Effect of Q-Box size on liver stiffness measurement by two-dimensional shear wave elastography

Purpose To investigate the effect of the Q-Box size on liver stiffness (LS) measurement by two-dimensional shear wave elastography (2D SWE). Methods Ninety-eight patients with chronic liver disease were enrolled. Each patient was continuously measured five times. The Q-Box diameter was adjusted to 10, 20, and 30 mm each time. The liver stiffness values (LSVs) at different diameters were compared in the following groups: LSVs <= 6.2 kPa, 6.2 kPa < LSVs <= 11 kPa, LSVs >11 kPa. The reliability and repeatability of LS measurement at different diameters were evaluated. Results The differences in LSVs at different Q-Box diameters were statistically significant only when LSV <= 6.2 kPa (p = 0.004). There were no statistically significant differences in standard deviation (SD), SD/median, coefficient of variation (CV), and interquartile range (IQR)/median at different Q-Box diameters (p > 0.05). There were statistical differences in minimum LSVs and percentage of minimum LSVs <= 0.2 kPa as well as in stability index (SI) and percentage of SI <90% at different Q-Box diameters (p < 0.05). The intraclass correlation coefficients (ICCs) were up to 0.98 at Q-Box diameters of 10, 20, and 30 mm. Conclusions Our study showed that Q-Box size may lead to significant differences in LSVs, especially when LSVs <= 6.2 kPa. The Q-Box size had a large effect on the reliability of a single LS measurement but did not affect the repeatability of multiple measurements.