Fig. 2
Quantitative measurement of tumor stiffness on shear-wave elastography (SWE) and immunohistochemical staining. a. Quantitative elasticity parameters were measured on the elasticity color map image. Two round 2-mm-diameter regions of interests were positioned on the hardest part of the mass and adjacent adipose tissue. The ultrasound system automatically displayed average elasticity of the tumor (Eaverage) with standard deviation, average elasticity of the adjacent fat with standard deviation, and elasticity ratio between the tumor’s average elasticity and the average elasticity of adjacent fat (Eratio). Two quantitative SWE parameters, Eaverage (yellow box) and Eratio (green box), were extracted to investigate the relationships between stiffness parameters on SWE and immunohistochemical staining. b–c. On immunohistochemical staining, the area fraction of positive reactions was measured. Each color image was converted to a binary image. The positive areas—brown area for glucose transporter-1 protein (GLUT1) staining (× 100) (b)—were converted to red (c). The area fraction of positive GLUT1 reaction was determined as the percentage of red pixels in the binary image