oDual-MRF: An Optimized Dual-Alternating MR Fingerprinting Sequence.

Area of Science:

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

Background:

• Magnetic Resonance Fingerprinting (MRF) enables simultaneous T1 and T2 mapping.
• Conventional MRF sequences like FISP-MRF face challenges in quantitative accuracy, particularly for T2 values.
• Improving the precision of MRF parameter quantification is crucial for clinical applications.

Purpose of the Study:

• To introduce and evaluate the Dual-MRF sequence for enhanced T2 mapping accuracy in MRF.
• To optimize Dual-MRF parameters using Cramer-Rao Bound (CRB) for minimized estimator variance.
• To compare the performance of Dual-MRF against conventional FISP-MRF.

Main Methods:

• Developed the Dual-MRF sequence by alternating FISP and PSIF acquisitions within the MRF framework.
• Optimized sequence parameters (flip angle, repetition time, alternation scheme) for the oDual-MRF using CRB.
• Validated sequence performance through extensive simulations, phantom studies, and in vivo experiments.

Main Results:

• Dual-MRF demonstrated superior T2 quantification accuracy compared to standard FISP-MRF.
• The optimized oDual-MRF sequence further improved T2 accuracy.
• Both Dual-MRF and oDual-MRF maintained high T1 accuracy without compromising T1 map quality.

Conclusions:

• CRB-based optimization of the Dual-MRF sequence significantly enhances T2 quantification accuracy.
• The proposed method preserves T1 accuracy, enabling reliable multiparametric MRF.
• Dual-MRF presents a promising advancement for precise quantitative MRI.