Diagnostic utility of radiological heterogeneity in acute severe (fulminant) autoimmune hepatitis

Background Histological examination is useful for the diagnosis of acute severe (fulminant) autoimmune hepatitis (AIH), but it is sometimes difficult to perform liver biopsy due to the complicated coagulopathy and ascites. We have shown that heterogeneous hypoattenuation on unenhanced computed tomography (CT) is a characteristic imaging feature of acute severe (fulminant) AIH. In the present study, we examined the utility of the imaging feature by applying the score to diagnose acute severe (fulminant) AIH. Methods Twenty-three patients with acute severe (fulminant) AIH were analyzed retrospectively. Modified AIH score was created by adding three points to AIH score with/without histological points in case of the presence of heterogeneous hypoattenuation on unenhanced CT. Results Areas of hypoattenuation were present in 15 (65%) patients, all of which were heterogeneous pattern. Five (22%) patients were diagnosed as "definite" AIH, 16 (69%) as "probable" and two (9%) as "non-diagnosis" by the revised original score without histological score. By adding three points, two of "non-diagnosis"changed to "probable" AIH, and all patients were diagnosed as AIH. Conclusions Modified AIH score using heterogeneous CT image finding would be beneficial especially for patients in whom histological examinations cannot be performed because of complications.