Diagnostic Performance of a Dedicated 1.5-T Breast MR Imaging System

Abstract

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. 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. 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. High accuracy was achieved by using dedicated breast MR imaging.