Spiral CT of the liver.

The usefulness of CT in the detection and characterization of hepatic disease is well established. Requirements for high-quality examinations include rapid bolus infusion of iodinated contrast materials, rapid acquisition of axial images, and minimal respiratory motion in the patient. These requirements are satisfied in spiral or helical CT. Spiral CT is the latest advance in rapid scanning techniques. In the spiral scan mode, image acquisition is continuous, as patients are advanced at a constant rate through the CT gantry. This eliminates the interscan delay and the gap between scan slices. Because the scan can be completed within a single breath-hold, respiratory misregistration of adjacent scan slices is eliminated. These factors also contribute to high-quality multidimensional displays (e.g., coronal and sagittal views). In this pictorial essay, we illustrate the advantages and applications of spiral CT scanning for imaging the liver.