Improved quantitative myocardial T₂ mapping: Impact of the fitting model

Area of Science:

• Magnetic Resonance Imaging
• Cardiovascular Imaging
• Biomedical Engineering

Background:

• Myocardial T2 mapping is crucial for assessing tissue properties in cardiovascular MRI.
• Conventional T2 mapping using balanced steady-state free-precession (bSSFP) sequences often relies on a two-parameter fit.
• This two-parameter model may be susceptible to inaccuracies due to imaging pulse effects and RF imperfections.

Purpose of the Study:

• To develop an improved T2 prepared (T2 prep) bSSFP sequence for myocardial T2 mapping.
• To introduce a novel signal relaxation curve fitting method for more robust T2 quantification.

Main Methods:

• A new T2 mapping sequence was developed, incorporating an additional image with saturation preparation.
• This allows for a three-parameter fit model, accounting for imaging pulse effects and RF imperfections.
• Phantom and in vivo studies compared the proposed three-parameter model with the conventional two-parameter model and a spin echo reference.

Main Results:

• The proposed three-parameter model yielded T2 values independent of T2 prep echo times.
• Results from the three-parameter model were not statistically different from reference values in phantom studies.
• The conventional two-parameter model showed dependence on T2 prep echo times and significant deviation from reference values.

Conclusions:

• The novel imaging sequence and three-parameter model enable accurate myocardial T2 measurements.
• This method provides T2 values robust to variations in T2 prep echo time and sequence imperfections.
• The findings suggest improved reliability for T2 mapping in clinical cardiovascular MRI applications.