FUNCTIONAL MAPPING OF HUMAN MOTOR CORTICAL ACTIVATION WITH CONVENTIONAL MR-IMAGING AT 1.5-T

A conventional 1.5-T magnetic resonance (MR) imager was used to detect signal intensity changes on T2*- weighted images of human motor and sensory cortices during performance of hand and tongue movements. Narrow receiver bandwidths were used to improve the signal-to-noise ratio. Protocols consisting of baseline, motor task, rest, and second motor task periods were performed by nine volunteers. Two-dimensional cross correlation was applied to correct in-plane translation and rotation of the head during the imaging session before the control images were subtracted from the task images. Measurements obtained during finger movement tasks indicated a 3%-8% increase in signal intensity near the contralateral central sulcus and smaller ipsilateral signal intensity increases. Bilateral signal intensity increases were also observed during tongue movement studies. A retrospective image registration technique was used to map the signal changes onto conventional anatomic images, which were used to create integrated three-dimensional models of brain structure and function. These integrated images showed that the highest signal intensity due to hand movement was near the putative central sulcus.