................................................ 337 Adult Lumbar Spine (with Metal): # 7.16/7.17/7.18 ............................................... 341 Stroke Deluxe - Total Cerebrovascular: # 1.6/1.13/11.16/11.17 ........................... 345 CTA Head Only (Stenosis, Aneurysm, Unknown Bleed): # 1.7/11.18/11.19 .......... 352 CTA Neck Only (Cerebrovascular Disease): # 3.11/11.22/11.23 .......................... 359 CT Venography: #1.9/11.24/11.25 ........................................................................ 363

Pediatric Protocols*: Routine Abdomen/Pelvis: # 16.1.1/16.2.1/16.4.1/16.6.1/16.8.1 ............................ 368 Acute Appendicitis - Abdomen/Pelvis: # 16.1.1/16.2.1/16.4.1/16.6.1/16.8.1 ......... 371 Renal Stone/Flank Pain: # 16.1.2/16.2.2/16.4.2/16.6.2/16.8.2 .............................. 373 Triphasic Liver: # 16.1.3/16.2.3/16.4.3/16.6.3/16.8.3 ............................................ 376 Trauma Abdomen/Pelvis: # 16.1.4/16.2.4/16.4.4/16.6.4/16.8.4 ............................ 384 Chest - Standard (Routine & High Resolution): # 15.1.1/15.2.1/15.4.1/15.6.1/15.8.1 389 Peds Chest Dynamic 3D Airway: # 15.1.2/15.2.2/15.4.2/15.6.2/15.8.2 ................. 393 Chest Pectus: # 15.1.3/15.2.3/15.4.3/15.6.3/15.8.3 .............................................. 398 CTA Chest for PE: # 15.1.4/15.2.4/15.4.4/15.6.4/15.8.4 ....................................... 401

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Pediatric Protocols* (cont.): Routine Chest/Abdomen/Pelvis: # 15.1.5/15.2.5/15.4.5/15.6.5/15.8.5 .................. 405 Trauma Chest/Abdomen/Pelvis: # 15.1.6/15.2.6/15.4.6/15.6.6/15.8.6 .................. 409 * NOTE: Neuro protocols for pediatric patients are in the Neuro Protocols section.

Pediatric Higher Image Quality (HIQ) Protocols*:

Routine Abdomen/Pelvis: # 16.1.6/16.2.6/16.4.6/16.6.6/16.8.6 ............................ 416 Acute Appendicitis - Abdomen/Pelvis: # 16.1.6/16.2.6/16.4.6/16.6.6/16.8.6 ......... 418 Renal Stone/Flank Pain: # 16.1.7/16.2.7/16.4.7/16.6.7/16.8.7 .............................. 419 Triphasic Liver: # 16.1.8/16.2.8/16.4.8/16.6.8/16.8.8 ............................................ 421 Trauma Abdomen/Pelvis: # 16.1.9/16.2.9/16.4.9/16.6.9/16.8.9 ............................ 425 Chest - Standard (Routine & High Resolution): # 15.1.8/15.2.8/15.4.8/15.6.8/15.8.8 428 Chest Pectus: # 15.1.10/15.2.10/15.4.10/15.6.10/15.8.10 .................................... 430 CTA Chest for PE: # 15.1.11/15.2.11/15.4.11/15.6.11/15.8.11 ............................. 432 Routine Chest/Abdomen/Pelvis: # 15.1.12/15.2.12/15.4.12/15.6.12/15.8.12 ........ 434 Trauma Chest/Abdomen/Pelvis: # 15.1.13/15.2.13/15.4.13/15.6.13/15.8.13 ........ 436 * NOTE: Neuro protocols for pediatric patients are in the Neuro Protocols section.

Protocol Resources

Pediatric Bony Pelvis Protocol Selection ..................................................................... 441

Position Tutorial ........................................................................................................... 442

Size Selection .............................................................................................................. 445

Size Selection for Neck and C-spine ........................................................................... 446

Instructions for Adjusting Protocols for Pediatric Extremities and Bariatric Patients .... 447

Weight-Based Contrast Instructions ............................................................................ 449

Creatinine Guidelines (with values for eGFR) ............................................................. 450

Pediatric Contrast Guidelines ...................................................................................... 451

CT Perfusion Protocol: (Specific Instructions) ............................................................. 452

Thoracic Outlet Instructions ......................................................................................... 457

Scout Ranges and Anatomical Landmarks.................................................................. 458

Window Width and Window Level ............................................................................... 459

Instructions for Avoiding the Lens of the Eye on Head Exams .................................... 460

How to Send the ECG Trace to PACS ........................................................................ 461

Frequently-Asked Questions (FAQ’s) .......................................................................... 462

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ChangesfromRevision2toRevision3

AspartofourongoingUWMadisonCTprotocoloptimization,wehavemadethefollowingchangesbetweentheRevision2andRevision3release.AllofthesechangeshavebeeninternallyreviewedandvalidatedbyourteamofRadiologists,Physicists,andCTTechnologists,therebyfulfillingTheJointCommissionmandateonprotocolreview.DetaileddocumentationofourcompliancewithTheJointCommissionStandardsregardingtheperformanceelementforCTprotocolreviewispostedonourwebsite(https://www.radiology.wisc.edu/protocols/CT/resources.php).NewProtocolsAddedThefollowingprotocolsarenewtotheRevision3protocolrelease:Neck(ParathyroidAdenoma)Adult;HighImageQualityCancerFollow­UpAbd/Pelvis;Urothelialtumorfollow­up;SoftTissueExtremitywithIVContrast;ChestWall/Clavicle/ACJoint/SCJoint/Sternum/Ribs;PedsChestDynamic3DAirway;Prospectively­GatedLeftAtrialAppendage.GlobalChangesMadetotheUWProtocolsWeturnedonautovoicewhenusingsmartprep.Uponinteractingwithusersofourprotocols,werealizedmostusersexpectedthisfeaturetobeturnedonbydefault.Windowwidthandwindowlevelhavebeenstandardizedacrossallprotocols.Thereisnowasystematicapproachtosettingwindowwidthandwindowlevel,whichisincludedintheProtocolsManual.ScoutstartandendlocationshavebeenstandardizedforallprotocolsandaredocumentedinanewsectionoftheProtocolsManual.Thisincludesastandardizationoflandmarksex:om,sn,xy,ic.Theanatomicallandmarksonallnon­scoutseries/groupshavebeenstandardizedaswell.Tablesforreformatshavebeencreatedinallsections;previousversionslackedreformattablesforsomeprotocols.Thenamingofallseriesdescriptionshasbeenstandardizedtosofttissue,thinsofttissue,bone,thinbone,axialsofttissue,etc.Tooptimizeimagequality,allreformatshavebeenchangedtosetintervalsatonehalfofthereformattedslicethickness.TheSmartprepphasewasmistakenlycalledaseries;thisisnowcorrectedintheprotocoldocumentation.Referencesmadeinthereformatinstructionswerechangedfromthereconnumbertotheseriesdescriptionofthesourcereconstruction.AlloralcontrastandIVinstructionswereupdatedtobeuniformwithrespecttotheirunits.CreatinineGuidelinesandPediatricContrastGuidelineswerealsoaddedtotheprotocolresourcessectionofthemanual.Revolution Discovery CT / Discovery CT750 HD 1 Rev: 3.0 / December 2017

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AbdominalProtocolsToassistCTtechnologistsinchoosingthecorrectsizeprotocol(small/medium/large),allmediumDFOVwerechangedfrom36to40cm.Thismeanspatientstoobigtobescannedassmallormediumwillrevealtissueextendingoutsideofthe“bluetargetregion”onthescoutimages,promptingthetechnologisttoselectalarger­sizedprotocol.ThethresholdforswitchingfromsmalltomediumwasmovedfromascoutAP+Lateralmeasurementof55to60cmtoimprovetheimagequalityofpatientsonthesmallersideofwhatcouldbeconsideredamediumpatient.Alllargeprotocolswitha50DFOVwerechangedfromsofttoastandardalgorithmtoincreasetheresolutionanddecreasethe“blurry”appearanceofthelargeprotocol’ssofttissuereconstructions.RealizingthatsomeorganizationsmaynothavetheP3TpowerinjectoroptionontheirBayerinjector,aweight­basedcontrastchartwascreatedfornon­P3Tsites.ThisislocatedintheProtocolResourcesSectionoftheProtocolsManual.Tosavepatientdoseduringthesmartprepphase,themonitoringdelaywasincreasedfrom30to40secondssincecontrastusuallyneverpeaksbefore40seconds.Adedicated“OncologyCancerFollow­up”protocolwascreatedtobettervisualizesubtlelesionsoncancerfollow­uppatients.DMPRwasaddedtothewithoutseriesontheAdrenalGlandAdenomaprotocol,andonallthreephasesoftheliverdonorwork­up.Realizingthetext­basedinstructionsprovidedinpreviousversionsoftheprotocolswereconfusingforsome,aneasiertouseformulaandpictureswerecreatedtocalculatethetimingfortheLiver­Triphasicandliverdonorprotocols.ThecontrastamountwasupdatedforChest/Abd/Pel/Neck(100cccontrast/50ccchaser)andChest/Neck(75cccontrast/75ccchaser).The“examsplit”featureisnowutilizedontheChest/Abd/Pelvisprotocols(boththewithandwithoutcontrast),whichallowsmultiplesectionstoreaddifferentbodyregions(i.e.,theChestsectionreadsthechestportionoftheexamandtheAbdominalsectionreadstheAbd/Pelvisportionoftheexam).TheDMPRsonthechestportionoftheChest/Abd/Pelvisprotocolwerealsoupdated.Trauma­Chestexamsarenowstartedatthebottomofthespleentoimprovevisualizationofanyarterialinjuriesinthatorgan.TheTrauma­Cystogramprotocol,whichwasscannedatatrauma­leveldose,wasremoved.Thisprotocolwasfoundtobeunnecessarysincenospinereconstructionswereperformedwiththatprotocol.Fortraumacases,theCystogram(NonTrauma)protocolisnowrecommended,whichincludesawithoutcontrast,awithcontrast,andadelayphase.Fortraumapatients,thewithoutphaseisskipped.IntheTrauma­Chest/Abd/Pelvisprotocol,recon#10waschangedtoathoracic/lumbarspineinsteadofthebonypelvis.Revolution Discovery CT / Discovery CT750 HD 2 Rev: 3.0 / December 2017

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TheAbd/Pelvis­Urographyprotocolhasbeenchangedtoa115seconddelay.Thescanandinjectionshouldbestartedatthesametimeandthedelayisbuiltintotheprotocol.Inthisprotocol,theneedtodomanualobliquesagittalreformatswasremoved,aswellastheadvicetohavearadiologistcheckmidscanforanyage;instead,allpatientsgettheentireexam.TheAbd/Pelvis–R/OHerniaprotocolhasbeenremovedfromthescanner.InsteadusetheroutineAbd/Pelvisprotocolandfollowtheclinicalinstructionsinthismanualregardingtherequesttothepatienttobeardown(Valsalvamaneuver).ThePancreasprotocols(pre­opandscreening)werecombinedintoasingleprotocolnowcalled“PancreasCancer”.ChestProtocolsDMPRcoronalandsagittalreformatswereaddedontheChestprotocols(includingtheTrauma–ChestfromtheAbdominalprotocols).TheobliquesagittalMIPreformat(i.e.,“thecandycaneview”)wasremovedintheTrauma­Chest.ThelargepatientcontrastvolumeintheCTAforPEprotocolwasupdatedtouseIsovue370insteadofa300mgI/ccstrengthagent.AnaxialimageoftheheartwasaddedtothePEprotocoltoshowthesmartpreplocation(i.e.,wepointoutthelocationoftheleftventricle).Cardiovascular(CV)ProtocolsForsiteswithouttheBayerMedradP3TPAoption,aweight­basedchartforIsovue370isavailableintheProtocolResourcessectionoftheManual.AllCVreformatswerechangedtomimictheroutinechestreformats.Ifyourscannerhastheoption,itisrecommendedthatyouturnonMARStotherunoffprotocol(i.e.,lowerextremityCTA)tomitigatemetalartifactsfromorthopedicimplants.Thisisaselectableboxonthereconstructionoptionstabonyourscanner.Alungreconwasaddedtocoronaries(thisusesaboneplusreconstructionkernel).Ifyourscannerhastheoption,itisrecommendedthatyouturnonMARSforCTAChest/Abd/Peltoreduceartifactfromstentsandotherhigh­contrastimplanteddevices.Retro/ProspectiveCoronaryCTAbreathinginstructionswereupdatedforallphasestonowbeconsistentwitheachother;beforetheinstructionsvariedbetweenthetimingbolusandtheCTA.ItisrecommendedtosendECGtraceinformationongatedstudiestoPACS.Thiswillfacilitatetroubleshootingwhenthestudydoesnotcomeoutasintended.InstructionsfordoingthisareincludedintheProtocolsManual.TheUpperandLowerExtremityCTAprotocolshavebeenchangedfromusingatimingbolustousingasmartprep.Revolution Discovery CT / Discovery CT750 HD 3 Rev: 3.0 / December 2017

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ThoracicOutletinstructionsareprovidedintheProtocolResourcessectionoftheManual.ThisindicationiscommonlyscannedusingMRIwhenavailable.ACTversionisincludedhereforsiteswhodonothaveaccesstoMRI.Musculoskeletal(MSK)ProtocolsNewreformatsforFAI(i.e.femoralacetabularimpingement)werecreatedaspartoftheroutinebonypelvisprotocol.FYI,“FemoralAnteversion”isaseparateprotocol.Forpatientsunabletoraisetheirarms,instructionshavebeenaddedthroughouttheMSKprotocolsforhowtoscananextremityprotocolwitharmsdownattheirsides.Ifyourscannerhastheoption,itisrecommendedthatyouturnonMARSforthemetalextremityprotocols.Neuroradiology(Neuro)ProtocolsTomakeiteasiertounderstandthereformatneedsoftheNeuroprotocols,tablesforCTAheadandneckreformatshavebeenaddedthroughouttheNeuroProtocols.Theinjectionratewaschangedto4cc/secfortheCTAhead/neckprotocols.TheBrain(AxialMode)protocolwaschangedfrom20mmto10mmbeamcollimation.Thiswasdonetolessentheslab­to­slabartifactthatsometimesoccurswhendoingangledaxialsscanning.Pediatricaxialheadswerechangedtobescannedat5mmslicethickness.SagittalreformatswereaddedforallroutineheadwithoutscansthroughouttheNeuroProtocols.TheASiRpercentageontheNeuroprotocolswaschangedto60%on5mmand80%on1.25mmsofttissuereconstructions.ThischangeaffectsthemajorityoftheNeuronon­spineandnon­angioprotocols.Ifyourscannerhastheoption,itisrecommendedthatyouturnonsmartMARSforanySpinewithmetal,CTAHead,CTAhead/neck,routineneck,andmaxifaceprotocols.Thiswillhelpwithartifactsfromcoils/clips/stentsetc.TheAdultRoutineNeckprotocolwaschangedtoscantopdown,andtheinjectiontimingandcontrastamountwerechangedfrom110mlsto100mls.TheCervical,Thoracic,andLumbarSpineprotocolswerechangedfromstandardtosoftreconforthesofttissuereconstructions.TheUniversityofWisconsinMadisonusesRAPID(iSchemaViewInc,RedwoodCity,CA)softwareforperfusionmapprocessingandwereferencethisinourprotocol’snetworkingsection.TheCTAstrokedeluxeCTAupperthorax/neck/headCTAphasewaschangedfrom20to40mmbeamcollimationtospeedupthescanandavoidvenouscontamination.Weaddedinstructionstotheneckprotocoltousethesmallversion(lowerdose)onanysizedpatientthatisbeingscannedasafollowupforlymphoma.Revolution Discovery CT / Discovery CT750 HD 4 Rev: 3.0 / December 2017

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Theslicethicknessonthepediatrictemporalboneprotocolwaschangedtobethesameastheadult.Thepediatricstereotacticheadwaschangesfroma1secondtoa0.5secondrotation.PediatricProtocolsMSKguidanceforpediatricscanning(i.e.,howtochangetheprotocoltolowerthedose)wascreatedbasedontheadultMSKprotocolsandisincludedintheProtocolResourcessectionoftheManual.Inaddition,guidanceforscanningpediatricbonypelvisandbonypelviswithspicacastwasalsocreatedandcanalsobefoundinthatsection.TheindicationsinthePediatricChestWithandWithoutIVContrastprotocolswereupdated,andthetwoprotocolswerecombinedtomatchtheAdultChestprotocol.Theexpirationphasehi­reschestwithoutwasupdatedtomatchtheadultroutinechestprotocol.GuidanceandcriteriaforpediatriccontrastadministrationwasaddedtotheManualintheProtocolResourcesSection,includingIVaccess,needle,gauge,flowrate,etc.ThePediatricTraumaHeadandthePediatricRoutineHeadwerecombined.Detailedinstructionsforthespecialreformatsneededfortraumacases(3DNAT)havebeenprovidedintheBrain­RoutineandPediatricNAT/Trauma(HelicalMode)Protocol.

