Using diffusion tensor imaging and immunofluorescent assay to evaluate the pathology of multiple sclerosis

Area of Science:

• Neuroimaging
• Histopathology
• Multiple Sclerosis Research

Background:

• Diffusion tensor imaging (DTI) is a neuroimaging technique used to assess white matter integrity.
• Histopathology provides detailed cellular and tissue-level information, crucial for understanding disease mechanisms.

Purpose of the Study:

• To evaluate the predictive capability of principal DTI indices for underlying histopathology in ex vivo human cervical spinal cord.
• To correlate DTI metrics with myelin and neurofilament staining via immunofluorescent assay (IFA).

Main Methods:

• Conventional T2 and 3D multishot-diffusion weighted echoplanar imaging (3D ms-DWEPI) were performed on a fixed ex vivo human cervical spinal cord.
• 170 regions of interest (ROIs) were analyzed, categorized as high intensity lesions (HIL), low intensity lesions (LIL), and normal-appearing white matter (NAWM).
• Longitudinal diffusivity (λl), radial diffusivity (λr), and fractional anisotropy (FA) were calculated, and histopathology was assessed using IFA for myelin and neurofilament.

Main Results:

• Elevated λl and λr values were observed in HIL compared to NAWM and LIL.
• HIL showed significant demyelination with minimal axon loss on IFA.
• Reduced FA values were found in HIL and LILs, correlating with increased λl and λr.

Conclusions:

• Aberrant DTI indices (λl, λr, FA) are strong indicators of demyelination in the spinal cord.
• DTI metrics are not specific for detecting axon loss.
• IFA is a reliable method for assessing myelin and axon pathology in ex vivo settings.