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Variation of heart rate and electrocardiograph trigger interval during ultrafast computed tomography
S S Mao1, R J Oudiz, H Bakhsheshi
1Saint John's Cardiovascular Research Center, and Harbor-UCLA Medical Center, Torrance, CA 90502, USA.
American Journal of Cardiac Imaging
|October 1, 1996
Summary
Cardiac ultrafast computed tomography (UFCT) scanning shows significant heart rate and ECG trigger interval variability, especially early in the scan. Delaying scanning improves image quality by allowing heart rate stabilization.
Area of Science:
- Cardiovascular Imaging
- Medical Physics
Background:
- Cardiac ultrafast computed tomography (UFCT) relies on electrocardiographic (ECG) triggering for image acquisition.
- Variability in heart rate and ECG trigger intervals can impact image quality and diagnostic accuracy.
Purpose of the Study:
- To analyze heart rate and ECG trigger interval variability during cardiac UFCT.
- To develop a protocol for improved ECG triggering software.
Main Methods:
- 118 patients underwent cardiac UFCT imaging.
- Patients were divided into three groups based on heart rate and ECG trigger conditions.
- Thirty high-resolution slices were acquired per patient.
Main Results:
- Heart rate and ECG trigger interval decreased during the first four slices of acquisition.
- Heart rate nadir occurred at the 4th slice, with significant reductions compared to initial rates.
- Heart rate and ECG trigger interval progressively increased from the 4th to 30th slices, with reduced variability in later slices.
Conclusions:
- Significant heart rate and ECG trigger interval variations occur during cardiac UFCT, particularly in the initial seconds after breath-holding.
- Current UFCT triggering software may acquire images during suboptimal cardiac phases.
- A delayed scan initiation (6-10 seconds post-breathold) can improve imaging during stable heart rate periods, enhancing ECG triggering precision.
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