Comparison of radial 4D Flow-MRI with perivascular ultrasound to quantify blood flow in the abdomen and introduction of a porcine model of pre-hepatic portal hypertension
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Objectives of this study were to compare radial time-resolved phase contrast magnetic resonance imaging (4D Flow-MRI) with perivascular ultrasound (pvUS) and to explore a porcine model of acute pre-hepatic portal hypertension (PHTN).
Abdominal 4D Flow-MRI and pvUS in portal and splenic vein, hepatic and both renal arteries were performed in 13 pigs of approximately 60 kg. In six pigs, measurements were repeated after partial portal vein (PV) ligature. Inter- and intra-reader comparisons and statistical analysis including Bland–Altman (BA) comparison, paired Student’s t tests and linear regression were performed.
PvUS and 4D Flow-MRI measurements agreed well; flow before partial PV ligature was 322 ± 30 ml/min in pvUS and 297 ± 27 ml/min in MRI (p = 0.294), and average BA difference was 25 ml/min [−322; 372]. Inter- and intra-reader results differed very little, revealed excellent correlation (R 2 = 0.98 and 0.99, respectively) and resulted in BA differences of −5 ml/min [−161; 150] and −2 ml/min [−28; 25], respectively. After PV ligature, PV flow decreased from 356 ± 50 to 298 ± 61 ml/min (p = 0.02), and hepatic arterial flow increased from 277 ± 36 to 331 ± 65 ml/min (p = n.s.).
The successful in vivo comparison of radial 4D Flow-MRI to perivascular ultrasound revealed good agreement of abdominal blood flow although with considerable spread of results. A model of pre-hepatic PHTN was successfully introduced and acute responses monitored.
• Radial 4D Flow-MRI in the abdomen was successfully compared to perivascular ultrasound.
• Inter- and intra-reader testing demonstrated excellent reproducibility of upper abdominal 4D Flow-MRI.
• A porcine model of acute pre-hepatic portal hypertension was successfully introduced.
• 4D Flow-MRI successfully monitored acute changes in a model of portal hypertension.
KeywordsPhase contrast magnetic resonance imaging Blood flow Portal hypertension 4D Flow-MRI Animal model
Field of view
Generalized autocalibrating partially parallel acquisitions
Hepatic arterial buffer response
Hepatic venous pressure gradient
Spatial and temporal
Left renal artery
Magnetic resonance imaging
Principal component analysis
Research Animal Resources Center
Right renal artery
Standard error of the mean
Velocity encoding sensitivity
The authors would like to thank Sara John and Kelli Hellenbrand for their support in conducting this study. We also wish to thank the NIH, the University of Wisconsin Department of Radiology R&D committee, Bracco Diagnostics and GE Healthcare for their support.
Compliance with ethical standards
The scientific guarantor of this publication is Dr. Alex Frydrychowicz.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
This study has received funding by NIH (R01DK09616, R01HL072260, K24DK102595), the University of Wisconsin Department of Radiology R&D committee, Bracco Diagnostics and GE Healthcare.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Approval from the institutional animal care committee was obtained.
performed at one institution