Evaluation of the Hepatorenal B-Mode Ratio and the "Controlled Attenuation Parameter" for the Detection and Grading of Steatosis.

Purpose:  The aim of this study was to evaluate the hepatorenal index ratio of Supersonic Imagine (B-mode ratio) and the controlled attenuation parameter (CAP) of FibroScan for the noninvasive diagnosis and grading of steatosis.

Materials And Methods:  Two centers prospectively included patients who underwent liver biopsy, B-mode ratio and CAP evaluation all on the same day between June 2017 and July 2019. MRI and histological morphometry were also performed in center 1. Histology (classic semiquantitative score and morphometry) was used as the reference.

Results:  Concerning the B-mode ratio, the AUROCs for ≥ S1, ≥ S2 and ≥ S3 were respectively 0.896 ± 0.20, 0.775 ± 0.30 and 0.729 ± 0.39 with the best cut-off values being 1.22 for ≥ S1 (Se = 76.4 %, Sp = 93.2 %), 1.42 for ≥ S2 (Se = 70.2 %, Sp = 71.2 %) and 1.54 for ≥ S3 (Se = 68.4 %, Sp = 69.8 %). The correlation between the B-mode ratio and morphometry was moderate (Rs = 0.575, p < 0.001) and the correlation between the B-mode ratio and MRI was good (Rs = 0.613, p < 0.001). Concerning the CAP, the AUROCs for ≥  S1, ≥ S2 and ≥ S3 were 0.926 ± 0.18, 0.760 ± 0.30 and 0.701 ± 0.40, respectively, with the best cut-off values being 271 dB/m for ≥ S1 (Se = 84 %, Sp = 88.2 %), 331 dB/m for ≥ S2 (Se = 64.5 %, Sp = 74.7 %) and 355 dB/m for ≥ S3 (Se = 55.3 %, Sp = 75.1 %). The correlation between the CAP and morphometry and between the CAP and MRI was moderate in both cases (Rs = 0.526, p < 0.001 and Rs = 0.397, p < 0.001, respectively). The B-mode ratio was better at ruling in and the CAP was better at ruling out the disease.

Conclusion:  B-mode ratio and CAP show similar and good performance for the diagnosis of steatosis (≥ S1). However, both techniques are limited with respect to differentiating mild to moderate (≥ S2) or severe (≥ S3) steatosis.