Determination of the integrated CT number of the whole liver in patients with severe hepatitis: as an indicator of the functional reserve of the liver.

A study was conducted to estimate the functional reserve of the liver of patients with severe hepatitis by computed tomography (CT), in particular employing the integrated CT number of the whole liver (ICTN). ICTN was calculated by integrating the product of "area" times "mean CT number" of the liver in each CT slice for the entire height of the liver. The following results were obtained: 1) In patients with fulminant hepatitis (FH) as well as those with subacute hepatitis (SAH), ICTN was found to be significantly lower as compared to that of patients with acute hepatitis (AH) or non-hepatic diseases. In addition, in FH and SAH patients, ICTN showed a larger degree of decrease when compared with such conventional parameters as either estimated liver volume or mean hepatic CT number. Thus, ICTN seems to more sensitively reflect the changes in functional reserve of the liver. 2) ICTN showed significant positive correlations with prothrombin time and plasma BCAA/AAA ratio, and a significant negative correlation with plasma methionine level. 3) Time course of changes in ICTN correlated well with the clinical features of severe hepatitis. In particular, patients with initial ICTN values above 20 l.HU/m2 of body surface area showed significantly higher survival rate than those with initial ICTN below 20. In conclusion, ICTN well indicates the functional reserve of the liver, and is further suggested to be valuable as a parameter to predict the prognosis of patients with severe hepatitis.