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Updated: Nov 9, 2025
Retrospective Cardiac Gating with A Prototype Small-Animal X-ray Computed Tomograph
Published on: February 21, 2025
The setting of heartbeat acceptance windows on gated myocardial perfusion single-photon emission computed tomography
Kunihito Tsuboi1,2, Akio Nagaki2,3, Takayuki Shibutani3
1Department of Central Radiology, Gifu Prefectural Gero Hot Spring Hospital, Gero.
Insights
For patients with variable heartbeats, using a single peak for gated myocardial perfusion SPECT improves accuracy in measuring left ventricular function. This method is more reliable than using two peaks, as confirmed by echocardiography.
Area of Science:
- Nuclear medicine
- Cardiology
- Medical imaging
Background:
- Arrhythmias like bigeminy and trigeminy cause variable heart rates.
- Gating errors in myocardial perfusion SPECT (MPS) can affect left ventricular (LV) functional assessments.
- Cadmium zinc telluride (CZT) cameras are used for cardiac imaging.
Purpose of the Study:
- To evaluate the impact of gating error on LV functional parameters in patients with consistently variable heart rates.
- To compare the accuracy of LV functional measurements using different heartbeat acceptance windows in gated MPS.
- To use echocardiography as a reference standard for LV function.
Main Methods:
- Sixteen patients with consistently variable heart rates underwent gated MPS using a D-SPECT camera.
- Two types of heartbeat acceptance windows were applied: one including a single peak and another including two peaks of maximum counts.
- Echocardiography was performed for comparison.
Main Results:
- Left ventricular ejection fraction (LVEF) was 51.3% with a one-peak window, 47.1% with a two-peak window, and 54.1% with echocardiography.
- Measurements of LV volumes and ejection fraction differed between the one-peak and two-peak windows.
- The mean difference in LVEF between the two-peak window and echocardiography was greater than between the one-peak window and echocardiography.
Conclusions:
- Setting the heartbeat acceptance window to include a single peak is suitable for accurate LV function measurement in consistently variable patients.
- This approach minimizes gating errors and improves the reliability of MPS in this patient group.
Objectives:
Consistently variable with several peaks in heart rate histogram (e.g. bigeminy and trigeminy) is one of the arrhythmia types. We investigated the effects of gating error by consistently variable patients on left ventricular (LV) functional with cadmium zinc telluride (CZT) camera. The purpose of this study is to evaluate LV functional parameters by setting different heartbeat acceptance windows on gated myocardial perfusion single-photon emission computed tomography (SPECT) (MPS) in consistently variable patients, using echocardiography (echo) as a reference.
Materials And Methods:
Sixteen consistently variable patients underwent the gated MPS using a D-SPECT. The MPS images were obtained by setting two different types of heartbeat acceptance windows. The heartbeat acceptance windows were set to include only one peak and two peaks of the maximum count peaks, respectively.
Results:
Mean end-diastolic volume, end-systolic volume and left ventricular ejection fraction (LVEF) were 112.7 mL, 62.2 mL and 51.3% for one peak, 114.5 mL, 66.1 mL and 47.1% for two peak, and 113.0 mL, 54.2 mL and 54.1% for echo, respectively. The mean differences between two peaks and echo in LVEF were larger than those of between one peak and echo.
Conclusion:
Our study suggests that setting the heartbeat acceptance window of one peak was suitable for accurate measurement of LV function in consistently variable patients.
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