Development, Diagnostic Performance, And Interobserver Agreement Of An Automated Relative Perfusion Quantitation System Of Flurpiridaz F 18 Pet Myocardial Perfusion Imaging

102 Objectives: Computerized methodologies help standardize the myocardial perfusion imaging (MPI) interpretation process, known to be subject to reader variability. We sought to adapt our previously developed automated relative perfusion quantitation method to 18F-Flurpiridaz MPI, a novel positron emission tomography (PET) radiopharmaceutical, determine normal limits and criteria for abnormality, and compare performance metrics of automation with that of expert visual reads. Methods: PET MPI studies from all n=678 evaluable participants of the phase 301 trial of 18F-Flurpiridaz were included. Following adaptation of an automated method, normal limits for automated relative quantitation were obtained in n=40 patients undergoing pharmacological or exercise stress. The polar map approach was used to represent the left ventricular myocardial 18F-Flurpiridaz perfusion distribution. Then, n=90 additional studies were selected in a derivation group to analyze both normal and coronary artery disease (CAD) patients categorized according to ≥ 70% and ≥ 50% stenosis on invasive coronary angiography. Following receiver operating characteristic curve analysis, various standard deviations below the mean normal for all pixels in the myocardium were used as cutoffs for significant CAD, and interobserver variability determined. Accuracy, sensitivity, and specificity, was compared between blinded visual readers from the trial core and blinded derivations of automated relative quantitation in all the remaining n=548 validation patients. Results: Overall, both approaches yielded comparable accuracies for the detection of global CAD, reaching 71% and 72% by visual reads, and 72% and 68% by automated relative quantitation, when using CAD ≥ 70% or ≥ 50% stenosis for significance, respectively. Similar results were observed when analyzing individual coronary territories. In both forms of stress, automated relative quantitation demonstrated significantly more interobserver agreement than visual reads. Conclusions: We present a comprehensive automated method of relative perfusion analysis, providing a quantitative, objective, and highly reproducible, assessment of 18F-Flurpiridaz PET MPI, paving the way for future clinical applicability.