Repeatability and Variability of Myocardial Perfusion Imaging Techniques in Mice: Comparison of Arterial Spin Labeling and First-Pass Contrast-Enhanced MRI

Purpose: Preclinical imaging of myocardial blood flow (MBF) can elucidate molecular mechanisms underlying cardiovascular disease. We compared the repeatability and variability of two methods, first-pass MRI and arterial spin labeling (ASL), for imaging MBF in mice. Methods: Quantitative perfusion MRI in mice was performed using both methods at rest, with a vasodilator, and one day after myocardial infarction. Image quality (score of 1-5; 5 best), between-session coefficient of variability (CVbs), intra-user coefficient of variability (CVintra-user), and inter-user coefficient of variability (CVinter-user) were assessed. Acquisition time was 1-2 min for first-pass MRI and approximately 40 min for ASL. Results: Image quality was higher for ASL (3.94 +/- 0.09 versus 2.88 +/- 0.10; P<0.05). Infarct zone CVbs was lower with first-pass (17 +/- 3% versus 46 +/- 9%; P<0.05). The stress perfusion CVintra-user was lower for ASL (3 +/- 1% versus 14 +/- 3%; P<0.05). The stress perfusion CVinter-user was lower for ASL (4 +/- 1% versus 17 +/- 4%; P<0.05). Conclusion: For low MBF conditions such as infarct, first-pass MRI is preferred due to better repeatability and variability. At high MBF such as at vasodilation, ASL may be more suitable due to superior image quality and lower user variability. First-pass MRI has a substantial speed advantage. (C) 2015 Wiley Periodicals, Inc.