FUNCTIONAL MAGNETIC-RESONANCE-IMAGING AT 1-T - MOTOR CORTEX, SUPPLEMENTARY MOTOR AREA AND VISUAL-CORTEX ACTIVATION

Functional activation of the brain has been visualized using magnetic resonance imaging (MRI). Early studies used echo planar imaging and ma gnetic fields of 2 T and above. However, recent studies have successfu lly shown the activation of visual and motor areas of the brain using conventional clinical 1.5 T MRI systems. The purpose of the present st udy was to replicate these studies at a lower field strength. Eight mo tor and two visual activation studies were performed using a 1 T clini cal scanner. Activation was seen in the contralateral motor cortex dur ing motor stimulation in six of the eight volunteers. Activation was a lso documented within the contralateral supplementary motor area in fo ur of the six volunteers with motor cortex activation. The supplementa ry motor area was located in the posteromedial aspect of the superior frontal gyrus. Both volunteers subjected to photic stimulation showed activation within the visual cortex. Results show that functional imag ing can be successfully carried out with a 1 T clinical scanner. The s ize of the image intensity on activation change suggests that contrast may not be due solely to susceptibility changes.