Abstract
Recent rapid development of the MRI system has enabled us to diagnose pricisely the disorders of the central nervous system (CNS) also in neonates and young children. Because of a long studying time, the use of oral chloral hydrate or other alternative drugs for sedation, such as secobarbital and meperidine, is necessary for young children under 6 years of age. The advantages of MRI are the optional plane imaging, a high contrast resolution, and the artifact-free imaging from the surrounding bones and air. MRI can detect myelination disorders and the lesions in the posterior fossa, the middle fossa, and the spinal canal. These abnormalities are difficult to depict with conventional X-ray CT scanning. MRI is useful also for the survey of various congenital anomalies of the brain and the spine. Furthermore, it is sensitive enough to detect the CNS blood flow and the cerebrospinal fluid (CSF) flow. Arteriovenous malformation, moyamoya disease, and sinus thrombosis are diagnosed by MRI without using contrast media, CSF flow void phenomena in the aqueduct and the Monro's foramina are indexes of the CSF pathway obstruction and of normal pressure hydrocephalus.
