Comparison of respiratory motion suppression techniques for 4D flow MRI

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Magnetic Resonance Imaging

Background:

• Four-dimensional Flow Magnetic Resonance Imaging (4D Flow MRI) is crucial for assessing cardiovascular hemodynamics.
• Respiratory motion introduces artifacts that can compromise the accuracy of 4D Flow MRI data.
• Effective suppression of respiratory motion artifacts is essential for reliable clinical applications.

Purpose of the Study:

• To evaluate the detrimental effects of respiratory motion on 4D Flow MRI.
• To compare the efficacy of various techniques for suppressing respiratory motion artifacts.
• To investigate the influence of spatial resolution on motion artifact reduction.

Main Methods:

• A 3D aorta phantom based on computational fluid dynamics was utilized for simulations.
• Simulated motion-distorted 4D Flow MRI data were analyzed.
• Techniques evaluated included fixed-window gating, adaptive window gating, and k-space reordering.
• The impact of different spatial resolutions was also assessed.

Main Results:

• Respiratory motion was found to degrade image quality and introduce significant flow rate errors (up to 30%).
• All tested motion suppression techniques demonstrated improvements in data quality.
• Advanced methods like weighted gating and combined gating with k-space reordering reduced errors to below 2.5%.
• Spatial resolutions finer than the accepted motion range did not yield further improvements.

Conclusions:

• Respiratory motion is a significant confounder in 4D Flow MRI.
• Several motion suppression strategies effectively mitigate motion-induced errors.
• Optimizing spatial resolution beyond the degree of respiratory motion does not enhance data quality.