Portal vein contribution to the right and left lobes of the liver using MRI and CFD

Chronic liver disease, which ultimately results in cirrhosis of the liver, is a growing and deadly problem in the United States. Liver disease preferentially occurs in the right lobe of the liver, inhibiting the ability of the right lobe to function. The left lobe of the liver can then grow to compensate for the loss of function. These pathophysiologic changes may be seen in the hemodynamics of the portal vein. This study seeks to utilize magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) to investigate hemodynamic changes in the portal vein in relation to liver volume. To date this study includes four patients with a diagnosis of cirrhosis and a set of seven normal subjects. The portal vein (PV), splenic vein, superior mesenteric vein, right portal vein and left portal vein were imaged with MRI and velocity data were obtained. The geometry was used to create a computational mesh, which was then imported into FLUENT to solve this 3D laminar flow field. Boundary conditions were obtained from the PC-MRI data. Results show that PV velocity per unit of liver volume is significantly decreased in patients. The CFD calculations showed an increase in secondary, swirling flow patterns in the PV of patients, likely due to the increase in resistance in the liver and to asymmetry in the inlets and outlets. These preliminary results illustrate hemodynamic changes due to chronic liver disease. In future studies the liver will be segmented by lobe to calculate flow per unit liver volume in each lobe in more subjects with varying degrees of disease. Long range significance may include non-invasive evaluation of progression of chronic liver disease incorporating hemodynamic parameters.