Ellen Xiameng Sun, Presenter: Nothing to Disclose

Wendie A. Berg MD, PhD, Abstract Co-Author: Research Grant, Gamma Medica, Inc Research Grant, General Electric Company Equipment support, Gamma Medica, Inc Equipment support, General Electric Company

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

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

Stiffness within a mass ± surrounding tissue on ShearWave elastography (SWE) correlates with increasing risk of malignancy; we sought to determine if stiffness distribution was predictive of malignancy.  

From 9/2008 to 9/2010, at 16 centers in Europe and USA, 1647 women with breast masses consented to repeat US and SWE imaging (SuperSonic Imagine, Aix-en-Provence, France). 1562 women/masses had acceptable reference standard; 37 were excluded due to artifacts. Uniplanar SWE images were reviewed for visual and quantitative stiffness as well as pattern of maximum stiffness: rim, scattered foci within and adjacent to mass, only within mass, adjacent region, adjacent focus, stiffness neither within nor adjacent to mass, or no stiffness. We also evaluated BI-RADS 3/4a masses for any rim stiffness.

1525 women (median age 50 yrs, mean 51.8, range 21-94) and masses (median 12 mm, mean 14, range 1-53) were evaluated, including 494 (32.4%) malignant. Maximum stiffness as a rim was seen with 342 (22.5%) of masses: 177 (51.7%) malignant (odds ratio, OR, 19, 95%CI 6.2-55, after correcting for grayscale BI-RADS assessment). Other patterns also correlated with increased risk of malignancy, including within mass (OR 17), adjacent region or focus (OR 18 and 11 respectively), and scattered foci within or adjacent to mass (OR 10). Stiffness not within or immediately adjacent to mass was not predictive of outcome, with 5/97 (5.2%) of such masses malignant (OR 1.8, 95%CI 0.4-8.3); this likely represents artifact. Of 254 masses without any stiffness, 6 (2.4%) were malignant. Of 428 BI-RADS 3 lesions, 9 (2.1%) were malignant; 8/105 (7.6%) with stiff rim were malignant. Among 390 BI-RADS 4a lesions, 40 (10%) were malignant; 27/110 (24.5%) with stiff rim were malignant; 4/62 (6.5%) soft masses with any SWE rim were malignant; and 5/31 (16%) otherwise stiff masses were malignant. 4/187 (2.1%) soft BI-RADS 4a masses without any stiffness or rim were malignant.  

Among BI-RADS 3 masses, 1/323 (0.3%) lacking a stiff rim on SWE were malignant. Among BI-RADS 4a masses, any pattern of SWE stiffness in or around the mass, or, for soft masses, a rim, would have identified 36/40 (90%) malignancies, leaving 4 (2.1%) malignancy rate among 187 remaining BI-RADS 4a masses.

The presence of absolute ± rim SWE stiffness among probably benign or low suspicion masses seen on breast US should prompt biopsy.  

Sun, E, Berg, W, Gay, J, Cohen-Bacrie, C, Rim and other Patterns of Stiffness on ShearWave™ Elastography (SWE) as Predictors of Malignancy in the BE1 Trial  .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007315.html