Comparison of virtual and true ECG-gated coronary CT angiography in patients with acute chest pain: a prospective cohort study

PurposeTo compare the clinical value of true electrocardiogram-gated and virtual electrocardiogram-gated coronary computed tomography angiography (CCTA), and to provide a reasonable and effective imaging strategy for patients with acute chest pain.MethodsA total of 254 patients with acute chest pain and suspected coronary artery disease who underwent CCTA were prospectively enrolled. Patients were alternately assigned according to examination date to the virtual ECG-gated group (n = 126), or the true ECG-gated group (n = 128). Examination time and radiation dose were recorded. Objectiveand subjective image quality parameters were evaluated. Objective parameters included image background noise, CT values of the aorta and coronary artery branches, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). Subjective image quality was assessed using a 5-point scale. In patients who underwent invasive coronary angiography (ICA) within 30 days after CCTA, diagnostic agreement was evaluated using ICA as the reference standard. Diagnostic performance was assessed at the vessel level using receiver operating characteristic (ROC) curve analysis, with the four major coronary arteries from each patient considered as the units of analysis.Results(1) The virtual ECG-gated group demonstrated significantly improved examination efficiency compared with the true ECG-gated group, with a shorter total examination time (2.83 ± 0.37 min vs. 4.15 ± 0.49 min, P < 0.001) and positioning time (0.89 ± 0.26 min vs. 2.03 ± 0.35 min, P < 0.001). However, the radiation dose was higher in the virtual ECG-gated group than in the true ECG-gated group (3.58 ± 0.69 mSv vs. 3.18 ± 0.54 mSv, P < 0.001). (2) Image quality analysis showed that the virtual ECG-gated group had lower image noise than the true ECG-gated group, as well as higher SNR and CNR values for the aorta and coronary artery branches (all P < 0.001). However, CT values and subjective image quality scores were comparable between the two groups (all P > 0.05). (3) In the ICA-validated subgroup, the virtual ECG-gated group showed a higher diagnostic agreement rate than the true ECG-gated group (92.00% vs. 85.58%), with corresponding vessel-level AUC values of 0.89 and 0.82, respectively. However, the virtual ECG-gated group was associated with a higher radiation dose than the true ECG-gated group (3.58 ± 0.69 mSv vs. 3.18 ± 0.54 mSv), representing a trade-off for achieving an ECG-independent acquisition strategy and maintaining diagnostic image quality.ConclusionVirtual ECG-gated CCTA can significantly improve examination efficiency while maintaining comparable image quality and diagnostic performance to true ECG-gated CCTA. Although this approach was associated with a modest increase in radiation dose, this represents a trade-off for reducing dependence on real-time ECG acquisition and simplifying the CCTA workflow. Therefore, virtual ECG-gated CCTA may serve as a feasible and efficient imaging strategy for selected patients with acute chest pain, particularly in clinical scenarios requiring rapid evaluation or simplified workflow.