Breast Imaging Protocol

PURPOSE

• Classify the nature of known breast masses distinguishing malignant from benign on the basis of contrast uptake rates.
• Identify other lesions of the breasts and chest wall

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RATIONALE

• Most MR breast techniques are quite sensitive (lesions can be detected) but are not very specific (can't discriminate between benign and malignant lesions).
• Specificity relies on observing the rate of early enhancement and the morphology of the enhanced lesion.
• The examination must provide serial T1 weighted images to display and plot the enhancement rates particularly in the first 3 minutes after injection.
• This protocol collects a pre-contrast axial scan, pre contrast coronal scan and a series of post contrast coronals, followed by a coronal fat suppressed series.  Both breasts are examined.

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COIL

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INJECTION EQUIPMENT

• 20 G Jelco
• 3 alcohol wipes
• Minimum Volume extension tube
• 1 x 10 ml. syringe (marked SALINE)
• 1 x 20 ml. syringe (marked CONTRAST)
• Tourniquet
• Tape to secure Jelco and extension tubing at puncture site.
• Y-type extension tube

CONTRAST DOSE

• 0.16 mmol/kg
• Volume = Weight (kg) divided by 3

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PREPARATION

Patient Preparation

• Stick a vitamin E capsule to any palpable breast masses
• Put in a 20 Gauge Jelco in a good Vein (preferably left arm) away from the elbow or wrist joint.
• Connect to a saline filled minimum volume tube.
• Cover the puncture site with the Tegaderm patch and secure a tension loop of tubing to the skin.
• Use ear plugs, Call button in right hand

Patient Positioning

• Position patient prone, head first into the scanner with arms by the side.   Head to one side and chest relaxed onto the breast coil.  Place a pillow under the ankles to keep feet off the pads.
• The breasts must be centrally placed in the coil recesses with minimal distortion.   Surround small breasts with soft padding (face washers) to minimise pendulous movement during breathing and scanning
• Keep the radiologist on-site through the exam and get them to read the instructions below so they understand the procedure

Instruction for Radiologist

• Don't do this task if you are pregnant
• Work from the left side of the scanner (away from the wires)
• Don't bump or lean on the scan table
• Test the line with saline; connect the contrast syringe, tap open to contrast syringe, full saline syringe ready to flush.
• Inject when the radiographer tells you, at the start of the second 3DFLASH sequence.
• Contrast must be injected rapidly (> 1ml./sec) and followed with a saline flush of 5 - 10 mls.
• This protocol runs the sequence 7 times.
• The first time is the pre-contrast images.
• There is a 10-second pause before the second run.
• The Radiographer will remind you to get ready to inject the contrast as soon as the second run starts
• Stay in the scan room until the end of the 7 scans (about 9 minutes after injection)

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SEQUENCES

Coil: Breast coil or CP Breast Array
Group: Dynamic
Protocols:
 

• Scout
• CORONAL_3D-FLASH_Contrast_run_14297
•  Water_Excitation_MP-RAGE

SCOUT

• MAP-Shim using the body coil, check centre frequency, switch back to Breast coil.
• Give axial, sagittal and coronal images

• Position from the scout images.
• Perform a MAP-Shim manually using the body coil assure that the X,Y,Z gradients reach shim convergence, and check the Centre Frequency.  See "Getting Better Fat Suppression Shimming and Centre Frequency Checks"
• Switch back to the breast coil
• Have Radiologist in the scan room, and ready to inject contrast, and understand the procedure. 
  (They should have read section, Instructions to Radiologists)
• LOAD the sequence
• This protocol runs the sequence 7 times.  The first time is the pre-contrast images.   There is a 10-second pause before the second run.   Tell the Radiologist to get ready to inject the contrast as soon as the second run starts.
• Start the sequence, during the 10-second pause remind the Radiologist and call the injection as the second scan starts.

• Use history to position as per the coronal 3DFLASH runs

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IMAGE HANDLING

SUBTRACTIONS

Use Evaluate Dynamic Analysis to subtract the precontrast coronal study form the 1st, 2nd, and last post contrast coronal studies.  The post contrast images are selected as the first operand and the pre-contrast images should be selected as the second operand.  It is easiest to use Select function.  Set operation to Subtract  Enter an appropriate Study name (eg. 90 sec post contrast sub) before pressing Go.

FINDING THE LESIONS

• Remember there may be lesions in the opposite breast.   Information collected from the patient before the scan can also help to locate suspicious areas.
• Use the MPR programme to review the images from each of the 3 subtraction series.   Do the same with the WE-MP-RAGE series.   Note the slice locations of all enhancing lesions for later filming and analysis.
• To verify that a region is enhancing, use the List platform under Exposure Interactive to quickly step through time with the unsubtracted images at the location of interest.

ENHANCEMENT CURVES

Put a contrasted image that best shows the lesion in segment 1.  Select Evaluate Mean/Curve  Type in the slice numbers of the slices for the pre and post contrast images at the location you are evaluating.  Select parameters as shown in the adjacent window.  Click on Draw  Click and drag the circle tool over the lesion.  Click Select and click on the circle. Adjust circle size to only include enhanced lesion.  Copy the circle and drag the second circle to a region of non-enhanced breast tissue (not fat)  Click GO  The time curve will appear in segment 2  Move the vertical sampling line to the second data point  Click Copy Segment for the graph and the image with ROIs and note the image number

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  FILMING

• Produce a single sheet of film for enhancing lesion, using the 12 format.
• Image the coronal images, labelling the time post contrast ie.
• Pre Contrast
• 30 Sec post contrast
• 90 sec post contrast
• 2.5 minutes post contrast
• 3.5 minutes post contrast
• 4.5 minutes post contrast
• 5.5 minutes post contrast
• Film the subtracted images from the 3 studies for the slice location.
• Produce the enhancement curves and film the image showing the ROI and the graph.

Full Sequence Listings

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