functional MRI of Language Area

ABSTRACT

PURPOSE: To evaluate the usefulness of functional MR imaging(fMRI) for language mapping and determination of language lateralization. MATERIALS AND METHODS: Functional maps of the language area were obtained during word generation tasks and decision task in ten volunteers(7 right handed, 3 left-handed). MR examination were performed at 1.5T scanner with EPI BOLD technique. Each task consisted of three resting periods and two activation periods with each period of 30 seconds. Total acquisition time was 162sec. SPM program was used for the postprocessing of images. Statistical comparisons were performed by using t-statistics on a pixel-by-pixel basis after global normalization by ANCOVA. Activation areas were topographically analyzed(p<0.001) and activated pixels in each hemisphere were compared quantitatively by lateralization index. RESULTS: Significant activation signals were demonstrated in 9 of 10 volunteers. Activation signals were found in the premotor and motor cortices, the inferior frontal, inferior parietal, and mid-temporal lobes during stimulation tasks. In the right handed seven volunteers, activation of language areas was lateralized to the left side. Verb generation task produced stronger activation in the language areas and higher value of lateralization index than noun generation task or decision task. CONCLUSION: fMRI could be a useful non-invasive method for language mapping and determination of language dominance.