Accuracy of quantitative ultrasound elastography for differentiation of malignant and benign breast abnormalities: a meta-analysis.

The purpose of this study was to systematically review recent literature on diagnostic performance of strain ratio and length ratio, two different strain measurements in ultrasound elastography, for differentiating benign and malignant breast masses. A literature search of PubMed and other medical and general purpose databases from inception through January 2012 was conducted. Published studies that evaluated the diagnostic performance of ultrasound elastography alone reporting either strain ratio or length ratio for characterization of focal breast lesions and using cytology (fine needle aspiration) or histology (core biopsy) as a reference standard were included. Summary diagnostic performance measures were assessed using bivariate generalized linear mixed modeling. Nine studies reported strain ratio for 2,087 breast masses (667 cancers, 1,420 benign lesions). Summary sensitivity and specificity were 88 % (95 % Credible Interval (CrI), 84-91 %), and 83 % (95 % CrI, 78-88 %), respectively. The positive and negative likelihood ratios (LR) were 5.57 (95 % CrI, 3.85-8.01) and 0.14 (95 % CrI, 0.09-0.20), respectively. The inconsistency index for heterogeneity was 6 % (95 % CrI, 1-22 %) for sensitivity and 8 % (95 % CrI, 3-24 %) for specificity. Analysis of three studies reporting length ratio for 450 breast masses demonstrated sensitivity and specificity of 98 % (95 % CrI, 93-99 %) and 72 % (95 % CrI, 31-96 %), respectively. Strain ratio and length ratio have good diagnostic performance for distinguishing benign from malignant breast masses. Although, this performance may not be incrementally superior to that of breast imaging reporting and data system (BIRADS) in B-mode ultrasound, the application of USE using strain ratio or length ratio in combination with USB may have the potential to benefit the patients, and this requires further comparative effectiveness and cost-effectiveness analyses.