SPIRAL COMPUTED-TOMOGRAPHY OF THE LIVER - CONTRAST AGENT PHARMACOKINETICS AND THE POTENTIAL FOR IMPROVED HEPATIC ENHANCEMENT

Rationale and Objectives. We conducted a prospective study of 131 pati ents to evaluate the contrast agent dose-response relationship for liv er spiral computed tomography (CT) and to test the hypothesis that spi ral CT scanning provides greater enhancement than does dynamic CT scan ning. Methods. Patients were assigned to one of two control groups (dy namic CT) or to one of five experimental groups (spiral CT). Dynamic C T patients received 150 ml and spiral CT patients received either 75, 100, or 150 ml of diatrizoate meglumine. All groups had a monophasic i njection rate of 2.5 ml/sec. Hepatic enhancement was compared among ex perimental and control groups. Results. In the experimental groups, th ere was a linear dose-response relationship (p < .0001) among the enha ncements achieved for the three dosages. The enhancement of the last s lice of liver for the spiral CT versus dynamic CT groups receiving 150 mi was significantly greater (p = .002). Peak, first liver slice, and average liver enhancement values were higher with spiral CT scanning, but the difference was not statistically significant (power > .55). C onclusion. Using uniphasic injection rates and identical doses of cont rast agent, spiral CT scanning has the advantage of improved enhanceme nt of the last part of the liver to be imaged.