Laura Heacock MS, MD, Presenter: Nothing to Disclose

Amy Noel Melsaether MD, Abstract Co-Author: Nothing to Disclose

Kristine M. Pysarenko MD, Abstract Co-Author: Nothing to Disclose

Hildegard B. Toth MD, Abstract Co-Author: Nothing to Disclose

Linda Moy MD, Abstract Co-Author: Nothing to Disclose

Critics of breast MRI point to the high cost of the exam, the false-positive rates and the detection of indolent breast cancers. A shorter MRI may be cheaper and still allow the detection of breast cancer. The purpose of our study was to evaluate the ability of an MRI protocol with one post-contrast (and subtracted) sequence at 90 seconds to detect biologically significant cancers.

An IRB approved retrospective review of 103 women with 180 findings who underwent a breast MRI at 3T was performed by 2 readers. 90 women were newly diagnosed with breast cancer and 13 were asymptomatic high-risk women. Prior to this study, each reader interpreted 228 abridged MRI exams. The scan time for the 3 T1-scans was 4 minutes; the scan time for the T2-sequence was 4 minutes. Final BIRADS assessment and confidence score was assessed for each lesion. Comparison was made to the original diagnostic interpretation.

Of 125 cancers, 4 were foci, 86 were masses, 25 were NME and 10 were categorized in the original report as both masses and NME. Seventy-nine were IDC, 10 were ILC, 23 were DCIS, and 13 were IDC and DCIS. The mean size was 1.7 cm (range 0.4 – 8.6 cm). All 11 mammographically occult contralateral malignancies were detected. Cancers with rim enhancement, spiculated margins or washout kinetics were identified with high confidence by both readers. The sensitivity for reader 1 was 99.2% (CI 95.0-99.9%) and reader 2 was 96% (CI 90.4-98.5%). Of 6 missed cancers, one was IDC, one was ILC and 4 were DCIS. Both invasive cancers were moderately differentiated and all DCIS were intermediate grade. Their mean size was 1.1 cm, range 0.4 - 2cm. All 6 malignancies were seen on the 2nd post-contrast scan and they had Type 1 kinetics. Three were NME and 3 were masses. Eight of 55 (14.5%) MR biopsy proven benign lesions were not identified by each reader, although 4 additional findings were identified by both readers.

An abridged breast MRI protocol yielded 98% sensitivity for invasive cancers, 83% sensitivity for DCIS and increased specificity as compared with a routine breast MR exam. Total acquisition time is 7 minutes compared to 35 minutes for the conventional exam.

Almost all biological significant cancers are detected with an abridged MRI protocol.

Heacock, L, Melsaether, A, Pysarenko, K, Toth, H, Moy, L, Sensitivity of an Abridged Breast MRI Protocol to Detect Biologically Significant Breast Cancers.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14015978.html