Maria Consiglio Buonocore

Hydrocephalus in Dandy–Walker malformation

IntroductionEven if the first description of Dandy–Walker dates back 1887, difficulty in the establishment of correct diagnosis, especially concerning differential diagnosis with other types of posterior fossa CSF collection, still persists. Further confusion is added by the inclusion, in some classification, of different malformations with different prognosis and therapeutic strategy under the same label of “Dandy–Walker”.MethodsAn extensive literature review concerning embryologic, etiologic, pathogenetic, clinical and neuroradiological aspects has been performed. Therapeutic options, prognosis and intellectual outcome are also reviewed.ConclusionThe correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a “real” Dandy–Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

Hydrocephalus and the Dandy-Walker Malformation

The vermis is clockwise divided into nine lobules (lingula, lobulus centralis, culmen, declive, folium, tuber, pyramis, uvula, nodulus) in normal anatomy (Fig. 1). Two deep main fissures (the primary fissure between the culmen and the declive, and the secondary fissure between the pyramis and uvula) divide them into three main lobes: an upper lobe composed of the lingula, lobulus centralis, and culmen, a middle lobe composed of the declive, folium, tuber, and pyramis, and a lower lobe composed of the uvula and nodulus [65].

Interhemispheric and quadrigeminal cysts.

BACKGROUND Interhemispheric and quadrigeminal cysts are rare lesions, similar in their propensity to present in young babies and to be associated with other central nervous system malformations, such as corpus callosum agenesia, holoprosencephaly, encephalocele, and neuronal heterotopias. Recently endoscopy has become increasingly popular in the treatment of arachnoid cysts, but experience with cysts located in the interhemispheric fissure and in the quadrigeminal cistern is limited. METHODS This study reviews the specific anatomy of interhemispheric and quadrigeminal cysts and their relationship with the ventricular system and subarachnoid cisterns to select the most appropriated treatment. It also reviews the literature on endoscopic treatment of interhemispheric and quadrigeminal cysts. RESULTS Interhemispheric and quadrigeminal cysts are not homogeneous, they have different extensions toward surrounding regions. In most cases it is presented as an area of contiguity between the cyst and ventricular system and/or subarachnoid cisterns, making endoscopic treatment feasible. The success rate for endoscopic treatment is not different from that reported in large series of arachnoid cysts elsewhere. CONCLUSIONS Endoscopic treatment should be considered the first-line option in the treatment of such lesions, even if some complications, such as subdural collections due to thinness of the cerebral mantle or subcutaneous CSF collections due to multifactorial associated hydrocephalus, must be expected.

Pathophysiology of Hydrocephalus

The three major clinical manifestations of spina bifida (hydrocephalus, paraplegia and urinary and bowel incontinence) are easily observable and have been described since ancient times, though they were not described in relationship to spina bifida until the seventeenth century [1].

Neuroimaging of Posterior Fossa Astrocytoma in Children

Pilocytic astrocytoma (PA) is the most common pediatric cerebellar neoplasm and the most common pediatric glioma, constituting 85 % of all cerebellar astrocytomas and 10 % of all cerebral astrocytomas in this age group. PAs are usually clinically benign and are classified as grade I by the World Health Organization (WHO).

Imaging of Medulloblastoma

Neuroimaging of brain tumors has evolved from a strictly morphology-based discipline to one that encompasses function, physiology, and anatomy.

Supratentorial Cerebral Malformations in Spina Bifida

In 1957, Cameron [1] first noted the association of spina bifida with several supratentorial abnormalities such as polymicrogyria, cortical heterotopia, corpus callosum dysgenesis, thickening of the massa intermedia, hypoplasia of the falx and aqueductal stenosis and forking. All of Cameron’s patients also suffered from the Chiari II malformation [2].