| Based on air studies, some authors have disputed the ability of computed tomography (CT) to diagnose posterior fossa cysts. The authors correlated the pneumoencephalographic, CT, and pathological findings in 4 patients with classic dandy-walker syndrome. Three cases had been misdiagnosed as retrocerebellar arachnoid cysts because the fourth ventricle was incorrectly considered normal on brow-up or erect air studies, reflecting the inability of such studies to evaluate an agenetic vermis and deficient posterior medullary velum which are characteristic of Dandy-Walker malformation. Careful correlation with autopsy findings showed that even with complete agenesis of the inferior vermis, if the slit between the cerebellar hemispheres is narrow, the fourth ventricle could be misinterpreted as normal on pneumoencephalography and sagittal CT. Radionuclide studies, a small amount of air, or metrizamide may be needed to determine whether the cyst communicates with the subarachnoid space. ( info) |
172/256. Fetal surgery for hydrocephalus: successful in utero ventriculoamniotic shunt for dandy-walker syndrome. The diagnosis of fetal hydrocephalus based on dilation of the ventricular system presents a broad range of management decisions. The options are presented and a case of dandy-walker syndrome managed by fetal ventriculoamniotic shunt placement is presented as an example. Under ultrasonic guidance, a shunt was placed at 30 weeks' gestation by later newborn Dubowitz examination. Delivery was delayed for five weeks, one to two weeks following probable shunt malfunction, after achieving fetal lung maturation. Follow-up six months after definitive neonatal ventricular shunting and three weeks after shunt revision revealed a socially active male infant with a motor development index of 87 and a psychomotor development index of 95. Potential advantages of fetal surgery including achievement of term gestation are presented. Proposed guidelines for determining the benefit of such procedures are also presented. ( info) |
173/256. Iniencephaly: a neuropathologic study. Five cases of iniencephaly are reviewed. Numerous central nervous system malformations were found at all levels, including microencephaly, polymicrogyria, heterotopic glial tissue in the leptomeninges, atresia of the ventricular system, marked disorganization of the brain stem, vermian agenesis, large cerebellar cyst, and disorganization of the spinal cord tissue. The cerebellum was normal in one case. Numerous skeletal anomalies were found as well as marked retroflexion of the craniocervical junction. We concluded that cerebral anomalies, although severe, are not specific for iniencephaly. Cerebellar anomalies, on the other hand, were considered to share some morphologic features between Dandy-Walker and Arnold-Chiari, i.e., Chiari type II and Chiari type III, malformations. ( info) |
174/256. Ultrasound evaluation of cystic intracranial lesions in the neonate. Ultrasound detected cystic intracranial lesions in 18 infants. Lesions included porencephaly (6 infants), hydranencephaly (1 infant), a quadrigeminal cyst (1 infant), dandy-walker syndrome (1 infant), and cavum septi pellucidi and Vergae (9 infants). Cystic lesions of the infant brain can be delineated accurately with ultrasound and distinguished from normal ventricular structures. ( info) |
| Two patients with the Dandy-Walker malformation first developed neurologic symptoms in adult life. In both patients there was normal motor and intellectual development during childhood, but as adults they had gradual evolution of brain stem and cerebellar signs and obstructive hydrocephalus. Following resection of the fourth ventricular cyst, both patients recovered. A review of the literature disclosed seven additional patients in whom the dandy-walker syndrome was first diagnosed in adult life. These cases illustrate that this congenital brain malformation may not only first become symptomatic later in life, but that it is possible for patients to remain asymptomatic. ( info) |
176/256. Dandy-Walker cyst associated with occipital meningocele. Two cases of Dandy-Walker cyst associated with occipital meningocele are presented. Only 9 cases with such association have been described in the literature. In our patients computed tomography clearly demonstrated direct communication of a posterior fossa cyst with an occipital meningocele at one end and with the fourth ventricle at the other. Occipital meningocele might simply be an expression of increased intracystic pressure in Dandy-Walker cyst in embryonic life, or such association might suggest its morphogenetic situation during embryogenesis. ( info) |
| Antenatal and postnatal ultrasonic findings of a case of cystic dilatation of the fourth cerebral ventricle (the dandy-walker syndrome) are presented. The triangular enlargement of the ventricle visualized ultrasonically was associated with mild widening of the lateral ventricles, and the finding was established postnatally by computer-assisted x-ray tomography. ( info) |
| Real-time ultrasonography of the brain is useful in the examination of neonates with suspected hydrocephalus. Abnormalities of the cerebral ventricles can be identified and changes in ventricular size determined with repeated studies performed at the bedside. The response of hydrocephalus to medical and surgical intervention can be monitored. We studied cases of hydrocephalic infants with myelomeningocele, posterior fossa cyst, posthemorrhagic hydrocephalus, meningitis, and congenital intracranial teratoma. We also studied the role of ultrasonography in the diagnosis and follow-up of these cases. ( info) |
179/256. Gray scale ultrasound studies in neonatal infants with malformation of the brain. Ultrasound findings in four newborn infants with neurological abnormalities and abnormal facies are described. The ultrasound images are compared with the images achieved by computerized tomography and with the findings at postmortem in 3 of the patients. Accurate neuroanatomical diagnosis confirmed by CT and/or autopsy findings is demonstrated in all 4 cases. It is concluded that ultrasound, particularly using an automated water path scanner, is a viable alternative in the investigation of brain malformation in the neonate. ( info) |
180/256. Dandy-Walker malformation in identical twins. The mother of a stillborn anencephalic child subsequently had twins with macrocephaly due to a cystic malformation of posterior brain structures, compatible with the dandy-walker syndrome. ( info) |