Non-contrast myocardial perfusion assessment in porcine acute myocardial infarction using arterial spin labeled CMR
© Do et al. 2016
Published: 27 January 2016
Following acute myocardial infarction (AMI), microvascular integrity and function may be compromised as a result of microvascular obstruction (MVO) and vasodilator dysfunction [1,2]. It has been observed that both infarct and remote myocardial territories may exhibit impaired myocardial blood flow (MBF) patterns associated with abnormal vasodilator response . Arterial spin labeled (ASL) CMR is a novel non-contrast technique that can quantitatively measure MBF [4-6]. The aim of this study was to investigate the feasibility of ASL-CMR in assessing MBF in a porcine model of AMI.
The Research Institute Animal Care Committee approved the protocol. The study involved a porcine model of AMI in which animals (N = 11) were subjected to a 90 min LAD occlusion followed by reperfusion. Animals underwent a CMR examination on a 3T scanner (MR750, GE Healthcare) at baseline (7 scans), at 1 day post-AMI (6 scans), and at 1 week post-AMI (5 scans). ASL-CMR, first-pass perfusion, and LGE imaging were all performed. First-pass perfusion and LGE were performed using product sequences while ASL-CMR was performed using our investigational pulse sequence  that uses flow-sensitive alternating inversion recovery (FAIR) labeling scheme and steady state free precession (SSFP) image acquisition with imaging parameters: TE/TR = 1.5/3.2 ms, FA = 500, slice thickness = 10 mm, FOV = 18-24 cm, matrix size = 96 × 96, parallel imaging factor of 2. Labeling and imaging were triggered at mid-diastole. ASL-CMR was analyzed in a manner previously described to obtain global and per-segment MBF and physiological noise (PN); values were reported as mean ± SD. Segments with temporal signal-to-noise ratio (tSNR = MBF/PN) < 2 were excluded in the regional analysis.
Cardiac ASL is able to assess myocardial perfusion in a pig model of myocardial infarction. ASL is a potentially useful quantitative tool for longitudinally monitoring myocardial remodeling, particularly in the remote territory, which develops hypertrophy and fibrosis in the high-risk patients.
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