US shear-wave elastography technique
2D-SWV based US elastography was performed using Toshiba Aplio i800
(Canon Medical systems, Japan) ultrasound system with an ultra-wideband
convex transducer (i8CX1). The images were obtained while the patients
lying in the lateral decubitus position with breath-hold during data
acquisition. The sample box was placed in the renal cortex of the upper,
middle and lower portions of each kidney, respectively (Fig. 1). A fixed
region-of-interest (ROI) size was chosen for each measurement. The
2D-SWV was measured 4-6 times for each renal portions and the mean of
the measurements were recorded accordingly. The mean 2D-SWV values of
the whole right and left kidneys were also calculated by averaging the
values of three renal portions. A second radiologist repeated the right
kidney average 2D-SWV measurements in randomly selected 10 healthy
subjects on the same day.