ISSN:0899-3459    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Magnetic resonance is the imaging modality of choice for the evaluation of infants and children with known or suspected cerebral and cerebrovascular abnormalities. Entities described include cephaloceles, holoprosencephaly, dysgenesis of corpus callosum, and anomalies of neuronal migration. Congenital vascular lesions described include aneurysm, arteriovenous malformation, cavernous malformation, and Galenic malformations.

ISSN:0899-3459    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Spinal cord development occurs through three consecutive periods. Gastrulation (weeks 2–3) is characterized by conversion of the embryonic disk from a bilaminar to a trilaminar arrangement and establishment of a notochord. Primary neurulation (weeks 3–4) produces the uppermost nine tenths of the spinal cord. Secondary neurulation and retrogressive differentiation (weeks 5–6) result in formation of the conus tip and filum terminale. Defects in these early embryonic stages produce spinal dysraphisms, which are characterized by anomalous differentiation and fusion of dorsal midline structures. Spinal dysraphisms may be categorized clinically into two subsets. In open spinal dysraphisms, the placode (non-neurulated neural tissue) is exposed to the environment. These disorders include myelomeningocele, myeloschisis, hemimyelomeningocele, and hemimyelocele, and are always associated with a Chiari II malformation. Closed spinal dysraphisms are covered by intact skin, although cutaneous stigmata usually indicate their presence. Two subsets may be identified based on whether a subcutaneous mass is present in the low back. Closed spinal dysraphisms with mass comprise lipomyeloschisis, lipomyelomeningocele, meningocele, and myelocystocele. Closed spinal dysraphisms without mass comprise complex dysraphic states (ranging from complete dorsal enteric fistula to neurenteric cysts, split cord malformations, dermal sinuses, caudal regression, and spinal segmental dysgenesis), bony spina bifida, tight filum terminale, filar and intradural lipomas, and persistent terminal ventricle. Magnetic resonance imaging is the imaging method of choice for investigation of this complex group of disorders.

ISSN:0899-3459    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Over the past 25 years, magnetic resonance imaging (MRI) has developed into the primary imaging tool for evaluation of the central nervous system. MRI is the essential imaging study in the twenty-first century for the evaluation of the child with a brain tumor for initial preoperative diagnosis, treatment planning and image-guided therapies. This article provides an overview of the locations and MRI features of common pediatric tumors of childhood.

ISSN:0899-3459    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Proton magnetic resonance (MR) spectroscopy is a complementary method to MR imaging for understanding disease processes in the pediatric brain. By demonstrating the presence of various metabolites in the sampled tissue, MR spectroscopy helps in the understanding of abnormalities detected by MR imaging or clinical examination. This capability is especially pertinent in the pediatric brain, where the manifestation of pathology is superimposed upon a background of normal or abnormal brain development. In this article, we review the major metabolites demonstrated by MR spectroscopy and present examples of MR spectra obtained in various pathological processes encountered in children.

ISSN:0899-3459    

出版商:OVID    

年代:2001

数据来源: OVID