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

Background: To investigate arrival-time parametric imaging (At-PI) in contrast-enhanced ultrasonography (CEUS) for diagnosing fibrosis in primary biliary cholangitis (PBC). Methods: Participants were 48 patients (male/female: 8/40; mean age, 60 ± 13 years) with PBC diagnosed by liver biopsy who underwent CEUS during 2009-2019. Of these, 27 (male/female: 4/23; mean age, 61 ± 13 years) who also underwent shear wave elastography (SWE) were further analyzed. SonazoidTM was intravenously injected and CEUS performed. Contrast dynamics of hepatic segment V and the right kidney were recorded. At-PI were generated from the recorded video clips. Contrast arrival time <5 s was displayed in red, and the ratio of red (ROR) area to the entire liver contrast-enhanced area was calculated. ROR and shear wave velocity (Vs) measured by SWE were compared by fibrosis stage (F0-F3), bile duct loss score, cholangitis activity, hepatitis activity (HA0-HA3), and disease stage (stage 1-4), as determined by liver biopsy.Results: ROR significantly differed between F0 and F2-F3 and between F1 and F2-3. Using ROR to diagnose ³F1 (³F2), area under the receiver operating characteristic curve (AUROC) was 0.77 (0.92) (cutoff, 36.7% [47.1%]; sensitivity, 0.75 [0.92]; specificity, 0.82 [0.81]). Vs significantly differed between F0 and F1, F0 and F2-3, and HA0 and HA1. For diagnosing ³F1 (³F2), Vs had AUROC of 0.84 (0.80) (cutoff, 1.23 m/s [1.40 m/s]; sensitivity, 0.75 [0.60]; specificity, 0.82 [0.86]).Conclusions: 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.