Determination of Fractional Flow Reserve by Anatomic Computed Tomographic Angiography

Inclusion Criteria: * Age \>18 years * Patients providing written informed consent * Scheduled to undergo clinically-indicated non-emergent invasive coronary angiography (ICA) * Has undergone \>64 multidetector row CCTA within 60 days prior to ICA * No cardiac interventional therapy between the CCTA and ICA Exclusion Criteria: * Prior coronary artery bypass graft (CABG) surgery * Prior percutaneous coronary intervention (PCI) for which suspected coronary artery lesion(s) are within a stented coronary vessel * Contraindication to adenosine, including 2nd or 3rd degree heart block; sick sinus syndrome; long QT syndrome; severe hypotension, severe asthma, , severe COPD or bronchodilator-dependent COPD * Suspicion of acute coronary syndrome (acute myocardial infarction and unstable angina) * Recent prior myocardial infarction within 40 days of ICA * Known complex congenital heart disease * Prior pacemaker or internal defibrillator lead implantation * Prosthetic heart valve * Significant arrhythmia or tachycardia * Impaired chronic renal function (serum creatinine \>1.5 mg/dl * Patients with known anaphylactic allergy to iodinated contrast * Pregnancy or unknown pregnancy status * Body mass index \>35 * Patient requires an emergent procedure * Evidence of ongoing or active clinical instability, including acute chest pain (sudden onset), cardiogenic shock, unstable blood pressure with systolic blood pressure \<90 mmHg, and severe congestive heart failure (NYHA III or IV) or acute pulmonary edema * Any active, serious, life-threatening disease with a life expectancy of less than 2 months * Inability to comply with study procedures