QS4-86716v1 Copyright 2012 by Hitachi Medical Systems America, Inc. All rights reserved. 9-1 There are two versions of the Oasis RAPID Breast coil: • Oasis 7-Channel RAPID Breast Coil with spacers • Oasis 8-Channel RAPID Breast Coil without spacers This chapter describes the breast imaging process with both versions of the coil. Follow the appropriate procedure according to your coil version. Oasis 7-Channel RAPID Breast Coil with spacers Oasis 8-Channel RAPID Breast Coil without spacers Chapter 9-1 Coil and Patient Positioning For detailed safety information, refer to Chapter 1, Safety, in the Oasis Reference manual. Caution Do not allow contact between the patient and the Breast Coil cable. Use towels or pads to prevent direct contact. Failure to comply could result in thermal injury. Caution Do not allow any RF receiver coil cables or gating leads to form loops when imaging patients. Failure to comply could result in thermal injury.
Transcript
QS4-86716v1 Copyright 2012 by Hitachi Medical Systems America, Inc. All rights reserved.
9-1
There are two versions of the Oasis RAPID Breast coil:
• Oasis 7-Channel RAPID Breast Coil with spacers
• Oasis 8-Channel RAPID Breast Coil without spacers
This chapter describes the breast imaging process with both versions of the coil. Follow the appropriate procedure according to your coil version.
Oasis 7-ChannelRAPID Breast Coilwith spacers
Oasis 8-Channel RAPID Breast Coil
without spacers
Chapter 9-1 Coil and Patient Positioning
For detailed safety information, refer to Chapter 1, Safety, in the Oasis Reference manual.
CautionDo not allow contact between the patient and the Breast Coil cable. Use towels or pads to prevent direct contact. Failure to comply could result in thermal injury.
CautionDo not allow any RF receiver coil cables or gating leads to form loops when imaging patients. Failure to comply could result in thermal injury.
QS4-86716v1 Copyright 2012 by Hitachi Medical Systems America, Inc. All rights reserved.
9-2
Oasis 7-Channel RAPID Breast Coil with spacers
The following items are included with the Oasis 7-Channel RAPID Breast Coil with spacers:
A. Head restB. 7-Channel breast coilC. Torso transition pieceD. Blue head rest padE. Blue breast coil positioning padF. Blue torso transition piece
positioning padG. Breast coil spacerH. Torso transition piece spacerI. Breast coil cup plugJ. Blue breast coil trough padK. Velcro straps (2)L. Black fat-saturation pad (single
Biopsy grids are single use and must be ordered separately to perform breast biopsies. Additional biopsy grids can be ordered from HMSA sales administration.Grid design Pillar-post design
MMMMMMMMMMMMMMMMMMMMLL
L
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Depending on the patient’s size, you will select from one of the following three positioning scenarios:
Plan APlace the Breast coil spacer (G) and Torso transition piece spacer (H) directly on the patient table between the red arrows and the head of the patient table.
Place the RAPID Breast coil (B) on top of its spacer.
Place the torso transition piece (C) on top of its spacer. Make sure the guide on the torso transition piece (C) fi ts into the slot in the base of the RAPID Breast coil (B).
Note: Using the Breast coil spacers is always recommended for optimal image quality, unless the patient’s size prohibits their use. If the patient’s back DOES NOT clear the gantry, proceed to Plan B.
Breast coil spacer (G)
Torso transition piece spacer (H)
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Spacers
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Chapter 9-1 Coil and Patient Positioning
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Place the head rest (A) on the patient table close to the top of the RAPID Breast coil.
Place the black, fat-saturation pad (L) on the sternum portion of the coil, under the blue positioning pad (E).
Place the patient on the coil in the head-fi rst, prone position.
Center the patient’s sternum on the bridge that separates the two halves of the coil. The patient’s breasts must be positioned within each open cavity, with the central part of each breast (in the head-to-foot direction) centered on the transaxial positioning mark on the coil.
Adjust the head rest to support the patient’s head.
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5Fat saturation pad (L)
Chapter 9-1 Coil and Patient Positioning
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Plan BIf the patient’s back is touching the gantry, remove the torso transition piece (C) and spacer (H). Place pillows or stack blankets under the patient’s abdomen for comfort. This allows the breast coil (B) to remain on the spacer (G) for optimal image quality. If the patient’s back STILL DOES NOT clear the gantry, proceed to Plan C.
Plan CIf the patient’s back is still touching the top of the gantry, remove the spacers (G) and (H) and place the torso transition piece (C) directly on the table without the spacers. The torso transition piece can also be removed, and in its place, stack pillows or blankets to position the patient comfortably. This allows the patient’s back to clear the top of the gantry.
Plan COasis 7-ChannelRAPID Breast Coil and torso transition piece placed directly on patient table.
Chapter 9-1 Coil and Patient Positioning
Plan BOasis 7-ChannelRAPID Breast Coil without the torso transition piece or torso transition piece spacer.
