In 1967, a study used radiologic features on ventriculography to define signs and different shapes of AS.23 Nevertheless, radiologic investigation of hydrocephalus currently relies on MR imaging examinations, and heterogeneous studies use variable and nonvalidated criteria to define AS: triventricular dilation with a relatively small 4th V, periventricular signs of CSF active resorption, the presence of a space-occupying lesion, a downward bulging of the 3rd V, and the absence of the flow void sign. In 1760, Morgagni published some rather pertinent views on the subject of hydrocephalus, and among his many speculations appears one that is singularly appropriate: a tumor of the head must infallibly arise when a large quantity of water is collected in the cranium. Blockage of the aqueduct can lead to hydrocephalus, specifically as a common cause of congenital and/or obstructive hydrocephalus. 2014 Jul;44(7):849-56. doi: 10.1007/s00247-014-2877-4. 36, No. To these cases were added several others collected from the Bronx Municipal Hospital Center and from St. Vincent's Hospital, New York, N. Y. Radiology. In 18 of 20 obstructed aqueducts, low intensity was seen within the aqueducts on GRE images. sharing sensitive information, make sure youre on a federal 4, No. 215, No. MRI features of aqueductal stenosis (web or diaphragm) with obstructive hydrocephalus. It appears that GRE imaging is useful in rapidly assessing aqueductal patency. 1 patients with late-onset as present with various clinical and radiologic features. RESULTS: None of the usually reported direct or indirect signs of aqueductal obstruction were seen in 7 patients in whom the clinical suggestion of AS was confirmed by PC-MR imaging results. Imaging findings in postnatally confirmed congenital aqueductal stenosis (disease group) were compared with those of ventriculomegaly cases from other causes (control group). Ten patients presented with unusual headaches, predominantly with an acute or subacute duration, and 7 patients, with gait and/or memory disturbance, principally with a chronic presentation. 2020 Dec;50(13):1948-1958. doi: 10.1007/s00247-020-04880-1. The absolute sum of this volume maximum change in the caudal and cranial directions during the CC defined the blood stroke volume responsible for the dynamic coupling and succession of cerebral flows, starting with the CSF cervical venting. It is obvious that frequently aqueductal stenosis presents relatively late in life. Seven patients in this population had a third ventriculostomy, and 5 of them were among those in whom conventional MR imaging failed to reveal signs of aqueductal obstruction. Conclusions: Strictures of the aqueduct of Sylvius (the iter) are congenital maldevelopments, characterized by a replacement of this channel with glial tissue, which is the only channel for passage of the cerebrospinal fluid that arises from the choroid plexuses of the third and lateral ventricles. The entity, aqueductal stenosis, includes a variety of lesions affecting the aqueduct of Sylvius. Clipboard, Search History, and several other advanced features are temporarily unavailable. The fourth ventricle posterior fossa basal cisterns are unremarkable, and the cortical sulci are effaced. Federal government websites often end in .gov or .mil. Regular CT images demonstrated obstructive hydrocephalus at the level of the Sylvian aqueduct. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username. 2, Annals of Vascular Surgery, Vol. Velocity (encoding) sensitization was set at 80 cm/s for the vascular flows, 10 cm/s for the aqueductal CSF flows, and 5 cm/s for the CSF at the cervical subarachnoid spaces and 4th V levels. These studies were based on animal models: The ventricular injection of kaolin clay resulted in inflammation of the meninges and, therefore, CSF resorption troubles.25 For these authors, an increased pressure in the venous system (particularly in the sagittal sinus) resulted in brain compliance decrease and was responsible for aqueductal blockage and ventricle dilation.4. Aqueductal stenosis is considered the most common cause of congenital obstructive hydrocephalus, It can also be seen in adults as an acquired abnormality as i. To assess the utility of gradient echo (GRE) magnetic resonance (MR) imaging in documenting aqueductal patency, spin-echo (SE) and GRE axial images were obtained with a 1.5-T system in 26 patients with aqueductal or periaqueductal lesions and in 26 control subjects. Materials and methods: The most studied pathologic model has been NPH, and hypotheses about CSF cervical resorption or venous drainage alterations have been suggested as the underlying mechanisms for communicating hydrocephalus.14,24 More recently, some authors4,24 have suggested similar mechanisms in obstructive hydrocephalus. Introduction Hydrocephalus secondary to narrowing of the Sylvian aqueduct was first reported in 1900 by Bourneville and Noir 1 and Oppenheim. This AVD was represented in terms of percentage of CC, with the zero reference corresponding to the arterial inflow peak. None of the other direct or indirect signs of aqueductal obstruction