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ScannerCompatibilityRevolutionDiscoveryHD750Introduction:ListedbelowaretheminimumscanneroptionsrequiredtousethissetofprotocolsonyourRevolution™Discovery™CTorDiscovery™CT750HDscanners.Theprotocolsinthisdocumenthavebeenvalidatedonascannercompatiblewiththerequirementslistedbelow.TheportabilityofUWprotocolstoscannerswithdifferentspecificationsmaybepossiblewiththeproperassistancefromyourinstitution’sCTprotocoloptimizationteam,butshouldnolongerbeconsideredvalidatedUWprotocols.Aswithanyprotocol“restore”operation,theexisting“user”protocolswillbedeletedwhentheseUWprotocolsareloadedontoyourscanner.WethereforerecommendyousaveandexportacopyofyourexistingprotocolstoaCDpriortoloadingtheUWprotocols.TheexportedfilecanbeusedasareferencetoaidinmanuallyaddingasingleprotocoltotheUWprotocolsetunderyour“user”tab.ProtocolscanbeexportedtoCDfromtheToolChestorfromDoseCheck.TheCDcanthenbeviewedonaPCandconvertedtoExcelformat.IMPORTANT—Thefollowingtworulesshouldalwaysbefollowedwhenrestoringprotocols:1)protocolsmustonlybetransferredbetweenscannersofthesamemodel,and2)protocolsmustonlybetransferredfromanotherscannerwithasoftwareversionthatisolderorequalinrevisionnumber,butnotnewer.Theseprotocolswerebuiltusingsoftwareversionnumber11MW44.11.V40_PS_HD64_G_GTL.Youshouldcontactyourserviceengineertoreceiveasoftwareupgradeifyourcurrentsoftwareversionisolderthanthis.ScannerCompatibilityList:ASiRwith64slicesacquisitionat0.625mmCardiacOptions:SmartScorePro,CardIQSnapShot,CardIQSnapShot­CineTuberotationtimes(helicalmode,non­cardiac):0.4,0.5,0.6,0.7,0.8,0.9,and1.0secondmAlimits/kVforlargefocalspot(exceptpediatricbodyandpediatrichead):715mAat140kV,835mAat120kV,800mAat100kV,and700mAat80kVmAlimits/kVforsmallfocalspot:490mAat140kV,570mAat120kV,680mAat100kV,and620mAat80kVmAlimits/kVforpediatricheadandpediatricbody:210mAat140kV,250mAat120kV,300mAat100kV,and375mAat80kV

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DirectMulti­PlanarReformat(DMPR)Protocols

Introduction:ADirectMulti­PlanarReformat(DMPR)isaprocesssetupandisexecutedaspartofthescanprotocol.ItcanusethesameprotocolthatmightbeusedinaGeneralReformat.InDMPR,theuserdefinesthereformatprotocolstobeexecutedandsetsasanAutomatedBatchmodeoraManualBatchmode.ItisthenexecutedontheExamRxdesktop.ReformatisavailableontheImageWorksDesktopandrequiresmanualloadingofthedataoncethescaniscompleted.DMPRProtocols:AreformatprotocolmustbecreatedtobeselectedforuseinprotocolswithDMPRenabled.ForDMPRtoworkwiththeUWprotocols,reformatprotocolswillneedtobebuiltwiththesamenamesasthoseusedintheprotocols.Tobuildreformatprotocols,youneedtoselectimagesfromanexamalreadyperformedtocreatetheinitialsame­namereformatprotocol.ReformatprotocolscreatedforuseinDMPRmustbesingle­stepprotocolsandcanonlybecreatedintheaxial,sagittal,orcoronalviewports.ReformatprotocolsforuseinDMPRneedtobesavedintheGeneralcategoryifusingVolumeViewer.YoumustcreatetheDMPRreformatprotocolonimagesfromthebodypartthattheprotocolwillbeusedfor(i.e.,aPediatricDMPRprotocolmustbecreatedonimagesforaPediatriccaseandanAdultDMPRprotocolmustbecreatedonimagesforanadultcase).UW­specificDMPRreformatprotocolnamesareidentifiedbelowwithwindowwidthandlevelvaluesforusewithUWProtocols:

BODY­WW/WL450/50COBODYSABODY

CHEST­WW/WL450/50(createdoffofaC/A/Pstudy)

SACO

CHEST­WW/WL1500/­700offbone+imagesMIPS

PEDSBODY­WW/WL550/100COPEDSSAPEDS

PEDSCHEST­WW/WL550/100SAPEDSCHESTCOPEDSCHEST

PEDSCHEST­WW/WL2100/­450PEDSCOCHESTPEDSSACHESTAllslicethicknessandintervalscanbefoundintheactualprotocols.

HowtoCreateaReformatProtocolforUseinaDMPRSession:1. Loadthinslices(makeyourreformat0.625/1.25)intoReformatselectedontheImageWorksdesktop.2. SelectBatchReformat.3. Settheslicethickness,interval,FOVandmodetothevaluesfortheprotocolitwillbeusedwith.4. Definetheoverage(numberofimages)forthereformatprotocolaccordingtotheanatomicalareafortheprotocol.5. AtthebottomoftheBatchscreen,clickADVANCED.6. ClickSAVEASPROTOCOL.7. EntertheProtocolName*andclickSAVE.Revolution Discovery CT / Discovery CT750 HD 7 Rev: 3.0 / December 2017

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*TheexactnamelistedabovemustbeusedinthenamingoftheprotocolsoDMPRwillusetheappropriatereformatprotocol,whichhasbeenpredefinedineachoftheprotocolsthatuseDMPR.Onceyoucreatethesereformatprotocols,youwillnotneedtodoitagain.Shouldyoudecidenottousethesesuggestedreformatprotocolnames,slicethicknesses,orintervals,youwillneedtocreateyourownreformatprotocolsandmodifyallprotocolsusingDMPRwithyourselections;otherwise,DMPRwillfailtooutputreformattedseries.RefertotheUserManualfordetailedinstructionsforcreatingBatchReformatProtocols.

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IntroductionDocument

UniversityofWisconsin­MadisonCTProtocolsIntroduction:WearepleasedtoprovideyouwiththeUniversityofWisconsin­MadisonComputedTomography(CT)ProtocolsaspartofyourGECTscannerpurchase.Wehopeyoutakethetimetolearnandunderstandourprotocolphilosophy.Forsomeofyouitwillbeasignificantchangefromyourcurrentpractice.Today'simagingliteratureandbulletinsfromimagingassociationsarefullofdirectivestodecreasepatientdose.Unfortunatelywearenotgivenmuchdetail,andtheburdenofexecutingthesechangesfallsonourshoulders.Formanyofus,ithasbeenalongtimesinceourphysicstrainingandfewofushavereallykeptuponourphysicsskills.Mostofushireaphysicsconsultant,andtheycomeinandhelpusgetourprotocolstoqualifyforACRaccreditationandensuretheX­rayequipmentisproperlycalibrated,butnotmuchmore.WiththeuniquerelationshipbetweenmedicalphysicsandradiologyattheUniversityofWisconsin­Madison,wecombinedourexpertiseanddevelopedaveryrobustsetofCTprotocols.Thetechnicalparametershavebeenfine­tunedspecificallyforthisscannerandthenvalidatedusingarigorousmanagementsystembasedontheISO9001standard.Withthehelpofourphysicists,wejuggledalltechnicalparametersthatcouldbemodifiedonthisscannerwithcarefulattentiontonotonlyhoweachindividualparameteraffectsimagequality,buttheinterplayofparameters.Thiswasacomplicatedtaskaidedbyspecially­writtensoftwarethatallowedustomodeltheeffectsondoseandquality.Weanticipatethatmostofyouwillfindthattheseprotocolsgenerateacceptableimagequality.Afewofyoumaybemoreevolvedandmaybetolerantofslightlynoisierimages.Itislikelythatsomeofyouwillfindtheseimagesnoisyandpossiblydifficulttoworkwithinitially.Wewouldliketodiscourageyoufrommodifyingourprotocolsettings.Bychangingoneormoreparameters,youdefeatthepurposeofbalancingtheeffectsofallparametersonimagequalityanddose.Pleasegiveyoureyesometimetoaccommodatebeforeyoumakechanges.Ifyoufindthatyouwouldliketochangesomeoftheacquisitionorreconstructionparametersinourprotocoldocuments,pleaserealizesomemodificationsmaydrasticallychangetheimagedoseandnoiselevel.Allchangesshouldbereviewedbyyourmedicalphysicist,GEapplicationspecialists,and/oryourinstitution’sCTprotocoloptimizationandqualitycontrolteam.Inmanycases,CTacquisitionparametersarelinkedtoreconstructionparametersinourprotocols.Forexample,halvingtheslicethicknessforthefirstreconstruction,whilekeepingthesamenoiseindex,willincreasethedosebyafactoroftwo!Thereisinterplaybetweentheautomaticexposurecontrolsettingandtheslicethicknessthatneedstobeunderstoodinordertomakeproperprotocolchanges.Inaddition,wehavedoneourbesttoensurethatthemAdoesnot“maxout”forlargepatientsizes(orforlownoisestudieswhichrequireextradose)bymonitoringtheeffectivemAsusedatourinstitutionoverawiderangeofpatientsizes.Tomaintaindiagnosticimagequalityatthelowestdoses,thekV,noiseindex,pitch,andtuberotationtimesallchangefordifferentprotocolsanddifferentpatientsizeswithineachprotocol.Revolution Discovery CT / Discovery CT750 HD 9 Rev: 3.0 / December 2017

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Otherseeminglytrivialchangeslikeswitchingfromapitchof0.516to0.969,changingfromthe“plus”to“full”reconoption,orchangingfrom“boneplus”to“bone”reconstructiontypesmayalsohavesignificantnegativeimpactsonimagequalityandpatientdoseduetospecialcharacteristicsoftheseparametersinadditiontothosethataremostobvioustotheuser.Changesofanyindividualprotocolparametermustbeperformedwhiletakingintoaccountalloftheparametersmakingupasingleprotocol.Therefore,weurgeyoutoonlymakeprotocolchangesafterdiscussingthemwithyourinstitution’sCTprotocoloptimizationteamorseekingexpertadvicefromGEapplicationspecialists.Werecognizetheseprotocolsarenotcomplete.Therearesomedeficiencies.Wehopetocorrectthemwithfuturereleases.Weencourageyourfeedback.Wewillbereachingouttoradiologists,physicists,andtechnologistsforfeedback.Hopefully,withyourinput,wecancreateanindustry­widestandardforCTprotocols.Theseprotocolswillbereviewedonanannualbasis,whichshouldsatisfytheACRrequirement.Networking:Wehaveprovidedguidanceinthe"Networking"sectionofeachprotocolonwhatimagestosendtoPACS.Insomecases,allimagesshouldbesenttoPACS.Inmanycases,however,thinreconstructionsarenotrequiredtobesenttoPACS.Thinreconstructionsareprimarilyusedforcreatingreformattedvolumes."ALI_Store"isthenameweusetorefertosendingimagestoPACS."ALI_Source"iswherewesendthinimagesthatarenotroutinelyreadbytheradiologists.Forstudiesrequiring3Dlabwork,weinstructyoutosendtheimagesto"CTAW1",whichreferstoaGEAdvantageWorkstation.Note:ifyousendallthinimagestoPACS,thismayslowdownyournetworktransfertimesandthetimeneededforareviewingradiologisttoopenthestudy.Thisiswhyourprotocolshaveanetworkingsectionforeachprotocolthatgivesguidanceonwhenthinimagesareneededforradiologistreview.Networkingfor"SeriesAutoTransfer":Somereconstructionsinourprotocolsethave"SeriesAutoTransfer"turnedon.Theyrefertonetworkingnamesaslistedabove.Ifyouwanttoavoidhavingtore­mapyournetworkinglocationsforeveryprotocol,youcanmakeasinglechangetoyourscanner'shosttable.YouneedtochangethehosttablenameofyourPACSto"ALI_Store"andofyour3Dlab(ifused)to"CTAW1".Wedonotautotransferthethinseries.Ifyouwishtoautotransferthem,youcansendthemtoyourregularPACS.AutoVoiceandBreathingLightsSelection:Liketheprotocols,ifyoudownloadAutoVoicetoyourscannerfromaUWdisc,youwilllooseanypre­recordedAutoVoiceoptions.TheonlycustomnonGEdefaultAutoVoicerecordingsinclude:Englishcardiaccoronaries(retroandprospective).AllotherUWprotocolreferencestoanAutoVoiceoptionaretodefaultGErecordings.Body:Weareawarethatmanyfacilitiesroutinelyscanpatientswiththreesequences—1)withoutintravenous(IV) contrast,2)withIVcontrast,and3)delayed.Althoughsuchrobustscanningmayaddalittlebitofinformation,itisrarelyworththeadditionaldose.Ifmostofyourcasescanbepre­protocoledtoaddressspecificclinicalconcerns,webelievetheseprotocolswillprovideadiagnosticstudywithanappropriatenumberofseriesandatanappropriatedose.Revolution Discovery CT / Discovery CT750 HD 10 Rev: 3.0 / December 2017

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Weprefertomaintainapolicyofgivingpatientspositiveoralcontrastformanyapplications.Webelieveitaddsdiagnosticvalue.Althoughmanycentersarenowperformingstudieswithoutoralcontrasttosavetime,westandbyourpositionthatthesmallamountofextratimerequiredtoopacifythegutandasmallinconveniencetothepatientiswellworththeincreaseindiagnosticaccuracy.Formostpatients,whentimeisnotanissue,weadministeriodinatedcontrastinwater.Forpatientsinwhomtimeiscritical,weadddilutepolyethyleneglycoltohelpdistendthelumenandacceleratetransit.Withaone­hourdrink,thevastmajorityofourEmergencyDepartmentpatientshavecontrastinthececum.Thisfacilitatesthediagnosisofappendicitis.Wepreferiodinatedcontrasttobariumsuspension.Inthepatientwithamoderatetoseverebowelobstruction,thebariumeventuallywillflocculateandprecipitate,causingaverydenseartifactiffurtherimagingisnecessary.Chest:ForChestCT’s,werefrainfromusingIVcontrastmaterialformostindications.IVcontrastaddslittleornovaluetodiagnosisandfollow­upofmostlungdiseases.Insomecases,theimagequalityofthelungscanbehamperedbystreakartifactfromundilutedcontrastintheSVCandothermediastinalveins.Furthermore,subtleartifactscanoccurinthelungsaroundcontrast­filled,smallervessels,especiallywiththinsection(high­resolution)techniqueandlowerdoseimaging.ThoracicindicationsrequiringIVcontrastincludeacuteandchronicpulmonarythromboembolism,thoracictrauma,andacuteaorticpathology.IVcontrastcanbehelpfulforknownmediastinalmassesorforlungneoplasmsthatinvolvethemediastinum.Nodules,infections,aorticaneurysms,pleuraldisease,andlymphadenopathycanusuallybeimagedwithoutIVcontrast.Cardiovascular:Generally,approachestobodyCTAfallintotwocamps:1)attempttoscanthevolumealongwiththepassageofthecontrastbolus,and2)opacifythevasculaturethroughouttheimagedvolumeandthenscanasfastaspossibletocapturea"snapshot"ofthevasculatureinthispseudo­steadystate.Thetremendousvariationinbolustransittimesacrosspatientsandthetechnicaldifficultyofbothassessingthistransittimeandappropriatelyadjustingthescanparameters(rotationspeedandpitch)maketheformerapproachdifficultforCTtechnologiststoperformconsistentlywithoutdirectphysiciansupervision.Wehavethereforeadoptedthelatterapproach.MostofourbodyCTAprotocolsinvolvetheuseofSmartPrepratherthanatimingbolustotriggertheacquisition,withadiagnosticdelayandoverallcontrastbolusintendedtogiveconsistentopacificationthroughouttheimagedvolumeduringthescan.Thisapproachisveryeasyfortechnologiststoperforminareliablefashionwithoutdirectphysicianmonitoring.

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Musculoskeletal:CTisanexcellentwaytovisualizebonesandjoints,especiallywhenreformattedinmultipleplanesrelativetoosseousorarticularlandmarks.However,theroleofCTforvisualizingthenon­radiopaquetissuesaroundbonesandwithinjointsisextremelylimited,andforthemostparthasbeensupplantedbyMagneticResonanceImaging(MRI)and/orUltrasonography.Toemphasizethis,werefertoourapplicationsas“BoneCT”ratherthan“MusculoskeletalCT”,sincewedonotuseCTtoimagemuscles.AppropriateapplicationsofBoneCTcanbedividedintotwodistinctpatientpopulations:1. thosepresentingwithsevereacutetraumatotheEmergencyDepartment(ED),and2. thosepresentingtoprimarycareorurgentcareclinics.Withregardstomusculoskeletalimaging,outsideoftheED,CTshouldneverbethefirststudyordered.Conventionalradiographs(commonlyreferredtoas“x­rays”)continuetobetheprimarymodalityusedtovisualizethebonesandjointsoftheextremitiesandspine.Indeed,theuseofCTissolimitedintheevaluationofnon­acutetraumaticboneorjointpainthatwesuggestthismodalitynotbeorderedbyprimarycareproviderswithoutfirstconsultingwiththeirradiologists.CertainlytherearesomespecificindicationsforwhichscheduledoutpatientCTisappropriate,butingeneralthisisrequestedbyspecialtycareproviders.IntheED,CTistheprimaryimagingmodalitywhenthereisaconcernforaspinefracture,especiallyinthecervicalspine.(CThasbeenshowntobemuchmoresensitivethanradiographsforthedetectionoffracturesinthecervicalspine.)Forotherbonesandjoints,radiographsshouldbeobtainedwheneverfracturesordislocationsaresuspected.Withcertainacutefractures,CTisanessentialsecondaryimagingmodality.Forexample,wheneveranacutefractureisdetectedinthebonypelvis,CTisalmostinvariablyobtainedsoonaftertomorefullyevaluatetheextentofpelvicringdisruption.Inaddition,orthopedicsurgeonswilloftenrequestCTforintra­articularfractures,particularlyoftheknee,toaidinsurgicalplanning.Bonesandjointsarecomplex3­dimensionalstructuresandtheirrelationshipsarebestdemonstratedwith2­dimensionalcross­sectionalimagingreformattedinmultipleplanes.Wehavedevelopedjoint­specificreformattingprotocolsdesignedtoaddressspecificclinicalneeds.VisualizingbonystructuresadjacenttoorthopedichardwarewithCTcanbechallenging,althoughmetallicartifactscanbereducedbywithuseof140kV.Therearefew,ifany,indicationsforadministeringIVcontrastforBoneCT.Ifthereisaclinicalconcernforinfection,anMRshouldbeperformed.IfthepatientisnotMRcompatible,theclinicalserviceshouldhaveadiscussionwiththeirradiologistaboutthebestwaytoanswertheclinicalquestions.ThefewindicationsforadministeringIVcontrastforboneCTs,areasfollows:1. Ifthereisaclinicalconcernforinfection,anMRshouldbeperformed.◾ Incaseswheretheclinicalconcernisspecificallytolookforsofttissuegasratherthanforsofttissueabscessorosteomyelitis(e.g.,necrotizingfasciitis),thenCTwouldbetheimagingmodalityofchoice;althoughIVcontrastwouldnotbenecessaryforgas.2. IfthepatientisnotMRcompatible,theprotocolingradiologistshouldhaveadiscussionwiththeclinicalserviceaboutthebestwaytoanswertheclinicalquestions.3. IfitisagreedthatCTisindeedtheimagingmodalityofchoice,thestudycanbeperformedwithoutIVcontrast.

