Kevin Strobel MD, PhD, Presenter: Nothing to Disclose

Nienke Lynn Hansen MD, Abstract Co-Author: Nothing to Disclose

Alexandra Barabasch MD, Abstract Co-Author: Nothing to Disclose

Simone Schrading MD, Abstract Co-Author: Nothing to Disclose

Christiane Katharina Kuhl MD, Abstract Co-Author: Nothing to Disclose

We investigated whether breast MRI can be used for non-invasive assessment of findings categorized as BI-RADS-4 on screening-mammography or ultrasound.

IRB-approved prospective study on 340 patients with 353 screening-mammography or screening-US-findings which, after appropriate conventional work-up, had been categorized as BI-RADS-4. Women then underwent standard DCE-MRI for further assessment. Women who, after a negative/benign MRI, did not proceed to biopsy did undergo intensified follow-up for at least 18 months; pure clustered microcalcifications (PCM) were followed for at least 24 months.

Of the 353 study-findings, 66 (18.7%) were finally shown to be true-positive (23 DCIS, 43 invasive), and 287 (81.3%) false-positive. MRI-assessment correctly diagnosed absence of breast-cancer in 264/287 (92%) study-findings without breast-cancer, and confirmed presence of breast-cancer in 63/66 malignancies. False-negative-rate for PCM was 12% (3/25) due to 3 non-enhancing low-grade-DCIS; in turn, MRI detected additional invasive-cancers in 3 women whose BI-RADS-4 study-findings had been false-positive (benign). For mammographic findings other than PCM, MRI increased the PPV from 17.5% (21/120) to 77.8% (21/27), with a false-negative-rate of zero. For all US-findings, MRI increased the PPV from 12.9% (20/155) to 69.0% (20/29), again with a false-negative-rate of zero. MRI caused false-positive findings that required MR-guided-biopsy in 5 participants (5/340, 1.5%).

MRI is useful for non-invasive work up of mammographic or ultrasound BI-RADS-4 findings, and can avoid 92% of unnecessary biopsy-procedures. For all ultrasound-findings and for all mammographic-findings except for PCM, the false-negative-rate was zero, and additional invasive cancers were identified in 3 women whose BI-RADS-4 study-findings had been false-positive.

MRI appears to be a reliable method to demonstrate absence, as well as confirm presence of breast cancer in women with possibly malignant findings on screening mammography and/or screening ultrasound, at least for findings not due to pure clustered microcalcifications.

Strobel, K, Hansen, N, Barabasch, A, Schrading, S, Kuhl, C, Utility of MRI for Assessment of BI-RADS Category 4 Findings Made in Screening Mammography and Screening Ultrasound.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14001616.html