Scientific Session 28Imaging with CT and MR

Utility of 16 Detector CT Angiography for PreoperativeEvaluation of Laparoscopic Renal Donors.S. Pojchamarnwiputh, UCLA, Los Angeles, CA, USA'S.S.Raman 'K Muangsomboon 'P.G Schulam oR.A. Gritsch'D.S.KLu

CONCLUSION: Chronic pelvic pain with PCS is a significanthealth problem, which affects parous and nulliparous patients.PCS is under-diagnosed in imaging and laparoscopic studies.Bilateral ovarian and internal iliac vein transcatheterembolizations provide statistically significant improvementin pain related to PCS in long-term without significant changein ovarian functions.

PURPOSE: To determine efficacy of 16 detector CTangiography (MDCTA) in preoperative evaluation of vascularanatomy of laparoscopic renal donors.

MATERIALS AND METHODS: Thirty consecutive kidneydonors (13 men, 17 women, mean age, 40.8 years) underwent16 channel MDCTA and nephrectomy. For all cases, imageswere acquired in the arterial and nephrographic phases.Volumetric 0.75 mrn collimation images were acquired with60% overlap and 0.6 mrn reconstruction in both phases. Ona 3D workstation, MDCTA images were evaluatedretrospectively by two independent abdominal imagers blindedto surgical results. Reviewers assessed the number andbranching pattern of renal arteries and veins, and evaluatedany other renal vascular anomalies. These results werecompared to findings at surgery.

RESULTS: Twenty-nine subjects underwent left laparoscopicnephrectomy and one underwent right nephrectomy. For bothreviewers, the sensitivity of MDCTA for all vessels> 0.5 mrnwas 100 % for both renal arteries (36/36) and veins (33/33).Both reviewers achieved 100% sensitivity (6/6) and specificity(24/24) for detection of supernumerary arteries, and 100%sensitivity (3/3) and specificity (27/27) for detection ofsupernumerary veins. Both reviewers missed one accessoryrenal artery « 0.5 mm), which was transected during surgerywithout complication. Both reviewers achieved 100%sensitivity (7n) in detecting early arterial bifurcation « 2 cmfrom aorta) and 75% sensitivity (3/4) in detection of latevenous confluence « I cm from aorta) confirmed at surgery.Both reviewers identified 100% (4/4) of major renal venousanomalies, (1 duplicated IVC, 2 circumaortic and I retroaorticleft renal vein), confirmed at surgery. Of 6 minor renal veinvariants including large draining gonadal or lumbar veins, andabnormal drainage of accessory renal venous branches, reviewerI detected 67% (4/6) and reviewer 2 detected 83% (5/6).Agreement between both reviewers evaluation of MDCTAand surgical findings was excellent for number of renal arteries,veins and major venous anomalies (kappa =1).

CONCLUSION: 16 channel MDCTA provides excellentpreoperative vascular anatomic information for laparoscopicrenal donor nephrectomy.

ExtrahepaticLocalizationAccuracy (%)SQ

00

Abstract No. 162

Abstract No,161

Hepatic LobarLocalizationAccuracy ('!o)nn

Speciticity forDelivery (%)

Real-Time MRI Monitoring of Transcatheter HepaticArtery Contrast Agent Delivery in Rabbits.KT. Sato, Northwestern University, Chicago, IL, USA'T.KRhee'A.C. Larson-A.A. Nemcek'R. Salem·R.A. Omary. eta!'

PURPOSE: The advent of hybrid systems combining x-rayDSA units with MRI scanners offers the potential to monitortranscatheter arterial drug delivery using MRI. In the future,these drugs will be tagged with contrast agents. However,demonstration that catheter-based delivery of contrast agentcan be monitored in real-time is first required. We tested thehypothesis that transcatheter hepatic artery delivery of dilutegadolinium (Gd) in rabbits can be monitored in real-time usingMRI.

CONCLUSION: In rabbits, MRI accurately monitorstranscatheter hepatic artery delivery of contrast agent in real­time. Localization accuracy is greater outside the liver thanwithin the liver. These results can be used as a baseline referencefor comparing the accuracy of delivery of Gd-tagged therapiesin the future.

