Passive range of motion functional magnetic resonance imaging localizing sensorimotor cortex in sedated children

Abstract

Object: In this study, the authors examined whether passive range of motion (ROM) under conscious sedation could be used to localize sensorimotor cortex using functional MR (fMR) imaging in children as part of their presurgical evaluation.

Methods: After obtaining institutional review board approval (for retrospective analysis of imaging data acquired for clinical purposes) and informed consent, 16 children underwent fMR imaging. All 16 had lesions; masses were found in 9 patients and cortical dysplasia was found in 4; the lesions in 3 patients were not diagnosed. Passive ROM was performed during blood oxygen level-dependent MR imaging sequences. Three of the patients also performed active motor tasks during the fMR imaging study. All patients were evaluated using passive ROM of the hand and/or foot; 3 patients were evaluated for passive touch of the face. In 9 cases, intraoperative electrocorticography (ECoG) was used. Five of the patients underwent intraoperative ECoG to evaluate for seizure activity. Four patients had intraoperative ECoG for motor mapping. Five of the patients had subdural grids placed for extraoperative monitoring.

Results: In 3 cases, the active and passive ROMs colocalized. In 4 patients ECoG was used to identify motor cortex, and in all 4 motor ECoG yielded results consistent with the passive ROM localization. Thirteen of 16 children have undergone resection based on passive ROM fMR imaging findings with no unanticipated deficits.

Conclusions: These preliminary data suggest that passive ROM fMR imaging can accurately detect functional hand, leg, and face regions of the sensorimotor cortex in the sedated child. This extends current extraoperative mapping capabilities to patients unable or unwilling to cooperate for active motor tasks.