Focal Cortical Dysplasia - A Study of Localization, Extension and MRI Signals in Medically Intractable Epileptic Patients
Abstract number :
C.02
Submission category :
Year :
2000
Submission ID :
3336
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Rosa M Valerio, Francois Dubeau, Andrea Bernasconi, Alexandre Bastos, Frederick Andermann, Montreal Neurological Hosp and Institute, Montreal, PQ, Canada.
RATIONALE: Focal cortical dysplasia (FCD) with or without balloon cells is frequently associated with severe and intractable epilepsy. Its identification rests primarily on high quality MRI METHODS: We reviewed the Montreal Neurological Institute (MNI) series of patients with cortical developmental malformations in order to identify the incidence of FCD. The diagnosis was based on neuroimaging, neuropathological analysis or both. The localization, extension and MRI features were reviewed and correlated with the pathology when available. RESULTS: In this series of 178 patients with cortical developmental malformations, the incidence of FCD was 39.4% (N=70). All but one had intractable epilepsy starting predominantly during the first decade of life. High resolution MRI studies were available in 32, who are the subjects of this study. The FCD was localized to the frontal lobe in 17 patients (53%), the central area in 8 (25%), parietal in 4 (12.5%) and temporal-parieto-occipital in 3 (10%). In the majority of cases (22 pts, 69%) the malformed cortex was well localized and restricted to one or two gyri, all but one frontal or central. Six patients (19%) had FCD which extended to more than 2 gyri in one lobe (3 parietal and 3 central). Only one patient had a frontal lobar malformation. The remaining three (9.5%) had multilobar FCD, all temporo-parietal-occipital. Macrogyria, thickening of the cortex and a blurred white-gray matter interface were present in all cases. White matter increased signal in T2 and proton density sequences was seen in 18 (56%). The ventricular system was mildly dilated on the side of the dysplasia in 5 (16%). The pathological characteristics of the tissue did not correlate with specific MRI features such as an increased signal of the white matter. CONCLUSIONS: Frontal and central dysplastic lesions are most frequently found and are usually small. Post central lesions are somewhat larger with the largest being parieto-temporo-occipital. In this series, temporal dysplasias were not represented. The increased signal does not seem to correlate with specific pathological changes.