[Differential diagnoses of biliary tract diseases : Computed tomography and magnetic resonance imaging]

Bile duct diseases can be found in all age groups and show an increased prevalence in northern Europe. Pathologies range from benign diseases to malignant tumors with very poor survival.

Magnetic resonance imaging (MRI) and computed tomography (CT) are the radiological methods of choice for a detailed evaluation of the bile duct system in addition to sonography. By assessing the lumen and the wall of the bile ducts as well as the surrounding structures, both obstructive and nonobstructive pathologies can be diagnosed and differentiated with high sensitivity and specificity.

Technical developments with postprocessing modalities as well as the use of biliary-excreted liver-specific MR contrast agents improve the diagnosis of bile duct diseases and enable morphological and functional assessment.

Due to high patient tolerance, minimal procedural risk in contrast to invasive endoscopic methods and the possibility of three-dimensional post-processing, beside CT, MRI with magnetic resonance cholangiography (MRC) represents the method of choice in patients with sonographically or clinically suspected bile duct disease and has significantly reduced the indications of diagnostic endoscopic retrograde cholangiopancreatography (ERCP). A complementary multimodality and multiparametric imaging approach is particularly helpful for preoperative assessment.

Rapidly evolving technology for both MRI and CT represent opportunities and challenges. By understanding the advantages and limitations of modern MR and CT techniques and by knowing the spectrum of bile duct pathologies, improved diagnosis and narrowing of possible differential diagnosis can be achieved.