Targeted Ultrasound of an Indeterminate Breast Lesion on Mammography: When Does It Influence Management?

OBJECTIVE To determine the change over mammographic diagnosis, BI-RADS category and management following targeted ultrasound of an indeterminate lesion seen on mammography and associated factors, if any. STUDY DESIGN Descriptive, analytical study. PLACE AND DURATION OF STUDY Radiology Department, The Aga Khan University Hospital and Clifton Medical Services, Karachi, from April 2010 to May 2011. METHODOLOGY Patients referred for targeted breast ultrasound following X-ray mammography were selected regardless of age. Targeted Ultrasound (TUS) was defined as a limited ultrasound of a specific lesion or breast part as indicated by the referring source. Comparison was made between the post mammography and post TUS lesion characterization, diagnosis and BI-RADS category (0-5) which was taken as a measure of management change. Those were evaluated to determine significance of age, marital status, parity, breast parenchymal pattern ( dense, fatty, heterogeneous), referring source for the TUS (radiology resident, radiologist or surgeon), lesion characteristics (density, echogenecity, shape, location, margins, size, depth-to-width ratio, enhancement or shadowing), presenting symptoms or signs and reason for TUS. Ap-value of 0.05 or less was taken as significant. RESULTS There were a total of 342 patients with mean age of 49.7 ±13.5 years. It assigned a definite category in 232 patients with an indefinite category (0) on mammography requiring further investigation. It decreased the suspicion for malignancy in 180 (77.58%) by assigning a low BI-RADS category and increased the suspicion in 52 (22.41%). The factors significantly associated with this changes included clinical indication being diagnostic (p < 0.001), lesion characteristics on imaging (p < 0.001), heterogenous breast parenchymal pattern (p < 0.001) and presence of known risk factors (p=0.049). CONCLUSION TUS served as a problem solving tool in the evaluation and management of an indeterminate breast lesion in a high number of patients, particularly when there was a lump as indication for imaging in the presence of risk factors in a patient with otherwise heterogeneously dense breast parenchyma.