Quantitative Liver Fat Assessment by Handheld Point-of-Care Ultrasound: A Technical Implementation and Pilot Study in Adults

Objectives: To implement, examine the feasibility of, and evaluate the performance of quantitative ultrasound (QUS) with a handheld point-of-care US (POCUS) device for assessing liver fat in adults.

Materials and methods: This prospective IRB-approved, HIPAA-compliant pilot study enrolled adults with overweight or obesity. Participants underwent chemical-shift-encoded magnetic resonance imaging to estimate proton density fat fraction (PDFF) and, within 1 mo, QUS with a POCUS device by expert sonographers and novice operators (no prior US scanning experience). Radiofrequency data from the liver collected with the POCUS device were analyzed offline using probe-specific calibrations to estimate two QUS parameters: attenuation coefficient (AC) and backscatter coefficient (BSC). Area under the receiver operating characteristic curve (AUC) of each parameter was estimated for classifying presence/absence of hepatic steatosis (defined as PDFF ≥ 5%). Spearman rank correlation between each parameter and PDFF was estimated and its significance assessed.

Results: Of 18 participants (mean age, 43 y ± 14; 17 women), 8 had hepatic steatosis (PDFF ≥ 5%). Both AC and BSC classified hepatic steatosis accurately with AUCs of 0.96-0.97 for expert and 0.88-0.89 for novice operators (p < 0.01 for all) and correlated significantly with PDFF with rho's of 0.65-0.69 for expert and 0.58-0.65 for novice operators (p < 0.02 for all).

Conclusion: QUS can be implemented on a POCUS device and can be performed by expert or novice operators after limited training in adults with overweight or obesity with promising initial results.