Comparison of uniphasic versus biphasic bolus contrast material injections for dynamic hepatic CT

This paper compares the CT intensity of contrast material enhancement of the hepatic parenchyma during uniphasic and biphasic bolus contrast material injections to determine the best method of contrast material administration. Two-hundred patients underwent dynamic hepatic CT with a GE 9800 CT/T scanner. One-hundred patients received 150 mL of 60% iodinated contrast material at a rate of 2.5 mL/sec times 20 seconds and 1 mL/sec times 100 seconds, and 100 patients at a rate of 2.5 mL/sec for 60 seconds. Aortic enhancement was measured on each scan. Hepatic attenuation was measured from 2 or 3 locations in the liver, and the average of the measurements and the time from initiation of the bolus were recorded. Uniphasic injection produced an earlier (81 seconds vs 119 seconds) and higher (118 HU vs 105 HU) peak hepatic enhancement, which was sustained (minimum, 2.5 HU last scan; maximum, 22.5 HU at 81 seconds) over the entire scan sequence. Peak aortic enhancement also was earlier (56 seconds vs 89 seconds) and higher (242 HU vs 188 HU) with the uniphasic injection