Vascular MR Elastography,D.A. Woodrum, Mayo Clinic, Rochester, MN, USA .u.H.Pandya 'A. Lerman-RL Ehman

PURPOSE: Magnetic resonance elastography (MRE) is anew technique to image tissue motion in the order of hundredsof nanometers enabling the imaging of the physical propertiesof tissue such as stress and strain. Our hypothesis is thatMRE can be used to image early hypertensive changes enablingtargeted therapy and prevention of secondary cardiovasculardisease. The purpose of this study is to demonstrate thatMRE can be applied to blood vessels and can identify earlyhypertensive changes.

MATERIALS AND METHODS: Using a thin-walled latexvessel model, harmonic mechanical pressure waves wereapplied at frequencies of 100-500 Hz, and imaged using amodified phase contrast MR technique sensitive to cyclicmotion. Changing the static pressure and wall thickness varied

MATERIALS AND METHODS: We inserted 2-F cathetersinto the hepatic arteries of 6 New Zealand White rabbits usingx-ray guidance and femoral access. After transfer to a SiemensSonata 1.5 T MRI scanner, we performed 26 separate hepaticartery injections of 2 mL of 4% Gd and 14 sham injectionswithout Gd. Real-time axial or coronal imaging of all injectionswas acquired using 2D projection inversion recovery-GRE(slice thickness = 20-30 mrn; 1.7 images/sec). Movies (-8 secduration) of these 40 injections, as well as 10 random repeats,were independently reviewed in a randomized, blinded fashionby 2 CAQ-certified interventional radiologists. Observersreported I) if Gd injection occurred; and 2) if so, location ofdelivery. For each observer, we compared sensitivity/specificity for injection and accuracy of localization. Inter­and intra-observer variability was assessed using the kappastatistic. X-ray DSA was the gold standard for all MRI studies.

RESULTS: Table shows outcome measures. Inter-observeragreement for delivery was outstanding (kappa=0.89 ±0.15;95% confidence interval, 0.73-1.0). Intra-observer agreementfor each observer was perfect (kappa=1.0).

Observer OutcomesObserver Sensitivity for

Delivery ('!o)

1 1002 100

1:42PM

1:54PM

Abstract No. 160

Monday, April 4, 20051:30 PM - 3:00 PMModerator(s): Reed A. Omary, MD

Gillez Soulez, MD

1:30PM

S58

CONCLUSION: The results indicate that this technique is asensitive method for evaluating vessel wall mechanicalproperties. Furthermore, the technique can be applied to exvivo aorta vessels and can detect early intramural hypertensivechanges that alter the elastic properties of blood vessel wallsbefore significant changes in wall thickness.

wall properties and tension. Further experiments wereperformed using ex vivo excised aortic segments ofhypertensive and normal pigs.

RESULTS: The experimental results demonstrated thatpropagating mechanical waves with amplitudes as small as Imicron in the model vessel wall can be readily visualized. Themeasured wavelength varied with changing wall thickness andtension in agreement with our mathematical model. In the exvivo aorta segments, the Young's mod.ulus-wall thicknessproduct was greater in the hypertensive vessels (54.1 ± 2.8kPa-cm) compared to normals (43.2 ± 1.5 kPa-cm). However,the histologic analysis demonstrated DO significant differencebetween the intima-media wall thickness in the control (0.049± 0.012 em) or hypertensive (0.054 ± 0.031 em) aortas atthree months.

Peripheral MRA: Comparison of Integrated ParallelAcquisition Technique (iPAT) with ConventionalMultistation MRA.L.L. Yao, University ofVirginia Health System, CharLottesville,VA, USA 'K.D. HagspieL ·E.A. Bissonette ·B. BurkhoLder·D.A.Leung ·l.F AngLe

PURPOSE: To assess the impact of iPAT on SNR, CNR,venous contamination and overall image interpretability forperipheral MRA using a dedicated phased array coil system.

MATERIALS AND METHODS: Conventional (CMRA) andiPAT peripheral MRA with three stations (pelvis, thigh, calf)was performed in 38 consecutive patients on a 1.5 T high­performance cardiovascular system (19 CMRA, 19 iPATMRA with iPAT factor 2). A total of 29 vessel segments perpatient were analyzed. For each segment, arterial, muscle andbackground signal were measured, SNR and CNR calculated,and repeated measures ANOVA was performed. For each ofthe three stations, the degree of venous contamination and theoverall confidence of interpretability were analyzed usingordinal logistic regression analysis accounting for correlatedoutcome data.

