SPIRAL K-SPACE MR-IMAGING OF CORTICAL ACTIVATION

Brain function can be mapped with magnetic resonance (MR) imaging sens itized to regional changes in blood oxygenation due to cortical activa tion. Several MR imaging methods, including conventional imaging and e cho-planar imaging, have been successfully used for this purpose, The authors investigated spiral k-space MR imaging, implemented with an un modified 1.5-T clinical imager, for imaging of cortical activation, A gradient-echo, spiral k-space imaging method was used to measure activ ation in the primary visual cortex (number sequence task), primary mot or cortex (fist-clenching task), and prefrontal cortex (verbal fluency task), Comparison of conventional and spiral k-space imaging in the v isual and motor cortex, in which signal-to-noise ratio, voxel size, an d imaging time were matched, showed that artifacts were reduced with t he spiral k-space method, while the area and degree of activation were similar, The number of sections that could be imaged in a fixed time interval was increased by a factor of four with this implementation of spiral k-space imaging compared with conventional imaging.