 The frequency of the primary safety outcomes death, myocardial infarction, unstable angina, ventricular tachycardia, asystole, severe bradycardia, allergic skin reactions, allergic respiratory reactions, hypotension, anaphylaxis and contrast induced nephropathy will all be summarized; 95 binomial confidence intervals for the proportions of these outcomes will be calculated. The additional safety outcomes involving CTP complications will be summarized with frequencies and 95 confidence intervals for proportions. Radiation dose and efficiency measures durations involving the CTP procedure will be summarized overall with median and 25th and 75th percentiles. Also minima and maxima will be provided. The investigators may explore possible associations between patient characteristics demographics gender, age, prior histories or indications and the binary safety outcomes using contingency table methods, t tests or Wilcoxon Rank Sum, as appropriate. Associations between radiation dose and patient characteristics may be explored with nonparametric methods. The investigators may also explore possible relationships between the CTA stenosis categories 0, 1-49, 50-100 and the dynamic and static CTP results. The occurrence of clinical events recorded at 30-day chart review will be related to the category of CTP final results Normal, Probably Normal, Equivocal, Probably Abnormal and Abnormal using methods for contingency tables which incorporate the natural ordering of CTP categories. 