Abstract 4721: First Clinical Experience Using PET/CT Fusion Imaging of Three-Dimensional Myocardial Scar and Left Ventricular Anatomy for Ventricular Tachycardia Ablation
Objectives: Image integration into clinical mapping systems could be used to display a 3D myocardial scar map and its border zone to assist substrate-guided ventricular tachycardia (VT) ablation. This study reports the first clinical experience of simultaneous display of 3D scar embedded into LV anatomy, characterization of scar and border zone using metabolic 18-F fluorodeoxyglucose (FDG) PET images and anatomic substrate evaluation using CT images.
Methods: Ten patients scheduled for VT ablation underwent contrast-enhanced CT and Rubidium-82/FDG PET imaging to create a 3D LV model and 3D FDG scar map. The FDG segment uptake with peak Rb perfusion was used as 100% to normalize FDG data. Using a novel imaging module LV and scar models were co-registered with a 3D mapping system and analyzed with a 17 segment model. Registration errors and alignment of 3D scar from FDG embedded into LV anatomy and voltage map were analyzed. Segments with all voltage values < 0.5mV were defined as scar only; those with some voltage values < 0.5mV as partial scar and those with all voltage values > 1.5mV as healthy. FDG uptakes were compared with endocardial voltages for scar and healthy segments. Metabolic thresholding was used to reconstruct the 3D border zone. Real-time display of high-resolution CT images was assessed during VT ablation.
Results: Co-registration (error 4.3 ±0.7mm) allowed simultaneous visualization of LV anatomy and embedded 3D-scar in all patients and guided additional voltage mapping. Scar only 3D FDG myocardium segment locations and partial scar segments matched 94.9% and 85.7%, respectively, with those in the voltage map. Voltage map scar-only and healthy segments had FDG uptakes of 40 ±13% and 89 ±30%. PET-derived scar and border zones with FDG thresholds of 40% and 46%, respectively, correlated best with voltage segments. Real time display of CT allowed detection of scar related anatomic changes.
Conclusions: Integration of PET/CT images allows simultaneous 3D display of myocardial scar and border zone embedded into LV anatomy as well as detailed scar anatomy. This multi-modality imaging may 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, AHA Mid-Atlantic Affiliate (Maryland, North Carolina, South Carolina, Virginia & Washington, DC).