Incomplete initial nutation diffusion imaging: An ultrafast, single-scan approach for diffusion mapping.

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Neuroscience

Background:

• Diffusion MRI is limited by long acquisition times, hindering the study of rapid microstructural changes.
• T2 variations accompanying diffusivity changes further complicate conventional diffusion MRI.
• Current methods struggle to capture fast dynamic processes in vivo.

Purpose of the Study:

• To accelerate diffusion MRI acquisition to a single-shot experiment.
• To enable quantitative diffusivity mapping without T2 bias.
• To detect rapid dynamic microstructural changes in vivo.

Main Methods:

• Introduced incomplete initial nutation diffusion imaging (INDI) methodology.
• INDI acquires two diffusion contrasts within a single shot, milliseconds apart.
• Validated INDI through phantom, ex vivo, and in vivo experiments at 16.4 and 9.4T.

Main Results:

• INDI-derived mean diffusivities closely matched diffusion tensor imaging and two-shot methods in phantoms.
• Excellent agreement was observed between INDI and conventional methods in ex vivo and in vivo mouse brains.
• Simulations identified optimal signal-to-noise conditions for INDI application.

Conclusions:

• INDI accelerates diffusion MRI to single-shot acquisition.
• This acceleration is crucial for mapping dynamic in vivo microstructural properties.
• INDI mitigates T2 bias in diffusion MRI measurements.