Reproducibility of Splanchnic Blood Flow Measured Using Phase-Contrast MRI.

Splanchnic vessel blood flow assessment can describe physiology or pathophysiology and also has clinical relevance for patients with altered abdominal blood flow, vascular neuropathy, or atherosclerotic conditions. Reliable and practicable methods for this assessment are needed. We assessed the reproducibility of non-invasive phase-contrast MRI (PC-MRI) for measuring splanchnic blood flow and its feasibility for detecting postprandial blood flow changes. We included measurements from two groups of healthy individuals (Group A: n = 10; C: n = 10) and a group of patients with type 2 diabetes (B: n = 10) from randomized, single-blind, placebo-controlled studies, and assessed blood flow with 2D PC sequences (3 Tesla Siemens Biograph MRI and 3 Tesla Philips Achieva). Blood flow was measured in the arteria mesenterica superior, truncus coeliacus, arteria hepatica (Group A only), and vena portae hepatis over multiple days, with repeated scans each day to assess variability and reproducibility. To confirm detection of postprandial changes, nine repeated measurements were acquired during ingestion of 75-g oral glucose tolerance test compared to water ingestion. Reproducibility was assessed by coefficient of variation (CoV) and limits of agreement with the mean (LoAM) using an extended Bland-Altman analysis. Blood flow in arteria mesenterica superior, truncus coeliacus, and vena portae hepatis demonstrated low intrasubject within session CoV (7%-22%) and intrasubject between session CoV (16%-26%). Blood flow in arteria hepatica had poorer CoV for both within sessions (12%) and between sessions (32%). Glucose ingestion induced a blood flow peak increase of 88% ± 52% in arteria mesenterica superior and 68% ± 36% in vena portae hepatis, both robustly detected, while no change was observed in the arteria hepatica or truncus coeliacus. In conclusion, PC-MRI is a reproducible and feasible technique for measuring blood flow in arteria mesenterica superior, truncus coeliacus, and vena portae hepatis with the ability to detect postprandial changes. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT05391581, NCT06426823, NCT06774807.