²³ Na-T₁ quantification with saturation recovery TrueFISP and variable flip angle GRE at 3T: A phantom study

Area of Science:

• Magnetic Resonance Imaging
• Quantitative MRI
• Sodium MRI

Background:

• Sodium-23 (23Na) MRI offers unique insights into tissue physiology.
• Accurate T1 relaxation time (T1) quantification is crucial for 23Na MRI applications.
• Comparing different pulse sequences for 23Na T1 estimation is essential for optimizing imaging protocols.

Purpose of the Study:

• To compare the reproducibility of 23Na T1 estimation between saturation recovery TrueFISP (SR-TrueFISP) and variable flip angle GRE (VFA-GRE) sequences.
• To evaluate the impact of spatial averaging on 23Na T1 estimation accuracy and reproducibility for both methods.

Main Methods:

• Phantom measurements using a 0.6% NaCl solution at 3 Tesla.
• Acquisition of 23Na images with SR-TrueFISP and VFA-GRE sequences.
• Application of varying degrees of spatial averaging (20 and 30 averages) and B1 correction.

Main Results:

• Both SR-TrueFISP and VFA-GRE yielded comparable 23Na T1 estimates (51 ± 3 ms and 53 ± 2 ms, respectively).
• Increased spatial averaging prolonged acquisition time but did not significantly alter 23Na T1 estimations.
• The variability in T1 estimates was minimal for both methods (|Δ| = 1.58 ms for SR-TrueFISP, |Δ| = 0.53 ms for VFA-GRE).

Conclusions:

• SR-TrueFISP and VFA-GRE are both reliable methods for 23Na T1 estimation in phantoms.
• Spatial averaging can be adjusted to balance acquisition time and signal-to-noise ratio without compromising T1 quantification.
• These findings support the use of either sequence for reproducible 23Na T1 measurements.