Usefulness of Technetium‐99 m‐2‐methoxy‐isobutyl‐isonitrile liver scintigraphy for evaluating disease activity of non‐alcoholic fatty liver disease

Abstract

Aim: Non-alcoholic steatohepatitis (NASH) is a progressive form of non-alcoholic fatty liver disease (NAFLD). Therefore, it is important to evaluate disease activity and distinguish NASH from simple steatosis in NAFLD. Technetium-99 m-2-methoxy-isobutyl-isonitrile (^99mTc-MIBI) is a lipophilic cation designed for myocardial perfusion scintigraphy in the diagnosis of ischemic heart diseases, and its retention reflects mitochondrial function. It was reported that hepatic mitochondrial abnormalities would be an important predictive factor for NASH disease progression. The aim of this study was to examine the clinical usefulness of ^99mTc-MIBI liver scintigraphy for evaluating disease activity of NAFLD and distinguishing NASH from simple steatosis in patients with NAFLD. Methods: Twenty-six patients with biopsy-proven NAFLD were enrolled. Clinicolaboratory tests and ^99mTc-MIBI liver scintigraphy were performed. To evaluate hepatic uptake, regions of interest were set at the liver and heart, and the uptake ratio of the liver to heart (liver/heart ratio) was calculated. Results: All patients with NAFLD were classified into three groups according to the NAFLD activity score: non-NASH (simple steatosis) (n = 4), borderline NASH (n = 11), and NASH (n = 11). Liver/heart ratios were significantly lower in NASH than in simple steatosis (P < 0.05). Moreover, liver/heart ratios were significantly correlated with NAFLD activity scores among the patients (r = −0.413, P < 0.05). Conclusions: The present study indicates that ^99mTc-MIBI liver scintigraphy would be a useful non-invasive functional imaging method with which to evaluate disease activity of NAFLD and distinguish NASH from simple steatosis.