were seen in 7 patients, in whom the clinical suggestion of AS was confirmed by PC-MR imaging results (Fig 2). All temporal parameters were expressed in terms of percentage of the CC. Imaging studies were also analyzed for malformations of cortical and cerebellar development. We present a case report of a 48 YOF who was evaluated for acute mental status changes with severe headaches. Further studies, by using PC-MR imaging, proposed a dynamic model for mechanical coupling between blood and CSF intracranial flows.11 The systolic arterial fill flow peak in the carotid arteries results in an instantaneous increase of the intracranial pressure. Also note flattened hypophysis due to bulging of the suprasellar cistern. Data were analyzed by using an in-house image-processing software,11 with an optimized CSF and blood-flow segmentation algorithm, which automatically extracts the region of interest at each level and calculates its flow curves over the 16 segments of the CC (for more details, refer to the description of the processing protocol in previous studies11,21). All children with aqueductal stenosis had . It is not usually visible in cases of benign stenosis but may be seen in membranous obstruction. All patients had their hydrocephalus evaluated with a morphologic MR imaging of the brain. Results: The entity, aqueductal stenosis, includes a variety of lesions affecting the aqueduct of Sylvius. On the other hand, PC-MR imaging can be used for neurologic and neurosurgical features to assess intracerebral and cervical CSF flows in qualitative and quantitative evaluations.911,18,20,26 PC-MR imaging enables reliable, noninvading, and rapid measurements of CSF flows and is sensitive even to slow CSF flows as seen at the aqueductal level.10,27. PC-MR imaging (not shown) showed a total absence of CSF flow at the aqueductal level and helped the neurosurgeon with the diagnosis of aqueductal stenosis. Please enable it to take advantage of the complete set of features! 42, No. sagittal T2: the absence of flow-void signal intensity at the aqueductal level has been suggested as a sign of aqueductal stenosis 3 The independent contribution of each prenatal finding was estimated as the error of CAS classification by the machine-learning algorithm compared with the error that results when that finding is negated. All of these 7 patients had a positive postsurgical outcome, with complete recovery of clinical symptoms and a follow-up duration longer than 1 year in all of them. To assess the utility of gradient echo (GRE) magnetic resonance (MR) imaging in documenting aqueductal patency, spin-echo (SE) and GRE axial images were obtained with a 1.5-T system in 26 patients with aqueductal or periaqueductal lesions and in 26 control subjects. Overview Narrowing of the cerebral aqueduct of Sylvius is termed aqueductal stenosis. Epub 2014 Mar 16. 4, Acta Radiologica. web, tumour). Would you like email updates of new search results? This site needs JavaScript to work properly. Background and purpose: Congenital aqueductal stenosis is a common cause of prenatal ventriculomegaly. GRE imaging was performed . 2018 by American Journal of Neuroradiology. AS diagnosis may be difficult in adults because of various clinical, etiologic, and radiologic features. Aqueductal stenosis due to web/diaphragm is a rare congenital condition in which there is a membrane obstructing the normal flow of the ventricular system between the third and fourth ventricle. Pak J Med Sci. Before Primary aqueductal stenosis with disruption of septal leaves due to increased intraventricular pressure. All SE images with a long repetition time (TR) were obtained with first-order gradient moment nulling. It is likely that some cases of aqueductal stenoses are the consequence of a compression of the brain stem by an overpressurized ambient cistern, whether communicating or not with the subarachnoid spaces. Similarly, CSF flow curves in the cervical and 4th V levels were integrated, providing the CSF stroke volumes, which represent the CSF volumes displaced in both directions through the considered region of interest at the corresponding level.9,10 These volumes represent the mobile compliance of the subarachnoid and ventricular compartments and contribute to rapid regulation of intracranial pressure throughout the CC. Most of these findings are secondary to the obstructive nature of the resulting hydrocephalus. Aqueductal stenosis (AS) includes a large variety of etiologies: posthemorrhagic or postmeningitic obstruction, compression of the aqueduct, or presence of a third ventricle mass.1 Patients with late-onset AS present with various clinical and radiologic features.13 New theories have emerged about the pathogenesis of AS in adults, and venous hypertension has been suggested as the primary phenomenon responsible for ventricle dilation and aqueductal obstruction.4 As a consequence, the determination of the underlying mechanism in hydrocephalus is relevant due to surgical implications because endoscopic third ventriculostomy (ETV) is mainly successful in obstructive hydrocephalus.5,6, Conventional MR imaging provides useful