Quantification of Myocardial Blood Flow Using Dynamic PET/CTA Fused Imagery

Inclusion Criteria: * Adult (≥18 years of age) - as the research topic to be studied is irrelevant to children * Written consent form * Patients with prior dynamic PET or CCTA or ICA for any indications Exclusion Criteria: * Previous history of allergy to iodinated contrast * Previous CABG * Serum creatinine levels \>1.8 mg/dl unless patient has end stage kidney disease, not producing any urine and dialysis * History of claustrophobia (CT tunnel length of more than 100 cm) * Significant arrhythmias or tachycardia * History of frequent asthma attacks or acting wheezing * Second- and third-degree heart block * Systolic blood pressure of \< 90 mmHg * Heart failure with NYHA class III-IV at the time of the CCTA procedure. If it is deemed that, the heart failure has been resolved or the patient was incorrectly labeled as having heart failure the radiology physician in charge will verify the absence of Heart Failure at the time of CCTA and perform the procedure. * Recent myocardial infarction * If the patient has been diagnosed with unstable angina within 24 hours prior to CCTA, the patient will not be consented. If the patient does not have the diagnosis of unstable angina and is consented, the radiology physician in charge will verify the absence of unstable angina at the time of CCTA. * Patients enrolled and consented for the invasive measurements that at the time of catheterization exhibit severe vessel disease and/or obstructions that prevent the operator from safely conducting the measurements will be removed from the study; further research imaging sessions - if planned - will be canceled and patients indicated as "screen failure" in our enrollment log.