A longitudinal study of changes in Diffusion Tensor Value and their association with cognitive sequelae among patients with mild head injury.
BACKGROUND
Diffusion tensor imaging (DTI) is an advanced and sensitive technique that detects sub-threshold pathology in normal imaging brain injury patients. Currently, there are no longitudinal DTI studies to look for time-based changes. The present study has investigated longitudinal imaging and its association with cognitive deficits.


METHODS
Twenty-one patients were available for MRI and neuropsychological test (NPT) assessment for all the 3 time points. Initially (<36 hours), all patients presented with GCS 15 and normal scan findings. The DTI (P<0.0001) and NPT scores (P<0.05) were analyzed using repeated-measure of analysis. The tensor values were correlated with specific time-point NPT scores using partial correlation (0.05).


RESULTS
Right cerebral-hemisphere showed significant alterations in both anisotropy and diffusivity values overtime. Cingulate gyrus and occipital lobe showed prominent changes in anisotropy value. Significant improvement in thalamo-cortical anisotropy value after 3-4 months after injury was seen. The changes in diffusivity values were mainly seen in frontal, parietal lobe, right inferior fronto-occipital and superior longitudinal fasciculus, and posterior supramarginal gyrus. Time-related changes of tensor values of thalamus, frontal and temporal lobe had persistent and significant association with attention and learning/memory aspects.


CONCLUSIONS
The findings of this study suggest that DTI detects and observes natural-recovery of brain regions affected by sub-threshold force.
Department of Clinical Neurosciences, National Institute of Mental Health and Neurosciences, Bangalore, India.
Ashok
A
Munivenkatappa
Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India - drindiradb@gmail.com.
Indira D
ID
Bhagavatula
Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, India.
Dhaval P
DP
Shukla
Department of Clinical Psychology, National Institute of Mental Health and Neurosciences, Bangalore, India.
Jamuna
J
Rajeswaran
D000328:Adult; D001924:Brain Concussion / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D002540:Cerebral Cortex / Q000000981:diagnostic imaging*; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D020127:Recovery of Function; D013788:Thalamus / Q000000981:diagnostic imaging*; D055815:Young Adult