Preoperative PET activation for assessment of motor cortex area in precentral chondroma

BACKGROUND A main problem in the preoperative planning for precentral tumor s is the exact assessment of the spatial relationship between the tumor and the functionally relevant brain areas, which may be difficult using only m orphologically oriented imaging (CT, MRI). Therefore, we applied motor acti vation PET and PET/MRI overlay in a patient with a precentral tumor. DESCRIPTION We report the case of a 21 year-old woman suffering from progre ssive right-sided headache and intermittent dysesthesia of the left leg. MR I showed a hypointense tumor with inhomogenous contrast enhancement in the right precentral area. For preoperative assessment of the spatial relations hip between the tumor and the motor cortex area, the patient underwent two F-18-fluorodeoxyglucose positron emission tomography (PET) scans (1. restin g condition and 2. motor activation of the left leg) and subsequent calcula tion of subtraction images of activation minus rest. Fusion of PET and MRI data (PET/MRI overlay) was performed for bimodal function and morphology pr esentation. PET revealed an activation pattern behind and below the tumor, indicating that the motor cortex area was shifted to the back. PET findings were confirmed by intraoperative electrophysiology. Cortical stimulation c ombined with intraoperative neuronavigation localized the motor area of the left foot and leg exactly at the dorsal border, below and lateral to the l esion. After complete resection of the solid tumor, histopathological exami nation revealed a chondroma. The postoperative course was uneventful, and t he patient was discharged without neurological deficits. CONCLUSIONS This case shows that biomodal imaging (PET/MRI) provides a noni nvasive exact assessment of functionally important cortex areas for preoper ative planning in patients with cerebral lesions. (C) 1999 by Elsevier Scie nce Inc.