CONGENITAL PORENCEPHALY - MR FEATURES AND RELATIONSHIP TO HIPPOCAMPALSCLEROSIS

PURPOSE: We determined the frequency of amygdalar-hippocampal atrophy in patients with congenital porencephaly-related seizure disorders to ascertain whether specific MR features of the porencephaly correlate w ith amygdalar-hippocampal atrophy and epilepsy. METHODS: We studied br ain MR images of 22 patients with congenital porencephaly and measured the volume of the amygdala, the hippocampal formation, and the porenc ephalic cyst. We then compared imaging features with seizure symptoms. RESULTS: Porencephaly was unilateral in 20 patients and bilateral in two, Eighteen patients had cortical or subcortical cavitation and four had encephaloclastic changes (noncircumscribed parenchymal destructio n associated with cystic components), The porencephaly was located in the middle cerebral artery territory in 12 patients, in the posterior cerebral artery in four, in the internal carotid artery in two, and in multiple vessels in four, The volume of the porencephalic cyst ranged from 1% to 32% of total intracranial volume (mean, 11%). Volumetry de tected atrophy of the hippocampal formation in 21 cases (II unilateral , 10 bilateral) and atrophy of the amygdala in 12 (nine unilateral, th ree bilateral), No correlation,vas found between size or location of t he porencephaly and degree of hippocampal atrophy. Seizure symptoms co rrelated with mesial temporal origin but not with cyst location. CONCL USION: Amygdalar-hippocampal atrophy often coexists with congenital po rencephaly (95%), and the atrophy may be bilateral despite unilateral cysts, Hippocampal structures should be carefully assessed in patients with porencephaly-related seizures.