Three-dimensional inhomogeneous magnetization transfer with rapid gradient-echo (3D ihMTRAGE) imaging.

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Physics

Background:

• Magnetization transfer (MT) techniques are crucial for enhancing contrast in MRI.
• Inhomogeneous MT (ihMT) offers improved sensitivity but requires specific preparation sequences.
• Integrating advanced MT preparations into established MRI sequences like MPRAGE is desirable for efficiency.

Purpose of the Study:

• To assess the feasibility of incorporating ihMT preparation pulses into an MPRAGE-style acquisition.
• To develop and evaluate a novel ihMT MPRAGE sequence (ihMTRAGE).
• To explore the benefits of reduced power deposition and modularity in 3D ihMT imaging.

Main Methods:

• Simulated an ihMT MPRAGE-style sequence (ihMTRAGE) to compare sequential and interleaved data acquisition.
• Implemented the ihMTRAGE sequence on a 3T clinical scanner for in vivo brain and spine imaging.
• Acquired ihMT data using both sequential and interleaved ihMTRAGE, and compared with steady-state ihMT acquisitions.

Main Results:

• Sequential ihMTRAGE yielded a significantly greater ihMT signal than interleaved acquisition.
• ihMTRAGE demonstrated reduced average power deposition compared to steady-state ihMT.
• The sequence allowed for greater ihMT signal at equal power deposition.
• Prospective motion correction did not significantly impact brain ihMT signal.
• Spatial saturation module successfully reduced phase wrap artifacts in cervical spine imaging.

Conclusions:

• The ihMTRAGE sequence provides a feasible and advantageous alternative for acquiring 3D ihMT data.
• ihMTRAGE offers reduced power deposition and optimized signal intensity compared to steady-state methods.
• The modular nature of ihMTRAGE facilitates integration with other useful MRI modules like motion correction and spatial saturation.