Ana P. Lourenco MD, Presenter: Nothing to Disclose

Michelle Tsang Mui Chung, Abstract Co-Author: Nothing to Disclose

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

To determine whether targeted ultrasound changes management in patients with BI RADS 3 breast MR exams.

3,211 consecutive contrast enhanced breast MR exams performed at our institution from 3/1/04 to 3/1/09 were retrospectively reviewed to identify all BI RADS 3 exams. Exams in which a targeted ultrasound was recommended were identified. The recommendation for undergoing targeted US was made at time of breast MR interpretation, with 6 month follow-up MR recommended if US was non-contributory. Cases in which targeted US was performed within 2 months of MR were identified. For each case, MR findings, targeted breast US results, and any breast pathology results corresponding to the MR findings were recorded. Frequency of identifying the MR-detected lesion and the rate at which the BI-RADS category was changed by the US were calculated for mass and non-mass lesions.

255 (8% of total MR exams) performed on 240 patients were assessed as BI-RADS category 3. Sixty-two patients (26%) with 64 BI-RADS 3 lesions underwent targeted US for evaluation of 38 masses and 26 areas of non-mass enhancement. Of the 64 lesions, 30 (47%) were seen by US. These included 20/38 (53%) masses and 10/26 (38%) non-mass lesions. Of the 30 lesions seen by US, 19 (63%) were upgraded to BI-RADS 4, including 13/38 (34%) of masses and 6/26 (23%) of non-mass lesions. Of the 19 lesions upgraded to BI-RADS 4, 2 (10%) were malignant at biopsy. Both of these were masses. There were 5/64 cases (8%) in which the targeted US resulted in a downgrade to BI-RADS 2. In the 221 patients with BI-RADS 3 MR exams in which biopsy was not performed, an additional 4 (1.8%) malignancies were detected at follow-up.

Selective use of targeted US in BI-RADS 3 MRI exams, particularly in masses, can help identify some of the malignancies immediately prior to initiating short interval follow-up.

“Second look” targeted US can help identify malignancies in lesions initially assessed as BI RADS 3 by MRI.

Lourenco, A, Chung, M, Mainiero, M, Targeted “Second Look” Ultrasound for BI-RADS 3 Lesions on MRI.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9014865.html