Controlled attenuation parameter (CAP): the clinical value based on MRI-PDFF in children with obesity

Controlled attenuation parameter (CAP) is a noninvasive and quantitative method to evaluate hepatic steatosis, which is not well evaluated in children. The aim of this study was to examine the diagnostic value of CAP for hepatic steatosis in children with obesity based on MR proton density fat fraction (PDFF).

About 108 pediatric patients with nonalcoholic fatty liver disease (NAFLD) who were assessed for PDFF, CAP, and other laboratory results were enrolled. In this study, pediatric patients were separated for the obese group (n=80) and the severe obese group (n=28). Hepatic steatosis grades (0-3) were classified according to PDFF using cutoff values of 6.4 , 17.4, and 22.1 %.

There are significant differences in CAP between the obese and severe obese groups (p<0.05). CAP showed a good correlation with PDFF in pediatric patients with NAFLD for diagnosing hepatic steatosis using a cutoff value of 265 dB/m (p<0.001). Meanwhile, ALT significantly outperforms CAP in receiver-operating curve (ROC) analysis for diagnosing hepatic steatosis grades. The diagnostic accuracy of CAP for steatosis is 77.8 %, and the diagnostic accuracy of ALT for steatosis is 83.3 %.

While CAP holds promise as a diagnostic tool for pediatric NAFLD, its diagnostic performance warrants some caution. The potential of CAP is evident; however, ALT emerges as a simpler and more accurate measure for detecting hepatic steatosis in children. Further research is essential to determine the optimal role of CAP in pediatric NAFLD diagnosis and management.