Characterization of mesenteric and portal hemodynamics using 4D flow MRI: the effects of meals and diurnal variation.

Abstract

To determine the variability of blood flow measurements using 4D flow MRI in the portal and mesenteric circulations and to characterize the effects of meal ingestion, time of day, and between-day (diurnal) variations on portal and mesenteric hemodynamics. In this IRB-approved and HIPAA-compliant study, 7 healthy and 7 portal hypertension patients imaged. MRI exams were conducted at 3T using a 32-channel body coil with large volumetric coverage and 1.25-mm isotropic true spatial resolution. Blood flow was quantified (L/min) in the hepatic and splanchnic vasculature. The first MR scan was performed after at least 8h of fasting. Subsequently, subjects ingested 574mL EnSure Plus® orally. A second acquisition was started 20min after the meal ingestion. A third scan was performed before lunch and a fourth acquisition took place 20min after lunch. A fifth scan was performed around 4pm. Finally, subjects returned one week later for a repeat morning visit, with identical conditions as the first visit. In healthy controls significant increase in blood flow was seen in the PV, SMV, SMA, HA, and SCAo in response to breakfast but only the SCAo, SMA, SMV, and PV had a significant response to lunch. In general, patients with cirrhosis showed reduced response to meals compared to that in healthy controls. Additionally, PV flow in patients had the highest value in the afternoon. Effects of meal ingestion, time of day, and between-day variations were characterized using Radial 4D flow MRI in patients with cirrhosis and healthy controls.