Diffusion tensor imaging detects chronic microstructural changes in white and gray matter after traumatic brain...

Area of Science:

• Neuroscience
• Medical Imaging
• Pathology

Background:

• Traumatic brain injury (TBI) is a leading cause of global disability and mortality.
• TBI initiates a cascade of secondary tissue changes, resulting in diverse long-term neurological deficits.
• Understanding chronic TBI-related changes is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the detectability of secondary injury at a chronic time-point using ex vivo diffusion tensor imaging (DTI) in a rat model of TBI.
• To correlate DTI findings with histological evidence of cellular-level alterations.
• To assess the feasibility of detecting these chronic changes using in vivo DTI.

Main Methods:

• Lateral fluid percussion (LFP) injury model in rats to induce TBI.
• Ex vivo and in vivo diffusion tensor imaging (DTI) at a chronic time-point post-injury.
• Histological examination of brain tissue, focusing on myelinated axons and iron accumulation.

Main Results:

• Ex vivo DTI revealed persistent microstructural changes in white matter tracts (corpus callosum, angular bundle, internal capsule).
• Histology showed loss of myelinated axons and/or iron accumulation in affected white matter.
• Gray matter (thalamus) showed increased fractional anisotropy, linked to neurodegeneration, fiber loss, and calcifications.

Conclusions:

• DTI is effective in detecting chronic microstructural alterations in TBI at both ex vivo and in vivo settings.
• These imaging findings correlate with underlying cellular pathology, including axonal damage and iron deposition.
• The study provides valuable insights into the long-term consequences of TBI and potential imaging biomarkers.