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4. Inlightoftheabovepolicy,itisappropriatefortheCTtechnologisttoconfirmwiththeprotocolingradiologistthattheydoindeedwanttoadministerIVcontrast.5. WhereIVcontrastisdeemedappropriateforaboneCT,thestandarddosingguidelinesshouldbefollowed:◾ Agent:Omnipaque3001. Ifpatienthasanallergytoiodinatecontrast,orhasrenalfunctionissues,thennoIVcontrastshouldbeadministered.◾ Dose:Perbodyweight(upto100ml)◾ Rate:AsappropriateforIVaccess(upto3ml/sec)◾ Delay:90sec

Neuroradiology:Dosereductionisanimportantfacettoimagingthatnotonlyradiologists,butcliniciansaswell,needtokeepinmindwhenprotocolingororderingstudies.Certainly,thelowestdosestudyistheunnecessaryonethatisnotperformed.Withthatbeingsaid,giventhecomplexandsubtleanatomypresentonneuroradiologicexaminations,dosereductionisnotasreadilypossibletothesamedegreeasotherregionsofthebody.Decreasingdosetothepointthatthestudyisminimallyornon­diagnosticshouldbeconsideredasoverdosing,astheradiationdeliveredwasessentiallyofnouse.Wehavereducedthedoseonourprotocolsasmuchaswefeelisappropriate,whilemaintainingsufficientdiagnosticquality.WeprefertoimagetheorbitsonourheadCTsbecausetheorbitisanextensionofthebrain,andpathology,includingtheresultoftrauma,oftenoccult,occursthere.Also,becauseofradiationoverscaninherentinexamacquisition,theorbitsreceiveradiationevenonorbitsparingprotocols.Ifyourfacilityfeelsstronglyaboutavoidingtheorbitsinscanning,wehaveincludedanorbitsparingprotocol.Ultimately,itiseachindividualinstitution’sandindividualradiologist’sdecision.Perfusionimagingisanotherareaofsomeconcernregardingradiationexposure.Ithasbecomeimportantinstrokeimagingandtumorimagingtohelpguidetreatment,aswellashelpassesstreatmentresponse.OurprotocolsresultinadosethatislessthanFDAguidelinessuggest,0.5Gy.Ratherthanthetypicalcoverageofapproximately3­4cm,theGEscannerwithshuttlemodedoublesthatamountwithnearwholebraincoverage.Wearecontinuingtostriveforevenlowerdoseperfusionexams.Pediatrics:OrderingcliniciansandradiologistsshouldalwaysconsiderwhetherornotalternativeimagingmodalitiessuchasultrasoundorMRcouldanswertheclinicalquestionasradiationexposurewouldbeavoided.WhenusingCTtoimagechildren,thegoalistogetdiagnosticimagesatthelowestradiationdosepossible.Thescanshouldbeconfinedtotheregionofinterestsoastoexposeaslittleofthepatient’sbodyaspossible.Duetotheirsmallersizeandthelowradiationdose,positioningisofgreatimportanceinordertoobtainadequateimagesfordiagnosis.OurstandardpediatricCTprotocolsareindeedverylowdose.Manyofyoumayfindtheseimagesdifficulttointerpret.Foryou,wehaveincludedasetofprotocolswithonlymoderatedosereductiontohelpyouaccommodate.Wehopeyouwilleventuallytransitiontothelower­doseprotocols.

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DesignPhilosophy­Abdominal

GEProtocol ProtocolType ProtocolNo.onScanner DesignPhilosophy

Abd/Pelvis Abdominal 6.1/6.2/6.3Thisisstandardabdomenpelvisprotocol.Itisthedefaultprotocolforthevastmajorityofstudies.Thisoneisusefulwhenageneralscreening

protocolisneeded.

Abd/Pelvis­R/OHernia Abdominal (Useroutine

abd/pelvisprotocol)

Thisprotocolisintendedfortheevaluationofhernias.ItasksthepatienttoperformaValsalvamaneuverduringthescantoenhancethe

prominenceofanyhernia.

HighImageQualityCancerFollow­Up

Abd/PelvisAbdominal 6.7/6.8/6.9

Higherimagequalityversionoftheroutineabdomenpelvisprotocol.Thisprotocolistobeusedforcancerfollow­uponpatientswith

pathologyknowntobeofasubtlenature.Theordershouldspecificallyaskforthisversionoftheabdomenpelvisroutineprotocolatthetimeofplacingtheorder.Typically,adeterminationwouldbemadebasedonageanddiseaseprocess(usuallydependentonwhethertheycouldhave

metastaticdiseasetotheliver).

Abd/Pelvis­FlankPain Abdominal 6.10/6.11/6.12

Thisprotocolisprimarilytargetedforthefirst­timeevaluationofobstructingrenalcalculus.Itisanon­contraststudy;therefore,notoptimalforimagingothercausesofabdominalpain.However,itmaysufficeinsituationswherethediseaseprocessesarenotsubtle.We

discourageitforappendicitis.

Abd/Pelvis­Pre­IVCFilterRemoval Abdominal 6.73/6.74/6.75

ThisprotocolisusedtoassessforboththepositionandforthepresenceofclotinanIVCfilterpriortoremoval.IVcontrastisusedandimagesareobtained180secondsaftercontrastinjectiontooptimizeopacificationof

theinferiorvenacavaandiliacveins.

LowDoseRenalStone(includinglimited

follow­up)Abdominal 6.13/6.14/6.15

Thisprotocolisintendedforfollow­upofpatientswithknownkidneystones;thosestatuspostlithotripsy;orthosepresentingtothe

emergencydepartmentwithtypicalflankpainandareknowntohavekidneystones.Imageresolutionissatisfactoryforidentifyingcalculi,but

notoptimalforotherpathology.

Abd/Pelvis­Colonography Abdominal 6.16/6.17/6.18

Thisprotocolisusedtoscreenthecolonforpolypsorcolonicmassdisease.Patientsundergobowelpreparationpriortothescan,andarethenscannedinthesupineandpronepositionsfollowingcolonicCO2insufflationviarectalballoon­tippedcatheter.Thesupine­prone

positioningismeanttodisplaceanyretainedfluidandfullyexposeallpartsofthecolonbetweenthetwoviews.Arightlateraldecubitusviewcanbeaddedifdistentionissuboptimalinacolonicsegment.Thestudy

isperformedwithoutIVcontrastandatlowdoseasitisusedinscreeningasymptomaticpatientsinmostcases.Ifapatienthasaknowncoloncancerandthereferrerdesiresscreeningofthecoloncombinedwithassessmentformetastaticdisease,IVcontrastcanbeadministered

onthesupineview.

Chest/Abd/PelviswithIVContrast Abdominal 5.4/5.5/5.6

Thisprotocolismostcommonlyappliedtopatientswithneoplasmthatmayaffecttheentiretorso,butisnotexpectedtoaffecttheheadand

neck.

Chest/Abd/PelviswithoutIVContrast Abdominal 5.7/5.8/5.9

ThisscanisusuallyperformedfortheevaluationoftumororotherconditionsthatmayaffecttheentiretorsoinpatientswhocannotgetIV

contrastduetoallergyorrenalfailure.Abd/Pelvis­Urography Abdominal 6.22/6.23/6.24 Thisprotocolisoptimizedforviewingthekidneysandtherenal

collectingsystem.Themostcommonindicationishematuria.

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Urothelialtumorfollow­up Abdominal 6.70/6.71/6.72

Thisprotocolwillbeforpatientswithknownurothelialcancer(bladderorureters)andNOcurrentevidenceoforsuspectedmetastaticdisease.Also,someofthesepatientswillnothaveabladder(sononeedforthose

tovoidastheywillhaveaurostomy)

Iftheyhavemetastaticdisease,routineCTA/Pwillsuffice.

Abd­Liver­Biphasic Abdominal 6.25/6.26/6.27Thisprotocolisoptimizedtoevaluatecirrhoticpatientsandsuspectedlivertumors.Itisalsoappliedfortheevaluationofhypervascular

metastaticdiseasetotheliver.

Abd­Liver­Triphasic Abdominal 6.28/6.29/6.30

Thisprotocolisoptimizedforthework­upofapotentiallivertransplantrecipient.Ithasahighresolutionarterialphaseforprecisehepatic

arterialanatomy;alatearterialphaseforthedetectionoftumor;andaportal/parenchymalphaseforthedemonstrationofvaricesandother

possiblepathology.Finally,athree­minutedelayedphaseisperformedtosatisfytheUNOSrequirementforHCCdetection.

Abd­Liver­HepatocellularCarcinoma(HCC)

Abdominal 6.82/6.83/6.84Thisprotocol,whichisusedtoruleoutHCC,issimilartothebiphasicliverprotocol,exceptitincludesanadditionaldelayedphaseas

mandatedbyUNOS.

Abd­AdrenalGland­Adenoma Abdominal 6.31/6.32/6.33

Thisprotocolisoptimizedforthecharacterizationofadrenalenlargementspecificallyforasuspectadenoma.Itwouldnotbeprotocol

ofchoicetoruleoutpheocromocytoma.

Abd­Pancreas­PancreasCancer

(NeoplasmScreening)Abdominal 6.40/6.41/6.42

Thisscanisusedinpatientswherethereissuspicionofpancreasmass.Thefirstphaseisscannedinthelatearterialphase.Sincepancreaticadenocarcinomaishypovascular,itisbestdetectedat40secondspostcontrastwhenthenormalglandulartissueenhancesoptimallyandthehypovasculartumordoesnot(optimizescontrastbetweenthelesionandthebackgroundpancreas).Thesecondphaseisportalvenous,toevaluatethesolidorgans,particularlytheliver,formetastaticdiseaseandfor

routineevaluationoftheabdomenandpelvis.

Alsoforpreoperativeevaluationofknownpancreaticneoplasm.Itisoptimizedtodetectvascularcompromise.

Abd/Pelvis­KidneyTumor Abdominal 6.49/6.50/6.51 Thisprotocolisoptimizedtoevaluatepatientswithsuspicionor

evaluationofsmallrenalneoplasm.

CTAAbd­RenalDonor Abdominal 6.52/6.53/6.54 Thisprotocolisoptimizedtoevaluatethepotentialrenaltransplantdonor.

Abd­SmallBowel­Enterography Abdominal 6.55/6.56/6.57 Thisprotocolisoptimizedfortheevaluationofthesmallbowel.Itis

specificallydesignedforinflammatoryboweldisease.CTAAbd­ObscureGI

Bleed Abdominal 6.58/6.59/6.60 Thisprotocolisoptimizedtoevaluatethesourceofobscuregastrointestinalbleeding.

CTAAbd­MesentericIschemia Abdominal 6.61/6.62/6.63 Thisprotocolisoptimizedtoevaluateformesentericischemia.

Trauma­Chest Abdominal 5.22/5.23/5.24

Thisprotocolisoptimizedfortheemergencyevaluationforaorticinjury,aswellasanyothersequeloftrauma.Thisistailoredforrapid

decelerationinjury.Note:Routinecreatininecut­offforIVcontrastadministrationdoesnotapplyinatrauma.

Trauma­Chest/Abd/Pelvis Abdominal 5.25/5.26/5.27

Emergencyevaluationforaorticinjuryand/ororgandisruption.Note:Routinecreatininecut­offforIVcontrastadministrationdoesnotapplyin

atrauma.

Trauma­Abd/Pelvis Abdominal 6.4/6.5/6.6

Emergencyevaluationfortraumaticorgandisruption.ThisisusuallyreservedforadirectblowtotheabdomenorlowvelocityMVA.Note:

Routinecreatininecut­offforIVcontrastadministrationdoesnotapplyinatrauma.

Cystogram Abdominal 8.10/8.11/8.12

Inthetraumasetting,toevaluatebladderfortrauma­inducedleak.(Typicallyperformedwhenthestandardtraumascanisinconclusivefor

abladderleak.)

Inthenon­traumasetting,specificallyfortheevaluationofbladdertumorandtoevaluatefornontraumaticorpostoperativebladderleak.

BodyPelvis Abdominal 8.16/8.17/8.18 Thisisastandardorroutineexaminationofthepelvismeanttoassessforpelvicpathologiesthatarenothypervascular.

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DesignPhilosophy­Chest

GEProtocol ProtocolType ProtocolNo.onScanner DesignPhilosophy

Chest­Standard(Routine&High­Resolution)

Chest 5.1/5.2/5.3

ThisprotocolisdesignedtoaddressnearlyallindicationsforchestCTwhilemaintainingverylowradiationexposurelevels.Itincludesdetailed

informationonthelungs,airways,andsofttissues.High­resolutionimagesforevaluatingthelungsareacentralpartofthisprotocol,avoidingtheneedtorescanpatientswhohavediffuselungdisease.Althoughintravenous

contrastmaterialcanbeadministeredatthediscretionoftheprotocollingradiologist,forthevastmajorityofindications,contrastisnotneeded.

Chest­LowDoseFollow­up Chest 5.10/5.11/5.12

Thisprotocolwasdesignedforfollow­upofnodules,pleuraleffusions,andotherabnormalitiesusingsignificantlylowerdosethanthestandardCT.Fornearlyallpatients,theeffectivedosewillbebelow3mSv,typicallyinthe1­

2mSvrange.

Chest­LowDoseScreening Chest 5.13/5.14/5.15

Thisprotocolisdesignedtobeusedexclusivelyforlungcancerscreening.ItmeetsthetechnicalstandardsputforthbytheAmericanCollegeofRadiologyandtheCentersforMedicareandMedicaidServices(CMS).

Chest­CTAforPE Chest 5.16/5.17/5.18

ThisprotocolisnearlyidenticaltotheroutinechestCTprotocol,andreconstructedaxialimagesareidentical.MultiplanarMIPsareincludedtomeetCPTcoderequirements.Thecontrastinjectionprotocolisdesignedto

limitthenumberofbolusfailuresandmaximizeopacificationofthepulmonaryvasculature.

Chest­Dynamic3DAirway Chest 5.70/5.71/5.72

Thisprotocolisdesignedtoevaluatethecentralairways,particularlytoassessfortracheobronchomalaciaorexcessivedynamicairwaycollapse.In

additiontostandardhigh­resolutionimagesofthelungs,theforcedexpiratoryimagesaccentuatecollapsibilityofthetracheaandcentral

bronchi.Thisprotocolincludesadditionalreformationsincludingminimumintensityprojections(MinIPs)andoptional3­Dvirtualbronchoscopic

images,whichreferringprovidersmightfindinformative.Forpatientswhohavearecentvolumetricthin­sectionCTofthechest,theexpiratory

sequenceofthisprotocolperformedalonemaybesufficient,minimizingadditionalradiationexposure.Becausethebreathingtechniqueisdifferentthantraditionalend­expiratorychestCT,propertrainingoftechnologistsandcoachingofpatientswithcloseradiologistoversightwillmaximizethe

utilityofthisprotocol.

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DesignPhilosophy­Cardiovascular

GEProtocol ProtocolType ProtocolNo.onScanner DesignPhilosophy

Non­GatedCTA(Chest/Abd/Pelvis) CV 5.28/5.29/5.30 Evaluateforknownorsuspectedtype“B”(descending)aorticdissection,

intramuralhematoma(IMH),aneurysm,leak,tear,orvasculitis.

Retrospectively­GatedCTAChest CV 5.31/5.32/5.33

Usedtoevaluatetheheartandgreatvessels(aortaandpulmonaryarteries)inpatientswithhigherratesorinpatientsinwhichcardiacfunctionisalsobeingassessed.Thisisfrequentlyusedinpatientswith

congenitalheartdiseasethathavecontra­indicationforMRI.

GatedChestandNon­GatedAbd/PelvisCTA CV 5.34/5.35/5.36

Usedtoevaluatepatientswithascendingaortaaneurysminadditionthoracoabdominalaorticaneurysms.Retrospectivegatingisusedto

minimizethedelaybetweenthegatedchestandthenon­gatedabdomenandpelvissections.

Prospectively­GatedCoronaryCTA CV 5.37/5.38/5.39 Usedtoevaluatethecoronaryarteriesinpatientswithappropriateheart

rates.Retrospectively­Gated

CoronaryCTA CV 5.40/5.41/5.42 Usedtoevaluatethecoronaryarteriesinpatientswithhigherratesorinpatientsinwhichcardiacfunctionisalsobeingassessed.

TAVICTA CV 5.43/5.44/5.45

Evaluationofpatientsbeingconsideredfortrans­catheteraorticvalvereplacement(TAVR).Thisincludesaretrospectively­gatedCTAofthehearttoevaluatetheaorticrootforimplantationofthevalveandanon­gatedCTAchestabdomenandpelvistoevaluatetheaortaandiliofemoral

arteriestoassessaccess.

Prospectively­GatedCTAChest(Non­

Coronary)CV 5.46/5.47/5.48

Evaluateforascendingaorticaneurysm,dissection,orinjury.Evaluatecardiacorvascularabnormalitywithoutcardiacmotion.(Note:A

prospectively­gatedchestCTAcannotbecombinedwithanon­gatedCTAabdomen/pelvis.IfgatedchestisneedalongwithCTAabdomen/pelvis,

useretrospectivegating.)

UpperExtremityCTA CV 5.49/5.50/5.51 Toevaluateupperextremityischemia.Thescanincludesvascularimagingfromtheaorticarchtothefingertips.