information in AS, because it may show triventricular dilation, CSF pathway obstruction at the aqueductal level on sagittal T2 sequences, downward bulging of the floor of the third ventricle (3rd V), anterior bulging of the 3rd V, etc.7 Nevertheless, these criteria depend on a subjective evaluation by the neuroradiologist, may be difficult to assess in some patients, and thus are hardly comparable in postsurgical outcome studies.6,8. PC-MR imaging is usually added to conventional MR imaging examinations in our clinic when hydrodynamic intracerebral dysfunction is suggested, especially with triventricular dilation observed on morphologic MR imaging sequences. The mean values of key parameters of arterial, venous, and AV blood flows in patients and control groups are shown in Table 3. We, therefore, suggest that this technique should be performed before CSF removal. Mirsky DM, Stence NV, Powers AM, Dingman AL, Neuberger I. Pediatr Radiol. Findings that significantly increase the probability of congenital aqueductal stenosis (high positive predictive value) included the following: enlarged third ventricular recesses, aqueduct funneling, hemorrhage in the cerebral aqueduct, ventricular diverticulum, rhombencephalosynapsis, and dystroglycanopathy-related cerebellar dysplasia. Conventional morphologic sequences were acquired in each patient, depending on the clinical request. 1996 Apr;12(4):188-91. doi: 10.1007/BF00301249. GRE imaging was performed with the use of the sequential section acquisition technique called gradient recalled acquisition in the steady state (GRASS), with a TR of 150 msec, an echo time of 14-17 msec, and a flip angle of 50 degrees, so to depict stationary cerebrospinal fluid (CSF) as low intensity and flowing CSF as high intensity. Normal neurologic development after 8 years followup. Increased supratentorial ventricles and stretching of corpus callosum. Notice the normal fourth ventricle size. The age distribution is skewed in such a fashion as to emphasize this fact, for most of the cases in this series were drawn from the National Hospital for Nervous Diseases, where there are few pediatric admissions. Postnatal magnetic resonance imaging showed triventricular hydrocephalus, suggesting aqueductal stenosis. The total cerebral vascular flow curve was generated by calculating the difference between arterial and venous flows throughout the CC. 2, Journal of Neurology, Neurosurgery & Psychiatry, Vol. It was with the aim of understanding the variations in radiologic features within the group of lesions causing aqueductal stenosis that we reviewed the clinical, radiologic, and pathologic (when available) features in 88 patients with aqueductal stenosis hospitalized at the National Hospital for Nervous Diseases, London, England, and at the Atkinson-Morley Hospital, Wimbledon, England. 4, Magnetic Resonance Imaging, Vol. A case of this kind is reported, with the clinical and postmortem observations, of a girl aged 7 years, admitted to the Montreal Neurological Institute on Oct. 24, 1939, with a history of whooping cough. This question is for testing whether or not you are a human visitor and to prevent automated spam submissions. If the address matches an existing account you will receive an email with instructions to reset your password. Dominant findings include enlargement of the third ventricle inferior recesses, size of the lateral and third ventricles (especially enlargement of the smaller lateral ventricle), and an abnormally thin and/or dysgenetic corpus callosum. MRI Axial T1 The MRI sequences demonstrate a marked dilatation of the 3rd and lateral ventricles with mild transependymal edema and normal size and configuration of the 4th ventricle. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. Friday, January 27, 2012 aqueductal stenosis , Neuroradiology This is a case of child with aqueductal stenosis and third ventriculostomy was done . Pediatr Radiol. In most reports, ETV success rates were important, up to 78%.28,29 However, the follow-up periods were limited, and the specific evaluation of nonresponsiveness and related factors was not addressed. The acquisition planes were selected perpendicular to the presumed direction of the flow and are represented in Fig 1. Childs Nerv Syst. Sagittal scout view sequences were used as localizers to select the anatomic levels for flow quantification. The .gov means its official. 3, No. It was with the aim of understanding the variations in radiologic features within the . Two-Dimensional Ultrasound Evaluation of the Fetal Cerebral Aqueduct: Improving the Antenatal Diagnosis and Counseling of Aqueductal Stenosis. It is not surprising, therefore, that the range of clinical and radiologic features within the group is hard to define in simple and precise terms. Diagnosis. web, tumor). First, aqueductal CSF evaluation may be hampered by the small size of the aqueduct and ventricular foramina. 3, American Journal of Neuroradiology, Vol. Semantic Scholar is a free, AI-powered research tool for scientific literature, based at the Allen Institute for AI.
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