CT of noncystic liver lesions: bolus enhancement.

The combination of rapid bolus injections of urographic contrast medium and timed sequential computed tomography (CT) scans permits recognition of different patterns of enhancement. In a series of 68 proven tumors of the liver, minimal enhancement was observed in 68% of the lesions, homogeneous positive enhancement in 9%, and complex patterns in 23%. Sequential scanning of these lesions demonstrated both early and late contrast enhancement. Early enhancement seems to be related to tumor vascularity, whereas delayed uptake may be caused by slow diffusion into an abnormally large extravascular space. Although the combination of bolus injection and serial scans seems very promising in the detection of solid liver tumors, the usefulness of the method is limited by present inability to study the entire organ sequentially.