Phase-based T₂ mapping with gradient echo imaging

Area of Science:

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

Background:

• Transverse relaxation time (T2) mapping is crucial for MRI applications.
• Existing T2 mapping methods often use spin-echo (SE) sequences, which are time-consuming.
• There is a need for faster and efficient T2 mapping techniques.

Purpose of the Study:

• To develop and validate a novel phase-based T2 mapping technique using rapid gradient echo (GRE) acquisitions.
• To encode T2 information into the signal phase for improved mapping efficiency.
• To demonstrate the feasibility and accuracy of the proposed method.

Main Methods:

• Utilized Bloch equation simulations to establish the T2-dependent phase behavior in GRE acquisitions.
• Acquired at least two datasets with different RF phase increments to isolate T2-dependent phase.
• Validated the technique in phantom experiments and in vivo across various anatomical regions (brain, knee, abdomen, pelvis).

Main Results:

• Phase-based T2 maps showed accurate results compared to SE-based T2 mapping in phantoms.
• Good qualitative agreement was observed between the proposed method and reference techniques in vivo.
• In vivo T2 measurements in different anatomies correlated well with literature values.

Conclusions:

• A novel phase-based T2 mapping technique has been successfully developed.
• The technique demonstrates feasibility and accuracy in both phantom and in vivo studies.
• This method offers a potentially faster and efficient alternative for T2 quantification in MRI.