Diffusion MR Imaging with T2-based Water Suppression (T2wsup-dMRI).

Area of Science:

• Medical Imaging
• Neuroimaging
• Biophysics

Background:

• Diffusion MRI (dMRI) is crucial for quantifying brain tissue properties and mapping white matter tracts.
• Cerebrospinal fluid (CSF) partial volume effects (PVEs) introduce artifacts, compromising the accuracy of dMRI-derived parameter maps (ADC, MD, FA) and fiber tractography (FT).
• Existing methods to mitigate CSF-PVEs have limitations in accuracy and signal-to-noise ratio.

Purpose of the Study:

• To propose and evaluate a novel dMRI technique combining T2-based water suppression (T2wsup) to overcome CSF-PVEs.
• To improve the quantification of dMRI parameter maps and the accuracy of fiber tractography in the presence of CSF-PVEs.
• To assess the performance of the T2wsup-dMRI technique against standard dMRI and alternative methods.

Main Methods:

• Acquired multi-b value diffusion-weighted imaging (DWI) data.
• Applied T2wsup by subtracting corrected multi-echo time images from water signal-dominant images.
• Generated quantitative parameter maps and fiber tractography using minimal data points.

Main Results:

• T2wsup-dMRI dramatically suppressed CSF-PVE artifacts, even at low b-values, while preserving tissue signal-to-noise ratio (SNR).
• Quantitative parameter maps accurately reflected pure tissue values in CSF-PVE voxels.
• Fiber tractography showed improved connectivity, particularly for the fornix adjacent to CSF.

Conclusions:

• The T2wsup-dMRI technique effectively resolves CSF-PVEs in dMRI with superior SNR compared to FLAIR or NBZ methods for healthy tissues.
• The proposed method is straightforward and shows potential for clinical application.
• Further optimization and clinical validation are needed, especially for tissues with long T2 relaxation times.