The Functional MR study of motor cortex

By certain functional stimulates, the brain cortex becomes active. The MR scan has been proven to image these cortex activities by comparing the images with and without functional stimulates. The signal differences between the image with and without functional stimulates is related with the hemodynamic and metabolic changes induced by functional activities. This signal difference is very small, but detectable by MR system, and is the functional MR signal. The MR scan displaying the functio…

The Functional MR study of motor cortex

Objective To observe the motor cortex activities on fMR imaging.Method The fMR study of motor cortex was performed in 15 normal volunteers using 1.5T superconducting MR system, EPI pulse sequences, and BOLD fMR imaging. Six axial slices centered approximately at the precentral gyrus was obtained with or without both hands finger tapping motion under the operator instruction during the scanning. Pixels with significant signal differences (P<0.0001) between with and without finger tapping were calculated as functional signal. The functional signal was superimposed on the corresponding T1WI and brain water images. Results The motor cortex activities stimulated by finger tapping show as the area of increased signal intensity. The location of activities is correspondent very well with the location of motor cortex. Most of activities present at the lateral aspect of precentral gyrus. In our group, the motion activities of left hemisphere is larger than that of right side in 10 volunteers, almost same size in 3 volunteers, smaller than that of right side in 1 volunteer. The fMR scan failed in 1 volunteer. Superimposing the functional signals on the brain water image may help to display the location of the activities. Conclusion fMR can show the location and size of motor cortex. It is simple, fast, noninvasive, and very convenient to implements with routine MR study.