Phase-contrast MR flow imaging: A tool to determine hepatic hemodynamics in rats with a healthy, fibrotic, or cirrhotic liver

Abstract

Purpose: To test a magnetic resonance (MR) scanning protocol as a noninvasive tool to determine hepatic hemodynamics and to assess the degree of liver fibrosis in an animal model of liver fibrosis and cirrhosis. Materials and Methods: Fifty-four male Wistar rats were studied. Thirty-nine received thioacetamide (TAA) in their drinking water for either 12 or 16 weeks. MR measurements were performed using flow-sensitive 2D phase-contrast MRI and a 9.4T preclinical scanner. The following hemodynamic parameters were investigated: portal cross-sectional area, mean portal flow velocity, and portal and aortic flow volume rate. Therefore, rats (n = 46) were divided into three groups: CON (control, n = 13), FIB (fibrosis, n = 25), and CIR (cirrhosis, n = 8). Furthermore, the degree of liver fibrosis was assessed by a self-established MR score and verified by a standardized histological score (n = 48). Results: Portal and aortic flow parameters could be reliably detected. A significant decrease in portal flow velocity was found in FIB (FIB vs. CON: –21%, P = 0.006 and CIR vs. CON: –17%, P = 0.105) and in portal flow volume rate in FIB and CIR (FIB vs. CON: –20%, P = 0.009 and CIR vs. CON: –25%, P = 0.024). If the histological score is taken as standard, the self-established MR score enabled discrimination between healthy and diseased livers (sensitivity to identify diseased livers: 89% and specificity to identify healthy livers: 100%). Conclusion: This MR scanning protocol presents a noninvasive tool to determine hepatic hemodynamics in healthy and diseased rats. Level of Evidence: 2. Technical Efficacy: Stage 1. J. Magn. Reson. Imaging 2017;46:1526–1534.