A pilot study investigating the use of 4D flow MRI for the assessment of splanchnic flow in patients suspected of mesenteric ischaemia.

The most common cause of chronic mesenteric ischaemia is atherosclerosis which results in limitation of blood flow to the gastrointestinal tract. This pilot study aimed to evaluate 4D flow MRI as a potential tool for the analysis of blood flow changes post-prandial within the mesenteric vessels. The mesenteric vessels of twelve people were scanned; patients and healthy volunteers. A baseline MRI scan was performed after 6 h of fasting followed by a post-meal scan. Two 4D flow datasets were acquired, over the superior mesenteric artery (SMA) and the main portal venous vessels. Standard 2D time-resolved PC-MRI slices were also obtained across the aorta above the coeliac trunk, superior mesenteric vein, splenic vein and portal vein (PV). In the volunteer cohort there was a marked increase in blood flow post-meal within the PV (p = 0.028), not seen in the patient cohort (p = 0.116). Similarly, there were significant flow changes within the SMA of volunteers (p = 0.028) but not for the patient group (p = 0.116). Our pilot data has shown that there is a significant haemodynamic response to meal challenge in the PV and SMA in normal subjects compared to clinically apparent CMI patients. Therefore, the interrogation of mesenteric venous vessels exclusively is a feasible method to measure post-prandial flow changes in CMI patients.