Diagnostic accuracy of computed tomography coronary angiography and evaluation of stress-only single-photon emission computed tomography/computed tomography hybrid imaging: Comparison of prospective electrocardiogram- triggering vs. retrospective gating

Abstract

AimsTo determine diagnostic accuracy, effective radiation dose, and potential value of computed tomography coronary angiography (CTCA) for hybrid imaging with single-photon emission computed tomography (SPECT) comparing prospective electrocardiogram (ECG)-triggering vs. retrospective ECG-gating.Methods and resultsTwo hundred patients underwent standard myocardial stress/rest- SPECT perfusion imaging, which served as standard of reference. One hundred consecutive patients underwent 64-slice CTCA using prospective ECG-gating, and were compared with 100 patients who had previously undergone CTCA using retrospective ECG-gating. For predicting ischaemia, CTCA with prospective ECG-triggering and a stenosis cut-off >50 had a per-vessel sensitivity, specificity, negative, and positive predictive value of 100, 84, 100, and 30; respective values for CTCA with retrospective ECG-gating were similar (P = n.s.): 86, 83, 98, and 33. Combining CTCA with stress-only SPECT revealed 100 clinical agreement with regard to perfusion defects, and provided additional information in half the patients on preclinical coronary findings. Effective radiation dose was 2.2 ± 0.7 mSv for CTCA with prospective ECG-triggering, and 19.7 ± 4.2 mSv with retrospective ECG-gating (P < 0.001) (5.4 ± 0.8 vs. 24.1 ± 4.3 mSv for hybrid imaging).ConclusionProspective ECG-triggering for CTCA reduces radiation dose by almost 90 without affecting diagnostic performance. Combined imaging with stress-only SPECT is an attractive alternative to standard stress/rest-SPECT for evaluation of coronary artery disease, offering additional information on preclinical atherosclerosis.