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Retrospective Cardiac Gating with A Prototype Small-Animal X-ray Computed Tomograph
Published on: February 21, 2025
Optimized heart rate for 320-row cardiac CT can be feasibly predicted from prescan parameters
Eriko Maeda1, Nobuo Tomizawa2, Kodai Yamamoto3
1Department of Radiology, Graduate School of Medicine, University of Tokyo Bunkyo-ku, 7-3-1 Hongo, Tokyo, 113-8655 Japan.
Insights
Heart rate (HR) significantly decreases during breath holds and cardiac CT scans. A predictive formula for cardiac CT scan HR was accurate only for patients whose HR decreased during breath holds.
Area of Science:
- Cardiovascular Imaging
- Radiology
- Physiology
Background:
- Heart rate management is crucial for optimal cardiac CT image quality.
- Understanding heart rate dynamics during breath holds and scans is essential.
Purpose of the Study:
- To assess heart rate (HR) changes at rest, during breath holds, and during cardiac CT.
- To develop and validate a predictive formula for HR during cardiac CT scans.
Main Methods:
- Retrospective analysis of HRrest, HRtest, and HRscan in 563 patients undergoing 320-row cardiac CT.
- Multiple regression analysis to derive predictive formulas for HRscan.
- Evaluation of formula accuracy based on a ±5 bpm threshold.
Main Results:
- Average HRtest (65.3 bpm) and HRscan (63.7 bpm) were significantly lower than HRrest (68.4 bpm).
- The derived predictive formula (HRscan = 3.601 + 0.113HRrest + 0.8HRtest) was accurate only in patients with decreased HR during breath hold (Group Dec).
Conclusions:
- Cardiac CT examinations and breath holds lead to significant heart rate reduction.
- An accurate predictive formula for heart rate during cardiac CT scans is feasible only for patients exhibiting decreased heart rate during breath holds.
Abstract:
To evaluate the degree of heart rate (HR) changes at rest (HRrest), during breath hold (HRtest), and during cardiac CT examinations (HRscan) in a large group of patients , and to derive and asses the feasibility of a predictive formula for HRscan. HRrest, HRtest, and HRscan were retrospectively compared in a total of 563 consecutive patients who underwent 320-row cardiac CT. Multiple regression analysis was performed to derive predictive formulae for HRscan in the entire study population and, in each group of patients with decreased (Dec) or increased (Inc) HR during breath hold. The predictive formula was evaluated as accurate when less than 5 % of the actual HRscan exceeded the predicted HRscan by ±5 beats per minute (bpm). The average values of the HRtest (65.3 ± 12.0 bpm) and HRscan (63.7 ± 11.9 bpm) significantly decreased from those of the HRrest (68.4 ± 11.9 bpm) (p < 0.0001). The predictive formula (HRscan = 3.601 + 0.113HRrest + 0.8HRtest) was determined to be accurate only in Group Dec. The HRtest significantly decreased from the HRrest, and the HRscan significantly decreased from the HRtest. An accurate predictive formula for HRscan could be built only for Group Dec.
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