2:06PM Abstract No. 163

2:18PM Abstract No. 164

RESULTS: On the left side, early branching of renal arteries« 2 em of aorta) was present in 21 % (231111) andsupernumerary arteries were identified in 18% (20/111).

Surgically Relevant Renal Anatomy in PotentialLaparoscopic Renal Donors: Evaluation with 16 ChannelMDCT.S. Pojchamarnwiputh, UCLA, Los AngeLes, CA, USA'S.S.Raman·K. Muangsomboon 'P.G SchuLam 'H.A. Gritsch ·D.S.KLu

CONCLUSION: iPAT MRA leads to reduced SNR and CNRin the pelvis and thigh, but this does not affect interpretabilityof these stations. The temporal gain results in significantlyincreased interpretability due to less venous contamination inthe calf station. iPAT MRA is superior to CMRA forperipheral MRA.

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Abstract No. 1652:30PM

PURPOSE: To quantify and describe laparoscopically relevantrenal anatomy in renal donors with preoperative 16-channelMDCT angiography & urography.

MATERIALS AND METHODS: III consecutive potentialrenal donors underwent 16-channel MDCT preoperatively.Images were acquired on unenhanced, arterial, nephrographicand excretory phases using 0.75 mm collimation with 60%overlap and 0.6 rom reconstruction. On a 3D workstation,MDCTA and CTU images were evaluated retrospectively inconsensus by three abdominal imagers. As requested by thelaparoscopic surgical team, the number and branching patternof renal arteries and veins, relationship to gonadal and lumbarveins and other abnormalities were evaluated.

RESULTS: 1018 vessel segments were available for analysis(477 CMRA, 541 iPAT MRA). Compared to CMRA, iPATMRA resulted in decreased SNR and CNR in the pelvis andthigh station but no change in the calf station. The differencein the pelvis was statistically significant (p<O.OOI). Venouscontamination of the calf station was significantly less oniPAT MRA (p<0.OO3) with no significant differences in theother stations. The overall confidence of interpretability withiPAT MRA was significantly better on the lower station(p<0.009) with no difference detected for the upper twostations.

Evaluating Upper Extremity Arterial Disease withMultidetector-Row CT Angiography: Experience in 40Examinations.l. C. Hellinger, Stanford University MedicaL Center, Stanford,CA, USA .£.£. Williamson ·D. FLeischmann ·GD. Rubin

PURPOSE: To assess the utility of multidetector-row CTangiography (MDCTA) for evaluation of patients withsuspected or known upper extremity (UE) arterial disease.

MATERIALS AND METHODS: 40 UEs were examined withMDCTA. Indications included claudication (N=10), acuteischemia (N=10), suspected thoracic outlet syndrome (N=8),vasculitis (N=9), rest pain (N=2), and a nonhealing ulcer (N=I).Studies were acquired on either 4- (N=5), 8- (N=4), or 16­(N=31) channel systems. Scan parameters included thefollowing: 0.938-1.75 pitch, 0.5-2.0 rom slice thickness, and0.5-1.25 mm reconstruction interval. 100-150 cc of nonioniccontrast medium was delivered at 3-5 cc/sec. VR, MIP, andCPR images were generated to assess for stenosis, occlusion,dissection, wall thickening, and / or aneurysms. The successof clinical management based upon MDCTA interpretationswas assessed by clinical follow-up of at least 6 months (mean25 months). When available, MDCTA findings were correlatedwith those of conventional angiography (N=2) or surgery(N=12).

RESULTS: All studies were technically adequate. 22.5% werenormal. Vascular findings included vasculitis (25%), occlusion(22.5%), stenosis (12.5%), dissection (7.5%), aneurysm (5%),and congenital hypoplasia (2.5%). In I exam (2.5%), MDCTArevealed a ganglion cyst to be an alternative and correct diagnosisfor exertional wrist pain. Management was determined byMDCTA findings in 82.5% - observation (22.5%), medical(25%), endovascular (5%), or surgical (30%). In the remaining17.5%, continued medical management was supported. In the14 UEs managed with surgical or endovascular therapy,MDCTA findings were confirmed and there were no immediateor delayed procedural complications. For the 26 UEs managedwith observation or medical therapy, no endovascular orsurgical therapies were later required.

