Comparison of the clinical characteristics and imaging findings of acute cholangitis with and without biliary dilatation.

OBJECTIVE: To evaluate the causes of acute cholangitis without biliary dilatation and to compare the clinical characteristics and the imaging findings between patients with acute cholangitis with and without biliary dilatation. METHODS: 93 patients diagnosed with acute cholangitis underwent contrast-enhanced CT. Among them, 17 patients were classified as not having biliary dilatation (Group 1) and 76 patients were classified as having biliary dilatation (Group 2). The causes of acute cholangitis were evaluated in both groups. Clinical characteristics and imaging findings were compared between the two groups. RESULTS: The causes of acute cholangitis without biliary dilatation included common bile duct (CBD) stones (n=11), CBD sludge (n=3), a passed stone (n=1) and unknown causes (n=2). The total bilirubin levels of Group 1 were significantly lower than those of Group 2 (p=0.001). By contrast, Group 1 had higher median alanine aminotransferase (ALT) levels than Group 2 (p=0.04). The length of hospital stay was significantly longer in Group 2 than in Group 1 patients (p<0.001). In the imaging findings, the extent of transient hepatic attenuation differences (THADs) (p=0.003) were significantly smaller in Group 1 than in Group 2. CONCLUSION: CBD stones and sludge were the most common causes of acute cholangitis in patients without biliary dilatation. These patients showed lower levels of bilirubin and higher levels of ALT than those with acute cholangitis with biliary dilatation, and had a shorter duration of hospital stay. The extent of THADs was the only discriminative CT finding between the two groups. ADVANCES IN KNOWLEDGE: Acute cholangitis can present without biliary dilatation on imaging, and the most common causes are CBD stones and sludge. The patients with acute cholangitis without biliary dilatation have different clinical characteristics and imaging findings compared with those with acute cholangitis presenting with biliary dilatation.