Dynamic CT of acute cholangitis: early inhomogeneous enhancement of the liver.

OBJECTIVE: Our objective was to describe the dynamic CT findings of acute cholangitis, especially early inhomogeneous enhancement of hepatic parenchyma. MATERIALS AND METHODS: Inhomogeneous enhancement of hepatic parenchyma was retrospectively evaluated on dynamic CT in 406 consecutive patients without irregular fatty liver or multiple hepatic tumors. Dynamic CT scans were obtained 30 sec (early phase) and 90 sec (late phase) after starting the contrast material injection. Thirteen patients were diagnosed as having acute cholangitis (cholangitis group), and the remaining 393 patients were classified as the control group. The frequency of inhomogeneous enhancement was compared between these two groups. In nine of the 13 patients in the cholangitis group, we also evaluated changes in inhomogeneous enhancement on follow-up dynamic CT scans obtained after the patients had undergone treatment for acute cholangitis. RESULTS: In the cholangitis group, 11 (85%) of 13 patients showed nodular, patchy, wedge-shaped, or geographic inhomogeneous enhancement throughout the liver in the early phase on dynamic CT. In the control group, 19 (5%) of 393 patients also showed inhomogeneous enhancement in the early phase on dynamic CT. The frequency of inhomogeneous enhancement was significantly higher in the cholangitis group than in the control group (p < 0.001). Follow-up dynamic CT performed after treatment for acute cholangitis showed decreased inhomogeneous enhancement or no inhomogeneous enhancement in seven (78%) of nine patients in the cholangitis group. CONCLUSION: Inhomogeneous enhancement in the early phase on dynamic CT is frequently seen in patients with acute cholangitis; this finding usually disappears after treatment.