Diagnostic Performance of Ultrasound Shear Wave Elastography in Solid Small (≤4 cm) Renal Parenchymal Masses.

The aim of the study was to analyze the diagnostic performance of shear wave elastography (SWE) in differentiating between malignant and benign solid renal parenchymal masses ≤4 cm, compared with conventional ultrasound. A total of 20 healthy volunteers and 117 patients had been included in this study. Conventional ultrasound and SWE were performed in all volunteers and patients. The elasticity of healthy cortex and the elastic parameters of tumors such as mean elasticity (Emean), minimum elasticity (Emin), maximum elasticity (Emax), standard deviation and elasticity ratio of the lesion to surrounding cortex (Eratio) were measured on SWE images. Diagnostic performance of SWE was compared with that of conventional ultrasound. The cortical elasticity values of healthy right and left kidneys were 4.7 ± 1.7 and 4.5 ± 1.5 kPa, respectively. Of the 117 renal tumors, 68 were renal cell carcinomas (RCCs) and 49 were benign. Emean, Emin and Eratio were significantly lower in RCCs compared with benign lesions: Emean 7.2 ± 2.5 kPa versus 10.0 ± 2.4 kPa, Emin 2.5 ± 2.4 kPa versus 5.6 ± 2.3 kPa, Eratio 1.6 ± 0.5 versus 2.2 ± 0.6 (all p values < 0.001). The cutoff values of 9.15 kPa for Emean, 3.55 kPa for Emin and 1.99 for Eratio had the highest areas under the receiver operating characteristics curve (0.801 for Emean, 0.832 for Emin and 0.806 for Eratio). Combining Emean, Emin and Eratio with conventional ultrasound improved the specificity for predicting RCCs to 87.8%, but the sensitivity was not increased.