Influence of region of interest size and ultrasound lesion size on the performance of 2D shear wave elastography (SWE) in solid breast masses

•Optimal cut-off for benign/malignant differentiation depends on lesion size.•Region of interest size influences measurements of mean elasticity and standard deviation.•Large lesions are stiffer than small lesions.•Optimal cut-off for benign/malignant differentiation should increase with increasing lesion size.•Region of interest of 2 mm achieved best compromise of the diagnostic performance for all SWE parameter.