LowerExtremityCTA CV 5.52/5.53/5.54 Foriliacocclusivedisease,peripheralvasculardisease,andpatientswitha“coldfoot”.

Post­EndostentNon­ConVolumeChange(Abd/Pelvisonly)

CV 5.58/5.59/5.60Measureabdominalaorticaneurysmvolumeafterendovascularrepair.Ifthevolumeisstableorhasdecreasedsincethepriorexamination,no

hemodynamically­significantendoleakispresent.

Prospectively­GatedLeftAtrialAppendage CV 5.73/5.74/5.75

Evaluationforleftatrialthrombus,pre­opfordevice(Watchman(TM))implant.Includestwoscanphases,aCTAonexpirationanda1minute

delay.Bothphasesareprospectivelygated.

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DesignPhilosophy­Musculoskeletal

GEProtocol ProtocolType ProtocolNo.onScanner DesignPhilosophy

BonyPelvis/Hips/SI/Femur/FAI(WithoutMetal)andBonyPelvis/Hips/SI/Femur/FAI

(WithMetal)

MSK 8.1/8.2/8.3and8.4/8.5/8.6

Thisprotocolisdesignedtoexaminethecortexofthepelvicringandacetabuli.ScansoftheBonyPelvisaremostoftenobtainedinthe

settingofacutetrauma,orintheevaluationoffracture,SIjoints,andprosthesis.Orthopedicsurgeonsmayrequestpost­operativescansto

assesshealing,hardware,orosteolysis.

Knee/Tibia(WithoutMetal)andKnee/Tibia

(WithMetal)MSK 9.3and9.4

TheprimaryindicationforakneeCTistoassessthealignmentanddegreeofdisplacementoffracturefragments,particularlyatthe

articularsurfaces.Thesecanalsobeusedtoassesstheintegrityofthebonearoundprosthesis.Onrareoccasions,aCTwillbedone

immediatelyafteranarthrogramoftheknee.Ankle/Foot/DistalTibia(WithoutMetal)and

Ankle/Foot/DistalTibia(WithMetal)

MSK 9.1and9.2Thereisonesinglescanningprotocolforallanklesandfeet,whichistypicallyusedtoevaluatefortrauma.Inmostcasesitisdesirableto

scanbothankles/feetatthesametime.

FemoralAnteversion MSK 9.8/9.9/9.10Thisprotocolisanon­contrastCTthroughbilateralhips,knees,andankles(excludingthefemur,tibia,andfibulashafts)toallowfor

measurementoftheversionanglesofthefemoraand,ifdesired,tibiae.

Shoulder/Humerus(WithorWithoutMetal) MSK 4.1/4.2/4.3

AroutineshoulderCT(non­arthogram)isusedtoevaluateforfracturesofthescapulaand/orproximalhumerus,dislocation,

shoulderprosthesis,ormasses/infectioninapatientwhoisnotMRcompatible.TheprimaryindicationforashoulderarthrogramCTisto

evaluatetherotatorcuffandlabruminapatientwhoisnotMRcompatible.

Elbow/Forearm(WithoutMetal)and

Elbow/Forearm(WithMetal)

MSK 4.6and4.7

Thisprimaryindicationistoevaluateforfracture,dislocation,orosteochrondritis.Theelbowisthemostdifficultjointtoscanasitis

usuallydifficulttooptimallypositiontheelbow,particularlywhenitisinacast.

Wrist(WithoutMetal)andWrist(WithMetal) MSK 4.8and4.9

Thisscanisusedtoevaluateforwristfracture,andsimilartotheelbow,itisimportanttopositionthearmoverthehead,withthearm

asstraightaspossible.

SoftTissueExtremitywithIVContrast MSK 9.13/9.14/9.15

Thisprotocolisusedfordetectionorcharacterizationofmassorinfection.Bonydetailisnotimportantforthesescanswhichuseadose

levelsimilartoanextremityCTA.

ChestWall/Clavicle/ACJoint/SC

Joint/Sternum/RibsMSK 4.11/4.12/4.13

Detectionorcharacterizationoffractures,evaluationoftreatedfracturestoevaluatetheprogressofosseoushealingoradequacyoffracturefixation.Alsofortheevaluationofarthritis,mineralizedboneandsofttissuelesions,andtoevaluateosteoarthritis.Forinfection,

contrastwilllikelybeneeded.

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DesignPhilosophy­Neuroradiology

GEProtocol ProtocolType ProtocolNo.onScanner DesignPhilosophy

Brain­RoutineandPediatric

NAT/Trauma(HelicalMode)

Neuro 1.1/11.1/11.2

Forroutineheadimagingandemergentimagingincludingtrauma,hemorrhage,hydrocephalus,tumor,andpreliminarystrokescreening.Mayneedtoaddcontrastformoresensitiveevaluationoftumoror

infection.

Brain­HelicalScanwithAngledAxialReformations

Neuro 1.2/11.3/11.4

Usethisprotocolwhentheheadcannotbeproperlypositionedforaroutinehelicalheadscan.Example:whenyoucannotmovethepatient’sheadintoproperposition(trauma,cervicalcollar,rigidneck).Forroutine

headimagingandemergentimagingincludingtrauma,hemorrhage,hydrocephalus,tumor,andpreliminarystrokescreening.Mayneedtoadd

contrastformoresensitiveevaluationoftumororinfection.

Brain(AxialMode) Neuro 1.3/11.5/11.6

HelicalmodeshouldbeusedroutinelyforadultheadCTscans.Onlyuseaxialmodewhenyoucannotmovethepatient’sheadintoproperposition(trauma,cervicalcollar,rigidneck),anddonotwishtoperformahelicalscanwithangledaxialreformats.ThisaxialmodecanalsobeusedinunstablepatientsintheEDwhentheCTscantimemustbeexpedited.

Stealth­StereotacticHead(WholeBrainTreatmentPlanning)

Neuro 1.10/11.11/11.12

Thisisaprotocolwhichdeliversthinsectionimagesforuseinwholebrainradiationtreatmentplanning,intraoperativeneuronavigation,and

cranioplastyplanning.Imagerequirementsforthesoftwareassociatedwiththeseusesvaries,andverificationofcompatibilityisrecommended.

Orbit­Routine Neuro 2.1/12.1/12.2

Forevaluationofinfection,inflammatory,orneoplasticprocessesmayaddcontrastasneededtoincreasesensitivity.Mayalsobeusedfortrauma,bluntorpenetrating,localizedtotheorbit.Nottoevaluatediffusefacialtraumaorinfection/inflammatoryprocesses,asthisrequiresaCT

maxillofacial.

FacialTrauma­Routine Neuro 2.5/12.9/12.10

MaxillofacialCTdoneforevaluationoffacialtrauma,bluntorpenetrating,facialinfectionsorinflammation,aswellasassessmentofcongenitalabnormalities.Contrastmaybeaddedforsensitivity,particularlyin

infection,aswarranted.3Dreconstructionsmaybeperformedifrequestedbyclinicalservice.

Sinuses­Diagnostic Neuro 2.7/12.13/12.14

Forevaluationofroutinesinusinflammatorydisease,assessmentofboneinvolvementfrominfectious,inflammatory,orneoplasticprocesses,andsinonasalneoplasms.Mayaddcontrastasneededtypicallyfornon­routinesinusinflammatorydisease.Notforevaluationoffacialtraumaororbital

processes.

TemporalBone(withoutContrast) Neuro 2.10/12.18/12.19

Forevaluationofhearingloss,congenitalabnormalities,infection,trauma,andneoplasms.Contrastmaybeaddedasneededforinfectionor

neoplasms.UsedinconjunctionwithMRItoevaluateneoplasmstypicallyunlesscontraindicationtoMRI.

TemporalBone(withContrastOnlyorwith&withoutContrast)

Neuro 2.11/12.20/12.21

ThisprotocoladdscontrasttothestandardCTtemporalbone,foruseincasesofinflammation/infectionorconcernforsigmoidsinus

compromise.Thisprotocolisalsousedforcasesinwhichthereisaconcernforacerebellopontineanglemasscausingsensorineuralhearing

loss.

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AdultNeck­Routine Neuro 3.1/3.2/3.3Forevaluationofheadandneckcancer(preandposttreatment),infection,softtissuetrauma,orinflammatoryprocesses.Notforevaluationofcervicalspinetraumaorsuspectedvascularinjury.

PediatricNeck­Routine Neuro 13.1.1/13.2.1/13.4.1/13.6.1/13.8.1

Thisisanage­specificprotocoldesignedtogiveadiagnosticandappropriatelylowdoseexaminationthroughtheneck.Thisprotocolisforevaluationofcervicallymphadenopathy,

developmentalanomalies(suchabranchialcleftcysts),aswellasinfectious,andinflammatoryconditionswithinthepediatric

neck.

Neck(ParathyroidAdenoma)Adult Neuro 3.5/3.6/3.7/13.1.9/13.1.10

Indicationsincludehypercalcemia,parathryoidadenoma(suspectedorconfirmed),andparathyroidsurgicalplanning.On

earlyarterialanddelayedcontrastenhancedimagestheenhancementofparathyroidadenomascanbeconfusedwiththeintrinsicallyCThyperdensethyroidgland.Thisprotocolincludes

anadditionalnoncontrastphasetoenablemoreconfidentdetectionanddiscriminationofparathyroidadenomasfromthe

adjacentthyroidtissue.AdultCervicalSpine(withoutMetal)andAdultCervicalSpine

(WithMetal)

Neuro 3.16/3.17/3.18and3.19/3.20/3.21

Forevaluationofspinetrauma,degenerativedisease,infection,andbonetumors.Mayaddcontrastasneeded.Notforprimary

evaluationofsofttissues.

AdultThoracicSpine(withoutMetal)andAdultThoracicSpine

(withMetal)

Neuro 7.4/7.5/7.6and7.19/7.20/7.21 Forevaluationoftrauma,degenerativedisease,infection,andbonetumors.Mayaddcontrastasneeded.

AdultLumbarSpine(withoutMetal)andAdultLumbarSpine

(withMetal)

Neuro 7.1/7.2/7.3and7.16/7.17/7.18 Forevaluationoftrauma,degenerativedisease,infection,andbonetumors.Mayaddcontrastasneeded.

StrokeDeluxe–TotalCerebrovascular Neuro 1.6/1.13/11.16/11.17

Forevaluationofstroke,vasculartrauma,aneurysm,vasospasm,andatheroscleroticdisease.RequiresadministrationofIV

contrast.CTAHeadOnly

(Stenosis,Aneurysm,UnknownBleed)

Neuro 1.7/11.18/11.19 Forevaluationofintracranialstenosis,aneurysm,vascularmalformation,unknownbleed,vasospasm.

CTANeckOnly(Cerebrovascular

Disease)Neuro 3.11/11.22/11.23

Assessmentofatheroscleroticdisease,traumawithsuspectedvascularinjury,orvascularneoplasms.Requiresadministration

ofIVcontrast.

CTVenography Neuro 1.9/11.24/11.25Thisprotocolconsistsofaslightlydelayedphaseofvascularimaging,foruseincasesofsuspectedvenoussinusthrombosis

orocclusion..

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DesignPhilosophy­Pediatrics

GEProtocol ProtocolType ProtocolNo.onScanner DesignPhilosophy

RoutineAbdomen/Pelvis Peds

16.1.1/16.2.1/16.4.1/16.6.1/16.8.1­­­forHigherImageQuality:

16.1.6/16.2.6/16.4.6/16.6.6/16.8.6

Forevaluationofnonspecificabdominalpain,abscessesinpostoperativepatientsoracutelyillinflammatoryboweldiseasepatients,feverofunknownorigin,aswellasforappendicitisinoutpatients.Additionallyusedforinitialdiagnosisandfollow­upofabdominalneoplasmwhen

concurrentchestCTimagingisnotindicated.

AcuteAppendicitis­Abdomen/Pelvis Peds

16.1.1/16.2.1/16.4.1/16.6.1/16.8.1­­­forHigherImageQuality:

16.1.6/16.2.6/16.4.6/16.6.6/16.8.6

Alowdoseprotocolforpatientsinwhomtheonlyclinicalconcernistoruleoutappendicitis.Thiswillnotimagethelungbasesandwillminimallyimagetheinferioraspectsof

thesolidorgans.

RenalStone/FlankPain Peds

16.1.2/16.2.2/16.4.2/16.6.2/16.8.2­­­forHigherImageQuality:

16.1.7/16.2.7/16.4.7/16.6.7/16.8.7

Thisprotocolaimstoevaluatepatientswithrenalcolicorhematuriainwhomrenalandbladderultrasoundhasbeenunabletoidentifyasourceforthesymptomsoronwhomrenalandbladderultrasoundcannotbeperformed.

TriphasicLiver Peds16.1.3/16.2.3/16.4.3/16.6.3/16.8.3­­­

forHigherImageQuality:16.1.8/16.2.8/16.4.8/16.6.8/16.8.8

Thisprotocolshouldonlybeorderedbysurgeonsforlivertumorevaluationpriortosurgicalresectioninordertofully

assessthetumor’srelationshiptothehepaticarteries,portalveins,andhepaticveins.Thiswillalsoassessfor

variantarterialorvenousanatomy.

TraumaAbdomen/Pelvis Peds

16.1.4/16.2.4/16.4.4/16.6.4/16.8.4­­­forHigherImageQuality:

16.1.9/16.2.9/16.4.9/16.6.9/16.8.9

Thisprotocolisdesignedtoevaluatepatientswhohavesufferedfrombluntorpenetratingtraumaforpossibleinternalinjuries.Delayedimagesmayberequiredattheradiologist’sdiscretiontoevaluateforactivebleeding,butthefieldofviewshouldbelimitedtotheareaofconcernonlysoastokeepradiationdoseaslowaspossible.This

protocolshouldalwaysbedonefollowingadministrationofIVcontrastasevaluationforsolidorganinjuries,andtoalesserextentbowel/mesentericinjuriesissignificantlylimitedonnon­contrastexaminations.Thisisespeciallytrueinpediatricpatientswithlittlemesentericfat.

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Chest­Standard(Routine&High­Resolution)

Peds15.1.1/15.2.1/15.4.1/15.6.1/15.8.1­­­for

HigherImageQuality:15.1.8/15.2.8/15.4.8/15.6.8/15.8.8

Thisnon­contrastprotocolisperformedtoevaluatethelungparenchymaforevidenceofinterstitiallungdisease,bronchiectasis,oraspiration.Aspediatricpatientshavelittlemediastinalfat,evaluationformediastinalorhilarlymphadenopathy,aswellasmediastinalpathologyin

general,wouldbelimited.

ChestwithIVContrast Peds XXX­­­forHigherImageQuality:xxxxx

Thisprotocolisdesignedtofurtherevaluatepatientswithchestinfectionssuchaspneumoniawithorwithout

empyema,neoplasm,feverofunknownorigin,vascularringsandslings,aswellasmasslesionssuchascongenitalcysticadenomatoidmalformationandsequestration.

Additionally,thiscouldbeusedinevaluationofpatientswhohavesufferedbluntorpenetratingtraumatothe

chestonly.

ChestPectus Peds15.1.3/15.2.3/15.4.3/15.6.3/15.8.3­­­for

HigherImageQuality:15.1.10/15.2.10/15.4.10/15.6.10/15.8.10

Techniqueforthepectusexcavatumprotocolwasoptimizedforevaluatingthebonythorax.TheseimagesallowforprecisecalculationoftheHallerandcorrection

indices,aswellasforpre­surgicalplanning.

CTAChestforPE Peds15.1.4/15.2.4/15.4.4/15.6.4/15.8.4­­­for

HigherImageQuality:15.1.11/15.2.11/15.4.11/15.6.11/15.8.11

Thisprotocolisdesignedtoevaluatepatientswhoaresuspectedofhavingpulmonaryembolism.

RoutineChest/Abdomen/Pelvis Peds

15.1.5/15.2.5/15.4.5/15.6.5/15.8.5­­­forHigherImageQuality:

15.1.12/15.2.12/15.4.12/15.6.12/15.8.12

Thisprotocolisintendedtoinitiallydiagnoseandfollow­upmalignancyandtoevaluateforinfection/feverof

unknownorigininpatientswithnonspecificsymptomsorwhoareimmunocompromised.

TraumaChest/Abdomen/Pelvis Peds

15.1.6/15.2.6/15.4.6/15.6.6/15.8.6­­­forHigherImageQuality:

15.1.13/15.2.13/15.4.13/15.6.13/15.8.13

Thisprotocolisdesignedtoevaluatepatientswhohavesufferedfrombluntorpenetratingtraumaforpossibleinternalinjuries.Delayedimagesmayberequiredattheradiologist’sdiscretiontoevaluateforactivebleeding,butthefieldofviewshouldbelimitedtotheareaofconcernonlysoastokeepradiationdoseaslowaspossible.ThisprotocolshouldalwaysbedonefollowingadministrationofIVcontrastasevaluationforvascularandsolidorganinjuries,andtoalesserextentbowel/mesentericinjuriesissignificantlylimitedonnon­contrastexaminations.Thisisespeciallytrueinpediatricpatientswhohavelittle

mediastinalandmesentericfat.

PedsChestDynamic3DAirway Peds

15.1.2/15.2.2/15.4.2/15.6.2/15.8.2­­­Nohigherimagequalityversionofthis

protocol

Thisprotocolisdesignedtoevaluatethecentralairways,particularlytoassessfortracheobronchomalaciaor

excessivedynamicairwaycollapse.Inadditiontostandardhigh­resolutionimagesofthelungs,theforcedexpiratoryimagesaccentuatecollapsibilityofthetracheaandcentralbronchi.Thisprotocolincludesadditionalreformationsincludingminimumintensityprojections(MinIPs)andoptional3­Dvirtualbronchoscopicimages,which

referringprovidersmightfindinformative.Forpatientswhohavearecentvolumetricthin­sectionCTofthechest,theexpiratorysequenceofthisprotocolperformedalone

maybesufficient,minimizingadditionalradiationexposure.Becausethebreathingtechniqueisdifferentthantraditionalend­expiratorychestCT,propertraining

oftechnologistsandcoachingofpatientswithcloseradiologistoversightwillmaximizetheutilityofthis

protocol.

