Michelle Tsang Mui Chung, Presenter: Nothing to Disclose

Ana P. Lourenco MD, Abstract Co-Author: Nothing to Disclose

Martha Beretta Mainiero MD, Abstract Co-Author: Nothing to Disclose

To determine how frequently BI RADS 3 results were given for breast MRI in our practice, the cancer yield of cases initially categorized as probably benign, and the rate of patient compliance with follow-up recommendations.

The 3,211 consecutive contrast-enhanced breast MRI exams done at our institution from March 1, 2004 to March 1, 2009 were retrospectively reviewed. For those exams assessed as BI RADS 3, the clinical indication for breast MRI, breast MRI findings, any follow-up breast imaging, and any available breast pathology results were collected from radiology and pathology reports, as well as the electronic medical record. The frequency of BI RADS 3 MRI interpretations, cancer yield in these cases, and rate of patient compliance with follow-up were calculated.

Two hundred fifty five (8 % of total breast MR exams) exams performed on 240 patients were assessed as BI RADS 3. The most common indications for breast MRI in the BI RADS 3 cases were personal history of breast cancer (36%), family history of breast cancer (31%), and abnormality on mammography or ultrasound (12%). Lesions included 105 masses and 144 non-mass lesions (103 foci, 18 non-masslike enhancement, 14 parenchymal enhancement, and 9 other). Six (3%) cases initially assessed as BI RADS 3 on MRI were later found to be malignant. Three of these lesions were masses, and three were non-mass lesions. The malignancy rate for masses was 3% (3/105), and for non-mass lesions was 2% (3/144). Forty three of the total 240 patients did not return for follow-up breast imaging as recommended. Mean follow-up interval was 20 months (range 1 to 58, median 18).

BI RADS 3 assessments were utilized in 8% (255/3211) of our total breast MRI exams. Rate of malignancy among BI RADS 3 MRI exams in our practice was 3% (6/197). Eighteen percent (43/240) of our patients did not return for the recommended follow-up breast imaging.

Knowing the malignancy rate and patient compliance rate for BI RADS 3 breast MR is important, as criteria for probably benign findings and length of follow-up required remains uncertain for MR.  

Chung, M, Lourenco, A, Mainiero, M, Probably Benign Breast MRI Lesions: Is “Probably” Good Enough?.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010824.html