Karen S. Johnson MD, Presenter: Nothing to Disclose

Jay Alan Baker MD, Abstract Co-Author: Consultant, Siemens AG

Sheila Lee MD, Abstract Co-Author: Nothing to Disclose

Mary Scott Soo MD, Abstract Co-Author: Nothing to Disclose

To determine the cancellation rate of MRI-guided breast biopsies due to non visualization of lesions detected at 3.0T and to assess associated features and outcome.

Over 29 months, 1358 contrast enhanced breast MRI exams were performed using Siemens and GE 3T scanners; biopsy was recommended for 164 lesions (99 patients, 7%). With IRB approval, we reviewed records of a subset of 122 lesions (80 patients) to determine lesion type, background parenchymal features, hormonal status, reason for biopsy cancellation, and follow-up. Of the 122 lesions detected at 3.0T, 19 were biopsied by ultrasound, 7 underwent MRI-guided wire localization, 9 were axillary lymph nodes evaluated with ultrasound or sentinel node biopsy, 9 underwent mastectomy, 4 were considered benign after other biopsies, 2 were lost to follow up (LTFU). The remaining 72/122 underwent MRI-guided biopsy on a 1.5T scanner.

MRI guided biopsies of 15/72 (21%) breast lesions identified on a 3.0T scanner were cancelled. Reasons for cancelled biopsies were 1) lesion no longer seen (n=13, 18%); 2) lesion too far posterior (n=1, 1%); and 3) lesion determined to be benign (n=1, 1%). Lesions not visualized on day of biopsy were: non-mass-like enhancement (NME) 9/13 (69%) [linear NME 5/13 (38%); stippled NME, 2/13 (15%); nonspecific (NOS) NME, 2/13 (15%)], single focus of enhancement 3/13 (23%), and a mass 1/13 (8%). Hormonal status did not affect lesion non visualization [6/13 (46%) pre-menopausal; 6/13 (46%) post-menopausal; unavailable in 1 (8%)]. Background enhancement for cancelled cases was minimal (3/13 [23%]), mild (7/13 (54%]), moderate (1/13 [8%]), and marked (2/13 [15%]). Of cancelled non-visualized 3T lesions, 9/13 (69%) were no longer seen on follow-up imaging (median, 22 months; range, 6-40 mo.), 1/13 (7%) underwent mastectomy, and 3/13 (23%) were lost to follow-up. No cancers were found among cancelled biopsies.

Biopsy cancellation of 3.0T detected lesions does not appear to relate to hormonal status or background parenchymal features. However, the cancellation rate due to non visualization on the day of biopsy was 18%, higher than previously published for 1.5T detected lesions (12-13%).

The cancellation rate of MRI-guided biopsy for suspicious breast lesions initially detected on a 3.0T MRI scanner has not previously been reported.

Johnson, K, Baker, J, Lee, S, Soo, M, Biopsy Cancellation Rate of MRI-detected Breast Lesions Identified at 3.0T.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9001408.html