Use of dynamic phase subtraction (DPS) map in dynamic contrast-enhanced MRI of the breast.

摘要

BACKGROUND: The Breast Imaging Reporting and Data System (BI-RADS) of the American College of Radiology recommends careful examination of the region of interest (ROI) in areas that seem to show a washout pattern on time-intensity curve (TIC). However, it is difficult to identify malignancies because many benign lesions also show enhancement, and these include cysts, hemorrhage, fibrosis, and necrosis in the mass. PURPOSE: This study was performed to assess the performance of the dynamic phase subtraction (DPS) map for dynamic contrast-enhanced magnetic resonance imaging (MRI) of the breast. A DPS map is a map image with pixel-by-pixel subtraction of an early-phase image from a delayed-phase image obtained in a dynamic study. MATERIALS AND METHODS: The use of the DPS map was analyzed retrospectively in 53 patients (32-84 years old) who underwent dynamic contrast-enhanced MRI of the breast. Sensitivity and specificity were compared with and without a DPS map for masses diagnosed as malignant lesions by biopsy. In addition, the patterns of time-intensity curves 30 seconds, 90 seconds, and 5 minutes after injection of contrast agent were compared with and without a DPS map. RESULTS: Sensitivity increased from 0.78 to 0.95, and specificity increased from 0.71 to 0.95 with reference to the DPS map. The pattern of TIC changed from continuous to a plateau in 9 cases, from a plateau to washout in 21 cases, and from continuous to washout in 7 cases. CONCLUSION: Use of the DPS map of dynamic contrast-enhanced MRI of the breast results in high detection rates of malignant masses, allows accurate ROI setting of TIC, and reduces operator's task.