Ultrasonographic differentiation of malignant from benign breast lesions: a meta-analytic comparison of elasticity and BIRADS scoring

There has been controversy regarding the accuracy of breast ultrasound elastography (USE) compared to conventional B-mode Ultrasound (USB). The purpose of this study was to conduct a direct comparative effectiveness analysis of USB versus USE or their combination in differentiating breast lesions through systematically reviewing recent literature. An extensive literature search of PubMed and other medical and general purpose databases from inception through August 2011 was conducted. Published studies that reported a direct comparison of the diagnostic performance of USE, using elasticity score versus USB, using breast imaging reporting and data system (BIRADS) for characterization of focal breast lesions were included. Summary diagnostic performance measures were assessed for each of the tests and their combination using bivariate generalized linear mixed modeling. The two tests were combined as: (1) conjunctive, where the outcome of the combination of tests is positive only if both test results are positive; (2) disjunctive, where the outcome of a combination of tests is negative only if both tests are negative. Twenty nine studies provided relevant information on 5,511 breast masses (2,065 cancers, 3,446 benign lesions). Sensitivity of USB, USE, and their conjunctive and disjunctive combinations were 96% (95% credible interval (CrI), 93-98%), 79% (95% CrI, 74-83%), 73% (95% CrI, 67-78%), and 99% (95% CrI, 98-99%), respectively. Specificity of USB, USE, and their conjunctive and disjunctive combinations were 70% (95% CrI, 55-83%), 88% (95% CrI, 82-92%), 97% (95% CrI, 95-99%), and 56% (95% CrI, 43-69%), respectively. The application of USE as a single test is not superior to USB alone. However, in low risk patients it is recommended to perform an USE following a positive USB result to decrease the rate of unnecessary biopsies.