Radiology, Vol 195, 23-29, Copyright © 1995 by Radiological Society of North America
Topography of the cortical motor hand area: prospective study with functional MR imaging and direct motor mapping at surgery
TA Yousry, UD Schmid, AG Jassoy, D Schmidt, WE Eisner, HJ Reulen, MF Reiser and J Lissner
Department of Diagnostic Radiology, Ludwig Maximilian University, Munich, Germany.
PURPOSE: To localize the cortical motor hand area with functional magnetic
resonance (MR) imaging and electrical stimulation at surgery and to detect
changes due to central lesions. MATERIALS AND METHODS: Fast-gradient-echo
and functional MR images of the brain were acquired in four healthy
volunteers and six patients with tumors in the central region before,
during, and after repetitive opening and closing of the hand. Open brain
surgery was performed, and the exposed cortex was stimulated. RESULTS: At
functional MR imaging, circumscribed changes in signal intensity that
correlated in time with the task were seen in the central region of the
contralateral brain. In the healthy volunteers, the area of change was
spotlike and projected into the posterior bank of the precentral gyrus. In
four of the six patients, this area was diffuse and projected into the
precentral gyrus. The locations of the cortical hand area as determined
with intrasurgical mapping and functional MR imaging were identical.
CONCLUSION: Identification of the cortical area responsible for motor hand
function was similar with functional MR imaging and with direct stimulation
at surgery. A space- occupying lesion can change the cortical
representation of motor hand function.
