Rational arrangement of measuring shear wave speed in the liver

Figure 3 Deviation from an ideal shear wave speed. A: Virtual touch quantification (VTQ) and 2-dimensional shear wave elastography (2dSWE) were measured on the same day in 18 cases and were significantly correlated with each other (P < 0.0001, r = 0.95). The bold and dotted lines indicate the best hit and 95% confidence bands based on the linear regression model of least-squares. b. A residual sum of squares (%Σdi²) was calculated using 1000 bootstrap resamples with the assumption of measuring the VTQ at 12 sites or fewer in each case and expressed as a percentage against a calculated value from the VTQ based on the linear regression model of least-squares between VTQ and 2dSWE. %Σdi² increased as the number of acquisition sites were decreased, and the difference of %Σdi² from that in 12 measurements reached significance as the number of acquisition sites decreased to 7 (^bP = 0.027). Circles and horizontal bars indicate medians and interquartile ranges of %Σdi², respectively. The dotted horizontal line indicates a %Σdi² of 8.0% in 12 measurements.