Impaired regulation of portal venous flow in response to a meal challenge as quantified by 4D flow MRI

Abstract

Purpose-Portal and mesenteric hemodynamics is greatly altered in portal hypertension patients. This study utilizes four-dimensional flow MRI to visualize and quantify changes in abdominal hemodynamics in patients with portal hypertension undergoing meal challenge.Methods & Materials-Twelve portal hypertension patients and six healthy subjects participated in the study. Baseline MRI was acquired after 5 hours of fasting. Post-meal MRI was obtained 20 minutes after subjects ingested EnSurePlus®(574mL). Imaging was performed at 3T using 4D flow MRI with an undersampled radial acquisition. Flow measurements were performed blinded to subject status (fasting/meal). Flow values for each vessel were compared before and after the meal challenge using paired Student t-tests (P<0.05).Results-After meal challenge, significant increases in blood flow were observed in supra-celiac aorta, portal vein, superior mesenteric vein and artery, in both groups (p<0.05). In patients, hepatic artery (p=0.001) and splenic vein (p=0.045) flow decreased while azygos vein flow (p=0.002) increased.Conclusion-Portal venous flow regulation to adjust the increasing mesenteric venous flow after a meal challenge may be impaired in patients with cirrhosis. The ability to comprehensively quantify the hemodynamic response of the abdominal vasculature to a meal challenge using 4D flow MRI reveals the potential of this technique to noninvasively characterize portal hypertension hemodynamics.

Splanchnic, Thoracoabdominal, and Cerebral Blood Flow Volumes in Healthy Children and Young Adults in Fasting and Postprandial States: Determining Reference Ranges by Using Phase-Contrast MR Imaging

“…It allows time-resolved three-dimensional visualization and retrospective quantification of blood flow at any location in a three-dimensional volume (14). Feasibility of four-dimensional flow in morphologic and hemodynamic assessment of the hepatic and splanchnic vasculature in adults with cirrhosis and portal hypertension has been demonstrated (27) and has also been used recently to measure the hemodynamic response of the portal venous system to a meal (28,29).…”

Comprehensive assessment of the global and regional vascular responses to food ingestion in humans using novel rapid MRI

“…Most studies have been carried out in animals, with little data from humans, and studies have generally relied on techniques with limited reliability and accuracy to estimate regional blood flow. Recently, a study in humans using novel 4D-flow MRI has been carried out (9). This showed that postprandial blood flow responses in the splanchnic territory in patients with liver cirrhosis were impaired, compared with controls.…”

Four-dimensional Flow MRI as a Marker for Risk Stratification of Gastroesophageal Varices in Patients with Liver Cirrhosis

“…Previous studies (10) validated the accuracy of radial 4D flow MRI in the abdominal vasculature in a porcine model. This technique can make visible the vascular tree including collaterals and possibly gastroesophageal varices, and quantify the flow in these vessels (11) and characterize alterations in collateral blood flow (12). Furthermore, it is known that portal hypertension increases the azygos flow, which can be measured at phase-contrast MRI (13).…”

“…Assessment of the intra-and interreader variability of flow measurements made at 4D flow MRI is important when evaluating the performance of quantitative markers. Fortunately, the intra-and interreader variability of the radial 4D flow MRI method describing this work was extensively evaluated and previously reported by multiple authors (12,14,33). Another limitation is that we used only 4D flow MRI-based MR angiography for a morphologic assessment of varices.…”