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Tips for patient positioning:
1. For routine breast imaging, remove the immobilization plates (M) and biopsy mechanism arms (N) from the coil. Then insert the blue breast-coil trough pad (J). This helps lift larger breasts away from the bottom of the coil and maintains isocenter positioning as much as possible for large breasted patients.
2. For patients whose breasts do not touch the bottom of the coil, the biopsy mechanism arms (N) holding the immobilization plates (M) can be applied and adjusted to gently hold the breasts in place, but DO NOT compress the breast tissue. Use these only when the patient’s breasts do not contact the bottom of the coil. Check with your radiologist to see if the immobilization plates are wanted for suppression.
3. For breast biopsy procedures, always use the biopsy mechanism arms and appropriate biopsy grids.
Chapter 9-1 Coil and Patient Positioning
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9-7
Oasis 8-Channel RAPID Breast Coil without spacers
The following items are included with the Oasis 8-Channel RAPID Breast Coil without spacers:
A. Head restB. 8-Channel breast coilC. Torso transition pieceD. Blue head rest padE. Blue breast coil positioning padF. Blue torso transition piece
positioning padG. Breast coil cup plugH. Velcro straps (2)I. Black fat-saturation pad (single
Biopsy grids are single use and must be ordered separately to perform breast biopsies. Additional biopsy grids can be ordered from HMSA sales administration.
JJJJJJJJJJJJJII
I
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Depending on the patient’s size, you will select from one of the following three positioning scenarios:
Plan APlace the RAPID Breast coil (B) directly on the patient table between the red arrows and the head of the patient table.
Place the torso transition piece (C) on the patient table. Make sure the guide on the torso transition piece (C) fi ts into the slot in the base of the RAPID Breast coil (B).
Place the head rest (A) on the patient table close to the top of the RAPID Breast coil.
Place the black, fat-saturation pad (I) on the sternum portion of the coil, under the blue positioning pad (E).
Chapter 9-1 Coil and Patient Positioning
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Place the patient on the coil in the head-fi rst, prone position.
Center the patient’s sternum on the bridge that separates the two halves of the coil. The patient’s breasts must be positioned within each open cavity, with the central part of each breast (in the head-to-foot direction) centered on the transaxial positioning mark on the coil.
Adjust the head rest to support the patient’s head.
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Chapter 9-1 Coil and Patient Positioning
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Plan BIf the patient’s back is touching the gantry, remove the torso transition piece (C). Place pillows or stack blankets under the patient’s abdomen for comfort.
Tips for patient positioning:
The biopsy mechanism arms (K) holding the solid immobilization plates (J) can be applied and adjusted to gently hold the breasts in place, but DO NOT compress the breast tissue.
Check with your radiologist to see if the solid immobilization plates are wanted for gentle suppression
Chapter 9-1 Coil and Patient Positioning
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Connect the coil cable to the patient table connector.
On the gantry control panel, press and hold the SET button to move the patient table into the magnet isocenter. The longitudinal move counter displays zero and the patient table stops moving when the imaging region is in the center of the magnetic fi eld.
Load your site’s breast protocol. If your site does not have one, select the breast protocol from the system library.
In the Protocol Properties area, click the Scanogram SCA / S-Map scan task.
Click .
Chapter 9-2 Breast Imaging
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In the Protocol Properties area, click the Shim task. Load the Scanogram SCA images. To achieve optimal Shim results, perform an Axial Shim ONLY for all breast studies.
Adjust the number of Shim slices per patient so that only the bulk of the breast tissue is covered. Too many slices may result in poor fat saturation.
Chapter 9-2 Breast Imaging
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Set the presat at the most posterior portion of the FOV box. It is used to null signal from the two bright spots you may see on the posterior chest wall. The bright spots are caused by the proximity of the chest wall to the transmitter located behind the top gantry cover. DO NOT move the presat.
You may not see two bright spots on the posterior chest wall for every single patient. Even if you do not see the bright spots, DO NOT move the presat.
DO NOT adjust the size of the Presat. It is optimized at 40mm thick.
Click .
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Chapter 9-2 Breast Imaging
Spots of signal intensity on posterior chest wall
Presat is 40mm thick
nnal intensity nal in
Pr
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10 To perform axial breast imaging, select an axial scan task. Adjust the position and number of slices to cover the entire breast.
When performing axial breast FatSat imaging, adjust the Regional Shim box (purple box) to cover both breasts.
Average to large-breasted patients Set up the Regional Shim box to include the breast tissue up to the anterior chest wall.
Small-breasted patients Set up the Regional Shim box to include the breast tissue and the anterior third of the chest so that the system sees Shim data from a large-enough portion of anatomy.
NOTE: Sagittal TIGRE breast system scan tasks are saved with Shim Mode set to Volume to achieve optimal, more consistent fat suppression.
