Diffusion Tensor MRI and Spherical-Deconvolution-Based Tractography on an Ultra-Low Field Portable MRI System

Area of Science:

• Medical Imaging
• Neuroscience
• Biophysics

Background:

• Ultra-low-field MRI (ULF-MRI) offers cost-effectiveness, portability, and accessibility advantages over high-field MRI.
• Despite lower signal-to-noise ratio, advanced computational methods make ULF-MRI contrasts like diffusion-weighted imaging (DWI) feasible.
• ULF-MRI holds potential for large-scale deployment and broader accessibility in research and clinical settings.

Purpose of the Study:

• To investigate the capabilities and constraints of ULF tractography.
• To assess the feasibility of ULF-MRI for mapping white matter microstructure.
• To compare ULF-MRI tractography results with high-field MRI references.

Main Methods:

• Acquired ULF-MRI data on a 0.064 T mobile scanner.
• Performed tractography to identify major white matter bundles.
• Analyzed diffusion tensor imaging (DTI)-derived scalar maps (fractional anisotropy, mean diffusivity).
• Reconstructed fibre orientation distribution functions (fODFs).

Main Results:

• Most major white matter bundles were successfully retrieved in healthy adults within clinically acceptable scan times.
• ULF-MRI derived scalar maps showed strong correspondence with high-field MRI data.
• Reconstructed fODFs from ULF data agreed well with high-field references, confirming tractography feasibility.

Conclusions:

• ULF-MRI is a feasible technique for reliable tractography and assessment of white matter microstructure.
• This technology democratizes microstructural MRI, extending advanced imaging to underserved populations and settings.
• Findings support the use of ULF-MRI for studies on brain health, development, and disease progression.