Hemodynamic investigation of the liver using magnetic resonance imaging and computational fluid dynamics

Abstract

Cirrhosis is a leading cause of death in the United States and has severe and costly complications. Because of the clinical significance of cirrhosis, it is important that noninvasive methods be developed to detect cirrhosis early and to monitor its progression with advancing liver disease. Previous studies on portal venous hemodynamics have been performed mainly with ultrasound with mixed results. Magnetic Resonance Imaging offers several advantages over ultrasound including acquisition of both high quality anatomical and hemodynamic information. Phase-Contrast MR was used to gather velocity data for the portal venous system. Methods were developed to perform registration, segmentation and isolation of the portal vein geometries and velocity data. Computational Fluid Dynamics was also employed to further investigate the flow within the portal vein. Velocity data for the portal vein, superior mesenteric vein, splenic vein and the right or left portal vein was acquired in varying numbers for both data sets. Even with the limited number of subjects a few parameters were significant. Patients with cirrhosis had a significantly increased portal vein area and a significantly decreased average velocity per liver volume and velocity variance. Patients with cirrhosis had a significantly increased splenic vein area and average flow rate per liver volume. While these results are preliminary due to small sample size, they are promising and require further investigation and more subjects including varying stages of disease.