Wendie A. Berg MD, PhD, Presenter: Research grant, Naviscan, Inc Researcher, Naviscan, Inc Speaker, SuperSonic Imagine Researcher, SuperSonic Imagine Medical Advisory Board, Koninklijke Philips Electronics NV Author, Gamma Medica Ideas, License, Merge Healthcare

David Owen Cosgrove MBBCh, FRCR, Abstract Co-Author: Research Consultant, SuperSonic Imagine Research Consultant, Bracco Group Speakers Bureau, Toshiba Corporation

Caroline Dore, Abstract Co-Author: Consultant, SuperSonic Imagine

Fritz K.W. Schaefer MD, Abstract Co-Author: Nothing to Disclose

William Svensson MD, Abstract Co-Author: Equipment support, Siemens AG Speaker, Siemens AG Speaker, SuperSonic Imagine Research support, SuperSonic Imagine

Joel Gay, Abstract Co-Author: Employee, SuperSonic Imagine

Jean-Pierre Henry, Abstract Co-Author: Employee, SuperSonic Imagine

Claude Cohen Bacrie MD, PhD, Abstract Co-Author: Executive Vice President, SuperSonic Imagine Officer, SuperSonic Imagine

To validate performance prospectively when shearwave elastographic (SWE™) features are added to BI-RADS® assessments of breast masses.

From 9/2008 to 9/2010, 701 women consented to repeat breast ultrasound plus quantitative SWE examination in this IRB-approved, HIPAA-compliant protocol conducted at 16 centers in Europe and the United States. BI-RADS (BR) features and assessments were recorded. Mean, maximum (Emax), and minimum elasticity of the stiffest portion of the mass and surrounding tissue, lesion-to-fat elasticity ratio, ratio of SWE-to-B-mode lesion diameter, SWE lesion shape, and homogeneity were evaluated. 623 masses were analyzable: 42 BR 2 masses were assumed benign, and reference standard was available for 581 BR 3 or greater masses. We used reclassification thresholds developed on an earlier series of 939 masses to selectively upgrade BR 3 masses to biopsy and downgrade 4a masses to follow-up, and impact of SWE after BR on sensitivity, specificity, and AUC was determined. 

Median participant age was 50.4 years (mean 51.7, range 21.1 to 89.6) with median mass size 12 mm (mean 14.3, range 2 to 50); 213/623 (34.2%) masses were malignant. 3/137 (2.2%) BR 3 masses were malignant as were 22/208 (10.6%) 4a, 17/48 (35.4%) 4b, 22/35 (62.8%) 4c, and 149/153 (97.4%) of BR 5 lesions. Calibration of original model in the validation sample showed no evidence of significant lack of fit (p=0.51). All SWE features except diameter ratio significantly improved specificity (p≤0.001). Using SWE homogeneity or Emax ≤80 kPa to downgrade BR4a and inhomogeneity or Emax ≥160 to upgrade BR3 improved specificity from 176/410 (42.9%) for BI-RADS alone to 315/410 (76.8%, p<.0001) and 298/410 (72.7%, p<.0001) respectively, without significant change in sensitivity; AUC increased from 0.942 with BI-RADS alone to 0.952 (p=.04), and 0.954 (p=.01) respectively. The 0.954 AUC for the validation sample was similar to our original model (0.962).

In a prospective, multicenter validation set of 623 masses, we confirm that addition of SWE maximum elasticity ≥160 kPa to upgrade BI-RADS 3 masses and ≤80 kPa to downgrade BI-RADS 4a masses yields a 30% absolute improvement in specificity of breast ultrasound mass assessment without loss of sensitivity.

Addition of SWE to standard breast ultrasound can significantly reduce unnecessary biopsies among low suspicion breast masses.

Berg, W, Cosgrove, D, Dore, C, Schaefer, F, Svensson, W, Gay, J, Henry, J, Cohen Bacrie, C, Specificity Is Improved When Shearwave Elastography (SWE) Is Added to BI-RADS® for Breast Ultrasound: Prospective Multicenter International Validation in the BE1 Study.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11007397.html