Combining inhomogeneous magnetization transfer and multipoint Dixon acquisition: Potential utility and evaluation

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering

Background:

• Inhomogeneous magnetization transfer (ihMT) is a novel MRI technique primarily used for central nervous system imaging.
• Future applications in peripheral nerves and muscles require understanding fat's influence on ihMT signals.

Purpose of the Study:

• To investigate the partial volume effect of fat on the ihMT signal.
• To develop an efficient fat-separation method compatible with ihMT measurements.

Main Methods:

• Simulations were performed to assess fat's impact on ihMT signal.
• The ihMT sequence was integrated with multi-echo Dixon acquisition for fat separation.
• The combined sequence was validated in 9 healthy volunteers at 3T, comparing results with standard fat suppression techniques.

Main Results:

• Simulations revealed TE-dependent variations in ihMTR due to fat.
• Water-only ihMT multi-echo Dixon reconstructions showed good agreement with unsuppressed data.
• Standard fat suppression reduced ihMTR by 24%-35% compared to unsuppressed acquisition.

Conclusions:

• Fat presence within a voxel influences ihMTR calculations.
• The ihMT multi-echo Dixon method preserves the ihMT effect and can mitigate fat's influence.