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Updated: Feb 12, 2026
Identifying Coronary Artery Calcification on Non-gated Computed Tomography Scans
Published on: August 28, 2018
Diagnostic performance of coronary computed tomography (CT) angiography without electrocardiographic (ECG)-gating:
Kun Wang1, Ai'zhu Sheng2, Xi Hu1
1Department of Radiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Insights
A new non-electrocardiogram-gated coronary computed tomography angiography (ECG-less CCTA) protocol accurately diagnoses coronary artery disease (CAD). This method is effective even in patients with arrhythmias or high heart rates, improving diagnostic accessibility.
Area of Science:
- Cardiology
- Radiology
- Medical Imaging
Background:
- Coronary artery disease (CAD) is a major global cause of mortality, necessitating effective noninvasive diagnostic tools.
- Invasive coronary angiography (ICA) is the gold standard but carries risks.
- Conventional coronary computed tomography angiography (CCTA) is limited by electrocardiographic (ECG) gating, hindering use in patients with arrhythmias or high heart rates.
Purpose of the Study:
- To evaluate the diagnostic accuracy of a non-ECG-gated CCTA (ECG-less CCTA) protocol for detecting obstructive CAD.
- To compare ECG-less CCTA against ICA as the reference standard.
Main Methods:
- A retrospective single-center study included 110 patients with suspected CAD.
- ECG-less CCTA was performed using a 256-row CT scanner with optimized parameters and advanced image reconstruction techniques.
- Two radiologists assessed stenosis (≥50%) using the SCCT 18-segment model, with subgroup analysis based on heart rate and calcium burden.
Main Results:
- ECG-less CCTA demonstrated high patient-level sensitivity (92.1%) and specificity (91.5%) for obstructive CAD.
- Excellent vessel- and segment-level specificity (93.6%/96.2%) and negative predictive value (95.1%/97.2%) were observed.
- While specificity decreased with higher calcium burden, sensitivity remained unaffected by heart rates >75 bpm.
Conclusions:
- ECG-less CCTA shows high diagnostic agreement with ICA for obstructive CAD, with excellent specificity and NPV.
- The protocol's tolerance to varying heart rates and streamlined workflow enhance its utility in emergency settings and for patients with arrhythmias.
- This approach offers a valuable alternative by eliminating the need for ECG gating and beta-blockers.
Background:
Coronary artery disease (CAD) is a leading cause of death worldwide, and noninvasive diagnostic methods are essential. Although invasive coronary angiography (ICA) is the reference standard, it is invasive and carries procedural risks. Conventional coronary computed tomography angiography (CCTA) is limited by its dependence on electrocardiographic (ECG)-gating, which reduces its feasibility in patients with arrhythmias, high heart rates (HRs), or in emergency settings. Therefore, this study aimed to assess the diagnostic accuracy of a non-ECG-gated CCTA (ECG-less CCTA) protocol for identifying obstructive CAD, using ICA as the reference.
Methods:
This retrospective single-center study included 110 patients with suspected CAD undergoing ECG-less CCTA [256-row computed tomography (CT) with simulated ECG signals, automated tube voltage selection (80-120 kV], and tube current modulation [noise index: 20 Hounsfield units (HU)]. Contrast administration (0.6 mL/kg) was optimized via bolus tracking. Images were reconstructed using deep learning (TrueFidelity™) and motion correction (SnapShot Freeze 2). Two blinded radiologists assessed stenosis ≥50% [Society of Cardiovascular Computed Tomography (SCCT) 18-segment model], with non-diagnostic segments classified as positive. Subgroups were stratified by HR [≤75 vs. >75 beats per minute (bpm)] and calcium burden (Agatston ≤400 vs. >400).
Results:
ECG-less CCTA showed patient-level sensitivity of 92.1% [95% confidence interval (CI): 85.6-96.2%] and specificity of 91.5% (82.3-96.4%). Vessel- and segment-level specificity/negative predictive value (NPV) were 93.6%/95.1% and 96.2%/97.2%, respectively. Non-diagnostic segments (6.4%) were conservatively positive. Radiation dose was 1.4±0.5 mSv. Specificity decreased in Agatston >400 (84.6% vs. 94.1%, P=0.02), whereas HR >75 bpm did not significantly reduce sensitivity (89.7% vs. 94.1%, P=0.12).
Conclusions:
ECG-less CCTA achieves high diagnostic concordance with ICA for obstructive CAD, demonstrating excellent specificity/NPV across analysis levels. Its tolerance to variable HRs and streamlined workflow support clinical utility in emergency settings or arrhythmic patients, avoiding ECG dependency and β-blockers.
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