Dynamic liver scan with spiral CT

Dynamic liver scan with spiral CT during a single breath hold was performed for to determing the optimal timing of scanning and the degree of the enhancement of liver and vessel. Liver spiral CT was performed on 143 patients and dynamic sequence scan on 2 normal volunteers. After baseline spiral CT without contrast enhancement, spiral CT was performed after administration of a bolus of 100 ml of nonionic contrast material intravenously with mechanical power injector at the constant injection rate of 2 mm/sec. Cephalocaudal scanning was started 45 seconds after the beginning of injection. In the majority of cases was employed 16-24 continuous scanning with table feed of 10 mm, slice thickness of 10 mm, and reconstructed in 5 or 10 mm section increments. We measured degree of enhancement of aorta, IVC, and liver parenchyma in all images. We have achieved bolus phase at all images from the following measured date: 170-250 H.U at aorta, 110-150 H.U at IVC, 80-125 H.U at liver parenchyma, 100-130 H.U at spleen, which shown contrast difference between aorta and IVC at least 45 H.U. At the dynamic sequence scan, aoritc and vascular CT attenuation reaches a peak at 55-60 sec and peak hepatic enhancement occurred at 70-75 sec with relative plateau achieve at 45 sec. Spiral CT also showed elimination of variation in diaphragmatic excursion. We could get the desirable phase imaging at overall examination from the dynamic liver scan around 45-60 seconds after injection of contrast media