Adenosine Dual Source Computed Tomography (CT) Versus Adenosine Single Photon Emission Computed Tomography (SPECT)

The DSCT scanner is able to assess cardiac blood flow (myocardial perfusion) at the same time as coronary anatomy. The results derived from these scans will be compared to standard SPECT imaging. To further evaluate obstruction in the coronary arteries, physicians may refer for an invasive Coronary Angiogram, the current gold standard for diagnosis of Coronary Artery Disease (CAD). By validating the DSCT scanner as a system with which to assess the extent of obstruction in the coronary arteries, physicians may be able to lessen the occurrence of an invasive exam. Procedures: Each pilot anticipates enrolling 20 subjects. Pilot 1: Clinical Follow-up Rest/Stress Adeno-SPECT and Research Stress /Rest Adeno-DSCT obtained in the same patient during the same period of stress testing * Radiation: Thallium injection for rest SPECT * Drug: Single dose Adenosine Infusion for DSCT and SPECT * Radiation: Sestamibi injection for stress SPECT * Drug: CT contrast * Radiation: Stress DSCT /Rest DSCT Pilot 2: Research Stress/ Rest Adeno-DSCT obtained within 30 days of initial positive SPECT finding * Drug: Adenosine Infusion for DSCT * Drug: CT contrast * Radiation: Stress DSCT /Rest DSCT Both pilot studies will relate results to subject history, ECG and cardiac angiogram, if available