Abstract
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Objectives Cardiac PET and SPECT perfusion and viability measurements have the potential to guide electrophysiology (EP) voltage mapping and ablation procedures for ventricular tachycardia. Though qualitative comparisons of PET/SPECT left ventricular myocardial perfusion and metabolism with EP voltage maps are useful, our aim was to develop methods for quantitative comparison of EP voltages with PET/SPECT uptake in the standard 17 segment and higher resolution heart models.
Methods Cardiac PET (F-18 FDG, Rb-82) and SPECT (e.g. Tl-201, Tc-99 sestamibi) uptakes were quantified using commercial software (PMOD) that permitted export of 720 values (20 axial x 36 angular samples). Samples were grouped for parameter calculations (e.g. mean, range) in the standard 17 heart segments, as well as in a higher resolution 68 segment model. EP endocardial voltages were obtained using a catheter-based system to map scar, border zone and normal myocardium. Voltages were obtained at discrete locations and sampling was non-uniform. Voltages and their 3-D coordinates were exported and segment identifiers were computed for each point. Segment attributes were computed for 17 and 68 segment cardiac models. The analyses for PET/SPECT and EP voltages were implemented in a spreadsheet, requiring simple pasting of exported data into a template.
Results The developed tools automate analysis of clinical EP voltages as well as PET/SPECT data and have been used on 27 EP, 18 PET and 7 SPECT datasets. Quantitative segmental analysis is being used to study the relation between EP and PET/SPECT inferred tissue properties.
Conclusions Methods for automatic quantitative segmental analysis of cardiac EP voltage datasets for comparison with PET/SPECT have been developed and are in routine use in our laboratory.
Research Support Supported in part by American Heart Association Scientist Development Grant (0635304N