Dynamic CT densitometry of hepatic tumors.

Forty-two patients with hepatic tumors were examined by serial computed tomography (CT), using bolus injection of contrast medium. Scanning was at 15, 60, and 120 sec postinjection at a slice level containing the tumor. The densities of the tumor, liver, and aorta were sampled on these and on precontrast CT images. The tumors were divided into four types according to the pattern derived by sequential plotting of the density difference between the tumor and the liver parenchyma. Type I manifested rapid and prolonged high tumor enhancement, in type II the tumor was enhanced rapidly but then quickly became less dense than the liver, in type III there was no significant change over time in the density difference between the tumor and the liver, and type IV showed no, or very little, tumor enhancement. All cavernous hemangiomas belonged to type I while two-thirds of the hepatomas wer type II. There was a good correlation between tumor vascularity on CT and angiography. We suggest that dynamic serial CT scanning technique may be an improvement over the conventional drip-infusion technique in assessing liver tumors.