What imaging study is usually used to diagnose primary sclerosing cholangitis?

MRCP (Magnetic Resonance Cholangiopancreatography) is the preferred imaging study for diagnosing primary sclerosing cholangitis due to its ability to provide detailed images of the bile ducts without the need for invasive procedures. This non-invasive technique uses MRI technology to visualize the biliary tree and can reveal the presence of strictures and bile duct irregularities characteristic of primary sclerosing cholangitis.

The findings on MRCP often include multiple bile duct strictures with intervening dilatation, which are hallmark features of this condition. Additionally, MRCP does not expose patients to ionizing radiation, making it a safer option, especially for those who may require follow-up imaging.

While other imaging modalities like ultrasound and CT can be useful in the evaluation of liver and biliary diseases, they are not as specific for diagnosing primary sclerosing cholangitis as MRCP. Ultrasound may show bile duct dilatation but lacks the detail needed for a definitive diagnosis, and CT scans do not provide the same level of clarity for the bile ducts as MRCP.