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Updated: Feb 23, 2026
Registered Bioimaging of Nanomaterials for Diagnostic and Therapeutic Monitoring
Published on: December 9, 2010
Incomplete initial nutation diffusion imaging: An ultrafast, single-scan approach for diffusion mapping
Andrada Ianuş1,2, Noam Shemesh1
1Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.
Purpose:
Diffusion MRI is confounded by the need to acquire at least two images separated by a repetition time, thereby thwarting the detection of rapid dynamic microstructural changes. The issue is exacerbated when diffusivity variations are accompanied by rapid changes in T2 . The purpose of the present study is to accelerate diffusion MRI acquisitions such that both reference and diffusion-weighted images necessary for quantitative diffusivity mapping are acquired in a single-shot experiment.
Methods:
A general methodology termed incomplete initial nutation diffusion imaging (INDI), capturing two diffusion contrasts in a single shot, is presented. This methodology creates a longitudinal magnetization reservoir that facilitates the successive acquisition of two images separated by only a few milliseconds. The theory behind INDI is presented, followed by proof-of-concept studies in water phantom, ex vivo, and in vivo experiments at 16.4 and 9.4 T.
Results:
Mean diffusivities extracted from INDI were comparable with diffusion tensor imaging and the two-shot isotropic diffusion encoding in the water phantom. In ex vivo mouse brain tissues, as well as in the in vivo mouse brain, mean diffusivities extracted from conventional isotropic diffusion encoding and INDI were in excellent agreement. Simulations for signal-to-noise considerations identified the regimes in which INDI is most beneficial.
Conclusions:
The INDI method accelerates diffusion MRI acquisition to single-shot mode, which can be of great importance for mapping dynamic microstructural properties in vivo without T2 bias. Magn Reson Med 79:2198-2204, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Insights
This study introduces incomplete initial nutation diffusion imaging (INDI), a novel diffusion MRI technique. INDI enables rapid, single-shot acquisition, overcoming limitations in detecting dynamic microstructural changes.
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.
