Abstract 252: Feasibility of Three Dimensional Anatomic, Dynamic and Perfusion Imaging of Myocardial Scar Using Contrast Enhanced Multi-Detector Computer Tomography to Guide Ventricular Tachycardia Ablations
Introduction: Advances in contrast-enhanced (CE) multidetector CT imaging enable detailed characterization of the left ventricular (LV) wall. As the targets of substrate-guided ventricular tachycardia (VT) ablations, myocardial scars display abnormal anatomic, dynamic and perfusion characteristics and can be identified during first pass CT imaging. This study assesses the feasibility of integrating 3D scar characterization into clinical mapping systems to guide VT ablations.
Methods: Eleven patients with ischemic cardiomyopathy underwent CE-CT prior to VT ablation. Segmental anatomic (end-systole/diastole wall thickness, ESWT, EDWT), dynamic (wall thickening and wall motion, WT, WM) and perfusion (hypoenhancement) information was extracted. ROC curves assessed the ability of CT-derived parameters to determine myocardial abnormality, with voltage value as the gold standard. Epi and endocardial LV surfaces and scar were manually delineated, reconstructed into 3D volumes, co-registered and compared to voltage maps using a 17-segment model in a clinical 3D mapping system.
Results: Abnormal anatomic, dynamic and perfusion data were detected in all patients and correlated well with abnormal endocardial voltages of < 1.5mV (r=0.75, p=0.072). Using 1.5mV as the cut off for abnormal myocardium, ROC areas for EDWT, ESWT, WT and WM were 0.83±0.05, 0.75±0.06, 0.79±0.06 and 0.68 ±0.06, respectively. Multivariate stepwise logistic regressions showed that ESWT combined with WT builds the best prediction with an ROC area of 0.85±0.05. 3D images could be reconstructed into the clinical mapping system with a registration error of 4.7± 0.9mm and allowed the prediction of homogenous abnormal voltage areas (<1.5 mV) in 78% of the analyzed segments. CT hypoperfusion correlated better with scar and border zone areas than scar alone and encompassed curative ablation lesions in nine of the eleven cases.
Conclusions: Anatomic, dynamic and perfusion imaging using CE-CT allows comprehensive characterization of LV anatomy and 3D scar substrate. Integration of the reconstructed 3D dataset into clinical mapping systems may provide supplementary information to the voltage mapping approach and enable a new image-guided approach to substrate-guided VT ablation.
This research has received full or partial funding support from the American Heart Association, Mid-Atlantic Affiliate (Maryland, North Carolina, South Carolina, Virginia & Washington, DC).