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Pages 23-440 are not a part of this manual preview. The full manual, along with an accompanying disc for your CT scanner come with new CT scanner purchases from GE or can be ordered for your current scanners. Contact your apps or salesperson with questions on this process.

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Peds Bony Pelvis Protocol SelectionIf you get an order for a pediatric bony pelvis:

Is the pediatric a teen/obese with an AP + LAT size over 55

cm?

Use the appropriate adult protocol

(probably the adult small without metal)

YesNo

Is the order for a spica casting for developmental

dysplasia of the hips (probably on a kid <

1 yo)?

The order should be for a trauma or avascular necrosis (AVN), if it is not please

consult the pediatric attending. Use the pediatric trauma abd/pelvis protocol with a coverage of top of the illiac crests to the

lesser trochanters

Use the pediatric chest pectus protocol but change the

coverage to top of the illiac crests to

the lesser trochanters

Yes

NoWhy use a chest protocol on the pelvis? This is

our lowest dose pediatric

protocol so it has the right technique for spica planning

Note: you will need to adjust the scout landmark and scan ranges based on the flow chart above to cover the desired anatomy.

Note: please provide the radiologist with 3 mm by 3 mm coronal and sagittal reformats using a boneplus recon.

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PositionTutorialBodyPositioning

◾ ParticularlyimportantforPediatricsandSmallAdultsToprovidethebestimagequalityatthelowestdose,properpatientpositioningisalwaysimportant.ItisparticularlyimportantwiththesmallerpatientsscannedassmalladultsandinpediatricimagingusinglowkVtechniques.Positioningerrorsusuallyoccurwiththepatientbeingpositionedtoolow.Thiserrorcausessignificantproblemswithpediatricprotocolsinwhichthepatientmayactuallyneedtobepositionedabithightooutwardappearances:Ideallythemostattenuatingpartofthepatientshouldbecenteredinthescan.Toaccomplishthis,oneshouldpositionthepatienthighenoughsothatthehorizontallaserlightiscenteredonthelumbarspineandisjustanteriortothethoracicspine.Thisisdemonstratedinthescoutimagesbelow,wheretheredlineistheactualmidpointofthescoutimageandthebluelineiswherethepatientshouldhavebeencenteredonthescout.Onlythescoutontheupperrightshowscorrectpositioning;themidpointofthisscoutisshownasapurpleline.Alltherestarecenteredtoolow.

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DecubitusPositioning

◾ ProperpositioningforthedecubitusportionoftheCTCscreeningexamJustaspatientpositioningiscriticalinourroutinesupineandproneexams,itisalsocriticalinthedecubitusportionofourvirtualcolonoscopyscreeningexam.Toprovidethebestimagequalityatthelowestdose,properpatientcenteringinthescannergantryiscriticallyimportant.Youcannotsimplyhavethepatientrolltotheirside,thiswillleavetheirpelvisinanoffcenterposition!Youmusthavethepatientrollandthenconfirmthattheyhaveshiftedtheirpelvisbacktothescannerofthecouch.Rollandshift!Aimtogetthepatient'siliumbonescenteredinthescanner.Note,itisalsopossiblethatafterproperpositioning,thepatientmaytilttothesidebeforethescan.Tiltingtothesideisanaturalresponsetobeingplacedinthedecubitusposition.Pleasewatchforthisandinstructthepatienttoreturntotheproperposition.PoorPosition GoodPosition

BadLookingScout GoodLookingScout

ResultingBadLookingImageResultingGoodLookingImage

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ShoulderRelaxation

◾ Loweringthepositionoftheshouldersisimportantinbothallowingadequatevisualizationofthecervicothoracicjunctionandinloweringthedoserequiredfortheexam.◾ FasteningtheCTtablestraparoundthetorsoonly,ascomparedtoaroundthetorsoandarms,decreasestheleveloftheshouldersbyonevertebralbodylevel.◾ Simplyencouragingappropriatepatientsto“pull”theirshouldersdownhasalsobeenfoundtobeeffective.◾ Havingpatients“walk”theirhandsdownafoldedbedsheetwrappedaroundthefeetisalsohelpfulforchallengingcases.

Examplesofgoodandbadshoulderpositionrelativetotheneck.Thetechniqueslistedabovecangetapatientfromhavingapoorpositioningoftheshouldertoagoodposition.Note:trytorecognizeimpropershoulderrelaxationbeforeyouscout.If,however,youonlynoticethisafteryouscout,thereisnoneedtore­scoutthepatientaftertheymovetheirshoulders.

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SizeSelectionAdults:Small/Medium/LargeAllAdultBodyProtocolsaredividedintoSmall,Medium,andLargeAdultProtocols.

SmallAdultBodyProtocolsshallbeusedforallpatientswithacombinedAPplusLateralsizeof60cmorless.MediumAdultBodyProtocolsshallbeusedforallpatientswithacombinedAPplusLateralsizeofgreaterthan60cmandlessthan80cm.LargeAdultBodyProtocolsshallbeusedforallpatientswithacombinedAPplusLateralsizeof80cmorgreater.ThesesizesshallbemeasuredoffoftheScoutimageoverthelargestanatomyofclinicalinterest.Withtheuseofthese3protocols,matchedtopatientsize,thereshouldnotbeanyneedfortheCTtechnologisttomakefurtheradjustmentstothescantechniqueswhenscanninganypatient.

Pediatrics:ColorCodeWhenselectingthepatientsizeprotocoltouse,thecombinedAPplusLateralSizeofthepatientistheprimarydeterminingfactor.ThissumoftheAPplusLateraldimensionsofthepatientshouldbemeasuredoffofthescoutimageoverthelargestanatomyofclinicalinterest.Foraccuratemeasurement,thepatientmustbeproperlycentered.Alsothewindowwidthmustbeadjustedwideenoughsothatthemeasurementscanbetakenfromthesurfaceoftheskin.ForpatientswithacombinedAPplusLateralSizeabove60cm,useaMediumAdultprotocol.Thepediatriccolorcodingschemedividespediatricintofivesizescodedbycolor.Theapproximateageofpatientsandsizerangesaregivenasfollows:

PinkNewborns.TypicalAP+Lateralsizeof0­26cm.Red/Purple6months­2.5years.TypicalAP+Lateralsizeof27­31cm.Yellow/White3­7years.TypicalAP+Lateralsizeof32­37cm.Blue/Orange8­12years.TypicalAP+Lateralsizeof38­43cm.Green/Black13­18years.TypicalAP+Lateralsizeof44­55cm.The9colorsthatareusedinthisschemearederivedfromtheBroselowtapescalewhichwasoriginallyusedtocolorcodedosesofmedicationgiveninpediatriccare.

Neuro:Adult/Child/InfantSomeoftheneuroprotocolshavescanparametersthataredividedintothreegroupsfor:Adults,children(3­6yearsold),andinfants(0­3yearsold).

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SizeSelectionforNeckandC­spine1. VerifythatthearmsareoutsideoftheCTwrap,andthattheshouldersarerelaxeddowntowardthefeetasfaraspossible.Measurethewidthoftheshouldersthroughthelevelofthemid­humeralhead,asshownbelow.2. CheckBMIinEPIC(underSnapShot)3. Selectsmall,mediumandlargebasedonthetablebelow.NOTE­ifthepatienthaslymphomaandthestudyisafollow­up,usethesmallneckprotocol(regardlessofthepatientsactualsize)sinceitwillprovidealowerdose

Measurewidththroughmid­humeralheadsSmall Medium Large

Shoulderwidthlessthan46cmORBMIlessthan26 ShoulderWidth46to50cm

Shoulderwidthgreaterthan50cmORBMIgreaterthan35

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InstructionsforAdjustingProtocolsforPediatricExtremitiesandBariatricPatientsPediatricExtremityAdjustmentsWedonothaveseparatepediatricprotocolsforextremityimagingintheMSKsectionofourmanual.Toimagepediatricextremitiesforpatientslessthan13yearsold,pleaseselecttheadultextremityprotocolandlowerthekV1step.TheseprotocolsareallsettousemanualmA,sodecreasingthekVwilldecreasethepatientdosebyroughly50%.Theseinstructionsapplytothefollowingprotocols1. Knee/Tibia(WithoutMetal)9.32. Knee/Tibia(WithMetal)9.43. Ankle/Foot/DistalTibia(WithoutMetal)9.14. Ankle/Foot/DistalTibia(WithMetal)9.25. Elbow/Forearm(WithoutMetal)4.66. Elbow/Forearm(WithMetal)4.77. Wrist(WithoutMetal)4.88. Wrist(WithMetal)4.9Forexample,yougetanorderforapediatricanklescan.Thereisnometalinthefieldofviewsoyouselecttheprotocol:Ankle/Foot/DistalTibia(WithoutMetal)9.1.Whenyougettothetomographicphasesoftheexam(helicalscanseries),simplychangethekVfrom120kVto100kV.kVStepsBy1step,wemeanthefollowing:

IftheadultiskV ThenchangethekVto140 120120 100100 80

Note:wedonothaveanyMSKextremityprotocolsthatuse80kVforadults.

Note:youdonothavetochangethekVforthescouts.

AdjustmentsforBariatricPEStudiesWedonothaveabariatricprotocolforchestPEstudies.Ourlargeprotocolisalreadydesignedtodeliverahighermaximumdosethanthemediumandsmalladultprotocols,butituses120kVtomaximizeiodinecontrast.Otherlargeadultprotocolsthatarenotangiogramsuse140kVforlargeadults.Therefore,forbariatricPEpatientswho1.fillthescoutviewor2.maxoutthemAtablepleaseincreasethekVfrom120kVto140kV.Note:IfyouknowthepatientislikelytomaxoutthemAtablebeforetakingthescout,youshouldincreasethescoutkVfrom120to140.

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Exampleofapatientfillingthescoutview

ExamplepatientfillingthescoutAPview

Examplepatientfillingthescoutlateralview resultingpoorimagequalityfromapatientwhofillsthescout

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Weight­BasedContrastInstructionsContrastvolumeforuserswithouttheMedradP3TOption(whatUWusesformostroutinenonangioimaging)Thistableassumesuseofcontraststrengthat300mgI/ccandaninjectionrateof3ml/secPatientWeight(lbs) ContrastVolume(mlorcc)

130andless 80(minimumamounttoload)140 86150 92160 98165 101170 104175 107180 110190 116200 122210 129220 135230 141240 147

250andlarger 150(maxamounttoload)ContrastvolumeforuserswithouttheMedradP3TPAOption(whatUWusesforangios)Thistableassumesuseofcontraststrengthat370mgI/ccandaninjectionrateof5ml/secPatientWeight(lbs) ContrastVolume(mlorcc) SalinechaserVolume(mlorcc)

150andless 100 60150­200 125 60

200andhigher 150 60

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CreatinineGuidelines(withvaluesforeGFR)Ifapatienthas1Kidney,partialNephrectomy,kidneytransplant,orRCCandtheyareborderlineforournon­diabeticcriteriaidentifycreatininetrend.IfthecreatininehasbeenstablefollowourcurrentguidelineswithoutchangingtoIodixanol.Diabetic Creatinine eGFRIohexol <1.4 >50Iodixanol 1.4­1.8 40­50NoContrast >1.8 <40

Non­Diabetic Creatinine eGFRIohexol <1.8 >40Iodixanol 1.8­2.4 30­40NoContrast >2.4 <30

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PediatricContrastGuidelinesPurpose:Toidentifyappropriateintravenous(IV)accessforCTstudiesrequiringintravenouscontrast.Achievingappropriatecontrastinjectionratesiscriticaltoachievingaqualitydiagnosticstudy.◾ Inordertodecreasedelaysfrominjectiontoimageacquisition,apower­injectorwillbeusedbytheCTtechnologists.◾ IfapatientarrivesfortheCTandhasanIVorcentrallinethatisnotfunctioningappropriatelyforcontrastinjectionattherequiredrate,thepatientwillnotbescanneduntilanewIVisplaced.◾ PreferablyIVaccessshouldbeobtainedinanupperextremity.PIV=peripheralIV

TypeofExam IVCatheterRequirements PowerInjectorRate RNtoAccompanytoCTforInjection

CTAngioExams PIV(<1year):22G 22G:3mL/sec NoPIV(>1year):18G­20G 18G­20G:4mL/sec NoPowerinjectablecentralcatheter(tunneledornon­tunneled) Powerinjectablecatheter:4mL/sec NoRoutineCTExam

PIV:22Gorlarger >22G:2mL/sec No24Gcatheter(mustflushwell) 24G:HANDINJECT0.8­1mL/sec YesPowerinjectablecentralcatheter(tunneledornon­tunneled) Powerinjectablecatheter:2mL/sec NoNon­powerinjectablecentralcatheter(tunneledornon­tunneled):<4Fr PlacePIV>22G:2mL/sec NoNon­powerinjectablecentralcatheter(tunneledornon­tunneled):>5Fr Non­powerinjectablecatheter:HANDINJECT1­1.5mL/sec *YesHandInjectionbyRN:Patient’sRNmustaccompanypatientorCTifanon­power­injectablelineistobeusedforhandinjectionofcontrastforaCT.TheRNwillbeintheroomandinjectthecontrast.TheCTtechcanthenstartthescanattheappropriatetimefollowingcontrastadministration.IfthereareclinicalconcernsregardingIV/centrallinesizeorfunctionlimitingourabilitytoperformadiagnosticCTscan,adiscussionshouldbehadbetweenthepatient’sattendingphysicianandtheattendingpediatricradiologist.RadiationSafetyGuidelinesforRNsinroomduringthestartofCTexams:◾ TheRNshouldbewearingaleadapron(wraparoundtype)andthyroidshield.◾ TheRNshouldtrytostandasfaraspossiblefromthepatientwhilestillbeingabletoadministerthecontrastagentduringthetimewhentheCTscannerison(thescannerhasanotificationlightonthefrontandbacksidestoshowpeopleintheroomwhenitiscreatingx­rays).◾ Aftertheinjectioniscomplete,theRNshouldback/stepawayfromthepatient/scannerandleavetheroomiftimeallows◾ ForpregnantRN’sintheroom,refertoyoursitesowninternalpolicyguidelines.ContraindicationsforUsingthePower­Injector◾ Tunneledcathetersthatarenotpower­injectable(siliconeHickmanorBroviaccatheter):Duetotheinabilitytoinjectatanappropriaterate.

◾ PatientwillneedtohaveaperipherallineplacedforanyCTA◾ Ifthetunneledcatheterissmallerthan5Frenchordoesnotflushwell,aperipherallinewillneedtobeplaced

◾ Umbilicalvenouscatheters:duetothepossibilityofinjectingthecontrastbolusdirectlyintotheliver.◾ Patientswillneedtohaveaperipherallineplaced.◾ Ifnoothervenousaccesscanbeattained,thepatient’sattendingphysicianneedstospeakwiththeattendingpediatricradiologistpriortothescanbeingperformedtodiscussoptions.

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CTPerfusionProtocol:(SpecificInstructions)Setup1. PatientSupine,APandlateralscouts,nogantrytilt2. PatientPositioning:Tiltthepatient’sheadsothatalineconnectingthelateralcanthusoftheeyeandtheEACisperpendiculartotheCTtabletop(seeheadCTprotocol).3. UsuallydoneinconjunctionwithaCT/CTAoftheHeadorCT/CTAofHead/Neck4. Besttouse64(4cmdetectorcoverage)slicescannersExamCTPerfusion1. ScanTypeCine2. CineDuration65seconds3. PerfusionArea(nextpage)4. ContrastAdult:40mlof370Isovue(14.8gIodine)with30mlsalinechasePeds:0.25mg/kgIsovue370with10mlsalinechase1. InjectionRateAdult:5mlpersecPeds:3­4mlpersec(Dependsonsizeofneedleandageofpatient)1. PrepDelay5seconds2. PerfusionSlabsUsemaximumnumber(4­8­16)ofcontiguous5mmslabsallowedbyeachspecificCTscanner(usetoggle/shuttlemodeifpossible)DFOV1. Preferred22cmPerfusionPostProcessing(seebelowforfurtherdetails):1. Prospectivelyreconstructtheimagesto.5seconds.Thisisfoundunderthick/speed­(underrecon2).2. Whenyouareinrecon2,entertheRAScoordinatesmanually.3. NetworkrawperfusionimagestoALIStoreAcquisitionParametersCine AdultandChildnonRevolution AdultandChildRevolution

ScanTypeRotationTime

BeamCollimationDetectorRows

DetectorConfigurationScanFOV

NumberofimagesperrotationkV

SmartorManualmAManualmAforAdults

ManualmAforPed<6y/oCineDuration(sec)SliceThickness(mm)

Interval(mm)

Cine1.04064

64x0.625Head8i80

ManualmA15075655.00

Cine1.080128

128x0.625Head16i80

ManualmA200100655.00Note:Apply30%ASiR/ASiR­Vtotheperfusionrecons.

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Shuttle AdultandChildScanType

RotationTimeBeamCollimationDetectorRows

DetectorConfigurationScanFOV

NumberofimagesperrotationkV

SmartorManualmAManualmAforAdults

ManualmAforPed<6y/oCineDuration(sec)SliceThickness(mm)

Interval(mm)

Shuttle0.54064

64x0.625Head8i80

ManualmA400

noshuttlescansforpeds655.00Note:Apply30%ASiR/ASiR­Vtotheperfusionrecons.

