Analyzing functional, structural, and anatomical correlation of hemispheric language lateralization in healthy subjects using functional MRI, diffusion tensor imaging, and voxel-based morphometry.
BACKGROUND
To evaluate the efficacy of diffusion fiber tractography (DFT) and voxel-based morphometry (VBM) for lateralizing language in comparison with functional magnetic resonance imaging (fMRI) to noninvasively assess hemispheric language lateralization in normal healthy volunteers.


OBJECTIVE
The aim of the present study is to evaluate the concordance of language lateralization obtained by diffusion tensor imaging (DTI) and VBM to fMRI, and thus to see whether there exists an anatomical correlate for language lateralization result obtained using fMRI.


METHODS
This is an advanced neuroimaging study conducted in normal healthy volunteers.


METHODS
Fifty-seven normal healthy subjects (39 males and 18 females; age range: 15-40 years) underwent language fMRI and 30 underwent direction DTI. fMRI language laterality index (LI), fiber tract asymmetry index (AI), and tract-based statistics of dorsal and ventral language pathways were calculated. The combined results were correlated with VBM-based volumetry of Heschl's gyrus (HG), planum temporale (PT), and insula for lateralization of language function.


METHODS
A linear regression analysis was done to study the correlation between fMRI, DTI, and VBM measurements.


RESULTS
A good agreement was found between language fMRI LI and fiber tract AI, more specifically for arcuate fasciculus (ArcF) and inferior longitudinal fasciculus (ILF). The study demonstrated significant correlations (P < 0.05) between blood-oxygen-level dependent (BOLD) fMRI activations, tract-based statistics, and PT and HG volumetry for determining language lateralization.


CONCLUSIONS
A strong one-to-one correlation between fMRI, laterality index, DTI tractography measures, and VBM-based volumetry measures for determining language lateralization exists.
Jija S
JS
James
Sheela R
SR
Kumari
Ruma Madhu
RM
Sreedharan
Bejoy
B
Thomas
Ashalatha
A
Radhkrishnan
Department of Imaging Science and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India.
Chandrasekharan
C
Kesavadas
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D056324:Diffusion Tensor Imaging; D005260:Female; D007839:Functional Laterality; D064368:Healthy Volunteers; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male