MIMOSA: Multi-parametric Imaging using Multiple-echoes with Optimized Simultaneous Acquisition for highly-efficient...

Area of Science:

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

Background:

• Quantitative MRI enables precise tissue characterization.
• Existing multi-parametric mapping sequences often face trade-offs between speed, resolution, and accuracy.
• Development of accelerated acquisition techniques is crucial for clinical translation.

Purpose of the Study:

• To introduce MIMOSA, a novel MRI sequence designed for highly-efficient multi-parametric mapping.
• To enable simultaneous quantification of T1, T2, T2*, proton density (PD), and source separation quantitative susceptibility mapping (QSM).
• To achieve accelerated acquisition without compromising accuracy.

Main Methods:

• MIMOSA combines 3D turbo Fast Low Angle Shot (FLASH) and multi-echo gradient echo modules with a spiral-like Cartesian trajectory.
• Sequence optimization was performed using simulations.
• A multi-contrast/-slice zero-shot self-supervised learning algorithm was used for reconstruction; accuracy and repeatability were assessed in phantom and in-vivo studies at 3T and 7T.

Main Results:

• MIMOSA demonstrated improved parameter estimation accuracy and better agreement with reference techniques compared to 3D-QALAS.
• In-vivo experiments achieved acceleration factors up to R=11.8 with high repeatability (ICC > 0.947 for all parameters).
• Whole-brain quantitative maps (T1, T2, T2*, PD, QSM) were acquired with 1 mm isotropic resolution in 3 minutes at 3T and 750 µm isotropic resolution in 13 minutes at 7T.

Conclusions:

• MIMOSA is a highly-efficient sequence for multi-parametric MRI.
• It enables rapid, accurate, and repeatable quantitative mapping of key tissue properties.
• The sequence shows significant potential for advancing quantitative imaging in clinical and research settings.