Abstracts

MRI is the method of choice to detect and characterize developmental malformations of the cerebral cortex. One of these particular entities is focal cortical dysplasia (FCD). Its diagnostic characteristic, based on the MRI findings, is loss of differentiation between grey and white matter, without oedema or mass effect. A diagnosis of Focal Transmantle Cortical Dysplasia (FTCD) is made when the focal lession extends from subarachnoid space to ventricular wall.The aim of this study was to determine if FTCD, a MRI-based diagnostic entity, could be considered a particular type of FCD. We selected those patients with a diagnosis of FCD based on MRI findings from our Epilepsy Centre. They were divided into two groups; A) Focal Transmantle Cortical Dysplasia (FTCD): with focal lesion extending from the superficial cortex to the ventricular wall and; B) non-FTCD (NFTCD): with focal lesion not extending to the ventricular wall. We analyzed average age (AA), sex, age of onset of epilepsy (AOE), developmental delay (DD), history of pregnancy or perilabour trauma (PT), annual seizure frequency (ASF), family history (FH) and epileptogenic zone (EZ). Group A: (n=10; 4 men); AA: 38 [plusmn] 14 years; AOE: 12.1 [plusmn] 8.9 years; DD: 1; PT: 1; ASF: 238.6 [plusmn] 279.9; FH: 2; EZ Temporal in 4. Group B: (n=13; 9 men); AA: 32.3 [plusmn] 15.1 years; AOE: 16.6 [plusmn] 17.4 years; DD: 0; PT: 7; ASF: 81.7 [plusmn] 119.2; FH: 4; EZ Temporal in 6. PT was significantly more frequent in NFTCD group (p=0.038 Fisher exact test). FTCD seems to be a different type of FCD involving less acquired factors in its genesis and affecting less frequently the temporal lobe than NFTCD. MRI characteristics allowed to define a particular subset of FCD.