title: Use of Caval Subtraction 2D Phase-Contrast MR Imaging to Measure Total Liver and Hepatic Arterial Blood Flow: Preclinical Validation and Initial Clinical Translation.
abstract: Purpose To validate caval subtraction two-dimensional (2D) phase-contrast magnetic resonance (MR) imaging measurements of total liver blood flow (TLBF) and hepatic arterial fraction in an animal model and evaluate consistency and reproducibility in humans. Materials and Methods Approval from the institutional ethical committee for animal care and research ethics was obtained. Fifteen Sprague-Dawley rats underwent 2D phase-contrast MR imaging of the portal vein (PV) and infrahepatic and suprahepatic inferior vena cava (IVC). TLBF and hepatic arterial flow were estimated by subtracting infrahepatic from suprahepatic IVC flow and PV flow from estimated TLBF, respectively. Direct PV transit-time ultrasonography (US) and fluorescent microsphere measurements of hepatic arterial fraction were the standards of reference. Thereafter, consistency of caval subtraction phase-contrast MR imaging-derived TLBF and hepatic arterial flow was assessed in 13 volunteers (mean age, 28.3 years ± 1.4) against directly measured phase-contrast MR imaging PV and proper hepatic arterial inflow; reproducibility was measured after 7 days. Bland-Altman analysis of agreement and coefficient of variation comparisons were undertaken. Results There was good agreement between PV flow measured with phase-contrast MR imaging and that measured with transit-time US (mean difference, -3.5 mL/min/100 g; 95% limits of agreement [LOA], ±61.3 mL/min/100 g). Hepatic arterial fraction obtained with caval subtraction agreed well with those with fluorescent microspheres (mean difference, 4.2%; 95% LOA, ±20.5%). Good consistency was demonstrated between TLBF in humans measured with caval subtraction and direct inflow phase-contrast MR imaging (mean difference, -1.3 mL/min/100 g; 95% LOA, ±23.1 mL/min/100 g). TLBF reproducibility at 7 days was similar between the two methods (95% LOA, ±31.6 mL/min/100 g vs ±29.6 mL/min/100 g). Conclusion Caval subtraction phase-contrast MR imaging is a simple and clinically viable method for measuring TLBF and hepatic arterial flow. Online supplemental material is available for this article.
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Manil D
authors.identifier: 0000-0001-5903-1002
authors.initials: MD
authors.lastname: Chouhan
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Rajeshwar P
authors.identifier: 0000-0002-6275-9384
authors.initials: RP
authors.lastname: Mookerjee
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Alan
authors.identifier: 0000-0001-7783-7747
authors.initials: A
authors.lastname: Bainbridge
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Simon
authors.initials: S
authors.lastname: Walker-Samuel
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Nathan
authors.initials: N
authors.lastname: Davies
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Steve
authors.initials: S
authors.lastname: Halligan
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Mark F
authors.initials: MF
authors.lastname: Lythgoe
authors.affiliation: From the University College London Centre for Medical Imaging (M.D.C., S.H., S.A.T.), Institute for Liver and Digestive Health (R.P.M., N.D.), and Centre for Advanced Biomedical Imaging (S.W.S., M.F.L.), Division of Medicine, University College London, 250 Euston Rd, 3rd Floor East, London NW1 2PG, England; and Department of Medical Physics, University College London Hospitals NHS Trust, London, England (A.B.).
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Taylor
mesh_terms: D000328:Adult; D000818:Animals; D001783:Blood Flow Velocity; D003287:Contrast Media; D005260:Female; D064368:Healthy Volunteers; D006499:Hepatic Artery / Q000000981:diagnostic imaging*; D006801:Humans; D008102:Liver Circulation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013382:Subtraction Technique; D014463:Ultrasonography / Q000379:methods
chemical_list: D003287:Contrast Media