Reduction of motion artifacts in cine MRI using variable-density spiral trajectories

Area of Science:

• Medical Imaging
• Magnetic Resonance Imaging (MRI)
• Cardiovascular Imaging

Background:

• Dynamic cardiac MRI requires high spatial and temporal resolution, plus signal-to-noise ratio (SNR).
• Single-shot MRI techniques are insufficient for these demands.
• Multishot MRI techniques introduce motion artifacts due to data inconsistencies between views.

Purpose of the Study:

• To design and evaluate variable-density spiral MRI trajectories for reducing motion artifacts.
• To assess the effectiveness of these trajectories in computer simulations and human volunteer scans.
• To investigate the trade-off between artifact reduction and SNR for these trajectories.

Main Methods:

• Design of several variable-density spiral MRI trajectories.
• Evaluation of artifact reduction efficiency via computer simulations.
• Testing in scans of normal volunteers to assess real-world performance.
• Analysis of the signal-to-noise ratio (SNR) compromise associated with each trajectory.

Main Results:

• Variable-density spiral trajectories effectively reduce motion artifacts in dynamic cardiac MRI.
• Oversampling specific regions of kappa-space proved particularly efficient for artifact reduction.
• The tested trajectories demonstrated a small loss in SNR compared to uniform density counterparts.
• Computer simulations and volunteer scans confirmed the artifact reduction capabilities.

Conclusions:

• Variable-density spiral trajectories offer an effective method for reducing motion artifacts in dynamic cardiac MRI.
• These trajectories provide a favorable balance between artifact reduction and SNR preservation.
• This approach presents a valuable advancement over traditional signal averaging techniques for motion artifact mitigation.