CT evaluation of the liver: principles and techniques.

Technical advances within the past decade have dramatically improved the diagnostic capabilities of CT, primarily due to helical CT scanners coupled with mechanical injectors for i.v. administration of contrast media. There is no such thing as a generic "abdominal CT scan"; rather, specific protocols should be utilized for optimal detection and characterization of hepatic masses (or other suspected pathologic processes). Multiphasic CT protocols are especially important for detecting hypervascular liver tumors. We present the principles and rationale for various CT protocols along with some of the common pitfalls. Understanding this background material will allow the reader to better understand subsequent articles dealing with specific applications of CT and other abdominal imaging techniques.