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Optimal electrocardiographic pulsing windows and heart rate: effect on image quality and radiation exposure at
Annick C Weustink1, Nico R Mollet, Francesca Pugliese
1Department of Radiology, Erasmus Medical Center, PO Box 2040, Room Hs 218, 3000 CA Rotterdam, The Netherlands.
Insights
Optimizing electrocardiographic (ECG) pulsing windows in cardiac CT reduces radiation exposure without compromising image quality. This study identified heart rate-dependent optimal windows for enhanced patient safety and diagnostic accuracy.
Area of Science:
- Cardiovascular imaging
- Radiological physics
- Medical imaging technology
Background:
- Coronary artery disease (CAD) diagnosis relies on computed tomography (CT) imaging.
- Electrocardiographic (ECG) pulsing is crucial for synchronizing CT acquisition with the cardiac cycle.
- Optimizing ECG pulsing windows is essential for balancing image quality and radiation dose.
Purpose of the Study:
- To determine the optimal width and timing of ECG pulsing windows.
- To evaluate the impact of these windows on heart rate (HR), image quality, and radiation exposure.
- To develop a heart rate-dependent ECG pulsing protocol for suspected CAD patients.
Main Methods:
- Dual-source CT was performed in 301 patients with suspected CAD.
- A wide ECG pulsing window (25%-70% of R-R interval) was used.
- Data sets were reconstructed in 5% steps; image quality was assessed, and optimal windows were calculated for different HRs.
Main Results:
- High-quality images were obtained at end diastole for low HR (< or = 65 bpm), end systole for high HR (> or = 80 bpm), and both for intermediate HR (66-79 bpm).
- Optimal ECG pulsing windows were identified as 60%-76% (low HR), 30%-77% (intermediate HR), and 31%-47% (high HR) of the R-R interval.
- Effective radiation dose was significantly reduced across all HR categories with the optimized protocol.
Conclusions:
- Optimal ECG pulsing windows can significantly reduce radiation exposure in cardiac CT.
- This optimization is particularly beneficial for patients with low or high heart rates.
- Preservation of image quality is maintained with the proposed heart rate-dependent ECG pulsing protocol.
Purpose:
To determine the optimal width and timing of the electrocardiographic (ECG) pulsing window within the cardiac cycle in relation to heart rate (HR), image quality, and radiation exposure in patients who are suspected of having coronary artery disease.
Materials And Methods:
The institutional review board approved the study, and all patients gave informed consent. Dual-source computed tomography (CT) was performed in 301 patients (mean HR, 70.1 beats per minute +/- 13.3 [standard deviation]; range, 43-112 beats per minute) by using a wide ECG pulsing window (25%-70% of the R-R interval). Data sets were reconstructed in 5% steps from 20%-75% of R-R interval. Image quality was assessed by two observers on a per-segment level and was classified as good or impaired. High-quality data sets were those in which each segment was of good quality. The width and timing of the image reconstruction window was calculated. On the basis of these findings, an optimal HR-dependent ECG pulsing protocol was designed, and the potential dose-saving effect on effective dose (in millisieverts) was calculated.
Results:
At low HR (< or = 65 beats per minute), high-quality data sets were obtained during end diastole (ED); at high HR (> or = 80 beats per minute), they were obtained during end systole (ES); and at intermediate HR (66-79 beats per minute), they were obtained during both ES and ED. Optimal ECG pulsing windows for low, intermediate, and high HR were at 60%-76%, 30%-77%, and 31%-47% of the R-R interval, respectively, and with these levels, the effective dose was decreased at low HR from 18.7 to 6.8 mSv, at intermediate HR from 14.7 to 13.4 mSv, and at high HR from 11.3 to 4.2 mSv.
Conclusion:
With optimal ECG pulsing, radiation exposure to patients, particularly those with low or high HR, can be reduced with preservation of image quality.
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