Abstract P4-02-13: Breast ultrasound surveillance with image fusion technique in a short-interval follow-up for BI-RADS category 3 mass lesions

Abstract

Abstract PURPOSE: Breast ultrasound (US) is a diagnostic imaging modality that is now widely used as an adjunct to mammography for evaluation of breast abnormalities. In the Breast Imaging-Reporting and Data System (BI-RADS) lexicon, a solid mass with an oval shape, well-circumscribed margins and parallel orientation is classified as category 3 (BI-RADS category 3 mass lesions) . This mass should have a risk of malignancy of < 2%. Surveillance breast US in short-interval follow-up for BI-RADS category 3 mass lesions is an acceptable alternative to biopsy. The surveillance US is recommended 6 month after initial lesion identification and then every year for at least 2 y. However, inconsistent reproducibility for US due to operator dependence is still a clinical issue. The aim of our study was to verify the utility of US using real-time virtual sonography (RVS) - to coordinate present US images with past US images reconstructed from previously acquired US volume data using magnetic tracking system – in a short-interval follow--up for BI-RADS category 3 mass lesions. METHOD AND MATERIALS: We enrolled 20 women (23 lesions) with more than 24 months of follow-up after classification as BI-RADS category 3 during initial US. US surveillance was scheduled at 6, 12 and 24 months. Three-dimensional assessment of morphologic features was performed while serially checking past US volume data corresponding to the present US probe position. Measurement of the target lesion diameter was performed after the probe was adjusted to include the maximum diameter of a past US image at each visit. RESULTS: RVS was technically successful in 100% of patients. All target lesions were detected, including two iso-echoic lesions. The mean target lesion diameters at baseline and at 6, 12 and 24 months were 8.2+4.2, 8.4+4.5, 8.1+4.5 and 8.3+5.0 mm, respectively . Statistical analysis using a Friedman test with multiple comparisons revealed no significant difference between the diameters at each time point (p = 0.785). RVS was used to directly compare the US morphologic characteristics and sized of lesions. Furthermore, the RVS data can be reproduced in their entirety for independent review at a later date by using stored US volume data. CONCLUSION:Our results suggest that RVS is reproducible, operator-independent technique for comparison of US images of BI-RADS category 3 mass lesions obtained at different time points. Citation Format: Nakano S, Fujii K, Kousaka J, Mouri Y, Ando T. Breast ultrasound surveillance with image fusion technique in a short-interval follow-up for BI-RADS category 3 mass lesions [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-02-13.