Ultrafast and robust T 2 mapping using optimized single-shot multi-echo planar imaging with alternating blips

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Quantitative Imaging
• Biomedical Engineering

Background:

• T2 mapping is crucial for tissue characterization in MRI.
• Motion artifacts and geometric distortions limit the clinical utility of conventional T2 mapping techniques.
• Developing motion-robust and distortion-corrected methods is essential for broader clinical application.

Purpose of the Study:

• To develop a rapid, motion-robust T2 mapping technique suitable for clinical use.
• To enable T2 mapping across the entire body, including motion-prone areas.
• To enhance the clinical feasibility of quantitative T2 mapping.

Main Methods:

• Implemented a novel single-shot multi-echo spin-echo EPI sequence with alternating phase encoding.
• Acquired multiple echoes from a single RF excitation for T2 measurement.
• Utilized alternating phase encoding polarity for EPI distortion correction and optimized spoiler gradients to remove stimulated echoes.

Main Results:

• Phantom studies demonstrated high precision and repeatability with no significant difference from reference T2 values.
• In vivo brain T2 maps showed comparable anatomical detail and contrast to reference sequences.
• Achieved high-quality diffusion-weighted images with minimal distortion and demonstrated applicability in kidney and fetal brain imaging.

Conclusions:

• The developed single-shot multi-echo EPI sequence enables rapid and accurate T2 relaxation mapping.
• The technique effectively corrects distortions and mitigates motion artifacts.
• This method significantly enhances the clinical feasibility of quantitative T2 mapping across diverse anatomical regions and patient populations.