Three main clinical outcomes will be assessed:

1. Post-test resource utilization as assessed by referral rate to catheterization within 90-days of the index study;
2. Incremental prognostic value and risk stratification for predicting cardiac death and myocardial infarction;
3. Cost-effectiveness

To this end, SPARC is organized with two distinct specific objectives with important differences in patient population and endpoints.

Specific Aim 1: To evaluate the impact of stress perfusion imaging with SPECT or PET, CT Angiography, and hybrid PET-CT on post-test resource utilization.

The primary endpoint of specific aim 1 is to compare the impact of combined myocardial perfusion-coronary anatomy data to that of perfusion only [stress SPECT, stress cardiac PET (without CTA)] and anatomy only (CTA alone) on post-test resource utilization, as measured by referral to cardiac catheterization within 90 days of index noninvasive testing, in patients without CAD.

Secondary endpoints:

1. to compare the diagnostic accuracy for detection of epicardial CAD of stress PET and hybrid PET-CT, stress SPECT, and CTA, as defined by coronary angiography;
2. to compare the referral rate to revascularization within 90 days of cardiac catheterization.

Specific Aim 2: To compare the incremental prognostic value and risk stratification of stress perfusion imaging with SPECT or PET, CT coronary angiography, and combined perfusion-anatomy imaging approaches.

The primary endpoint of specific aim 2 is to compare the incremental value of stress perfusion only (stress PET and stress SPECT), coronary anatomy only (CTA data), and combined perfusion-anatomy studies (PET+CTA and SPECT+CTA) over clinical, historical and stress test data for the prediction of cardiac death and nonfatal myocardial infarction.

Secondary endpoints:

1. to compare the incremental value of these noninvasive imaging approaches over clinical, historical and stress test data for the prediction of a composite endpoint including cardiac death, nonfatal myocardial infarction, late (>6 month from index study) referral to revascularization, or late (>6 month from index study) hospitalization for chest pain or heart failure;
2. to compare the incremental value of these noninvasive imaging approaches over clinical, historical and stress test data for the prediction of all cause mortality. In addition, the ability of these modalities -together and separately- to risk stratify patients is a primary goal of specific aim 2.

Inclusion Criteria:

• Referred for a clinical stress SPECT, stress PET, CTA or PET-CT study
• Intermediate to high pretest likelihood for CAD (>.25;as defined by ACC/AHA Stable Angina Guidelines) without prior MI/PCI/CABG. These are considered diagnostic patients.

or

• Documented known CAD as defined by prior MI/PCI/CABG
• Provide signed informed consent to participate in the study

Exclusion Criteria:

• Low pretest likelihood for CAD (<=.25; as defined by ACC/AHA Stable Angina Guidelines).
• Major concomitant noncardiac disease or social condition/situation that in the opinion of the investigator will preclude the patient from participation in the study follow-up.
• Concurrent or prior(within last 30 days) participation in other research studies using investigational drugs or devices.
• Presence of a permanent automated internal cardiac defibrillator (AICD)
• Known non-ischemic cardiomyopathy
• Chest pain at rest within 48 hours prior to the index noninvasive imaging test

Patients with known coronary artery disease and patients with suspected CAD and an intermediate-High Likelihood of disease