MRI Findings in the Liver in Biliary Atresia Patients after the Kasai Operation

Abstract

To evaluate liver function in biliary atresia (BA) patients after the Kasai operation, magnetic resonance imaging (MRI) was carried out 28 times in 19 BA patients. Sixteen of these were divided into three groups on the basis of the serum level of total bilirubin (t-bil), glutamic pyruvic transaminase (GPT) and γ-glutamyltransferase (γ-GTP) in the postoperative follow-up period (2-11 years). In group 1 (n=7) the t-bil was continuously kept under 1 mg/100 ml. In group 2 (n=4) the t-bil was continuously kept under 1 mg/100 ml, but GPT and γ-GTP remained high (GPT>100 IU/liter, γ-GTP>200 IU/ liter) for more than 2 years. In group 3 (n=5) an increase in the t-bil level reappeared (1-2 mg/100 ml; n=4, >2 mg/100 ml; n=1). The differences between MRI finding in the 3 groups, and the correlation between MRI findings and laboratory data (t-bil, cholinesterase; ChE, GPT and γ-GTP), which were taken around the time of MRI examinations, were studied. The results were as follows: (1) All 19 patients had normal or high signl areas of various sizes on T1 weighted images (WI). (2) Eighteen of 19 patients had high signal areas of various sizes on T2 WI in the portal system areas and/or liver parenchyma, and these areas were enhanced by gadolinium-DTPA in about half of the patients. (3) Ten of 16 patients had atrophic change over one liver lobe. (4) MRI findings for group 1 and the other groups were significantly different, and MRI findings, except for atrophic change, were correlated with the increase or decrease in laboratory data taken around the time of MRI examinations (p<0.05). These results indicate that a normal or high signal area on T1 WI shows functional tissue, and that a high signal area on T2 WI shows tissue damaged by inflammation and/or progressive fibrosis. MRI is useful for evaluating liver function, especially in terms of morphological features, in BA patients after the Kasai operation, and will be one method for establishing their prognosis.