Potential Pitfall of MR Cholangiopancreatography: Right Hepatic Arterial Impression of the Common Hepatic Duct

Abstract

Purpose: 

The purpose of this study was to evaluate the frequency and imaging characteristics of nonpathologic narrowing that is seen in the common hepatic duct on MR cholangiopancreatography (MRCP), which can be caused by impression of the right hepatic artery.

Method: 

MRCP images obtained in 52 patients were reviewed by two radiologists who attained consensus for evaluation of the frequency, degree, and length of narrowing of the common hepatic duct. Subsequent endoscopic retrograde cholangiopancreatography, CT, ultrasonography, and follow-up imagings performed in 3-6 months were reviewed for evaluation of the narrowing in the common hepatic duct seen with MRCP images.

Results: 

Smooth narrowing of the common hepatic duct that was presumably due to right hepatic arterial impression was seen in 11 (21%) of 52 patients. The extrinsic impression was severe in none, moderate in five, and subtle in six patients, ranging in length from 4 to 11 mm (mean 7.9 mm).

Conclusion: 

Radiologists should avoid misinterpreting a smooth and short narrowing in the common hepatic duct on MRCP images by recognizing the possible presence of the right hepatic artery that makes an impression on the common hepatic duct.