Abstract P2-03-06: Sonographic evaluation of MRI-detected lesions of the breast using image fusion technique with magnetic navigation

Abstract

Abstract [Back ground] Breast magnetic resonance imaging (MRI) is being increasingly evaluated in the screening of patients at high risk of breast cancer and screening of the contralateral breast in newly diagnosed breast cancer. However, the utility of MRI is restricted by its limited specificity and moderate positive predictive value (PPV) because of the overlap of imaging features in benign and malignant lesions. Therefore, tissue sampling should be required for definitive diagnosis of suspicious lesions, especially in cases of MRI-detected lesions. To localize MRI-detected lesions and confirm histopathologic results, MRI-guided biopsy has been introduced with high rates of success. If MRI-detected lesions can be detected with second-look sonography, sonography-guided biopsy, which is more broadly available, less costly, and less time-consuming, is recommended. [Purpose] The aim of this study was to verify the utility of second-look sonography using real-time virtual sonography (RVS), a coordinated sonography and MRI system that uses an image fusion technique with magnetic navigation, in the sonographic evaluation of MRI-detected lesions of the breast. [Materials and methods] Of 196 consecutive patients who were examined with breast MRI in our hospital from 2006 to 2009, those who underwent second-look sonography to identify MRI-detected lesions were enrolled in this study. MRI was performed using a 1.5-T imager with the patient in a supine position. To assess the efficacy benefits of RVS, the correlations between lesion detection rates, MRI features, distribution, and histopathological classification on second-look sonography using conventional B-mode or RVS were analyzed. [Results] Of 196 patients, 55 (28%) demonstrated 67 lesions initially detected by MRI, followed by second-look sonography. Of the 67 MRI-detected lesions, 18 (27%) were identified with second-look sonography using conventional B-mode alone, whereas 60 (90%) lesions were detected with second-look sonography using RVS (p < 0.001). The detection rates of 16 focal lesions, 46 mass lesions, 16 lesions sized <5 mm, 45 lesions sized 5-10 mm, 26 lesions situated within the mammary gland, 41 lesions situated around mammary fascia, 24 malignant lesions, and 43 benign lesions were 25%, 26%, 25%, 24%, 42%, 17% 33%, and 23% by conventional B-mode, and were significantly higher at 94%, 89%, 94%, 89%, 88%, 90%, 92% and 88% by RVS, respectively. Of the 7 lesions with no sonographic correlates, 5 could be biopsied by marking MRI information onto the body surface using RVS. Overall, 65 of 67 (97%) MRI-detected lesions were confirmed by histopathological results. [Conclusions] Our results suggest that the additional use of RVS on second-look sonography significantly increases the sonographic detection rate of MRI-detected lesions without operator dependence. The majority of MRI-detected lesions had sonographic correlates and sonography-guided biopsy could subsequently be performed by adding RVS. It might contribute to identifying cases in which MRI-guided biopsy is absolutely necessary. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-03-06.