Liver, Biliary Tract, and Pancreas
The diagnosis of diseases of the liver, biliary tract, and pancreas optimally depends on using both clinical and radiographic data. Understanding the proper use of these data and ordering radiographic studies in the optimal sequence are helpful for making the diagnosis most efficiently. Fre-quently, the clinical presentation and associated laboratory work provide most of the clues for diagnosis. Physical examination, history, and pertinent laboratory values are often helpful in making the diagnosis or at least in providing clues for selecting the optimal radiographic studies. If clinical in-formation is insufficient or if radiographic confirmation is necessary, plain films and contrast studies may be performed. Upright and supine plain radiographs are helpful for the de-tection of free air, calcifications, and other abnormalities. Contrast studies such as endoscopic retrograde cholan-giopancreatography (ERCP), magnetic resonance cholan-giopancreatography (MRCP) and percutaneous transhepatic cholangiography (PTC) are often helpful in analyzing dis-eases of the liver, biliary tree, and pancreas. For instance, pan-creatic or biliary ductal systems, fistulae from these ductal systems, and associated abnormalities such as encasing tu-mors can be diagnosed by cholangiography.
Digital cross-sectional imaging, nuclear medicine (NM) and an important form of NM called positron emission to-mography (PET), and angiography have provided consider-able information in analyzing diseases of these organs, which cannot be directly visualized with plain radiography, even using traditional contrast material, that is, barium. Cross-sectional techniques consist of ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging.