Volume 14 Supplement 1
Quantitative first-pass MRI measures increased myocardial perfusion after vasodilation in mice
© Antkowiak et al; licensee BioMed Central Ltd. 2012
Published: 1 February 2012
We used first-pass contrast-enhanced MRI to quantatively measure the myocardial Ktrans, a parameter indicating myocardial perfusion and vascular permeability, in mice with or without vasodilation. We measured a significant increase in myocardial Ktrans with vasodilation. We believe this may be the first report showing that first-pass imaging can quantify increased myocardial perfusion in mice relative to baseline.
First-pass contrast-enhanced MRI is a well-established technique for quantifying myocardial perfusion in humans and large animals and has recently emerged as a viable tool for quantifying myocardial perfusion in mice [1–3]. Applied in mice, first-pass MRI could be used to assess the roles of individual genes in perfusion and vascular permeability. The purpose of this study was test the hypothesis that first-pass contrast-enhanced MRI can measure increased myocardial perfusion after administration of a vasodilator in mice.
Imaging was performed on a 7T Clinscan MR system equipped with a gradient system having a full strength of 650mT/m and a slew rate of 6666 mT/m/ms, and using a 30mm diameter birdcage RF coil. A saturation-recovery spiral sequence was employed, with TE = 0.36 ms, TR = 3.9ms, interleaves = 14, FOV = 25.6 x 25.6mm, matrix = 128x128, saturation delay = 40 ms, alpha = 20°, and slice thickness = 1mm. Data acquisition required 55 ms/image, approximately 40% of the murine R-R interval, and was placed in the latter part of the cardiac cycle. C57Bl6/J mice were imaged with (n=5) and without (n=5) an intraperitoneal bolus injection of the vasodilator ATL313 (Adenosine Therapeutics, Charlottesville, VA). First-pass images were acquired for one mid-ventricular short-axis slice. A dual-bolus gadolinium injection technique was used, acquiring the arterial input and tissue functions (AIF and TF) in separate scans. Myocardial Ktrans, the product of myocardial perfusion and the first-pass extraction fraction of gadolinium, was quantified using a standard Kety model deconvolution method.
These findings indicate that first-pass MRI in mice can quantitatively measure increased myocardial Ktrans with a vasodilator. Taken together with our previous studies quantifying perfusion after myocardial infarction1, these results indicate that first-pass imaging can accurately measure myocardial perfusion in mice in a variety of flow conditions.
Funding was provided by NIH R01 EB 001763.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.