Abstracts

RATIONALE: Motor functional MRI has been validated in normal subjects and used in preoperative planning before resection of neoplasms and vascular malformations located nearby the sensorimotor cortex. However, little data on fMRI in patients with congenital lesions such as dysembryoplastic neuroepithelial tumor (DNT), focal cortical dysplasia (FCD) and infantile hemiplegia associated with intractable epilepsy, is available. METHODS: Twenty-eight consecutive patients presenting with chronic epilepsy involving the sensorimotor cortex underwent a fMRI with hand and foot motor task activation. Epilepsy was cryptogenic in 6 cases and symptomatic in 22 (infantile hemiplegia in 9, DNT in 7, cortical dysgenesis in 5, early trauma in 1). Twenty of these patients also underwent a stereo-EEG recording with one or more depth electrode implanted in the image-defined motor cortex. Responses to single shocks and train stimulations were topographically correlated to the activated areas on fMRI. RESULTS: Six patients with infantile hemiplegia had a non-conclusive fMRI exam, due to motor disability and motion artifacts ; in others, fMRI demonstrated abnormal responses concordant with depth electrode stimulation data. All patients with cryptogenic epilepsy had normal motor activation patterns. Patients with DNT had normal or reduced activation in normal cortex at the tumor periphery, but no within the tumor volume. Patients with FCD had motor activation and responses to stimulation within the lesion. Those findings were helpful for the resection planning. CONCLUSIONS: fMRI is a valuable tool in presurgical evaluation of partial intractable epilepsy and illustrates the early functional organization of the sensorimotor cortex associated with congenital lesions, as already demonstrated with invasive procedures.