Patient-independent, MHD-robust R-peak detection for retrospective gating in cardiac MRI imaging.

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Cardiovascular Research

Background:

• Cardiovascular magnetic resonance imaging (CMR) relies on electrocardiogram (ECG) gating for synchronizing image acquisition with cardiac motion.
• High-field MRI scanners (3T and 7T) introduce significant ECG signal distortion due to magnetohydrodynamic effects, challenging accurate gating.
• Current gating methods often require extensive prior training, limiting their immediate clinical applicability.

Purpose of the Study:

• To develop an efficient, retrospective ECG gating strategy for CMR that does not require pre-scanner training.
• To investigate the impact of the number of ECG leads on R-peak detection accuracy in high-field MRI.
• To assess the robustness and adaptability of the proposed gating method across different magnetic field strengths and patient orientations.

Main Methods:

• Utilized 12-lead ECG signals acquired during 3T and 7T MRI scans.
• Employed Independent Component Analysis (ICA) to separate cardiac signals from noise.
• Developed an automatic component selection process based on heart rate estimation and signal quality metrics for R-peak detection.

Main Results:

• Achieved high R-peak detection accuracy with low errors (2.4 ± 3.1 ms at 3T, 10.6 ± 15.4 ms at 7T), demonstrating robustness to field strength.
• Validated effectiveness across various subject orientations, indicating broad clinical applicability.
• Determined that using only three ECG leads, or at most five for 7T, maintains R-peak detection accuracy.

Conclusions:

• The proposed retrospective gating strategy is effective and robust for high-field CMR, overcoming ECG signal distortions.
• The method's independence from prior training and patient-specific parameters facilitates rapid clinical deployment.
• Reducing the number of ECG leads improves patient comfort and simplifies the acquisition process without compromising accuracy.