Intercenter differences in diffusion tensor MRI acquisition.

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Radiology

Background:

• Diffusion tensor magnetic resonance imaging (DT-MRI) is a powerful tool for assessing white matter integrity.
• Standardized acquisition protocols are essential for reliable DT-MRI data.
• Variability in DT-MRI data can arise from scanner differences and acquisition centers.

Purpose of the Study:

• To evaluate the impact of different MRI scanners on diffusion tensor (DT) magnetic resonance imaging (MRI) data.
• To determine the influence of acquisition center on DT-MRI metrics.
• To assess the variability of fractional anisotropy (FA), axial diffusivity (D(ax)), radial diffusivity (D(rad)), and mean diffusivity (MD) across different scanners.

Main Methods:

• Forty-four healthy controls and 36 multiple sclerosis patients underwent DT-MRI on eight different MR scanners.
• Acquisition protocols were standardized as closely as possible across all scanners.
• Region-of-interest (ROI) and histogram-based analyses were performed on FA, D(ax), D(rad), and MD.
• Analysis of variance (ANOVA) was used to determine the influence of acquisition center and patient/control group.

Main Results:

• The patient/control group explained approximately 25% of data variability for FA and D(rad) in the corpus callosum (CC).
• Global FA, MD, and D(rad) in white matter differentiated patients from controls, but with lower discriminatory power than CC.
• In gray matter, MD discriminated patients from controls, with 30% variability explained by group versus 17% by center.

Conclusions:

• Significant variability in DT-MRI data is attributable to the acquisition center, even with standardized protocols.
• Appropriate segmentation methods and statistical models are necessary for reliable DT-derived metrics.
• DT-MRI metrics can effectively differentiate patients from healthy controls when accounting for data variability.