• Hung-Yu Lin, Darren Freed, Trevor W R Lee, Rakesh C Arora, Ayyaz Ali, Waiel Almoustadi, Bo Xiang, Fei Wang, Stephen Large, Scott B King, Boguslaw Tomanek, and Ganghong Tian.
• Institute for Biodiagnostics, National Research Council Canada, Winnipeg, MB Canada. Hung-Yu.Lin@nrc-cnrc.gc.ca
• J Magn Reson Imaging. 2011 Jul 1; 34 (1): 203-10.

PurposeTo validate noninvasive cardiac output measurements of phase-contrast magnetic resonance imaging (PC-MRI) and cine MRI using an invasive pressure-volume (PV) loop technique on a swine model.Materials And MethodsWe compared three methods for evaluating cardiac function at rest and under pharmaceutical low-dose inotropic infusion conditions: 1) phase-contrast MRI, 2) cine MRI, and 3) PV loop relationship. These measurements were made in 14 domestic pigs under rest conditions. Identical MRI acquisitions and PV loop analysis were performed on six pigs from the same group that received an infusion of dobutamine 2.5 μg/kg/min. Cardiac outputs from all measurements were analyzed and compared using linear regression and Bland-Altman analysis.ResultsNoninvasive PC-MRI and cine MRI did not show any significant differences compared to an invasive PV loop technique for measurement of cardiac output under both rest (PC-MRI, cine MRI, and PV loop, 3.17 ± 0.45, 3.18 ± 0.61, 3.45 ± 0.41 L/min, respectively) and pharmaceutical low-dose inotropic infusion conditions (PC-MRI, cine MRI, and PV loop, 4.78 ± 0.53, 4.7 ± 0.6, 4.96 ± 0.48 L/min, respectively). Statistical analysis showed good agreement of cardiac output measurements at rest (R(2) = 0.83) and under low-dose inotropic infusion conditions (R(2) = 0.74) using PC-MRI and PV loop techniques. Cardiac output measurement using cine MRI and PV loop techniques also showed good agreement at rest (R(2) = 0.85) and under low-dose inotropic infusion conditions (R(2) = 0.76). Furthermore, cardiac outputs determined with the three modalities showed good agreement over a wide range of heart rates (90-180 bpm).ConclusionMRI can provide a reliable, noninvasive measurement of cardiac output that can be carried out without the complications that are inherent with current invasive procedures.Copyright © 2011 Wiley-Liss, Inc.

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