Sat 31st Aug 2013 Session 2 / Talk 3 11:06 – 11:25 BROOKLYN 3 MRI USER GROUP Sue MAYNE ABSTRACT This is an overview of MR guided Breast Biopsies and the technique utilised at St Georges MRI, Christchurch Radiology Group (CRG). MRI of the breast has improved the ability to detect breast lesions that have previously been occult on mammography and ultrasound. This is due to MRI’s higher sensitivity and increasingly specificity in the last 2 decades. However as MRI of the breast utilizes more resources, Radiologists time, is a more expensive imaging option and more invasive to the patient it will never completely surpass mammography, as the preferred modality. That said there are patients for whom a MRI scan is appropriate. These include high risk young patients, where an equivocal lesion has been found using other modalities and previous scarring due to treatment and surgery. Therefore there is the need to be able to biopsy these previously occult lesions using MRI. CRG have been providing MRI Guided Biopsies since mid 2008 and the demand is increasing. Over 5 years CRG have performed in excess of 60 procedures with 17 of these being in 2013 year to date (August 2013). Breast Biopsy under MRI Guidance at St Georges Radiology Sue Mayne MRI of the Breast MRI has become increasingly utilized diagnostic tool for imaging of the breast and in certain instances invaluable. Mammography will always be the tool of choice for breast screening. Due to MRI’s increasing ability to demonstrate occult lesions, there has become the need for MRI Guided Biopsies. Indications for MRI of the Breast Screening of high risk women, eg BRACA. Pre operative screening. Equivocal lesion on other modality. Previous scarring due to treatment. Positive axillary node found but no breast cancer evident. Monitoring or prior to treatment –chemo or radiotherapy. Breast implants ? Leakage ?Cancer Advantages of Breast MRI Better sensitivity than mammography. Increased specificity. Minimal compression required. Excellent soft tissue contrast. Non ionising Radiation. Performance unaffected by breast density. Multiplanar acquisition. Disadvantages of Breast MRI Cost. Availability. Time involved, Client 30 min appointment vs. 15 min mammo Radiologist 100’s images vs. 4-8 mammographs Some low grade DCIS maybe occult on MRI but visible micro calcifications on mammograms. Requires an IV injection of gadolinium. MR contra indications eg pacemaker or severe claustrophobia. MRI Breast biopsy’s Biopsy of the breast faces many challenges the biggest problem is if a lesion can not be demonstrated on mammography or ultrasound. Breast biopsies under MRI guidance can resolve this challenge. Sometimes the lesion can be found on a second look U/S and biopsied in this way. Challengers with MRI Guided Biopsy Compatible equipment. Patient Safety. Artefact due to metal needles. No real time imaging while positioning. Indications for MRI Breast Biopsy The lesion is not able to be demonstrated on either mammography or ultrasound. All our Breast biopsies are performed at St Georges Radiology. Although the majority of the Breast MRI’s done with CRG are at Hagley 3.0T, the biopsy’s are done at St Georges. St Georges has a 1.5T which all the equipment is compatible with. St Georges has the availability of Day Surgery onsite if the patient is having a hookwire and proceeding to theatre. Breastcare is on the same site also, if a post biopsy mammogram is required. GE 1.5 T Signa System A GE Array 4 channel dedicated breast coil The Invivo breast immobilization and biopsy device Since 2010 we have used The ATEC Suros Vacuum Assisted Biopsy (VAB) Hand Piece and Console. Titanium Biopsy Site MarkerCliplock by ATEC. Equipment Only the localization of the lesion and the verification of the position of needle are performed under MR guidance. Appointment is organized in conjunction with Specialised Radiologist and MRI Technologist availability. Review the previous MRI with the Radiologist - Position - Sequences Prior to Biopsy Patient arrives 30 min prior to appointment. Patient is already familiar with MRI, contrast and safety considerations. Re check Safety. Procedure consented by radiologist. Sedation is discussed. Patient changed into front opening gown. IV access obtained. Prior Biopsy to This is dependent on the lesion and the size of the breast. Patient Position Lateral Approach Patient is positioned prone with breast of interest positioned in the breast coil. The other breast is positioned out of the way by placing a pad over the breast coil. Patient Position The arms are positioned above the head Medial light compression is applied The breast needs to immobilized for the biopsy Patient Position Medial compression paddle Localisation Grid Compression It is important to immobilize the breast and push the breast up against the localization grid. Compression This will aid