Second Harmonic Generation Reveals Subtle Fibrosis Differences in Adult and Pediatric Nonalcoholic Fatty Liver Disease.

Objectives: Investigate subtle fibrosis similarities and differences in adult and pediatric nonalcoholic fatty liver disease (NAFLD) using second harmonic generation (SHG).

Methods: SHG/two-photon excitation fluorescence imaging quantified 100 collagen parameters and determined qFibrosis values by using the nonalcoholic steatohepatitis (NASH) Clinical Research Network (CRN) scoring system in 62 adult and 36 pediatric NAFLD liver specimens.

Results: Six distinct parameters identified differences among the NASH CRN stages with high accuracy (area under the curve, 0835-0.982 vs 0.885-0.981, adult and pediatric). All portal region parameters showed similar changes across early stages 0, 1C, and 2, in both groups. Parameter values decreased in adults with progression from stage 1A/B to 2 in the central vein region. In children, aggregated collagen parameters decreased, but nearly all distributed collagen parameters increased from stage 1A/B to 2.

Conclusions: SHG analysis accurately reproduces NASH CRN staging in NAFLD, as well as reveals differences and similarities between adult and pediatric collagen deposition not captured by currently available quantitative methods.