Zero Coronary Calcium Score Excludes Obstructive Stenosis in Select Patients

Objective: To evaluate whether a zero coronary artery calcium (CAC) score can exclude significant coronary artery stenosis in a homogeneous population with a low-to-intermediate pretest probability of coronary artery disease (CAD) and symptoms of stable angina. Design: Retrospective study. Participants: 868 patients who had a CAC score of zero were included. Methods: All patients had undergone myocardial perfusion imaging on a hybrid 64-section SPECT/CT with simultaneous CAC scoring. The SPECT study was performed using a 1-day technetium 99m-tetrofosmin myocardial perfusion imaging protocol. Stress and rest imaging were obtained followed by noncontrast low-dose CT to provide the attenuation map for attenuation correction. A 5-point scoring system was used to evaluate radiotracer uptake in the left ventricular myocardial segments. A segment with a score ≥2 was considered a defect. Defects were considered equivocal, reversible ischemic, or irreversible ischemic (scar tissue). For th more...