Utility of quantitative 99mTc-phytate scintigraphy to diagnose early-stage non-alcoholic steatohepatitis

Objective. In patients with non-alcoholic fatty liver disease (NAFLD), liver biopsy remains the only reliable method to differentiate simple steatosis from non-alcoholic steatohepatitis (NASH). The objective of this study was to evaluate the efficacy of non-invasive 99mTc-phytate scintigraphy in the diagnosis of NASH. Material and methods. Thirty-seven patients with suspected NAFLD at the time of liver biopsy also underwent 99mTc-phytate scintigraphy. Signal intensities of regions of interest (ROI) in the liver, spleen, and heart were measured. We also examined scintigraphic features in a nutritional model of NASH in rats fed a methionine- and choline-deficient (MCD) diet. Results. The liver/spleen uptake ratio determined by scintigraphy was significantly decreased in patients with NASH in comparison with patients with simple steatosis. The liver/spleen ratio was an independent predictor distinguishing NASH from simple steatosis. The decrease was observed for all stages of NASH, including the early stage (stages 1 and 0). In animal studies, the liver/spleen uptake ratio was significantly decreased in rats after 8 weeks of MCD dietary feeding in comparison with control diet-fed rats. Conclusions. The non-invasive 99mTc-phytate scintigraphy test is a reliable tool to differentiate NASH from simple steatosis.