Abstract 13163: Evaluation of Myocardial Ischemia At Different Levels of Coronary Flow Reduction in a Large Animal Model Using Stress Dynamic CT Perfusion Imaging
PURPOSE: The purpose of our study was to determine if stress myocardial perfusion imaging by Dual Source CT (DSCT) can be used to non-invasively quantify regional myocardial blood flow (MBF) using FFR measurements and activated microspheres as reference standard.
MATERIALS AND METHODS: In seven pigs a coronary flow probe and an adjustable hydraulic occluder were placed around the left anterior descending coronary artery (LAD) to monitor the coronary blood flow (CBF) and to induce several degrees of coronary flow reduction. Catheters were placed in the left atrium for microsphere injection, in the aortic arch and in the coronary artery distally to the occluder for pressure measurement and FFR determination. CT perfusion images, FFR and CBF measurements were acquired and microspheres injected at baseline and under maximal vasodilation. In addition regional endocardial-to-epicardial differences in CT-MBF were tested and compared to microspheres. Measurements under maximal vasodilation were repeated with the occluder inflated to obtain 25%, 50% and 75% coronary flow reduction.
RESULTS: Maximal vasodilation resulted in ∼2 fold increase in CT-MBF from 1.3±0.1 to 2.4±0.6 ml/g/min (p=0.004). CT-MBF decreased progressively with increasing flow-reduction severity with significant differences between groups (p<0.001) (Table). A strong correlation between CT-MBF and FFR was found (R=0.86, p<0.001). There was a moderate positive association between CT-MBF and microsphere-derived MBF (R=0.70, p=0.01). No significant correlation was found between CT-MBF and microspheres in individual endocardial and epicardial transmural layers.
CONCLUSIONS: Myocardial stress perfusion imaging by DSCT is suitable for the assessment of myocardial perfusion and can be used to discriminate between different clinically relevant degrees of coronary stenosis in a large animal model.
- © 2011 by American Heart Association, Inc.