Using MRI to study the alterations in liver blood flow, perfusion, and oxygenation in response to physiological stress challenges: Meal, hyperoxia, and hypercapnia

• Published in: Journal of magnetic resonance imaging Vol. 49; no. 6; pp. 1577 - 1586
• Main Authors: Cox, Eleanor F., Palaniyappan, Naaventhan, Aithal, Guruprasad P., Guha, I. Neil, Francis, Susan T.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.06.2019
• Subjects: Adult; Aged; Arteries - diagnostic imaging; Blood flow; Cirrhosis; Coefficient of variation; Feasibility studies; Female; Fibrosis - diagnostic imaging; Field strength; Food; Healthy Volunteers; Hemodynamics; Hepatic artery; Hepatic Artery - diagnostic imaging; Humans; Hypercapnia; Hypercapnia - diagnostic imaging; Hypercapnia - metabolism; Hyperoxia; Hyperoxia - diagnostic imaging; Hyperoxia - metabolism; Labeling; Liver; Liver - blood supply; Liver - diagnostic imaging; liver blood flow; Liver cirrhosis; liver perfusion; liver T2; Magnetic Resonance Imaging; Male; Mapping; meal challenge; Microscopy, Phase-Contrast; Middle Aged; Oxygen - metabolism; Oxygenation; Perfusion; Phase contrast; Portal vein; Portal Vein - diagnostic imaging; Postprandial Period; Prospective Studies; Reproducibility; Reproducibility of Results; Spin dynamics; Spin labeling; Spin Labels; Statistical analysis; Statistical tests; Stress (physiology); Veins; Veins & arteries; Velocity; Young Adult; meal challenge; liver perfusion; hyperoxia; liver T2; liver blood flow; hypercapnia
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.26341

Background Noninvasive assessment of dynamic changes in liver blood flow, perfusion, and oxygenation using MRI may allow detection of subtle hemodynamic alterations in cirrhosis. Purpose To assess the feasibility of measuring dynamic liver blood flow, perfusion, and T2* alterations in response to meal, hypercapnia, and hyperoxia challenges. Study Type Prospective. Subjects Ten healthy volunteers (HV) and 10 patients with compensated cirrhosis (CC). Field Strength/Sequence 3T; phase contrast, arterial spin labeling, and T2* mapping. Assessment Dynamic changes in portal vein and hepatic artery blood flow (using phase contrast MRI), liver perfusion (using arterial spin labeling), and blood oxygenation (T2* mapping) following a meal challenge (660 kcal), hyperoxia (target PETO2 of 500 mmHg), and hypercapnia (target increase PETCO2 of ∼6 mmHg). Statistical Tests Tests between baseline and each challenge were performed using a paired two‐tailed t‐test (parametric) or Wilcoxon‐signed‐ranks test (nonparametric). Repeatability and reproducibility were determined by the coefficient of variation (CoV). Results Portal vein velocity increased following the meal (70 ± 9%, P < 0.001) and hypercapnic (7 (5–11)%, P = 0.029) challenge, while hepatic artery flow decreased (–30 ± 18%, P = 0.005) following the meal challenge in HV. In CC patients, portal vein velocity increased (37 ± 13%, P = 0.012) without the decrease in hepatic artery flow following the meal. In both groups, the meal increased liver perfusion (HV: 82 ± 50%, P < 0.0001; CC: 27 (16–42)%, P = 0.011) with faster arrival time of blood (HV: –54 (–56‐30)%, P = 0.074; CC: –42 ± 32%, P = 0.005). In HVs, T2* increased after the meal and in response to hyperoxia, with a decrease in hypercapnia (6 ± 8% P = 0.052; 3 ± 5%, P = 0.075; –5 ± 6%, P = 0.073, respectively), but no change in CC patients. Baseline between‐session CoV <15% for blood flow and <10% for T2* measures. Data Conclusion Dynamic changes in liver perfusion, blood flow, and oxygenation following a meal, hyperoxic, and hypercapnic challenges can be measured using noninvasive MRI and potentially be used to stratify patients with cirrhosis. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:1577–1586.