CONCLUSION: MDCTA is a robust modality for evaluationof UE arterial disease. Reliable vascular and nonvasculardiagnoses can be provided for management decision making.

Coronary Calcium Scoring with EBCT and MDCT:Comparing Interscan Variation Using Two ScoringAlgorithms.A.s. Bracha, University of Hawaii John A. Burns School ofMedicine: Honolulu. HI, USA 'H.e. Yoon

PURPOSE: Sub-second MDCT scahners are increasingly beingused for coronary calcium scoring in lieu of EBCT scanners.Early data suggest that the two scanners yield comparableresults, but there is limited information on the precision andaccuracy of MDCT for coronary calcium quantitation.

MATERIALS AND METHODS: To determine whether thetwo modalities provide statistically similar results, wecompared absolute calcium score and interscanscore variationin 952 subjects who underwent two consecutive EBCT orMDCT s.cans. We also compared calcium volume score withAgatston calcium score in the MDCT group to assess whethervolume scoring reduces interscan variation with MDCT as itdoes with EBCT

RESULTS: The EBCT and MDCT groups were statisticallysimilar withrespect to age (p~O.08) and sex (p=O.2/). Therewas a significant difference between the two groups withregard to mean absolute calcium score, mean absolute interscanvariation, and mean percentage interscan variation. The EBCTgroup had a lower mean absolute calcium score (207 vs. 259,p<O.Ol) and lower mean absolute (30.3 vs. 48.0,p<O.Ol) andmean percentage (31.3% vs. 37.0%, p<O.Ol) interscan variationthan the MOCT group. The difference in mean absolute calciumscore was primarily attributed to the reduced partial volumeeffect in MDCT scans. The difference in mean absolute andpercentage interscan variation was primarily attributed to thelower temporal resolution and increased cardiac motion inMDCT scans. For the MDCT group, use of the calcium scoreyielded substantially greater interscan variation than thevolume score. There was a significant difference in meanabsolute score (259 vs. 103, p<O.Ol), mean absolute interscanvariation (48.0 vs. 19.4, p<O.Ol), and mean percentageinterscan variation (37.0% vs. 31.0%, p<O.OI). These findingsagree with those found in EBCT trials.

CONCLUSION: There appears to be a real difference in themean MDCT score and EBCT score in asymptomatic subjectsevaluated for coronary calcium. Thus, it may be inappropriateto use published reference ranges for EBCT scores when risk­stratifying subjects imaged with MDCT. Calcium volumedemonsu'ates less interscan variability than score for bothEBCT and MDCT data.

Venous anomalies were detected in 68% (75/111). Major renalvein anomalies (i.e. duplicated rvc or accessory veins draininginto IVC) were identified in Lj % (12/111), most commonly acircumaortic vein 7%. Minor renal venous anomalies weredetected in 57% (63/111) including> 5mm gonadal or lumbarvein draining to main renal vein 42% (47/111) or branch renalveins 13% (14/111), late confluence of veins « 1 cm of aorta)15% (17/111). Rare variants were found including prominentmultiple draining gonadal veins, communicating renal vein withhemiazygos or splenic veins. On the right side, early branchingof renal arteries was present in 15% (17/111) andsupernumerary arteries were present 23% (25/111). Venousanomalies were detected in 28% (31/111) most commonlysupernumerary vein in 24% (27/111), late confluence 9% (101111), and draining gonadal vein 3% (3/111). Parenchymalabnormalities were identified in 30% of kidneys, mostcommonly cysts or indeterminate subcentimeter low-densitylesions. Calyceal calcifications were found in 7 kidneys. Otherabnormalities were 3 focal infarcts, 3 cortical scars, and 1atrophic, scarred kidney. Urothelial variants included 1 caseof bilateral simple ureteroceles.

CONCLUSION: 16-channel MDCTA and CTU help provideexcellent preoperative laparoscopically relevant assessmentof the kidneys in renal donors.

2:42PMFEATUREDABSTRACT

Commentator: J. Bayne Selby. MD

Abstract No. 166

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