Arrival-Time Parametric Imaging in Contrast-Enhanced Ultrasound for Diagnosing Fibrosis in Primary Biliary Cholangitis.

Liver biopsy is usually required for diagnosing fibrosis in primary biliary cholangitis (PBC), but contrast-enhanced ultrasonography (CEUS) is a possible alternative. The aim of this study was to investigate arrival-time parametric imaging (At-PI) in for diagnosing fibrosis in PBC. Forty-eight patients (male/female, 8/40; mean age, 60 ± 13 years) with PBC diagnosed by liver biopsy underwent CEUS during 2009-2019. Of these, 27 who also underwent shear wave elastography (SWE) were further analyzed. Perflubutane was intravenously injected and CEUS performed. Contrast dynamics of hepatic segment V and the right kidney were recorded and At-PI generated. The ratio of red indicating contrast arrival time <5 seconds to the entire liver contrast-enhanced area was calculated and compared with shear wave velocity (Vs) measured by SWE by fibrosis stage (F0-F3), bile duct loss score, cholangitis activity, hepatitis activity (HA0-HA3), and disease stage, as determined by liver biopsy. Ratio of red significantly differed between F0 and F2-F3 and between F1 and F2-F3. Using ratio of red to diagnose ≥F1 (≥F2), area under the receiver operating characteristic curve was 0.77 (0.92) (cutoff, 36.7% [47.1%]; sensitivity, 0.75 [0.92]; specificity, 0.82 [0.81]). At-PI was useful for diagnosing fibrosis, especially F2 or worse, in PBC, suggesting that At-PI can correctly diagnose fibrosis regardless of hepatic inflammation.