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CTPerfusionCoverage

32andhigherslicescanners(shuttlemode)Obtain16contiguous5mmslicesfromEACUpward32andhigherslicescanners(cinemode)

64ChannelCTPerfusion:Non­shuttleMode(8x5mmslicecoverage)

64ChannelCTPerfusion:Non­shuttleMode(8x5mmslicecoverage)

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8­16Slicescanners(cinemode)

8­16ChannelCTPerfusion:(4x5mmslicecoverage)

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CTPerfusionAnalysisInstructionsSuggestionsforROIplacementshownbelow

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ThoracicOutletInstructionsIndicationEvaluationforsuspectedunilateralthoracicoutletobstruction.OralContrastNonePre­ScanInstructionsTwoCTAscans,onewithbotharmsdownandonewithaffectedarmup.Makesurehandinaffectedarmiswarm.Iforderedasabilateralscan:DotwoCTAscans,(A)onewithrightarmdownandleftarmupand(B)onewithrightarmupandleftarmdown.Makesurehandsarewarm.IVContrastParametersLoad135cccontrastIsovue370and80ccsaline.FieldofViewSameaspreviousstudyorassmallasappropriateScanDescription

◾ Part1◾ ScanDescription:ArmsDown

◾ Series1:PAandLateralScout◾ Coverage:Fromlowernecktodiaphragmoninspiration.Scanwiththescoutsfromtheroutineneckprotocol.

◾ Series2:SmartPrep◾ Coverage:CenterovertheaorticarchandplacetheROIontheproximalaorticarch.Startscanningat100HUtriggerlevel.

◾ Series2:ScanPhaseCTA◾ Coverage:Frombelowthecarinatolowerneckoninspiration.◾ IV:50mLIVcontrastat5mL/secfollowedby40mLsalineat5mL/sec

◾ Part2◾ ScanDescription:AffectedArmUp

◾ Series3:PAandLateralScout◾ Coverage:Fromcarinathroughfingertipsoninspiration.

◾ Series4:SmartPrep◾ Coverage:CenterovertheaorticarchandplacetheROIontheproximalaorticarch.Startscanningat100HUtriggerlevel.

◾ Series4:ScanPhaseCTA◾ Coverage:Fromaorticarchthroughfingertipsoninspiration.◾ IV:25mLIVcontrastat5mL/secfollowedby60mLIVcontrastat4mL/secthen40mLsalineat4mL/sec

◾ Part3◾ ScanDescription:DelayedCTA(Havethepatientkeeptheirarmraisedasitwasinthepreviousseries)

◾ Series5:ScanPhaseCTA◾ Timing:Thisscanshouldbestarted70secondsafterthecontrastinjectionfromthepreviousseries.◾ Coverage:Scanfromthecarinatotheelbow.

AcquisitionParametersScanthescoutsfromtheroutineneckprotocolwhenthearmsaredownandtheupperextremityrunoffprotocolwhenthearmsareup.Scanthetomographicportionswiththeupperextremityrunoffprotocol(turnthesmartprepoptionon).Revolution Discovery CT / Discovery CT750 HD 457 Rev: 3.0 / December 2017

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ScoutRangesandAnatomicalLandmarksThetablebelowlistsscoutstartandendrangesappropriateformostadults.Forpediatrics,adjustmentofthesevaluesshouldbebasedonpatientheight.ProtocolName/Type AnatomicalLandmark ScoutStartLocation ScoutEndLocation

Head(Brain),Orbits,FacialTrauma,Sinus,TemporalBone,Stereotactichead OM S150 I150CTAhead,ANDanyofthefollowingthatneedtosmartprepovertheaorticarch:Head

(Brain),Orbits,FacialTrauma,Sinus,TemporalBone OM S150 I300

StrokeDeluxe,Head/NeckVenography SN S300 I200Neck,CTAneck,CervicalSpine SN S200 I200

Shoulder/Humerus SN S150 I150Elbow/Forearm EJ S150 I150Wrist/Hand WJ S150 I150

Chest,LungCancerScreening,PulmonaryEmbolism,AllCardiacProtocols(gated/non­gated),DynamicAirway SN S50 I350

Subclavianvenogram,Pectus SN S75 I350Abdomen/Pelvis(thisincludesallprotocolsstartingwithAbd­Pelvisunlessotherwise

noted),LumbarSpine XY S50 I500

ChestAbdomenPelvis,TAVI/TAVR,PE/Abd/PelvisCombo,ThoracicSpine SN S50 I600BonyPelvis,Cystogram,BodyPelvis IC S50 I300

MAKOHip IC S50 I650MAKOKnee KN S350 I350Knee/Tibia KN S150 I150

FemoralAnteversion IC S100 I1000AnkleFoot,DistalTibia AJ S150 I150

UpperExtremityCTA(runoff) SN S800 I300LowerExtremityCTA(runoff) SN S100 I1700*

*Note, some scanners may only be capable of going to I1450.

OM=orbitalmeatal,SN=sternalnotch,EJ=elbowjoint,WJ=wristjoint,XY=xyphoidprocess,IC=iliaccrest,KN=knee,AJ=anklejoint

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WindowWidthandWindowLevelNote:STreferstosofttissue,wwreferstowindowwidth,wlreferstowindowlevel,PEreferstopulmonaryembolism.Allscouts(CTlocalizerradiographs)WW/WL=500/50Abdominal

Anatomybeingscanned WW/WLST 450/50Chest

Anatomybeingscanned WW/WLLungs 1500/­700ST 450/50PEAXMIPS 920/125Cardiovascular

Anatomybeingscanned WW/WLST 450/50Neuro

Anatomybeingscanned WW/WLBone(temporalandspines) 2500/350ThickST(generalhead/brain) 80/25GenericSTimages,CTAheadandneck 450/50ThinSTHead,Perfusion 180/25NeckST 300/35OrbitsST 300/0MSK

Anatomybeingscanned WW/WLBone 2500/350ST 450/50Peds

Anatomybeingscanned WW/WLChest/Body 550/80Lung 2100/­450

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InstructionsforAvoidingtheLensoftheEyeonHeadExams

Forroutineheadexamswhereonedesirestoavoidthelensoftheeye:1. Positioning:Tiltthepatientschintowardtheirchest“tuckedposition”(ortiltgantryalternatively)toproduceascananglethatisparalleltoalinecreatedbythesupraorbitalridgeandtheinnertableoftheposteriormarginoftheforamenmagnum(opisthion).2. HelicalmodeshouldbeusedroutinelyforadultheadCTscans.Ifyoucannotmovethepatient’sheadintoproperposition(trauma,cervicalcollar,rigidneck)thenperformahelicalscanwithangledaxialreformatsorperformanaxialscanwithgantrytilt.3. StartscansatthetopoftheC1laminaandscanthroughthetopofthecalvarium.4. Thefigurebelowdetailsthescanranges

Scanrangeforroutineheadimagingiftheeyelensistobeavoided(scanfromyellowlinetoyellowline,theredlinedenotesthebonylandmarksyouwanttogetalignedwiththescanplane)

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HowtoSendtheECGTracetoPACS

Forallgatedexams(prospectiveandretrospectiveforallindications/contrastphases/bodyregions(noncontrastchest,CTAnoncoronaries,CTAcoronaries,etc.)pleasesendtheECGtracetoPACS.Thiswillhelpdocumentthepatientsheartrate,heartratevariability,andthepresenceofanyirregularbeatsduringthescan.Ifyouperformanytriggerediting,itwillalsodocumenthowthateditingwasperformed.TosendtheECGtracetoPACS1. AftercompletingalloftheneededreformatsandpushingthestudytoPACS,opentheretroreconstructionscreenandselectthegatedseries.Donotselectthesmartpreporbolustrackingseriesifpresent.ForcoronaryCTA,pickthecoronaryCTA,notcalciumscoring.2. Adjustthescanreconstructionrangetoassmallaspossible(wewillbedoingaretrorecononlytosavetheECGtrace,nottoactuallysendtheimagessotherangedoesn'tmatterandthereforeshouldbeassmallaspossibletosavespaceonthescanner).Forexample,ifthescanstartedatS40andendedatI250,youcouldjustdoaretroreconfromS40toS39.3. Makesurethebuttonthatsays"ECGViewer"isselected(youshouldseetheECGtracewhenitisselectedinthetoprighthandcornerofthescreen)4. HitthesaveiconontheECGtrace(itisintheupperrightandcornerofthescreenandlookslikeafloppydisc).5. Nametheseries"ReconforECGTrace".6. Clickconfirm.7. Twonewserieswillshowupforthepatient,theoneyoujustmadenamed"ReconforECGTrace"andonenamed"ECGReport".Onlysendthe"ECGReport"toPACS.

ECGtraceshownonretroreconviewer HowtheECGreportshowsupontheimagebrowsertab

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Frequently­AskedQuestions(FAQ's)

CriticalCommentsonProperPatientCentering1. UsingtheUWprotocols,Isometimesfindthatpartsoftheimagearetoonoisy,particularlytowardstheposteriorpartofthepatient.Why?Toensureuniformimagequalityatthelowestdose,properpatientpositioningisveryimportant.Currentscannertechnologyincorporatesbowtiefilters.Theirpurposeistodecreaseradiationtotheperipheryofthepatient.Thisresultsinasweetspotforpatientpositioning.Improperpositioningwillresultindegradedimagequality.Itisparticularlyimportantinpediatricimagingandthesmalladultsspecifically,wheneverthesmallerbowtiefilterisusedrelativetotheselectedScanFieldofView(SFOV).ThesmallbowtiefilterisusedforallpediatricSFOV’s,fortheSmallBodyandSmallHeadSFOV’sontheLightSpeedVCTandtheDiscoveryCT750HD;andfortheSmallBodyandHeadSFOV’sontheRevolutionEVOandtheOptimaCT660.PropercenteringisalsomoreimportantwhenusinglowkVtechnique.Patientsofallsizesarefrequentlypositionedtoolowinthegantry,primarilybecauseitcanbedifficulttocorrectlyestimatetheAPcenterofthepatientsincepartofthepatientiseffectivelyhiddenbythecurveofthetable.Generallyitisbettertohavethepatientcenteredabithighratherthanlow,sinceitisoptimaltoplacethemostattenuatingpartofthepatientatthecenterofthescan.Thepatient'scenterofmassisusuallyabitposteriortothemeasuredcenterpointofthepatientfromskinlinetoskinline.Thus,makesurethatthetableisproperlyelevated.(Toaccomplishthiswithsmallerandpediatricpatients,oneshouldpositionthepatienthighenoughsothatthehorizontallaserlightiscenteredonthelumbarspineandisjustanteriortothethoracicspine.Thisisdemonstratedbythefiguresonthenextpage.)Ifthepatientispositionedtoolowinthegantry,severaldetrimentaleffectsoccur.TheyaremostproblematicwhenusingthesmallerSFOVbowtiefilterorlowerkVsettings.Firsttheimagenoisewillincrease,particularlytowardtheposteriorpartofthepatient.Secondthepatientdosewillincrease.ThepropersolutionisNOTtoavoidtheuseofthesmallerSFOVbowtiefilterortoavoidtheuseoflowerkVwhenappropriate.Ratherthebestsolutionisproperpatientpositioning–toobtainthebestoverallimagequalityatthelowestdose.Theprincipalsofproperlycenteringsmallandpediatricpatientsaredemonstratedinthescoutimagesbelow,wheretheredlineistheactualmidpointofthescoutimageandthebluelineiswherethepatientshouldhavebeencenteredonthescout.Onlythescoutontheupperrightshowscorrectpositioning;themidpointofthisscoutisshownasapurpleline.Alltherestarecenteredtoolow.

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PositioningExamplesGeneral1. WhydidGEpartnerwiththeUniversityofWisconsin­Madison?UniversityofWisconsin­Madisonhasoneofthelargestmedicalphysicsdepartmentsofanymajorinstitutionofferingthistypeofprogram,andtheirDepartmentofRadiologyhasyearsofexperienceinrefiningandimprovingCTprotocols.Together,thesetwodepartmentshavedevelopedclinicallyrelevantandtechnicallysoundCTprotocols.TheUniversityofWisconsin­MadisonandGEHealthcarehavehadalong­standingworkingrelationshipandstrategicalliance.Thisispartlyduetogeographicproximity.2. WhenIbuyanewGEscanner,mustIusetheseprotocols?Weencourageyoutotakethetimetoreviewtheprotocolsandapplythemastheyarewritten.Theseprotocolshavebeenrefinedtoprovideoptimalimagingforanumeroussetofconditions.Theyhavebeenfine­tunedtoeachspecificCTscannerandrefinedforthevaryingsizeofourpopulation.Butyoumaychoosetouseyourownprotocols.Justpleasetakethetimetooptimizethemforyournewscanner.That’stherightthingtodotomakesureyourpatientsgetthebestscanatthesafestdose.3. Whyaretheresomanydifferentprotocols?Theprotocolsarerefinedforcertaindiseasestates.Modificationsinpatientpositioning,oralandintravenouscontrastadministration,andtimingofseriesacquisitioncanhelptooptimizevisualizationofthesuspectclinicalcondition.4. Willtheseprotocolschange?ItisinevitablethatwithfurtherimprovementsinCTtechnologyand/oragrowingunderstandingofdiseaseconditions,theUniversityofWisconsin­Madisonprotocolswillevolve.Ourintentionistoreleasenewversionsofimprovedprotocolsonanannualbasis;however,anearlierreleasemaybeprovidedifamajormedicaladvanceoraprotocolissuecomestolight.Revolution Discovery CT / Discovery CT750 HD 463 Rev: 3.0 / December 2017

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5. IsthereareasonwhyDoseReductionGuidanceisnotusedintheprotocols?1. WhentheDoseReductionGuidanceisused,thereisalimitimposedontheminmAallowed,whichposesaproblemforourprotocols.2. DoseReductionGuidanceisnotavailableontheDiscoveryCT750HDscanner,andwewishedtobeconsistentinourprotocolsacrossGECTplatforms.3. OurradiologistshaveapprovedtheuseofacertainpercentASiRforthedifferentexamsanddonotwanttohaveitalteredbytheDoseReductionGuidance.6. Theseprotocolsincorporateoralcontrast.Howdoweusetheprotocolsifourinstitutionhasgottenawayfromusingoralcontrastinouremergencydepartment?TheUniversityofWisconsin­Madisonfirmlybelievesthatimagingofcertaindiseasestatesisenhancedbytheadditionoforalcontrast.Ifyourinstitutioniscomfortablewithscanningtheabdomenintheabsenceoforalcontrast,that'sfine.However,youareencouragedtoconsideroneuniqueaspectoftheoralcontrastcocktailthatwerecommend.TheUniversityofWisconsin­Madisonroutinelyaddspolyethyleneglycol(PEG)totheoralcontrastmix.Thisacceleratestransitthroughtheintestine.Whenourpatientsdrinkthiscontrastmixtureforonehour,weroutinelyseeopacificationoftheguttothelevelofthececum.Thissignificantlyincreasesconfidenceandinterpretation,especiallyforentericconditions.7. Ijustscannedasmallpatientandtheimagequalityisnotverygood.Why?Patientcenteringiscriticallyimportanttoachieveuniformimagequality.PleaserefertotheProperPatientCenteringinthissectionformoreinformation.8. WhydoyouuseSmartmAinsteadofAutomAorManualmA?TheUWprotocolsalwaysrelyontheSmartmAfunctionwhentheAutomAisturnedon.WedonotseeanysituationinwhichitwouldbeadvantageoustoturntheSmartmAfunctionoff.SmartmAincludesbothmAmodulationasthepatientattenuationchangesalongthelengthofthepatientandalsomAmodulationasthetuberotatesaroundthepatient.Thisisalwaysadvantageousandisessentialinareasoftheanatomywherepatientsize/attenuationvariesdramaticallywithdirection,suchastheshouldersandpelvis.Itisevenusefulinscanningthehead,sincetheAPandlateraldimensionsoftheheadarenotthesame.9. Whydon’ttheprotocolsuseDynamicTransitiononSmartPrep?DynamicTransitiontriggersthescanautomaticallywhenIVcontrastenhancementintheselectedregionofinterestreachesapredeterminedHUvalue.Somepatients,however,arestartledbytheinfluxofcontrastandmaymoveorbreathedifferently.Thiscouldshifttheregionofinterestandresultinanattenuationspikewhichmayprematurelytriggerthescantostartbeforeoptimalcontrastopacification.

