Magnetic Resonance Imaging of Malformations of Cortical Development-A Comprehensive Review

Malformations of cortical development (MCDs) are structural anomalies that disrupt the normal process of cortical development. These include microcephaly with simplified gyral pattern/microlissencephaly, hemimegalencephaly, focal cortical dysplasia, lissencephaly, heterotopia, polymicrogyria, and schizencephaly. They can present with intractable epilepsy, developmental delay, neurologic deficits, or cognitive impairment. Though the definitive diagnosis of MCD depends on histopathology, the pathologic tissue is rarely available; hence diagnosis begins with neuroimaging. This article shall briefly review the embryology, followed by specific magnetic resonance imaging features of MCD in an attempt to simplify the process of diagnosing these disorders with clinical and genetic correlation. A table has been included to highlight the embryologic, clinical, and genetic findings associated with various MCDs.