Malformations of cortical development: current concepts and advanced neuroimaging review

Abstract

Malformations of cortical development (MCD) result from disruptions in the complex process of the human brain cortex formation and are highly associated to severe epilepsy, neurodevelopmental delay and motor dysfunction. Nowadays, magnetic resonance imaging (MRI) is the cornerstone of the work-up of patients with epilepsy and modern advanced imaging techniques have improved not only our ability to detect and characterize cortical malformations, but also in identifying associated functional abnormalities that are far beyond the structural visualized lesions. Herein, we address the most currently used classifications of MCD and make a concise review of the embryological process of cortical development. Our main goal is to summarize recent advances and new trends in diagnostic imaging techniques concerning MCD. Thereafter, follows a brief discussion of specific disorders and their radiological features. Key words: malformations of cortical development, epilepsy, magnetic resonance imaging, diagnostic imaging.Malformações do desenvolvimento cortical: conceitos atuais e revisão de neuro imagem avançada RESUMO As malformações do desenvolvimento cortical (MDC) resultam de distúrbios no complexo processo do desenvolvimento do córtex cerebral humano e estão comumente associadas a epilepsia severa e disfunções neuropsicomotoras. Atualmente, as imagens por ressonância magnética (RM) são a pedra angular no manejo de pacientes com epilepsia e modernas técnicas avançadas de imagem melhoraram não só a nossa capacidade de detectar e caracterizar as malformações corticais, mas também levaram ao reconhecimento de anomalias funcionais associadas que estão muito além das lesões estruturais visibilizadas. Abordaremos as classificações mais utilizadas de MDC e revisaremos a embriologia do desenvolvimento cortical. Nosso principal objetivo é destacar os avanços recentes e as novas tendências em técnicas de diagnóstico por imagens relacionadas às MDC. Em seguida, faremos uma breve discussão sobre alguns transtornos específicos e suas características radiológicas. Palavras-chave: malformações do desenvolvimento cortical, epilepsia, imagem por ressonância magnética, diagnóstico por imagem.

Assessment of the diagnostic reliability of brain CT and MRI in pediatric epilepsy patients

“…It can be unilateral or bilateral and tends to involve the insular, precentral and postcentral regions (13). Closed lip schizencephaly is characterized by the presence of an indentation in the ependymal surface, the so-called nipple sign (14). In our study, 3 cases were diagnosed as closed lip schizencephaly and all showed the nipple sign.…”

“…MRI allowed increased recognition and more accurate diagnosis (14,15). In our study, Assessment of the diagnostic reliability of brain CT and MRI 9 2 cases of FCD were diagnosed by MRI while they were not evident on CT, one case of subcortical nodular heterotopia was diagnosed by MRI while it was not evident on CT. FCD is one of the most common forms of focal developmental disorders constituting approximately 25% of patients (13,16).…”

“…CT scan however can fail to make the diagnosis in more than 30% of affected patients (14). MRI allowed increased recognition and more accurate diagnosis (14,15).…”

“…In schizencephaly, adjacent areas of polymicrogyria or pachygyria may be seen (14). It can be unilateral or bilateral and tends to involve the insular, precentral and postcentral regions (13).…”

Malformations of cortical development: 3T magnetic resonance imaging features

“…Volumetric FLAIR sequence may be useful in the determination of small signal changes and correct delineation of the borders of MCD and related signal changes, especially in 3T. SWI is a new, full-velocitycompensated high-resolution 3D GE sequence, useful for the evaluation of various pathologies characterized with punctate hemorrhages and calcification in brain parenchyma [4,5] . Metabolic components of the brain tissue can be determined by proton MR spectroscopy in vivo.…”