Direct comparison of ultrasound-guided attenuation parameter and controlled attenuation parameter for steatosis using...

Hepatic steatosis, which is associated with liver diseases and adverse clinical outcomes, requires accurate, noninvasive diagnostic methods because of the limitations of liver biopsy. This study aimed to evaluate the effectiveness of the ultrasound-guided attenuation parameter (UGAP), a novel technique for assessing hepatic steatosis, and to compare its diagnostic performance with that of the controlled attenuation parameter (CAP), using magnetic resonance imaging (MRI)-derived proton density fat fraction (PDFF) as the reference standard.

A total of 255 patients with chronic liver disease who underwent CAP, UGAP, and MRI-PDFF were prospectively enrolled from three liver centers in Japan. Using the area under the receiver operating characteristic curve (AUROC) analysis, cutoff values for UGAP were determined according to steatosis grades based on MRI-PDFF. To minimize overfitting, diagnostic performance was validated using five-fold cross-validation.

CAP and UGAP values followed normal distributions, whereas PDFF values deviated from normality and were therefore log-transformed, yielding the variable MRI-logPDFF. CAP and UGAP demonstrated significant correlations with MRI-logPDFF, with intraclass correlation coefficients of 0.696 and 0.797, respectively. For MRI-PDFF-based grading, the AUROC (95% confidence interval) values of CAP and UGAP were 0.878 (0.813-0.923) versus 0.926 (0.867-0.960) for S0 versus S1-S3 (P=0.041), 0.820 (0.763-0.865) versus 0.908 (0.861-0.940) for S0-S1 versus S2-S3 (P<0.001), and 0.863 (0.811-0.902) versus 0.897 (0.852-0.930) for S0-S2 versus S3 (P=0.128), respectively. The validation analysis produced results consistent with those of the primary cohort.

UGAP showed greater diagnostic accuracy than CAP for hepatic steatosis, notably in detecting grades ≥S1 and ≥S2.