Abstract 17885: A Novel Porcine Model of Acute Myocardial Ischemia Guided by FFR for Accuracy of Dynamic CT Myocardial Perfusion Imaging Study
Purpose: Determine the degree of coronary stenosis in a porcine model of balloon-induced myocardial ischemia guided by Fractional Flow Reserve ( FFR). Optimize imaging methods and processing for myocardial perfusion assessment and quantification using dynamic MDCT.
Methods: Animals received a LAD stent over a FFR wire, followed by partial balloon occlusion against the stent to achieve a physiological significant ischemia defined by FFR values < 0.8. Prospective ECG-triggered images were acquired at end-systole (40% of RR) using 256-slice MDCT (Brilliance iCT-Philips), with 20ml of contrast at 4ml/s. Images were acquired at baseline (FFR = 1) and after balloon inflation (FFR < 0.8), 15 minutes apart. Both acquisitions were repeated at different kVp/mAs combinations ranging from 80 to 120 and 60 to 200, respectively. Qualitative and quantitative analysis were performed using FBP and iterative (iDose4) reconstructions (IR). Advanced imaging post processing was applied for testing the effect of beam hardening correction (BHC), 3D elastic registration, and spatio-temporal bilateral filtering (STBF). Quantitative perfusion was obtained with fluorescent microspheres injected in the left ventricle and imaged post mortem using CryoVizTM (BioInVision).
Results: Preliminary qualitative assessment of 2 animals shows good anatomic correlation between the site of the stent implant and the ischemic myocardial area supplied by LAD. Control scans prior to balloon occlusion gave very uniform images across the ventricular myocardium. Registration and STBF reduced CT-value fluctuations by up to 80%.
Conclusions: We demonstrated feasibility of a closed-chest porcine model of myocardial ischemia guided by FFR. This pre-clinical model will enable us to precisely change FFR valves and quantitatively examine effects on perfusion.
- © 2013 by American Heart Association, Inc.