M. Ferraz, São Paulo, BR

There is scarce published data on the MR imaging features of autoimmune hepatitis (AIH) and their frequency; moreover, no previous study has assessed the repeatability of such findings. Our purpose was to determine the frequency and interobserver reproducibility of the MR diagnostic features for AIH.

Material and methods

Two abdominal radiologists, blinded to pathology data, reviewed MRI exams of 20 patients with a confirmed diagnosis of AIH for the presence of patchy or heterogeneous liver enhancement, lymphadenopathy, findings of portal hypertension, chronic liver disease and its complications. Hepatic fibrosis was graded as reticular (mild, moderate or severe), or confluent. Inter-reader agreement was assessed through intraclass correlation coefficients and κ statistics.

Results

The most common abnormal finding was surface nodularity (85%), liver reticular fibrosis (80%) [mild (25%), moderate (43.8%), severe (31.2%)], heterogeneous enhancement (65%), splenomegaly (60%), caudate lobe enlargement (50%) and lymphadenopathy (40%). Overall inter-reader agreement was almost perfect for surface nodularity (0.83), ascites (0.89) and hepatic volume (0.95); however, it was just slight (0.12) and fair (0.25) for fibrosis degree and heterogeneous liver enhancement, respectively. It was also slight (0.14) or fair (0.36) for findings of chronic liver disease, such as expanded gallbladder fossa and enlarged preportal space, respectively.

Conclusion

Overall inter-reader agreement was satisfactory for surface nodularity (the most prevalent abnormal finding), ascites, hepatic volume and splenomegaly. Conversely, frequent but less objective criteria had only slight to fair inter-reader agreement. Further studies are necessary to establish more consistent and reproducible criteria for assessing the morphological changes inherent to AIH on MRI.

Collapse