New Measurement of Hepatic Blood Flow by Xenon CT System: An Animal Study with PGE1

Abstract

A new Xenon computed tomography (CT) system was developed to measure both hepatic arterial and portal venous tissue blood flow (HATBF/PVTBF) non-invasively. Despite its clinical trial, the effect of prostaglandin E1 (PGE1) on hepatic hemodynamics is not well investigated. In a rabbit model, we evaluated the accuracy of this system by comparing it with the electromagnetic blood flowmeter (EMBF), the pharmacological effect of PGE1 on the fractional hepatic hemodynamics. Seven NZW-rabbits were used. Serial abdominal CT scan was obtained every min before and during the 4 min inhalation of the Xenon gas, followed by 5 min administration of oxygen air. From these images, HATBF and PVTBF were separately calculated with a special new imaging system. We also used EMBF during laparotomy, and directly measured the hepatic arterial and portal venous flow with or without PGE1 administration. Xenon CT showed HATBF of 18.4 +/- 4.5 (ml/min/100 g) and PVTBF of 69.4 +/- 15.0, was almost identical with those of EMBF (19.8 +/- 5.7 and 67.2 +/- 19.1, respectively). After PGE1 administration, Xenon CT showed 22.9 +/- 4.6 and 76.5 +/- 20.5, while those with EMBF were 21.0 +/- 6.5 and 84.7 +/- 21.6, respectively. There were significant correlations (P < 0.01) in total HTBF, HATBF, and PVTBF between results of Xenon CT and EMBF. Xenon CT with a newly developed imaging system enables us to measure the fractional hepatic tissue blood flow in rabbits, differentially and accurately. Venous administration of PGE1 increased total hepatic blood flow, mainly affecting the portal blood flow.