Correlation between Cognitive Deficits and Tensor Magnetic Resonance Parameters in Patients with Chronic Diffuse Axonal Injury.

Background: The apparent diffusion coefficient (ADC) values and the fractional anisotropy (FA) values calculated from diffusion tensor imaging (DT1) in the acute stage of diffuse axonal injury (DAI) are mainly used for prediction of prognosis. However, neuropsychological outcome correlates more closely with magnetic resonance imaging (MRI) findings from the chronic stage than with those obtained during the acute phase. The purpose of the study was to design a protocol that will assess the spread of neural deficit and provide an accurate prognosis for patients with DAI. Methods: We compared ADC values and FA values calculated from DTI of the anterior and posterior corpus callosum in four patients (mean ± SD: 24.0 ± 4.5 years) with DAI and cognitive disorders with those of 10 normal control subjects (23.3 ± 1.3 years).All patients had chronic stage DAI with no significant MRI abnormality. Although they maintained self-care task, they were unable to adapt to social life because of cognitive disorders. Results: For the anterior corpus callosum, the FA values were higher and the ADC values were lower bilaterally in DAI patients than in the control subjects. The high FA values may be designated as pseudo FA values due to the gliosis of astrocyles around the degenerated nerve fibers in the anterior corpus callosum. Conclusions: Our results suggest a close association between pseudo-FA values and low ADC values of the anterior corpus callosum and cognitive disorders in patients with DAI who show no significant MRI abnormalities. [ABSTRACT FROM AUTHOR]