CardioViewer: A novel modular software tool for integrating cardiac electrophysiology voltage measurements and PET/SPECT data

A novel modular multiplatform software tool was developed for display, registration and fusion of cardiac electrophysiology (EP) voltage data with PET/SPECT cardiac images and their polar maps. The EP voltage measurements were acquired at discrete locations on the endocardial surface by a catheter-based electroanatomic mapping system as part of left ventricular tachycardia ablation procedures. These data were output as a list of voltages and 3-D mapping system coordinates. PET/SPECT data were 3-D short axis perfusion or viability images and derived polar maps. CardioViewer allows GUI menu-driven data input and display of EP and PET/SPECT data as well as their fusion in orthogonal slice, point cloud and polar map views. The software development environment was C++ using Qt Creator IDE, Open GL, ITK, freeglut and dicomlib. The modular program architecture facilitated addition of new functionalities and CardioViewer has been successfully run on Linux, Windows and Apple operating systems. Initial registration of EP and PET/SPECT datasets was achieved with user-input control points, after which the six degrees of freedom registration parameters could be interactively adjusted. EP voltage and PET/SPECT values can be output at matched polar map locations, which avoids regional averaging of tissue properties. CardioViewer is being used to investigate local prediction of EP tissue categories from PET/SPECT images. An example ROC analysis using Tl-201 SPECT data is provided.