Breast ultrasound appearances after Mammotome vacuumassisted biopsy. Poster No.: C-1924 Congress: ECR 2011 Type: Educational Exhibit Authors: R. Patel 1, G. R. Kaplan 2 ; 1 London/UK, 2 Herts/UK Keywords: Vacuum assisted biopsy, Localisation, Ultrasound, Breast DOI: 10.1594/ecr2011/C-1924 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 14
Learning objectives To demonstrate the ultrasound appearances of a post-mammotome 11G vacuum-assisted biopsy (VAB) cavity, allowing pre-operative localisation wires to be placed under ultrasound rather than mammographic guidance. To review our department's success rate in ultrasound guided pre-operative wire localisation following Mammotome VAB for microcalcification detected on mammography. To describe the advantages of stereotactic 11G VAB over other standard breast biopsy techniques. Page 2 of 14
Background Non-palpable breast lesions, particularly clustered microcalcifications, detected on mammography are increasingly being sampled using a 11G VAB device rather than the traditional spring-automated 14G biopsy method or surgical biopsy. Stereotactic biopsy requires 15-degree paired mammographic localisation of microcalcification. The computer generated x, y and z co-ordinates guides the positioning of the device probe within the breast. Vacuum is used to withdraw tissue into the probe and the specimen is removed without withdrawing the probe each time. Contiguous sampling is achieved by acquiring core samples at consecutive clock positions. Post procedural specimen radiographs are taken to check for the presence of microcalcification. Page 3 of 14
Fig.: Specimen radiographs demonstrating microcalcification within VAB samples following On this occassion, 3 sets of 6 cores samples have been obtained without withdrawing the probe. References: Radiology, Barnet Hospital - London/UK If post-biopsy specimen radiographs reveal core samples without microcalcification a second pass of the VAB needle is made. If post-biopsy imaging reveals that the lesion has largely or totally been removed, a metallic clip can be placed. This can then be used as a biopsy site marker should the patient require follow-up examination and/or surgery. Page 4 of 14
Current National Health Service Breast Screening Programme (NHSBSP) Guidelines for Breast Screening Assessment recommends performing large core VAB as the sampling method of choice in the following circumstances: 1. <5mm clusters of microcalcification 2. failed conventional needle core biopsy 3. B3/B4 needle core biopsy 4. indeterminate microcalcification requiring large volume of tissue 5. microcalcification difficult to sample using conventional needle core biopsy The 11G VAB device has many advantages over other standard biopsy techniques. It is minimally invasive, fast, simple, results in less operations and is less expensive than open surgery (1). The larger 11G VAB needle when compared to 14G needles allows for greater tissue yield without being more time-consuming and without additional complications (2). This consequently results in increased microcalcification retrieval (3), increased definitive diagnosis and reduction in inadequacy rates. (4). Additionally, 11G biopsy needles allow for more accurate clip positioning compared to 14G biopsy needles (5). The use of the prone Mammotome 11G VAB device within the North London Breast Screening programmes has brought to light another advantage. The residual post-mammatome VAB cavity can be visualised using ultrasound if 12 or more core samples have been taken. This allows for ultrasound rather than mammographic-guided preoperative wire localisation. Page 5 of 14
Imaging findings OR Procedure details In our institution, during the year 2009, 91 patients required preoperative wire localisation. Of these, 25 patients had been referred from the North London Screening programme following prone positioning Mammotome VAB. All 25 patients had an ultrasound examination of the biopsy site. 23 out of 25 patients (92%) demonstrated variable but typical post-biopsy ultrasound appearances. This allowed ultrasound guided pre-operative wire localisation. The longest time interval between biopsy and wire localisation was 6 weeks. In the remaining 2 patients, confident location of the biopsy site was not possible. These patients wents on the have stereotactic pre-operative wire localisations. In this study, typical post-biopsy ultrasound findings included: visible needle tract from the skin surface (focal skin thickening/disrution) to the cavity Page 6 of 14
Fig.: US following VAB demonstrating a visible needle tract between skin and VAB cavity. References: Radiology, Barnet Hospital - London/UK the cavity - this may be of variable size and appearance. The majority are fluid-filled. Page 7 of 14
Fig.: US following VAB. Well defined fluid-filled cavity References: Radiology, Barnet Hospital - London/UK some cavities appear echogenic, perhaps due to a post biopsy haematoma. Page 8 of 14
Fig.: US following VAB. Echogenic cavity. References: Radiology, Barnet Hospital - London/UK the clip inserted after the biopsy may or may not be visible. Page 9 of 14
Fig.: US following VAB. Metallic clip within fluid-filled cavity. References: Radiology, Barnet Hospital - London/UK The following selected cases demonstrate the ultrasound appearances of the post Mammotome VAB site alongside radiographs including screening, post 11G Mammotome VAB biopsy and post localisation mammograms. Case 1 Case 2 Case 3 Case 4 Page 10 of 14
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Conclusion The use of 11G VAB is now commonplace in breast screening programmes throughout the NHS Many advantages of the large core (11G) VAB technique have already been described in the literature. Experience in our department using a Mammotome VAB device suggests another advantage. The post Mammotome biopsy cavity is visible on ultrasound up to six weeks post biopsy if 12 or more core biopsy samples have been taken. The ultrasound appearances are typical: a cavity, focal skin thickening/ disruption at the skin entry site and a visible needle tract connecting the two. This saves the patient having to undergo a mammographic localisation, which is uncomfortable, has a radiation dose and is more time consuming. Page 12 of 14
Personal Information Dr Roopal R. Patel Specialist Registrar in Clinical Radiology Royal Free Hospital, London Email: roopalrpatel@hotmail.com Dr G. R. Kaplan, Consultant Radiologist Barnet & Chase farm NHS Trust and North London Breast Screening Service. Email: glenda.kaplan@bcf.nhs.uk Page 13 of 14
References 1. Calcification Highly Suggestive of Breast Malignancy - Comparison of Breast Biopsy Methods. Liberman L et al, AJR Am J Roentgenol.2001 Jul;177(1):165-72 2. Stereotactic breast biopsy:comparison of 14- and 11-gauge Mammotome probe performance and complication rates. Burbank F, Am Surg.1997 Nov;63 (11):988-95 3. Breast microcalcifications:retrieval failure at prone stereotactic core and vacuum breast biopsy --frequency, causes and outcome. Jackman RJ, Rodriguez-Soto J, Radiology.2006 Apr;239(1):61-70 4. Vacuum assisted stereotactic guided mammatome biopsies in the management of screen detected microcalcifications: experience of a large breast screening centre. Kumaroswamy V,Liston J, Shaaban A M, J Clin Pathology 2008;61:766-769 5. Clip placement after stereotactic vacuum-assisted breast biopsy. Liberman L et al, Radiology.1997 Nov;205:417-422 Page 14 of 14