Cardiac self-gating using blind source separation for 2D cine cardiovascular magnetic resonance imaging

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Signal Processing

Background:

• Electrocardiogram (ECG)-gating is standard for cardiac MRI but can be complex and sensitive to arrhythmias.
• Developing robust, non-contact gating methods is crucial for improving cardiac MRI acquisition efficiency and reliability.

Purpose of the Study:

• To develop and validate a novel cardiac self-gating algorithm utilizing blind source separation for 2D cine steady-state free precession (SSFP) imaging.
• To assess the performance of this self-gating technique against traditional ECG-gating in terms of cardiac cycle length, image quality, and volumetric measurements.

Main Methods:

• A standard cine SSFP sequence was modified to sample k-space center points with each excitation.
• Four blind source separation methods processed k-space data to detect heartbeats and assign data to cardiac cycle time points.
• Prospective validation was performed in 8 patients, comparing self-gating with ECG-gating.

Main Results:

• Cardiac cycle length agreement between self-gating and ECG-gating was excellent (bias 0.0 bpm, ±2.1 bpm limits of agreement).
• No significant differences in image quality metrics were observed between the two gating methods.
• Ventricular volumes, stroke volumes, and mass measurements showed high comparability (biases <5%) between self-gated and ECG-gated images.

Conclusions:

• The developed self-gating method offers comparable performance to ECG-gating for cardiac cycle length, image quality, and ventricular measurements.
• This technique has the potential to simplify patient preparation and enhance robustness in the presence of arrhythmias.
• The self-gating approach may also facilitate cardiac gating at higher magnetic field strengths.