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Chapter 9-2 Breast Imaging
Regional Shim set-up for axial imaging, large breast
Regional Shim set-up for sagittal imaging, large breast
Regional Shim set-up for axial imaging, small breast Regional Shim set-up for breast implants
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When performing fat suppression sequences on patients whose breasts touch the bottom of the coil, try using Volume Shim rather than Regional Shim if the anterior breast tissue does not fully suppress.
Click .
To perform sagittal breast imaging, select a sagittal scan task. Adjust the position and number of slices to cover the entire breast.
When performing sagittal breast FatSat imaging, adjust the Regional Shim box (purple box) to cover only the breast of interest.
NOTE: Sagittal TIGRE breast scan tasks are saved with Shim Mode set to Volume to achieve optimal, more consistent fat suppression.
Click .
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Chapter 9-2 Breast Imaging
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Chapter 9-2 Breast ImagingNavigating the Frequency Graph
Pay close attention to the Frequency Graph every time it is displayed. Sometimes the center frequency line is shifted to center on fat instead of water. In such cases, you must move the blue line over so that it is centered correctly on water before clicking Continue.
This is due to breast tissue composition. Patients with fattier breast tissue may not have much of a water peak, and the system sometimes centers on the more dominant peak (fat, silicone, or water).
NOTE: When performing breast imaging, always keep in mind what types of tissue the patient has as you look at the Frequency Graph.
Frequency graph before adjustment Frequency graph after adjustment
Examples of breast imaging frequency graphs
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Some radiologists prefer light silicone suppression while others prefer heavy suppression. Determine what the radiologist’s preference is, and save their protocols with the appropriate TI times.
Recommended TI Times: 400 TI = Light suppression 550 TI = Medium suppression 650 TI = Heavy suppression
The silicone suppression system scan tasks are saved with the TI set to 650ms.
Axial silicone suppression image acquired with TI = 400 demonstrates light silicone
suppression
Axial silicone suppression image acquired with TI = 650 demonstrates heavy silicone
suppression
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Chapter 9-3 Silicone ImplantsSilicone Only Protocol
Silicone Only system scan tasks are set up the way you see here.
The FatSat pulse is used to null the signal from water.
The inversion pulse and associated TI time (130ms) is used to null the signal from fat, NOT silicone.
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Chapter 9-3 Silicone ImplantsSilicone Only Imaging – Navigating the Frequency Graph
Silicone only imaging is used when we want to see the implant ONLY. Signal from fat and water are nulled, while silicone remains bright.
Silicone precesses at a frequency very-close-to but slightly-less-than fat. Therefore on a Frequency Graph, the peaks would be arranged from left to right as silicone → fat → water.
NOTE: Depending on implant size and the amount of breast tissue surrounding the implant, you may not always see 3 peaks. You may only see 2 peaks (one tall/wide silicone/fat peak and a smaller water peak). In every case, center the blue line over water. Always keep in mind the composition of the breast tissue you are imaging.
Silicone peak
Fat peakWater peakpe
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Chapter 9-3 Silicone ImplantsWhen the Frequency Graph is displayed and you have centered the Center Frequency (blue) line over water, you must type in an offset frequency of +260 and press ENTER. This will ensure that you have optimal water suppression while the fat and silicone signal are unaffected.
Frequency graph display after centering the blue line over water and entering 260 in the Offset Frequency [Hz] box.
NOTE: At times you will have to move the blue line over to the right a signifi cant amount. When you type 260 in the Offset Frequency [Hz] box and press ENTER, a value smaller than 260 may be displayed in the Offset Frequency [Hz] box. This is because the green line is shifted as far to the right on the graph as it can possibly go. When this occurs, don’t panic. Just click the CONTINUE button.
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Chapter 9-3 Silicone ImplantsSilicone Only Imaging – Image Examples
Remember:
The FatSat pulse is used to null the signal from water.
The inversion pulse and associated TI time (130ms) is used to null the signal from fat, NOT silicone.
Sagittal silicone only image examples
Axial silicone only image examples
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Chapter 9-3 Silicone Implants
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Saline suppression scans are FIR sequences with the TI set to null the signal from saline while fat signal remains bright.
The TR and TI are optimized according to the number of slices. Therefore, there are system scan tasks saved for specifi c slice ranges.
The TR and TI are directly related. Therefore, do not change the TR or TI on these scan tasks. If you do, you may not have optimal saline suppression.
Saline suppression scan tasks - system scan task library
Axial saline suppression image example
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Chapter 9-4 Saline Implants
Silicone/Saline Combo Implants
For patients who have implants that are composed of both saline and silicone, we recommend performing both the saline suppression and silicone suppression sequences.
Remember to manipulate the Frequency Graph when needed.
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Chapter 9-5 SubtractionBreast Subtraction
When performing manual breast subtraction, make sure that Subtraction is selected from the Operation list and Slice Position is selected from the Pairing Condition list in the AddSub Parameter area.
Move the Translucency slider to +8 to reduce background noise. This makes the subtraction images appear less noisy.
NOTE: Refer to chapter 5 of this manual for complete subtraction details.
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