Comparison between retrospective gating and ECG triggering in magnetic resonance velocity mapping

Area of Science:

• Cardiovascular Imaging
• Magnetic Resonance Imaging
• Hemodynamics

Background:

• ECG-triggered MRI studies face limitations like poor end-diastole imaging and signal artifacts.
• Retrospective gating offers a potential solution but requires raw data interpolation, which can affect signal quality.

Purpose of the Study:

• To compare ECG-triggered and retrospective gating strategies for quantitative MR velocity mapping.
• To evaluate the impact of time window duration on retrospective gating accuracy.
• To assess retrospective gating performance against 1D velocity mapping and Doppler ultrasound.

Main Methods:

• Quantitative MR velocity mapping was performed on the abdominal aorta in eight healthy volunteers and a pulsatile flow phantom.
• Data acquired using both ECG-triggered and retrospective gating were compared.
• Retrospective gating's performance was analyzed with varying time window interpolations.

Main Results:

• Retrospective gating introduced low-pass filtering, prolonging flow pulse duration and decreasing amplitude.
• Reducing the time window for retrospective gating interpolation improved agreement with ECG-triggered measurements.
• Flow measurements with optimized retrospective gating showed good agreement with ECG-triggered data.

Conclusions:

• Retrospective gating, particularly with a narrow interpolation time window, provides advantages for MR velocity mapping.
• This technique can overcome limitations of ECG-triggered MRI for cardiovascular flow assessment.
• Optimized retrospective gating offers a viable alternative for accurate hemodynamic quantification.