T₂ mapping with magnetization-prepared 3D TSE based on a modified BIR-4 T₂ preparation

Area of Science:

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

Background:

• T2 mapping is crucial for MRI-based tissue characterization.
• Standard T2 quantification methods are susceptible to errors from B1 and B0 field offsets.
• Accurate T2 measurements are essential for reliable diagnostic information.

Purpose of the Study:

• To evaluate the modified BIR-4 T2 preparation for T2 mapping.
• To develop a method for correcting T2 quantification errors caused by B1 and B0 field offsets.
• To enhance the accuracy and precision of T2 mapping.

Main Methods:

• Theoretical investigation of magnetization evolution under field offsets.
• Comparison of three fitting methods: two-parameter fit, three-parameter fit, and two-parameter fit with saturation preparation.
• Validation using simulations, phantom measurements, and in vivo human neck MRI with a 3D TSE readout.

Main Results:

• The standard two-parameter fit overestimated T2 values in regions with high B0 offsets.
• The three-parameter fit showed robustness to B0 offsets but with increased standard deviation.
• The proposed two-parameter fit with saturation preparation demonstrated robustness and comparable noise performance to the standard method, ensuring accurate T2 mapping.

Conclusions:

• The modified BIR-4 T2 preparation, combined with the proposed fitting approach, effectively removes T2 quantification errors.
• This method enables accurate and precise T2 mapping in the presence of significant B1 and B0 field offsets.
• The findings support the clinical utility of robust T2 mapping for improved MRI diagnostics.