Abstract 1543: Integration of True Three-Dimensional Scar Maps Simultaneously Displaying the Left Ventricular Anatomy (Derived from CT) and Left Ventricular Scar (Derived from PET) Into a Clinical Mapping System to Guide Ventricular Tachycardia Ablations
Background: Currently, image integration is only of limited use for substrate/scar-guided ablations of ischemic ventricular tachycardia (VT) as the clinical mapping systems allow only
the integration of a single dataset and
the dataset is represented as a “paperthin” surface reconstruction.
However, a useful system should display simultaneously the left ventricular (LV) anatomy and the embedded myocardial scar and show the myocardial wall as a three-dimensional (3D) structure with endo/epicardium.
Method: Contrast-enhanced CT and PET imaging was performed prior to VT ablation to create a high-resolution 3D LV model and a myocardial scar map, respectively. The matrix of the 3D CT-derived LV model and PET-derived scar map were fused using either fully automated or interactive semi-automatic volume registration. For the integration into the clinical mapping system the PET scar map was superimposed on the CT matrix and registered as a 3D model with the endocardial high-resolution voltage map. Position error and alignment was assessed after registration.
Results: Contrast-enhanced high resolution CT was able to delineate detailed LV anatomy including wall thinning in areas of prior infarction and papillary muscle location. PET imaging demonstrated myocardial scar involving 12.8±7.1% of the LV wall. Fully-automated and semi-automatic volumetric registration of the datasets was achieved after 20s and 4min, respectively and resulted in a registration accuracy of ≤3mm. This resulted in a fused model demonstrating simultaneously the 3D LV anatomy and the embedded LV scar allowing visualization of the endo, mid-myocardial and epicardial scar components. Registration into the clinical mapping system resulted in good alignment between voltage map and LV anatomy/LV scar map with a position error of 3.7±3.2mm. Areas of voltage-defined scar were accurately superimposed on the endocardial component of the displayed myocardial scar.
Conclusion: High-resolution CT/PET reconstructions can be fused to display myocardial scar (from PET) embedded into the LV wall (from CT) simultaneously and as 3D structures in clinical mapping systems. This may enable a completely novel image-guided approach to substrate-guided VT ablation.