Inversion recovery TrueFISP: quantification of T(1), T(2), and spin density.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biophysics
• Medical Physics

Background:

• TrueFISP (True Fast Imaging with Steady-state Precession) is a widely used MRI sequence.
• Quantitative MRI parameter mapping (T(1), T(2), spin density) is crucial for accurate tissue characterization.
• Existing methods for quantitative TrueFISP parameter extraction can be complex or limited.

Purpose of the Study:

• To develop a novel procedure for extracting T(1), T(2), and relative spin density from TrueFISP signal time courses.
• To validate the proposed method using phantom and human volunteer data.

Main Methods:

• Utilizing a series of TrueFISP images acquired after spin inversion.
• Modeling magnetization recovery with a three-parameter monoexponential function: S(t) = S(stst)(1-INV exp(-t/T(*) (1)).
• Deriving T(1), T(2), and relative spin density from fit parameters, including the inversion factor (INV).

Main Results:

• The ratio T(1)/T(2) can be directly extracted from the inversion factor (INV).
• Analytical expressions enable direct derivation of T(1), T(2), and relative spin density from fit parameters.
• Phantom studies demonstrated excellent agreement with reference measurements.
• Human volunteer studies yielded T(1), T(2), and spin density maps consistent with literature values.

Conclusions:

• The proposed novel procedure accurately extracts T(1), T(2), and relative spin density from TrueFISP sequences.
• This method enhances the quantitative capabilities of TrueFISP MRI.
• The findings support the clinical utility of this approach for improved tissue characterization.