NONNEOPLASTIC LIVER-DISEASE - EVALUATION WITH CT AND MR-IMAGING

A wide range of nontumorous hepatic diseases may have an impact on Liv er function and serve as indications for computed tomographic (CT) or magnetic resonance (MR) imaging. New imaging techniques such as spiral CT and fast MR imaging aid in detecting and characterizing these dise ase processes and in assessing the extent of disease. Infectious liver disease (eg, hepatic abscess, echinococcal disease, fungal infection) typically has low attenuation at CT and high signal intensity at T2-w eighted MR imaging. Cholangitis is characterized by ductal dilatation at both CT and MR imaging. In acute portal vein thrombosis, the thromb us has low attenuation at CT and is hyperintense relative to liver at MR imaging. Hepatic infarcts usually appear as well-circumscribed, per ipheral, wedge-shaped areas of decreased attenuation at CT. The causes or complications of cirrhosis can be most readily identified with MR imaging, In patients with chronic radiation-induced hepatitis, CT show s the irradiated parenchyma as a region of increased attenuation, wher eas T1- and T2-weighted MR imaging demonstrate geographic areas of low and high signal intensity, respectively. Hemachromatosis has homogene ously increased liver attenuation at CT and decreased signal intensity at gradient-echo MR imaging in particular. Familiarity with the CT an d MR imaging features of the spectrum of nonneoplastic conditions of t he liver is essential in making an accurate diagnosis.