in the visualization of the grid – the grid itself is not imaged but rather the indentations created by the grid. Only will good compression permit accurate needle positioning and therefore a successful biopsy or hookwire position be ach achieved. BUT moderate compression is recommended so contrast enhancement is not compromised. Medial Approach We do not have medial access with our Breast coil. The breast is positioned in the opposite breast coil with the unaffected side tilted slightly up. This will vary patient to patient due to patient physique. Patient Position 3 plane Localizer Calibration To scan allow for parallel imaging using ASSET Axial T1 Axial Vibrant Pre Contrast A T1 fat sat image specifically designed for breast imaging Fast 3D gradient sequence with high spatial and temporal resolution Axial Vibrant Post Contrast Sequences The sterilized grid is positioned against the disinfected breast and an oil capsule is put in the grid in approximate position, Scan Localizer Calibration Scan Axial T1 Axial Vibrant Pre Contrast Scan. The oil capsule maybe adjusted at this time before contrast is given if necessary. Procedure The previous 3.0T MR can be used to identify the target lesion and therefore Gd may not be required. The increased resolution and signal of 3 T is obvious when comparing with the 1.5 T Contrast is usually given but we often start with 5mls as opposed to 10mls of Gad Procedure In the IVI screen the lesion can be located in all planes. The cursor can now be used to accurately locate the lesion. Procedure Once the area is localized and the depth worked out the patient is brought out of the magnet. Sterile propacks and other equipment are opened. The radiologist will inject local anaesthesia. A small incision is made using a plastic handled scalpel. The block is positioned in appropriate grid space. Procedure Introducer Localization System Introducer Sheath Obturator Introducer Stylet Block Depth guide is adjusted on the sheath and the stylet is then placed in this sheath. The stylet and introducer are inserted in the breast via the appropriate grid hole. Procedure Stylet is removed and obturator (has low metal artefact) placed in introducer. The most appropriate sequence is preformed to check placement. Adjustments may need to be done and rechecked. The biopsy gun kit is opened and set up. Procedure The SUROS is tested and then the hand piece and foot peddle are brought into the MRI room. The console remains outside the room at all time. Procedure The Radiologist positions the needle at the required depth in the introducer and the biopsy is performed. The Radiologist will perform 6 - 10 samples in the one pass. Procedure When the biopsy gun is discharged the patient should not feel pain but will feel pushing. It is wise to warn the patient of the sound of the biopsy gun as it is imperative the patient is still at this important part of the procedure. Procedure Once the biopsy is complete a clip lock maybe inserted. This is detectable on Mammography, Ultrasound and MRI. Half the size of a staple. Helps to identify region for future procedures and treatment. Procedure Steristrips and opsite dressing are applied. 10-20 mins compression and icepack is applied to reduce swelling. Aftercare Form is given to the patient. If cliplock has been inserted a Mammogram is performed to confirm position. Aftercare What size and shape works best? The most difficult breast shape to work with is small dense breasts. Tips for small breasts Remove the pad on the coil. Displace the patient to the side of interest to bring them closer to the grid. Rolling the patient opposite side up will bring in more lateral tissue. Rolling the Patient affected side up can bring in more medal tissue. Padding the medial compression plate . Work load 2008 (6 months) 5 Cases 2009 5 cases 2010 9 cases – Suros intro July 2011 11 cases 2012 13 cases 2013 (7 mth) 17 cases to date August. What have we changed The use of Suros (VAB) has definitely speed up the procedure. Although patients are still consented for sedation unless the patient is very anxious or the procedure goes a lot longer than normal it is not usual to give it. Acknowledgements Thanks to Dr Jerry Sharr, Claire Overend, and my wonderful anonymous models. REFERENCES Philpotts, L E. (2010). Magnetic Resonance Imaging Clinics of North America, Breast MRI vol 18(323-332). MR Intervention : Indications, Technique, Correlation and Histologic. Meeuwis C, Veltman J, Hester N et al. (2012). Euro Radiology 22:341-349. MR-guided breast biopsy at 3T: diagnostic yield of large core needle biopsy compared with vacuum-assisted biopsy. Mann R. M, Kuhul C K, et al. Euro Radiol (2008) 18:1307-1318. Breast MRI: Guidelines from the European Society of Breast Imaging. Boo-Kyung H, Mitchell D S, et al. (2008) AJR, vol 191, number 6, 1798-1804.Outcome of MRIGuided Breast Biopsy.