The evaluation by magnetic resonance imaging of hepatic periportal fibrosis in infants with neonatal cholestasis: preliminary report.

ABSTRACT

PURPOSE: The aim of this study was to evaluate the potential role of magnetic resonance (MR) imaging cholangiography for the assessment of periportal fibrosis associated with neonatal cholestasis. METHODS: The authors have compared the findings on MR imaging cholangiography and on pathology in 10 infants evaluated because of neonatal cholestasis. The series included 3 patients with biliary atresia (BA), 3 patients with choledocal cyst, 2 with a neonatal hepatitis, and 2 with an inspissated bile syndrome. MR examinations were performed on a 0.5 Tesla magnet unit using Turbo Field Echo T1 and Turbo spin echo T2 sequences. A periportal hyposignal paralleling the portal vein branches and disappearing after Gadolinium injection was considered consistent with periportal fibrosis. The final type of hepatobiliary anomaly was established based on surgery (n = 6) or on laparoscopic cholangiogram (n = 10). The degree of periportal fibrosis was evaluated on pathology using a grading system from grade 0 (no fibrosis) to 4 (fibrosis with cirrhosis). The relationship between periportal hyposignal and fibrosis was tested using the exact chi2 test. RESULTS: MR imaging assessed correctly and more completely than ultrasound scan the morphology of the biliary tract in all 10 patients. A periportal hyposignal was present in the 3 patients with BA (2 patients displayed a grade 3 and one a grade 4 fibrosis on pathology) and in one with choledocal cyst (grade 3 fibrosis on pathology). No hyposignal was visualized in the 2 other patients with a choledocal cyst (grades 1 and 2), in the 2 patients with neonatal hepatitis (grades 1 and 2), or in the 2 patients with inspissated bile syndrome (both grade 0). A relationship between the hyposignal seen on MR and the degree of fibrosis seen on pathology was confirmed by the exact chi2 test (P =.019). CONCLUSIONS: This preliminary series confirms the potential role of MR imaging for the assessment of the morphology of the abnormal biliary tract and of the degree of periportal fibrosis. The presence of an hyposignal on an echo gradient TFE T1 sequence suggests an advanced fibrosis (grade 3 and higher).