Silent T₂^* and T₂ encoding using ZTE combined with BURST

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering

Background:

• Traditional MRI sequences can be noisy, potentially causing patient discomfort and limiting scan quality.
• Quantitative imaging of T2* and T2 relaxation times, as well as magnetic susceptibility, is crucial for diagnosing various neurological conditions.

Purpose of the Study:

• To develop and validate a novel, silent 3D imaging method for acquiring T2*-weighted and T2-weighted images.
• To enable the generation of quantitative T2*, T2, and magnetic susceptibility maps.
• To combine zero-echo-time (ZTE) imaging with gradient- and spin-echo BURST encoding for silent MRI.

Main Methods:

• A novel silent 3D imaging approach was developed, integrating zero-echo-time (ZTE) with gradient- and spin-echo BURST encoding.
• The method involves ZTE encoding followed by reversed k-space traversal to recall gradient echoes (BURST).
• Spin echoes were generated using 180° pulses, allowing for T2-weighted imaging. Data was reconstructed via 3D gridding and Fourier transformation.

Main Results:

• High-quality, silent T2*-weighted and T2-weighted brain images were acquired in vivo.
• Quantitative T2* and magnetic susceptibility maps were successfully extracted from gradient-echo ZTE-BURST data.
• Quantitative T2 maps were obtained from the spin-echo version of the sequence.

Conclusions:

• The combination of ZTE and BURST encoding facilitates silent acquisition of T2*- and T2-weighted brain images with excellent quality.
• This novel technique offers a promising approach for advanced quantitative MRI without acoustic noise.
• The method allows for comprehensive tissue characterization through multiple quantitative maps derived from a single silent acquisition.