Radiologic-pathologic correlation in focal cortical dysplasia and hemimegalencephaly in 18 children

To describe the radiologic-pathologic correlation in children who underwent epilepsy surgery for medically intractable epilepsy with pathologically co nfirmed focal cortical dysplasia and hemimegalencephaly, we conducted a ret rospective review on the magnetic resonance imaging and pathology of 18 chi ldren (10 boys and 8 girls). The preoperative MRIs were reviewed by one neu roradiologist who did not know the radiologic diagnosis and the pathology r eports. MRI revealed focal cortical dysplasia (10), hemimegalencephaly (3), hamartomas (2), polymicrogyria (1), pial hemosiderosis (1), and no abnorma lity (1). Pathologic examination revealed focal cortical dysplasia (9), for me fruste of tuberous sclerosis (5), hemimegalencephaly (3), and focal cort ical dysplasia with mesial temporal sclerosis (1). MRI was accurate in maki ng the preoperative diagnosis in 16 out of 18 patients. On MRI, 12 patients had abnormal gyral formation and 12 had abnormal cortical thickness. Eleve n patients manifested loss of gray-white differentiation, and 11 patients h ad abnormal signal on T-2- weighted image. Pathologically, 15 patients had neuronal heterotopia, 12 had misalignment or disorientation of neurons, 11 had large neurons, and 10 had abnormal cortical lamination. The presence of ectopic and large neurons and abnormal cortical lamination may be responsi ble for the MRI characteristics. (C) 2001 by Elsevier Science Inc. All righ ts reserved.