  Label-free metabolic imaging of non-alcoholic fatty liver disease (NAFLD)
mouse liver is demonstrated ex vivo by dynamic optical coherence tomography
(OCT). The NAFLD mouse is a methionine choline-deficient (MCD)-diet model, and
two mice fed MCD diet for 1 and 2 weeks are involved in addition to a
normal-diet mouse. The dynamic OCT is based on repeating raster scan and
logarithmic intensity variance (LIV) analysis which enables volumetric
metabolic imaging with a standard-speed (50,000 A-lines/s) OCT system.
Metabolic domains associated with lipid droplet accumulation and inflammation
are clearly visualized three-dimensionally. Particularly, the normal-diet liver
exhibits highly metabolic vessel-like structures of peri-vascular hepatic
zones. The 1-week MCD-diet liver shows ring-shaped highly metabolic structures
formed with lipid droplets. The 2-week MCD-diet liver exhibits fragmented
vessel-like structures associated with inflammation. These results imply that
volumetric LIV imaging is useful for visualizing and assessing NAFLD
abnormalities.
