Radiological‐pathological correlation of diffusion tensor and magnetization transfer imaging in closed head traumatic brain injury model

This study investigated the radiological‐pathological correlation between these imaging techniques and immunohistochemistry using a closed head rat model of TBI. Methods TBI was performed on female rats followed longitudinally by MRI out to 30 days post‐injury, with a subset of animals selected for histopathological analyses. A MRI‐based finite element analysis was generated to characterize the pattern of the mechanical insult and estimate the extent of brain injury to direct the pathological correlation with imaging findings. Results DTI axial diffusivity and fractional anisotropy (FA) were sensitive to axonal integrity, while radial diffusivity showed significant correlation to the myelin compactness. FA was correlated to astrogliosis in the gray matter while mean diffusivity was correlated to increased cellularity. Secondary inflammatory responses also partly affected the changes of these DTI metrics. The magnetization transfer ratio (MTR) at 3.5 ppm demonstrated a strong correlation with both axon and myelin integrity. Decrease in MTR at 20 ppm correlated with the extent of astrogliosis in both gray and white matter. Interpretation While conventional T2‐weighted MRI did not detect abnormalities following TBI, DTI and MTI afforded complementary insight into the underlying pathologies reflecting varying injury states over time, thus may substitute for histology to reveal DAI pathologies in vivo. This correlation of MRI and histology furthers understanding of the mic...
Source: Annals of Neurology - Category: Neurology Authors: Tags: Research Article Source Type: research
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