[PS16-2D-K] Developmental Changes in Pediatric Neuroanatomy Including the Fetus: Evaluation by MRI
Dynamic changes in anatomic structures in the central nervous system (CNS) with increasing age are discernible in children, particularly the fetus. To enable the more accurate diagnosis of CNS disease in children including the fetus, it is very important to know how these anatomical changes are visualized by MRI. In this lecture, according to morphogenetic events, such as neuronal proliferation, migration, gyration/sulcation, and myelination, the author summarizes the developmental changes in MRI findings with regard to the germinal matrix and neuroblast migration seen in the fetal brain, callosal formation, ventricular size and form, brain surface including gyration/sulcation, and specific peri-anterior horn structures (PAS) in the neonatal and infant brain. Based on these anatomic characteristics of the immature brain, the author presents some representative CNS anomalies with abnormal gyration such as migration disorders (e.g., classical lissencephaly, cobblestone lissencephaly and schizencephaly/polymicrogyria), microcephaly with a simplified gyral pattern and focal over-sulcation with thanatophoric dysplasia, which are diagnosed by fetal MRI, and discusses the difficulty and limitations of diagnosing migration disorders by fetal MRI, particularly in the early period of gestation (until the second trimester). In addition, the author describes the changes in the MR signal in the PAS in neonate and infant, and emphasizes the clinical significance of assessment of the PAS for evaluating pathological periventricular myelination such as perinatal asphyxia and other forms of encephalopathy.