Prognostic value of one millisievert exercise myocardial perfusion imaging in patients without known coronary artery disease

The aim of this study was to assess the prognostic value of normal ultra-low-dose exercise mpi with a czt camera. 1901 consecutive patients without known cad referred for exercise mpi with 1.8 mbq/kg (0.05 mci) of tc99m sestamibi or tetrofosmin and a czt camera were included prospectively. patients with an abnormal scan requiring an additional resting image (230) or a submaximal exercise test (271) were excluded. the 1400 remaining patients were followed for 39 months. the primary end-point was cardiac events (cardiac death, nonfatal myocardial infarction, and revascularization). the secondary end-point was noncardiac death. the mean injected activity was 145 ± 37 mbq (3.9 ± 1 mci), the mean acquisition duration was 10 ± 0.7 minutes, and the mean effective dose was 0.91 ± 0.13 msv. 1288 patients (92%) achieved full follow-up. we observed 22 cardiac events and 16 noncardiac deaths. the annualized rates were equivalent to 0.55% for cardiac events and 0.37% for noncardiac mortality. normal ultra-low-dose exercise mpi with a czt camera has a high negative predictive value. the effective dose was less than 1 msv, and the study thus allays concerns about radiation burden.