AbdominalCTProtocols1. Whyaretheretwoflankpainprotocols?Thestandarddoseflankpainprotocolisappropriateforthepatientpresentingforthefirsttimetotheemergencyroomwithsuspicionofrenalcalculiorappendicitis(althoughweencourageoralcontrastforsuspectentericpathology).Thelow­doseflankpainprotocolismoreappropriateforthefollow­upofpatientswithknownkidneystoneswhoarereceivingnumerousscans.Itistailoredtoprovidealevelofresolutiongoodenoughtovisualizerenalcalculi,butnottocharacterizeotherrenalabnormalities.2. WhyisthereanhepatocellularcarcinomaprotocolinadditiontothebiphasicCT?TheUnitedNetworkforOrganSharing(UNOS)hasmandatedthatpriortolistingapatientfortransplantation,theCTscanevaluatingthepossibilityofneoplasmmustincludeadelayedphase.Therefore,aspecialprotocolwascreatedtoaccommodatethismandate.ThebiphasicCT,however,ispreferredforevaluationofhypervascularmetastasestotheliver.3. Whyaretheresomanyreformattedimagesonatraumastudy?TheUniversityofWisconsin­MadisontraumaCTofthechestisperformedwithangiographictechnique.However,manycentersdonotprovidein­house3­Dservicesoff­hours.ThereforethisprotocolincludesanobliqueMIPreconstructionofthegreatvasculature.Itprovidesacandycaneprojectionoftheaorticarch,idealtoruleoutaorticinjury.4. Whydoyouscanthetraumachestfrombottomup?Bythetimethescanarrivesattheapexofthechest,mostoftheintravenouscontrasthasbeenwashedoutoftheveinsoftheupperthoraxbythesalinechaser.Thisdecreasesthestreakartifactsfromveins.Ifscannedtopdown,theseveinswouldbefilledwithverydensecontrastasitisbeingactivelyinjectedatthetimeofacquisition.5. Thedoseforthetraumachestabdomenpelvisappearsrelativelyhighcomparedtoastandardchestabdomenpelvisstudy.Whyisthatso?Atraumastudyroutinelyresultsinadditionalreformattedimagesofthespine.Toobtainappropriateresolutionforimagingoffractures,thetechniquemustberelativelyrobust.Thisismajorreasonwhytraumaimagingisperformedatahigherdosethanstandardbodyimaging.6. Whyisa0.5xx:1pitchused?UniversityofWisconsin­Madisonusesthe0.5xx:1pitchforseveralreasons:(1)itprovidesoptimizedhelicalreconstructions,comparedtohigherpitches;and(2)forthesameimagenoise,itproducesa20%lowerdosethandoesthe0.9pitch(whichiswhythatpitchisavoided).UniversityofWisconsin­Madisonuses0.4sor0.5srotationtimeswhenpossibletoreducescantimes

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withthelowerpitch.Whenthatisnotsufficient,asinPEstudies,thepitchisincreasedto1.375.TheuseofalowerpitchispossiblewiththeGE64­slicescannersbecauseofthewiderbeamcollimationof40mmcomparedto20mm,whichdoublesthetablespeedforanyparticularpitchandrotationtime.ThisalsoallowsthescanningoflargerpatientswithouthittingmaxmAanddegradingimagequality.ChestCTProtocols1. PleaseexplainwhyBonePlus(thincuts)areprescribedinRecon4?BonePlusisusedasa“lungalgorithm”.Wepreferitsdiagnosticimagequalitycomparedtothe“Lung”or“Bone”algorithm.ThincutsforbothsofttissueandlungimagesareperformedtocreatetheSagittalandCoronalreformattedimages.2. Whyisa0.5xx:1pitchusedexceptforPEstudies?Seesamequestionunder"AbdominalCTProtocols.CVCTProtocols1. Whyisaseparatenon­contrastscanincludedwiththeCTAstudies?Itallowsustodifferentiatecontrastfromcalciumwhenlookingforextravasationoraleak.Also,thenon­contrastscanisessentialfordetectionofintramuralhematomainacuteaorticsyndrome.2. Whyisthetime­of­arrivalofthetimingbolusmeasuredatthepoplitealarteriesduringrun­offsinsteadofintheaorta?Thereare2generalapproachestoperformingextremityCTArun­offstudies1. Thefirstattemptstoscanatroughlythesamerateasthecontrastboluspassesthroughtheextremityinorderto"follow"thebolusfromtheaortathroughthedistalextremity.Beforetheadventofmultidetectorfastscanners,thiswastheonlyrealoption.However,thetremendousvariabilityinthecontrastbolustransittimethroughtheextremity,especiallyinthepresenceofatheroscleroticdisease,madetimingdifficult.2. Thesecondapproach(whichtheUniversityofWisconsin­Madisonhasadopted)aimstoopacifyallofthelargerarteriesoftheextremitiesandthenscanasquicklyaspossible.Sincethecontrasttransittimevariesmarkedlyamongpatients,usingarteriesintheextremity(e.g.,poplitealarteriesforlowerextremityrunoffs)enablesbetterdeterminationoftheappropriatedelaybetweeninjectionandscan.Performinganimmediaterepeatoftheverydistalextremity(beginningatthekneesorelbow)alsohelpsensurethatthedistalarteriesareadequatelyevaluated.3. Whydoesn’tUniversityofWisconsin­MadisonuseprospectivegatingonthechestportionofacombinedCTA

chest/abdomen/pelvisinwhichgatingisneededinthechest?GEscannersarenotcurrentlyabletocombineaprospectivelygatedchestwithanon­gatedabdomen/pelvisinasingleacquisition.Therefore,whenitisessentialtouseECG­gatingonthechestportionofaCTAchest/abdomen/pelvis,retrospectivegatingmustbeused.MSKCTProtocols1. Whydoesthewrist/elbowneedtobeoverthehead?Thispositioningeliminatesbothexposuretoandscatterfromtherestofthebody.2. Whenpositioningthepatientwiththeirarmovertheirhead,doesitmatteriftheyareprone,supine,ordecubitus?No.Usewhateverpositionmakesthepatientmostcomfortable.3. Whenscanningankles/feet,whyarebothankles/feetincludedinthescanningFOV?Becausethereisnoappreciablescatterfromthenormalcontralateralside,andsometimesitisusefultohavethecontralateralsideforcomparison.4. If,whenscanningaknee/ankle/foot,thereismetalinthecontralateralside,whatshouldbedone?Thecontralateralkneeshouldbebenttomovethemetalknee/ankle/footoutofthescanningFOV.5. Howshouldthearmbepositionedwhenthereisacastinplace?Theidealpositionforscanningtheelbow/forearm/wristiswiththearmandelbowstraightsothatthearmisperpendiculartotheCTgantry.Whenthereisacastacrosstheelbow,thentheforearmshouldbepositionedsoitisobliquetotheCTgantry.6. Whyshouldn'tthepatientbepositionedwiththeforearmparalleltotheCTgantry?Thiscreatesanunacceptableamountofstreakingalongthelengthoftheforearmduetogreatlyincreasedx­rayattenuation.Theforearmshouldbepositionedperpendicular(preferred)orobliquetotheCTgantry.7. Whyaresomeofmyboneimagestooblurry,especiallythoseoftheshoulders?Therearetwoimportantrequirementstoretaintheimagesharpnessthatcanbeprovidedbythesharperimagealgorithmssuchas“bone”,“boneplus”,“edge”,and“ultra”.ThefirstrequirementistheuseofasmallDFOV,ideallyoflessthan20cm.Thisproducesapixelsizethatiscapableofreproducingthefullresolutionofthesharpalgorithms.ThelargerpixelsizethatresultswiththeuseoflargerDFOV’swilllimittheresolutionofwhichthesharpalgorithmsarecapable.Thesecondrequirementisthattheanatomyforwhichyouneedhighresolutionbepositionedclosetothecenterofthescan

fieldofview.Duetotheeffectsoffocalspotsizeanddetectorsize,themaximumlimitingresolutiondegradessignificantlyasRevolution Discovery CT / Discovery CT750 HD 465 Rev: 3.0 / December 2017

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youmovefartherfromthecenterofthescanfield.Forexample,whenusinganyofthesharpalgorithms,theactualresolutionneartheouteredgeofthescanfieldcandegradetothatofa“soft”algorithm.Toavoidthisblurring,thebestpolicyistopositiontheanatomywithinacentralareawithadiameterof15cmorless.Anotherrecommendation,whichwillincreasesizeofthiscentralsharpareaabit,istouseasmallfocalspot.Tomakesurethatthescannerisactuallyusingasmallfocalspot,themAinmanualmAmodemustbenomorethanavaluethatdependsonthekVsettingandthatcanbefoundintheTechnicalReferenceManualforthescannerbeingused.InautoorsmartmAmodethemaximummAsettingmustbelimitedtonomorethanthatsamevalue.HereareexamplevaluesfortheRevolutionEVO/OptimaCT660andfortheRevolutionDiscoveryCT/DiscoveryCT750HD,indicatingthemaximummAallowedforthesmallfocalspot:RevolutionEVO/OptimaCT660mAlimitsforsmallfocalspot RevolutionDiscoveryCT/DiscoveryCT750HDmAlimitsforsmallfocalspot

kV NormalScanMode Normal/HiResScanMode80 300mA 620/610mA100 240mA 650/490mA120 200mA 540/405mA140 170mA 460/350mAAsyoucanseefromtheabovetable,theRevolutionDiscoveryCT/DiscoveryCT750HDscannershaveanadditionalscanmode­­“HiRes”.Thisallowsanevengreaterincreaseinthesizeofthesharpcentral“sweetspot”inthescan.Thisscanmodecanbeusedwitheitherthelargeorsmallfocalspot,butthegreatestadvantageiswiththeuseofthesmallfocalspot.Pleasenotethattotakeadvantageofthisbenefitofusingthe“HiRes”scanmode,youDONOTneedtousetheadditional“HD”reconstructionalgorithmsthatareavailablewhenusingthisscanmode.Infact,youmaypreferthenormal,non­HDalgorithmssincetheHDalgorithmsmaycauseanunacceptableincreaseinimagenoiseandartifacts.TheHDalgorithmsusedintheHiResscanmodecanproducearesolutionlimitinthecenterofthescanfieldthatisupto50%greaterthanachievablewiththenormalscanmode,butthisgreaterresolutionisseldomneededordesirableconsideringtheincreaseinimagenoiseandartifactsthatcanresult.

NeuroCTProtocolsAdultBrain1. Whyishelicalmodeused?1. Helicalscanningallowsreconintervalsatlessthantheslicethickness.Thebestz­resolution,alongwiththefullestdisplayoftheclinicalinformationobtainedinthescan,isobtainedatreconintervalsofone­halfoftheactualslicethickness.Thesourceimagesthatareusedforanyreformattedimagesmustbethinslices(1.25mmforsofttissueand0.625mmforbone)withreconintervalsofone­halftheslicethicknessforoptimalimagequality.Thenearlyisotropicvoxelvolumetricdatathatthisprovidescanthenbeusedtogenerateaxialimagesatanyanglethroughthebrainorstraightentheimagesthroughthebrainifthepatientisnotproperlypositioned.Italsoallowsfortheabilitytocreate2­Dreconstructions.2. Whenthepatient’sheadcanbepositionedandangledproperlyforthescan,usehelicalmodeandtheaxialimagescanbereadwithoutreformatting.3. Ahelicalscanmodefollowedbyangledreconscanbeusedwhenonecannotadequatelypositionthepatient’shead(e.g.,cervicalcollar).2. Whyisaxialmodeused?Thisisusedwhenthepatient’sheadcannotbepositionedproperlyandalsowhenhelicalscanswouldproduceartifactfrommetalprojectingovertheposteriorfossa.3. Whynotuseanevenlowerdosethanwhat’sintheprotocol?Thiswouldresultindecreasedcontrastresolutionandaworsesignal­to­noiseratiomakingsubtlelesionsimperceptible.Grey­whitematterdifferentiationwouldalsobecomemoredifficult.4. DoyouscantheheadCTtoincludeorbitsortiptheheaddowntoexcludeorbits?Theheadisscannedtoincludetheorbitssinceweconsiderittobeanimportantpartoftheexam.Itisacknowledgedthatsomefacilitiesdonotwishtoimagetheorbitsbecauseoffearofinducingcataracts.Manyofthesefacilitiesmaynotrealizethatbyjustmissingtheorbits,theyarestillexposingthemtotheradiationbeam.UniversityofWisconsin­Madisondoesnotbelievethattheverysmalllevelofpossibleriskforinducingcataractsissufficienttoexcludethediagnosticinformationobtainedinthismethodofimaging.5. WhyisAuto/SmartmAusedonheads?AutomAorSmartmAisusedtooptimizeimagequalityatthelowestdose.Thebrainisnotauniformcylinder—obviouslyitissmallertowardthetopanditscross­sectionisovalandnotcircular.Headattenuationisalsonotthesameforallpatients(bonedensityandthickness).ThusthereisdefinitelyanadvantagetousingSmartmA,anditdoesnotcauseanyimagingproblems.Whentheaxialmodeisusedtoperformheadscans,thenManualmAisused.TheproblemhereisthenoticeablechangeinnoisetexturebetweenaxialslabsifthemAweretochange.Thisproblemisnotseenwithhelicalscanning.Helicalscanningallowsonetoreconstructatintervalsof½theactualslicethickness,whichimprovesdiagnosticinformationintheaxialscansandimprovesSagittalandCoronalreformats.Revolution Discovery CT / Discovery CT750 HD 466 Rev: 3.0 / December 2017

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6. Whyisthenoiseindexdifferentbetweentheadultbrainroutineandadultbrainhelicalscanwithangledaxialreformats?Effectivelytheyarethesame.Onenoiseindexissetforaninitialslicethicknessof5.0mmwhiletheotherissetforaslicethicknessof1.25mmandthereforeneedstobetwicethesettingusedfor5.0mm.

AdultOrbit1. Whenisintravenouscontrastused?IVcontrastisusefulinsuspectedorknowntumor,infection,orvascularmalformation.2. Whyistheboneplusalgorithmutilzied?Thishelpsinassessingbonychangesfromtumor(e.g.,smoothremodelingversusaggressivedestruction)orinfection.3. Whycan’tonesimplyusesofttissuealgorithmwithbonewindows?Thiswouldhavediminishedbonydetailcomparedtotrueboneplusalgorithm,andsubtledestructivelesionscouldbeobscured.4. WhyuseAuto/SmartmA?Exceptforscanningusingtheaxialmode,forallstandardscanninghelicalmodeisusedwithSmartmA.Thisincludestheprotocolsfortheorbit,sinus,facialbonesandtemporalbones.UsingSmartmAsimplygivesmoreconsistentimagequalityatthelowestdoseanddoesnotproduceanyimagequalityproblems.WeareunawareofanysituationinwhichitwouldbeadvantageoustoturntheSmartmAfunctionoffwhenusingAutomA.AdultMaxillofacial1. DoIneedtoscanthemandible,aswellastheface?Yes.Upto10%ofpatientswithfacialtraumawillhavecoexistentmandibularfractures.2. WhydoIneed0.625mmslices?Thisslicethicknessisneededforisotropicvoxelresolutionallowingforhighqualitymultiplanarreconstructions.3. Whyisn’talowerdoseused?Softtissueevaluationisalsomandatorywithfacialtraumaandhigherdoseisneededforadequatesofttissueimaging.4. WhydoIneedsomanydifferentreconstructions?Differentplanesmaybetterdemonstratesubtlefractures,allowingformoreaccuratediagnosis.5. DoIneedtodosofttissuereconstructionsinfacialtraumapatients?Facialtraumaalsoaffectsthesofttissuesoftheorbitandface.Theselesionswillnotbeadequatelyvisualizedonthebonealgorithmimages.6. WhyuseAuto/SmartmA?Seesamequestionunder'AdultOrbit'subsectionof"NeuroCTProtocols".AdultSinuses1. Wheniscontrastneeded?Forevaluationofsuspectedtumors,atypicalinfections,suspectedextra­sinusspreadofinfections,orpossiblevascularlesions.2. IsCTasgoodasMRIforevaluatingthesinuses?Itdependsontheproblemthatisbeingevaluated.Theyareoftencomplimentarystudies,especiallyforassessmentofsino­nasalmasses,andbothmayberequiredinsomeinstances.3. WhyuseAuto/SmartmA?Seesamequestionunder'AdultOrbit'subsectionof"NeuroCTProtocols".AdultTemporalBone1. Whatistheoptimalslicethickness?Fortemporalboneimaging,ingeneral,thethinnertheslice,thebetter.2. Wheniscontrastneeded?Forevaluationofinfectionorinflammatoryprocesses.Inaddition,itcanbeusedinevaluationofpossibletumorsinpatientswhocannothaveanMRI,althoughitisnottypicallyassensitiveasMRI.PleasenotethatadequatemAsmustbeutilizedforsofttissueresolution.3. Whyaren’tdirectcoronalimagesobtained?Ifadequateslicethickness(i.e.,0.625mm)isobtained,thenmultiplanarreconstructionswillbecomparableinqualitywithouttheadditionalpatientdose.Itsavesagreatdealoftimeandshortenstheexamconsiderably.Thecoronalplanecanbecorrectforeachpatientandnotlimitedbytiltorabilitytopositionpatientindirectcoronalposition.4. WhyuseAuto/SmartmA?Seesamequestionunder'AdultOrbit'subsectionof"NeuroCTProtocols".Revolution Discovery CT / Discovery CT750 HD 467 Rev: 3.0 / December 2017

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AdultNeck1. Whyis140kVused?ThishigherkVisneededforadequatepenetrationoftheshoulders.TheuseofalowerkVsettingwouldresultinstreakingartifactsthroughtheshouldersandreducedimagequalityincludingincreasedimagenoise.2. Whyisthescanstartedattheaorticarch?1. Thescanfollowsthecontrastbolus.2. Neededforevaluationoflefttruevocalfoldpalsy.3. Allowsassessmentofmediastinalnodaldisease,whichisoftenpresentinheadandneckcancer.4. Allowsforevaluationforthelowerlimitofretropharyngealpathology.3. Whyisonlya0.5xx:1pitchusedforaCTAneck?Thelowpitchreduceshelicalartifacts,particularlywhentheanatomyischangingsorapidlyasintheneck/shoulderregion.Also,thelowpitchavoidsreachingthescanner’smaximummAvalueinthelateraldirectionthroughtheshoulder,whichwouldcompromisetheimagequality.4. Pleaseexplaintherationalefor140kVand0.5xx:1pitch.140kVisusedtoassureproperpenetrationthroughtheshoulders,whichcanotherwisebeanannoyingsourceofnoiseandartifact.The0.5xx:1pitchistominimizeartifactsduetothesubstantialattenuationchangesfromthetransitionsfromtheshouldersandtoallowenougheffectivemAstopenetratetheshoulders.Forthesameimagenoisethedoseislowerusingthe0.5xx:1pitchcomparedtothe0.9xx:1pitchontheGE64­slicescanners,asnotedpreviously.AdultCervicalSpine1. Whyis140kVused?ThishigherkVisneededforadequatepenetrationoftheshoulders.TheuseofalowerkVsettingwouldresultinstreakingartifactsthroughtheshouldersandreducedimagequalityincludingincreasedimagenoise.2. Whyareimagessograinyinthelowercervicalspinewithsofttissuewindows?Theexamisobtainedwithanoiseindex,whichallowsforgoodvisualizationofthebonesforfracturesandadequateevaluationofmostsignificantsofttissuepathologywiththisdose.Adjustmentscanbemadefordosingperpreference.3. Whyaresofttissuereconstructionsobtainedintrauma?Theseareusedtodetectadditionaltraumasuchassofttissuehematomas,epiduralorsubduralhematoma,traumaticdischerniation,andpossiblespinalcordinjury.4. Whyare2­Dmultiplanarbonereformationsobtained?Because1)somefracturesmaybemoreadequatelyseenindifferentplanesthanothers;and2)multiplanar2­Dreformationsallowforimprovedvisualizationofsubluxation.PediatricRoutineCervicalSpine1. Whyuse0.8srotationtimeonachild,age3to6years?Toavoidreachingthescanner’smaximummAinthelateraldirectionthroughtheshoulder,whichwouldcompromisetheimagequality.AdultThoracicSpine1. WhyarereformatscreatedontraumaCTchest/abdomen/pelvis?1. ThisoptioncanbeusedwithunstablepatientswhoneedmultiplebodypartstobequicklyscannedandthereisnotadequatetimetoobtainstandardthoracicspineCTimages.2. Additionally,inpatientswithlowlikelihoodoftrauma,thishelpstoreduceradiationdose.Ifthereisahighlikelihoodofsignificantthoracicspinefracture,adedicatedthoracicspineCTshouldobtained.2. Whyaretheaxialsofttissuereconstructionsandsagittal2Dreformattedthoracicspineimagesthatareobtainedfrom

secondaryreconstructionsoftraumaCTchest/abdomen/pelvisstudiessograiny?AlowermAisutilizedwiththisoptiontolimitradiationdose.Ifthereisahighlikelihoodofthoracicspinalinjury,adedicatedthoracicspinestudyshouldbeperformed.Individualinstitutionsmayalsoincreasethedoseperpreference.VascularCTA1. WhyareimagesobtainedcranialtocaudalwithaheadandneckCTangiographyprotocol?Thisisdesignedtoreducevenouscontaminationintracranially,allowingforimprovedsensitivityforaneurysmdetection.2. Whyissmartprepusedinsteadofatimingbolus?Lesscontrastisutilized.Venouscontaminationisalsoavoided.Revolution Discovery CT / Discovery CT750 HD 468 Rev: 3.0 / December 2017

