Diagnostic performance of a dedicated 1.5-T breast MR imaging system.

PURPOSE: To assess diagnostic performance of dedicated breast magnetic resonance (MR) imaging at breast imaging centers by using a dedicated 1.5-T breast MR system that used high-spatial-resolution, high-contrast-resolution spiral trajectory acquisitions.
MATERIALS AND METHODS: The study was institutional review board approved and HIPAA compliant, with waiver of informed consent. Diagnostic performance was retrospectively assessed for 934 consecutive screening (n=347) and diagnostic (n=587) examinations performed from April 2006 to December 2007 in women aged 25-89 years old from four sites for which dedicated breast MR imaging reports and ground truth (biopsy for cancer cases, 1-year follow-up with negative results for cases with negative findings) were available. The sensitivity, specificity, and receiver operating characteristic (ROC) for breast MR imaging were determined.
RESULTS: The sensitivity and specificity for the dedicated breast MR imaging system were 92% (92 of 100) and 88.8% (741 of 834). For all cases, the negative predictive value (NPV) was 98.9% (741 of 749). The NPV for screening cases was 100% (326 of 326). The area under the ROC curve was 0.942. Of the 93 cases with false-positive findings seen at dedicated breast MR imaging, 25 (27%) were high-risk histologic findings for which excision is often recommended. The false-positive rate was 93 of 834 (11.2%) for all cases, but only 16 of 326 (4.9%) for the screening cohort.
CONCLUSION: High accuracy was achieved by using dedicated breast MR imaging. © RSNA, 2012.