Deep attenuation transducer to measure liver stiffness in obese patients with liver disease

Deep attenuation transducers (DAX) are capable of imaging at diagnostic depths of up to 40 cm. The feasibility of DAX for liver stiffness measurement (LSM) has not been reported clinically. We aimed to assess the feasibility and reliability of DAX for LSM.

Overall, 219 patients with chronic liver disease were enrolled. The success rate (acquired after ≥ 10 valid measurements) and inadequate measurements (interquartile range/median ≥ 0.3) for DAX were compared with those of conventional convex (c-convex) probes and M and XL probes of vibration-controlled transient elastography.

LSM was successfully performed for all patients using DAX through all degrees of skin-to-liver capsular distance (SCD). Especially in patients with an SCD ≥ 30 mm, the difference in the rate of acquisition of 10 valid measurements was remarkable: M probe (8/33, 24.2%), XL probe (26/33, 78.8%), c-convex probe (33/43, 76.7%), and DAX (44/44, 100%). In patients with an SCD ≥ 30 mm, the inadequate measurement rate of M probe (1/8, 12.5%), XL probe (8/26, 30.8%), and c-convex probe (6/33, 18.2%) was higher than that of DAX (1/43, 2.3%). The areas under the curve for diagnosis of F4 with shear wave speed by c-convex and DAX were 0.916 and 0.918, respectively. Between DAX and c-convex probes, the intraclass correlation coefficient of 0.937 (95% CI 0.918-0.952) was excellent. Bland-Altman plots revealed that there was no statistically significant bias.

Liver stiffness measured by DAX is feasible and reliable for all patient populations, while the XL probe is limited to use in obese patients.