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3. Whyaresomanyreconstructionsobtained?Thisallowsforimprovedpathologydetection.Individualinstitutionsmaymodifythereconstructionscreatedperpreference.IntracranialPerfusion1. CanImodifytheradiationdose?TheFDAhasstrictregulationsregardingdosewithperfusionimaging,andtherefore,itisnotrecommended.Futureupdatestotheseprotocolsmayutilizeevenlowerdoseparameters.2. WhyisVolumeShuttlemodeused?Thisincreasestheareaofbrainthatcanbecovered.Axialvs.HelicalPediatricHead1. Inpediatricprotocolsforthehead,doestheUniversityofWisconsin­MadisonuseManualmAorAutomaticExposure

Control?IfAutomaticExposureControl,isthemaxmAlistedintheprotocolstoohighfora3­6yearoldcomparedtothatlistedfora0­3yearold?TheUniversityofWisconsin­MadisonusesSmartmAforallscansperformedwithhelicalscanning.IntheunusualcircumstancethatManualmAisused,thescanparametersareselectedtogiveacomparabledoseandimagequalityascomparedtothehelicalscanning.Withhelicalscanning,theNoiseIndexisslightlyhigherwiththe0­3yearoldprotocolcomparedwiththe3­6yearoldprotocol,buttheimagequalityissimilarsincethe0­3yearoldprotocolisperformedusingalowerkV(bettercontrast).InprotocolsthatuseManualmA,themAsettingsareadjustedtogivecomparableimagequalitywithalowerkV,reducingdoseandincreasingimagecontrastforthe0­3yearoldprotocolcomparedtothe3­6yearoldprotocol.

PediatricCTProtocols1. Whyarethereonlyfivedifferentsize­basedprotocolsfromtheUniversityofWisconsin­MadisonwhereasGEhasnine?

GEhassetupnineseparateprotocolsbasedontheBroselowcolor­basedsystem.Thissystemispredominantlyusedforthepurposesofemergentmedicationdosingandequipmentselectionsuchascatheterandendotrachealtubesizeduringpediatricresuscitation.Thereisnotenoughdifferencebetweeneachoftheseninecategoriesintermsofscanparametersanddosetowarrantthismanygradations.UniversityofWisconsin­MadisonusesAP+lateralmeasurementstoplacethepediatricpatientsinto5categories,correlatingwithapproximateagesofnewborn(Broselowpink);6months­2.5years(Broselowredandpurple);3­7years(Broselowyellowandwhite);8­12years(Broselowblueandorange);and13­18years(Broselowgreenandblack).2. TheUniversityofWisconsin­Madisonpediatricprotocolshavedosesthatareactuallyhigherthanwhatourinstitutionhasbeenusinglately.Whatistherationalebehindthepediatricparameters?WeattheUniversityofWisconsin­Madisonapplaudyourdosereductioninpediatricimaging.Astheseprotocolsarebeingintroducedtheyaregoingtoawidespectrumofimagingcenters,someofwhichhavenotyetreducedpediatricCTdose.Inordertoprovideimagingqualitytotheunaccustomedeyeofaradiologygroupscanningatahigherdose,wehaveprovidedtwodifferentsetsofpediatricprotocols.OnesetcontainstherelativelylowdoseprotocolsthatweuseattheUniversityofWisconsin­Madison.Asecondsetcontainshigherimagequality,higherdoseprotocolsforthosemorecomfortablewiththisimagequalitylevel.Ifyouwouldliketocontinueusingyourexistingpediatricprotocols,weencourageyoutoconfirmthattheyareatanappropriatelylowdosewithadequateimagequality,acrossthespectrumofpediatricsizes.3. Whyaresomepediatricimagessonoisy?Itismandatorytokeepthedoselowforpediatricpatients.However,imagequalityshouldbeinterpretable.Ifyouareintermittentlyhavingpoorqualitypediatricstudies,weencourageyoutoreevaluatepatientcenteringinthegantry.Inourexperience,itisthemostfrequentcauseofpoorimagequality.Propercenteringiscriticaltoimagequalityinsmallpatients.4. WhyistheprotocoldifferentforoutpatientsversusERpatientsintheevaluationofappendicitis?Outpatientsaregenerallynotassick.Theyarelesslikelytohaveappendicitis,butmaybemorelikelytohaveanotherreasonfortheirabdominalpain,thusweshouldimagetheentireabdomenandpelvisratherthandecreasetheFOVtoincludeonlythelowerabdomenandpelviswheretheappendixlives.5. Whyistherenoprotocolforpediatricpatientswithbowelobstruction?Themostcommoncauseofbowelobstructioninachildisintussusception,forwhichultrasoundistheappropriatetesttoperform.Unlikeadults,mostchildrenhavenothadsurgeryandthereforedonothaveadhesionscausingobstruction.Ifachildhashadpriorsurgery,thentheroutineabdomenandpelvisprotocolshouldbeused.6. WhydopediatricCTA’snotincludeanon­contrastenhancedsetofimages?Thesemostoftendonotprovideadditionalinformationinchildrenandonlyaddtothetotalradiationdose.7. Whenevaluatingthechestformetastaticdiseaseinpatientswithosteosarcoma,whydoyounotgivecontrast?Osteosarcomametastasesoftencalcify,makingthemeasytodetect.Unlikeothertypesoftumors,osteosarcomadoesnot

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metastasizetolymphnodes,socontrastisnotnecessarytodelineatenormalmediastinalstructuresfromabnormallymphnodes.8. Whenevaluatingforinfectionand/orempyemainachild,whyiscontrastgiven?Contrastishelpfulinevaluationofpleuralthickeningandseptations.Additionally,thepresenceorabsenceofenhancementintheinvolvedlungishelpfulindeterminingthepresenceofnecrotizingpneumonia.9. Whyisthereaseparateprotocolfornon­contrastchestCTinevaluationofpectusexcavatum?Aroutinenon­contrastCTofthechestdoesnotincludetheentireribcage.Additionally,sincetheconcernisonlyabouttheosseousstructures,dosecanbereducedevenfarther.10. WhyisaroutinechestCTwithcontrastperformedratherthanaCTAwhenevaluatingpatientswithclinicalsuspicionofavascularring?Vascularringscaninvolvetheaorticarchorpulmonaryveins,sobothneedtobeopacifiedduringimageacquisition.PerformingaCTAwouldonlyopacifytheaortaandbranchvessels.Additionalscansmightberequiredtoevaluateforpulmonarysling,addingtothetotalradiationdose.11. Whyisa0.5xx:1pitchusedonthe13­18agegroup?ThisallowssufficientmArangewiththefastestrotationtime.The0.5xx:1pitchprovidesthebesthelicalimagequalityandalsoalowerdosethanthe0.9xx:1pitchatagivenimagequality.

Physics/TechnicalCommentsonScan&ReconstructionParameters1. IsthereareasonwhyDoseReductionGuidanceisnotusedintheprotocols?1. WhentheDoseReductionGuidanceisused,thereisalimitimposedontheminmAallowed,whichposesaproblemforourprotocols.2. DoseReductionGuidanceisnotavailableontheDiscoveryCT750HDscanner,andwewishedtobeconsistentintheprotocolsacrossGECTplatforms.3. OurradiologistshaveapprovedtheuseofacertainpercentASiRforthedifferentexamsanddonotwanttohaveitalteredbytheDoseReductionGuidance.2. WhydoyouuseSmartmAinsteadofAutomAorManualmA?TheUWprotocolsalwaysrelyontheSmartmAfunctionwhentheAutomAisturnedon.WedonotseeanysituationinwhichitwouldbeadvantageoustoturntheSmartmAfunctionoff.SmartmAincludesbothmAmodulationasthepatientattenuationchangesalongthelengthofthepatientandalsomAmodulationasthetuberotatesaroundthepatient.Thisisalwaysadvantageousandisessentialinareasoftheanatomywherethepatientsize/attenuationvariesdramaticallywithdirection,suchastheshouldersandpelvis.Itisevenusefulinscanningthehead,sincetheAPandlateraldimensionsoftheheadarenotthesame.3. WhyuseAuto/SmartmA?Exceptforscanningusingtheaxialmode,forallstandardscanninghelicalmodeisusedwithSmartmA.Thisincludestheprotocolsfortheorbit,sinus,facialbonesandtemporalbones.UsingSmartmAsimplygivesconsistentimagequalityatthelowestdoseandhasnotproducedanyimagequalityproblems.Also,nosituationhasbeenidentifiedinwhichitwouldbeadvantageoustoturntheSmartmAfunctionoffwhenusingAutomA.4. Whyisa0.5xx:1pitchusedformostoftheUWprotocols?UniversityofWisconsin­Madisonusesthe0.5xx:1pitchforseveralreasons:(1)itprovidesoptimizedhelicalreconstructions,comparedtohigherpitches;and(2)forthesameimagenoise,itproducesa20%lowerdosethandoesthe0.9pitch(whichiswhythatpitchisavoided).UniversityofWisconsin­Madisonuses0.4sor0.5srotationtimeswhenpossibletoreducescantimeswiththelowerpitch.Whenthatisnotsufficient,asinPEstudies,thepitchisincreasedto1.375.TheuseofalowerpitchispossiblewiththeGE64­slicescannersbecauseofthewiderbeamcollimationof40mmcomparedto20mm,whichdoublesthetablespeedforanyparticularpitchandrotationtime.ThisalsoallowsthescanningoflargerpatientswithouthittingmaxmAanddegradingimagequality.5. WhydoyouuseaHelicalScanTypeinsteadofAxialfornearlyallyourprotocols?TheuseofHelicalscanninghasseveraladvantagesoverAxial.Fasterareacoverage,withlesschanceofpatientmotionduringthescan,isanobviousadvantage.Helicalscanningdecreasestheeffectsofcone­beamartifactswithmulti­slicescanning.OnegreatadvantageofhelicalscanningistheabilitytoprescribeReconIntervalsatlessthantheslicethickness.Thebestz­resolution,alongwiththefullestdisplayoftheclinicalinformationobtainedinthescan,isobtainedatintervalsofone­halfoftheactualslicethickness.Inaddition,thesourceimagesthatareusedtocreateanyreformattedimagesmustbethinslices(1.25mmforsofttissueand0.625mmforbone)withreconintervalsofone­halftheslicethicknessforoptimalimagequality.Thisisanadvantageofhelicalscanningthatisoftennotutilized.6. WhydoyouconsistentlyuseaReconIntervalthatissmallerthantheslicethickness?Doesn’taReconIntervalequaltotheslicethicknessprovidealltheavailableclinicalinformation?TheUniversityofWisconsin­MadisonusesareconstructionIntervalthatishalfoftheactualslicethicknessbecauseusingaReconIntervalequaltotheslicethicknessdoesnotinfactprovidealltheavailableclinicalinformationfromthepatientscan.Bothmathematicsandclinicalexperienceshowthatthefulldisplayoftheclinicalinformationobtainedinthescanisobtained

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byusingintervalsofone­halfoftheactualslicethickness.YouDONOTwanttowasteanyinformationobtainedfromtheradiationexposureofapatient.7. WhydoyounotusethePediatricScanFieldofView(SFOV)foranyofyourpediatricprotocols?ThePediatricHeadandBodyprotocolssubstantiallylimitthemaximumallowedmAthatcanbeusedinmanualorAuto/SmartmAmodes.At140,120,100,and80kV,themaximummAislimitedto210,250,300,and375,respectively.Therationaleistolimitthedosetopediatricpatients.However,theactualresultistolimittheuseoffasterrotationtimesorhigherpitchesthatwillallowafasterexamwithlessmotionartifact.ThusweavoidtheuseofthepediatricSFOV’sforthisreason.WewouldprefertoobtainagivenpatientdoseandimagequalitywithahighermAandshorterrotationtime.8. Whyaresomeofmyboneimagestooblurry,especiallythoseoftheshoulders?Seesamequestionunder"MSKCTProtocols".9. Whydoyoutendtouseafastrotationtimewithalowpitch?Wouldnotapitchof0.9xx:1andarotationtimeof1.0sbeequivalenttoapitchof0.5xx:1andarotationtimeof0.5sec?Whileitistruethatapitchof0.9xx:1andarotationtimeof1.0swouldproduceanexamtimeessentiallyequaltoapitchof0.5xx:1andarotationtimeof0.5s,andwouldalsorequireaboutthesamemAvalues,itwouldNOTresultinthesameimagequality.The0.5xx:1pitchwillhavelesshelicalartifactthanthe0.9xx:1pitchandthe0.5srotationtimewillhavelessmotionartifactthanthe1.0srotationtime.Additionally,the0.5xx:1pitchisabout20%moredoseefficientintheGE64slicescannersthanthe0.9xx:1pitch.Forthesereasonsapitchof0.5xx:1andarotationtimeof0.5secismuchpreferabletoapitchof0.9xx:1andarotationtimeof1.0s.Withscannersthathavethisoption,weevenprefertousetheshortestrotationtimeof0.4swhenpossible.Forobesepatients,theuseofa0.5xx:1pitchallowsanappropriatetechniquetobeusedtoobtainasatisfactorilydiagnosticimage.Ifneeded,therotationtimecanbeincreasedupto1.0sforthesepatients.10. Whenisapitchhigherthan0.5xx:1usedandwhyisthe1.375pitchthengenerallyusedinsteadofapitchof0.9xx.1?UniversityofWisconsin­Madisonprincipallyusesthe0.5xx:1pitchforseveralreasons:(1)itprovidesoptimizedhelicalreconstructions,comparedtohigherpitches;and(2)forthesameimagenoise,itproducesa20%lowerdosethandoesthe0.9xx.1pitch(whichiswhythatpitchisavoided).UniversityofWisconsin­Madisonuses0.4sor0.5srotationtimeswhenpossibletoreducescantimeswiththelowerpitch.Whenthatisnotsufficient,asinPEstudiesandothersrequiringaveryshortexamtime,thepitchisincreasedto1.375.Thisisoftenpreferredtothe0.9xx:1pitchbecauseofbetterdoseefficiencyatthe1.375pitch.TheuseofalowerpitchispossiblewiththeGE64­slicescannersbecauseofthewiderbeamcollimationof40mmcomparedto20mm,whichdoublesthetablespeedforanyparticularpitchandrotationtime.ThisalsoallowsthescanningoflargerpatientswithouthittingmaxmAanddegradingimagequality.11. WhatisyourstrategyforselectionofkV?TheselectionofoptimalkVisdependentonthepatientsizeandtheimportanceofthevisualizationofiodinecontrastintheimages.Asanexample,forabdominalnon­contrastscansthekVwillvaryfrom80forthesmallpediatricpatientto140kVforaveryobesepatient.Ifthevisualizationofiodinecontrastisimportantintheimaging,suchasforangiography,thesamerangeofpatientsizewillhaveakVvariationof80to120kV.140kVisneveroptimalforvisualizingiodinecontrast,eveninthelargestpatients.12. Whydoyouconsistentlyusea“Plus”ReconOptionforHelicalScanninginsteadof“Full”?The“Plus”ReconOptionprovidesbetterimagequalitythan“Full”byreducingHelicalartifactsintheimages.Italsoreducesimagenoisebyabout10%byincreasingtheactualslicethicknessbyabout20%fromthenominalslicethickness.Ifaspecificnoiseindexisused,thenachangefrom“Full”to“Plus”willreducepatientdosebyabout20%.Thefollowingtableprovidesapproximatechangesinactualslicethicknessin”Plus”mode:

NormalSliceThickness ActualSliceThicknessusing"Plus"ReconOption OptimalReconInterval5.0mm 6.0mm 3.0mm3.75mm 4.5mm 2.25mm2.5mm 3.0mm 1.5mm1.25mm 1.5mm 0.625mm0.625mm 0.8mm 0.312mmThe20%increaseinslicethicknessgenerallyhaslittlenegativeclinicaleffectcomparedtotheadvantagesofusingthe“Plus”option.Infact,itispossibletoimprovez­resolutionevenwiththegreaterslicethicknessbyusingareconstructionintervalthatisone­halfoftheactualslicethickness,asshowninthetableabove.Thereconstructionintervalforthe1.25and0.625mmnominalslicethicknessremainsathalfofthenominalslicethickness.Thisallowstheuseof“IQEnhance”tofurtherimproveimagequalitybyreducinghelicalartifactsinthinslices.

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