Spiral CT of vascular liver lesions

Computed tomography (CT) has an important and undisputed role as a screening modality for suspected focal liver disease. Improvements in CT technology have dramatically increased our ability to detect and diagnose liver abnormalities. Spiral CT allows rapid imaging of the liver, resulting in improved contrast dynamics compared to conventional CT techniques. The timing of contrast administration and scan acquisition has become critical. With inadequate timing, lesions that in optimal conditions are easily visualized, can be ignored. Arterial phase imaging should be used when potential hypervascular neoplasms are suspected, and if possible, should include both arterial and portal venous phase imaging to ensure maximal lesion detection and visualisation of vascular structures. Portal venous phase imaging alone is optimal for evaluating most hypovascular tumors. This article reviews the principles of lesion detection and, to a lesser degree, lesion characterization. Special interest is focused on hypervascular lesions.