Functional CT with an experimental intravascular contrast agent in the assessment of liver vascular physiology

Rationale and Objectives, We evaluated liver vascular physiology with a functional spiral computed tomography (CT) technique and an intravascular contrast agent. Methods. Eleven rabbits were studied by means of continuous 40-second single-section data acquisition after bolus injection of an experimental contrast agent. Sequential images were reconstructed at 200-msec intervals. Aortic, portal and hepatic venous, and liver time- HU curves were obtained. From these, hepatic blood volume and flow, tissue transit times, and arterial and portal contributions to total liver blood supply were assessed. Results. The following measures were obtained: hepatic blood volume fraction, 0.33 +/- 0.03 (mean +/- standard error), total flow, 241.1 mL/min +/- 33.6 per 100 g of tissue (arterial component, 11.3 mL/min +/- 3.0 per 100 g of tissue; portal component. 226.4 mL/min +/- 30.7 per 100 g of tissue); arterial transit time, 5.7 seconds +/- 1.6: portal transit time, 8.7 seconds +/- 1.3; arterial to portal perfusion ratio, 0.06 +/- 0.01; and calculated arterial and portal perfusion indexes, 0.05 +/- 0.01 and 0.95 +/- 0.01, respectively. Conclusion. Functional CT is a promising, high-resolution tomographic imaging technique for evaluating liver perfusion.