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Optimal electrocardiographically triggered phase for reducing motion artifact at electron-beam CT in the coronary
1Department of Radiology, Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Science, Peking Union Medical College, Beijing.
Insights
Optimizing electrocardiographic (ECG) triggering in electron-beam CT significantly reduces coronary artery motion artifacts. Tailoring the trigger phase to heart rate improves image quality for coronary imaging.
Area of Science:
- Cardiovascular Imaging
- Medical Physics
- Radiology
Background:
- Coronary artery motion is a significant challenge in electron-beam CT imaging.
- Minimizing motion artifacts is crucial for accurate diagnosis and assessment of coronary artery disease.
Purpose of the Study:
- To investigate coronary artery movement using electron-beam CT.
- To determine the optimal electrocardiographic (ECG) triggering phase for reducing motion artifacts.
Main Methods:
- 151 patients without arrhythmia underwent electron-beam CT.
- Movie scans analyzed coronary artery displacement and velocity.
- Volume scans with 100 msec exposure used various ECG trigger settings.
Main Results:
- Coronary artery movement patterns correlated with heart rate.
- Optimal triggering phase varied: before atrial systole (slow heart rate) or ventricular end-systole (fast heart rate).
- Severe motion artifacts reduced from 43% to 0% with optimized ECG triggering.
Conclusions:
- Heart rate-dependent ECG triggering substantially reduces motion artifacts in electron-beam CT.
- Optimized triggering improves image quality for coronary artery imaging.
- Findings may inform ECG triggering strategies in other modalities like MRI.
Rationale And Objectives:
The authors performed this study to (a) investigate coronary movement with electron-beam computed tomography (CT) and (b) find the optimal electrocardiographic (ECG) triggering phase for eliminating motion artifact.
Materials And Methods:
One hundred fifty-one patients without arrhythmia were examined with electron-beam CT. First, movie scans were obtained to create displacement and velocity graphs of coronary artery movement. Then, a volume scan with an exposure time of 100 msec was obtained with various ECG trigger settings.
Results:
Movement patterns of coronary arteries varied with heart rate. Optimal triggering phase was before atrial systole (near 71% of the R-R interval) when heart rate was slower than 68 beats per minute and at ventricular end systole when heart rate was fast. Rate of severe motion artifacts decreased from 43% to 0% when triggering was altered from 80% of the R-R interval to the individual optimal value. Experimental values of the optimal phase at different heart rates were derived, and severe motion artifact was only 3.0% with these values.
Conclusion:
ECG triggering set according to the heart rate enables a great reduction in motion artifacts at electron-beam CT with a 100-msec exposure time. The results may have implications for magnetic resonance imaging of the coronary artery.