Gastroenterology and Hepatology

MR enterography is valuable for determining extent of inflamed bowel, discriminating between active inflammation and chronic fibrosing disease, detecting fistulae, and detecting strictures. Additionally, MRI can provide excellent delineation of the course of perianal fistulas, including relationships to sphincters and levators.

This is the MRI equivalent of a HIDA scan, but with anatomic detail. It requires administration of the contrast agent Eovist, which has biliary excretion. To work well, the bilirubin should be under 3 mg/dL in those patient's with otherwise normal liver function. In cirrhotic patients with compromised liver function, the bilirubin should be under 2 mg/dL.

This imaging exam provides volumes of the liver and its segments, as well as delineation of ductal, arterial, and venous anatomy to assess suitability for partial liver donation.

For pancreatic lesions, such as serous and mucinous tumors, and intraductal papillary mucinous tumors.

MRI is valuable in detecting etiologies and complications of pancreatitis. Potential etiologies include biliary stones and congenital anomalies. Complications are acute fluid collections, necrosis, aneurysms, hemorrhage, splenic vein thrombosis, abscess, and pseudocyst.

MRI may be used for detection and characterization of lesions in the cirrhotic level is based on T2 signal, diffusion, and contrast enhancement characteristics. Because there is no ionizing radiation in the exam, many images with different contrasts can be obtained of the cirrhotic liver, thereby increasing the sensitivity and specificity of the exam.

Note that if an exam is specified as a pre-transplant evaluation, reporting will conform to specific UNOS guidelines.

Characterization of liver masses by MRI is aided by the excellent soft tissue contrast of the modality.