PRESURGICAL IDENTIFICATION OF THE PRIMARY SENSORIMOTOR CORTEX BY FUNCTIONAL MAGNETIC-RESONANCE-IMAGING

The ability of functional magnetic resonance (MR) imaging to detect a selective sensorimotor cortex activation in healthy subjects and the f easibility of motor activation in patients with lesions around the cen tral sulcus were investigated. Twenty-five healthy volunteers performe d 100 motor activation trials. using a variety of motor tasks, which w ere monitored by several image analysis methods. The functional images were obtained using a 1.5-tesla standard MR imaging system magnet wit h blood oxygenation level-dependent contrast. Four patients were asses sed using functional MR imaging and invasive cortical mapping. Rolandi c cortex activation was observed in 98% of the trials performed on hea lthy subjects in which no head motion occurred. Nevertheless, the cort ical response was not selective in a task-rest analysis due to concurr ent activation of neighboring regions. Across-task comparison analyses were useful in canceling nonrelevant activity in most cases (86%). In the patient group, the region identified as the sensorimotor cortex b y invasive means corresponded accurately to the area that was activate d in functional MR imaging. Present data support the feasibility of de tecting selective activation of the rolandic cortex, even in the clini cal setting, leading the authors to suggest the usefulness of this wid ely available technique in surgical planning.