Assessment of nonalcoholic fatty liver function by photoacoustic imaging

Abstract

SignificanceThe assessment of liver function plays an important role in the diagnosis of nonalcoholic fatty liver disease (NAFLD). Current noninvasive imaging methods have limited applicability in this regard.AimWe report an application of multispectral photoacoustic imaging (PAI), an emerging modality, to visualize lipid accumulation and liver function in NAFLD.ApproachWe first demonstrated the liver function reserve with indocyanine green (ICG) to verify the organ’s dysfunction due to NAFLD in a rabbit model. We then noninvasively quantified lipid content in the liver using multispectral PAI. The in vivo PAI results were compared and verified with photoacoustic ex vivo images and liver biopsy.ResultsA significant difference in the lipidmean value was observed [lipidmean = 0.081 ± 0.0161 arbitrary units (a.u.) control versus NAFLD 0.198 ± 0.048 a.u., P = 0.003]. Similar to in vivo analysis, a significant difference in lipidmean was observed (lipidmean = 0.0673 ± 0.0165 versus 0.486 ± 0.073 a.u., P < 0.0001) between control and NAFLD group ex vivo. For liver function, the control group showed a rapid decrease after the peak point, whereas the elimination of ICG for the NAFLD group was slower.ConclusionsOur study shows that PAI has the potential to provide a noninvasive biomarker for the assessment of liver function and lipid accumulation for NAFLD diagnosis and treatment.