Magnetic resonance in medicine

1522-25948322020FebMagnetic resonance in medicineMagn Reson MedMeasuring extracellular volume fraction by MRI: First verification of values given by clinical sequences.662672662-67210.1002/mrm.27938To verify MR measurements of myocardial extracellular volume fraction (ECV) based on clinically applicable T1-mapping sequences against ECV measurements by radioisotope tracer in pigs and to relate the results to those obtained in volunteers.Between May 2016 and March 2017, 8 volunteers (25 ± 4 years, 3 female) and 8 pigs (4 female) underwent ECV assessment with SASHA, MOLLI5(3b)3, MOLLI5(3s)3, and MOLLI5s(3s)3s. Myocardial ECV was measured independently in pigs using a radioisotope tracer method.In pigs, ECV in normal myocardium was not different between radioisotope (average ± standard deviation; 19 ± 2%) and SASHA (21 ± 2%; P = 0.086). ECV was higher by MOLLI5(3b)3 (26 ± 2%), MOLLI5(3s)3 (25 ± 2%), and MOLLI5s(3s)3s (25 ± 2%) compared with SASHA or radioisotope (P ≤ 0.001 for all). ECV in volunteers was higher by MOLLI5(3b)3 (26 ± 3%) and MOLLI5(3s)3 (26 ± 3%) than by SASHA (22 ± 3%; P = 0.022 and P = 0.033). No difference was found between MOLLI5s(3s)3s (25 ± 3%) and SASHA (P = 0.225). Native T1 of blood and myocardium as well as postcontrast T1 of myocardium was consistently lower using MOLLI compared with SASHA. ECV increased over time as measured by MOLLI5(3b)3 and MOLLI5(3s)3 for pigs (0.08% and 0.07%/min; P = 0.004 and P = 0.013) and by MOLLI5s(3s)3s for volunteers (0.07%/min; P = 0.032) but did not increase as measured by SASHA.Clinically available MOLLI and SASHA techniques can be used to accurately estimate ECV in normal myocardium where MOLLI-sequences show minor overestimation driven by underestimation of postcontrast T1 when compared with SASHA. The timing of imaging after contrast administration affected the measurement of ECV using some variants of the MOLLI sequence.© 2019 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.NordlundDavidD0000-0002-6567-8459Department of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.XanthisChristosCDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.Laboratory of Computing and Medical Informatics, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.BidhultSebastianSDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden.JablonowskiRobertRDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.KanskiMikaelMDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.KopicSaschaSDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.CarlssonMarcusMDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.EngblomHenrikHDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.AletrasAnthony HAHDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.Laboratory of Computing and Medical Informatics, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.ArhedenHåkanHDepartment of Clinical Physiology, Clinical Sciences, Lund University and Lund University Hospital, Lund, Sweden.engJournal ArticleResearch Support, Non-U.S. Gov't20190816