A new approach for multislice spatiotemporal encoding MRI in a portable low-field system

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging Physics
• Biomedical Engineering

Background:

• Spatiotemporal encoding (SPEN) MRI is an alternative to echo planar imaging for low-field systems.
• Existing multislice SPEN schemes struggle with consistent signal-to-noise ratios (SNRs) and contrast across different slice settings.
• Portable low-field MRI systems often lack multiple receiver coils, limiting conventional techniques.

Purpose of the Study:

• To propose and validate a novel multislice SPEN scheme (SPENms) for portable low-field MRI.
• To achieve stable image quality, including consistent SNRs and contrasts, with varying slice numbers.
• To address distortion issues inherent in echo planar acquisition-based methods.

Main Methods:

• Introduced a modified SPEN sequence (SPENms) by inserting selective and non-selective π pulses before the frequency-swept π pulse.
• Conducted theoretical simulations to analyze the sequence's performance.
• Performed experimental validation on phantoms and human brains to assess SNR and contrast.

Main Results:

• Simulations and experiments confirmed consistent image quality with SPENms across various parameters and targets.
• The SPENms scheme demonstrated good resistance to image distortions and efficient scanning.
• Robust diffusion-weighted multislice SPEN images with diagnostic value were successfully acquired.

Conclusions:

• SPENms offers a robust and fast echo planar acquisition method for multislice 2D imaging.
• The technique provides reduced distortions and stable SNRs/contrasts on portable low-field MRI systems.
• SPENms enhances imaging capabilities for resource-limited MRI environments.