Nonuniform sliding-window reconstruction for accelerated dual contrast agent quantification with MR fingerprinting

Area of Science:

• Biomedical Imaging
• Magnetic Resonance Imaging

Background:

• Magnetic Resonance Fingerprinting (MRF) allows simultaneous quantification of multiple contrast agents for cell tracking.
• Faster scan times are crucial for in vivo MRF applications, but current methods like Sliding Window (SW)-MRF struggle to maintain T2* accuracy.
• T2* accuracy is critical for tracking iron-labeled cells in vivo.

Purpose of the Study:

• To develop an SW-MRF approach that preserves T2* accuracy.
• To enable accelerated concentration mapping of iron-labeled cells on single-channel preclinical systems.

Main Methods:

• A nonuniform SW was applied to the MRF sequence and dictionary, with shorter window lengths for T2*-sensitive segments.
• Phantoms with iron-labeled cells and gadolinium were used to compare uniform and nonuniform SW-MRF parameter maps (24x undersampled).
• Dual concentration maps were generated and compared between uniform and nonuniform MRF.

Main Results:

• Nonuniform SW-MRF showed significantly higher concordance correlation coefficients compared to uniform SW-MRF against gold standards.
• Statistical analysis revealed no significant difference between nonuniform SW-MRF and gold standards for T2* accuracy.
• Nonuniform SW-MRF outperformed uniform SW-MRF in concentration maps, balancing T2* sensitivity and signal-to-noise ratio.

Conclusions:

• Nonuniform SW-MRF enhances matching accuracy over uniform SW-MRF.
• This improved accuracy allows for higher acceleration in concentration mapping for preclinical MRF systems.