The evolutionarily conserved choroid plexus contributes to the homeostasis of brain ventricles in zebrafish.

The choroid plexus (ChP) produces cerebrospinal fluid (CSF). It also contributes to brain development and serves as the CSF-blood barrier. Prior studies have identified transporters on the epithelial cells that transport water and ions from the blood vasculature to the ventricles and tight junctions involved in the CSF-blood barrier. Yet, how the ChP epithelial cells control brain physiology remains unresolved. We use zebrafish to provide insights into the physiological roles of the ChP. Upon histological and transcriptomic analyses, we identify that the zebrafish ChP is conserved with mammals and expresses transporters involved in CSF secretion. Next, we show that the ChP epithelial cells secrete proteins into CSF. By ablating the ChP epithelial cells, we identify a reduction of the ventricular sizes without alterations of the CSF-blood barrier. Altogether, our findings reveal that the zebrafish ChP is conserved and contributes to the size and homeostasis of the brain ventricles.

Neuroendoscopy-Assisted Entire-Process Visualization Technique of Ventricular Puncture for External Ventricular Drainage.

OBJECTIVE: This study aimed to investigate the feasibility, safety, and efficacy of the neuroendoscopy-assisted entire-process visualization technique (NEAEVT) of ventricular puncture for external ventricular drainage. METHODS: Eighty-eight patients with cerebral hemorrhage who underwent unilateral ventricular puncture for external ventricular drainage in our hospital from June 2021 to June 2023 were analyzed. Patients were grouped according to puncture technique: NEAEVT (30 patients), freehand (30 patients), and laser-navigation-assisted (28 patients). Operation time, drainage tube placement, and catheter-related hemorrhage incidence were compared between the groups. RESULTS: Mean operation time significantly differed between the freehand, NEAEVT, and laser-assisted groups (17.07, 18.37, and 34.04 min, respectively; P <0.0001). The position of the drainage tube was optimal or adequate in all patients of the NEAEVT group; optimal/adequate positioning was achieved in 80% of the freehand group. No catheter-related hemorrhage occurred in the NEAEVT group. Three freehand group patients and 2 laser-assisted group patients experienced catheter-related hemorrhage. CONCLUSION: The NEAEVT of ventricular puncture is accurate and achieves ventricular drainage without significantly increasing surgical trauma, operation time, or incidence of hemorrhage.

New reference nomograms for the study of ventricular size in preterm infants.

INTRODUCTION: Transfontanellar brain ultrasound is an essential tool for monitoring the size of the ventricles in preterm neonates and has many advantages over other alternative diagnostic techniques, including its accessibility and non-use of ionizing radiation. When considering the normal ventricular size, it is essential to have reference measurements based on age-matched populations. The objective of this article is to present our reference measures, based on a sample of preterm infants that we have studied. METHODS: A retrospective observational study was conducted. Measurements of the Levene index, frontal horn thickness, and Evans index were obtained in preterm neonates from 25 to 45 weeks, over a period of 5 years, between January 2016 and December 2020. After applying the exclusion criteria, a sample of 199 patients and 350 ultrasound scans were obtained. The independent samples t-test and the Mann-Whitney test were used for the comparison of samples. RESULTS: The distribution of the right and left Levene indices was normal (Shapiro-Wilk test with p = 0.16 and 0.05, respectively), unlike the thickness distribution of the frontal horns (p < 0.05 on both sides). No significant differences were detected between the sexes (p = 0.08). A linear correlation was found between the biparietal diameter and the Levene index. CONCLUSION: From the results obtained in our study, we present reference tables for ventricular size, with the 3rd, 25th, 50th, 75th, and 97th, being the first ones made in our country.

Protocol for electroporating and isolating murine (sub)ventricular zone cells for single-nuclei omics.

In vivo genetic modification of neural stem cells is necessary to model the origins and pathogenesis of neurological disorders. Electroporation is a technique that applies a transient electrical field to direct charged molecules into living cells to genetically modify the mouse brain. Here, we provide a protocol to electroporate the neural stem cells surrounding the neonatal ventricles. We describe subsequent steps to isolate and prepare nuclei from the cells and their cellular progeny for single-nuclei omics. For complete details on the use and execution of this protocol, please refer to Riley et al.1.

Choroid plexus enlargement is associated with future periventricular neurodegeneration in multiple sclerosis.

BACKGROUND: The choroid plexus (CP), located within the ventricles of the brain and the primary producer of cerebrospinal fluid, has been shown to be enlarged in patients with multiple sclerosis (MS) and linked to periventricular remyelination failure. Atrophied T2-lesion volume (aT2-LV), a promising neurodegenerative imaging marker in progressive MS (PMS), reflects the volume of periventricular lesions subsumed into cerebrospinal fluid over the follow-up. METHODS: In a cohort of 143 people with relapsing-remitting MS (RRMS) and 53 with PMS, we used 3T magnetic resonance imaging (MRI) to quantify CP volume (CPV) at baseline and aT2-LV over an average of 5.4 years of follow-up. Partial correlations, adjusting for age and sex, and linear regression analyses were used to assess the relationships between imaging measures. RESULTS: In both cohorts, CPV was associated with aT2-LV in both the RRMS group (r = 0.329, p < 0.001) as well as the PMS group (r = 0.522, p < 0.001). In regression analyses predicting aT2-LV, ventricular volume (final adjusted R2 = 0.407, p < 0.001) explained additional variance beyond age, sex, and T2-lesion volume in the RRMS group while CPV (final adjusted R2 = 0.446, p = 0.009) was retained in the PMS group. CONCLUSION: Findings from this study suggest that the CP enlargement is associated with future neurodegeneration, with a particularly relevant role in PMS.

Modelling midline shift and ventricle collapse in cerebral oedema following acute ischaemic stroke.

In ischaemic stroke, a large reduction in blood supply can lead to the breakdown of the blood-brain barrier and to cerebral oedema after reperfusion therapy. The resulting fluid accumulation in the brain may contribute to a significant rise in intracranial pressure (ICP) and tissue deformation. Changes in the level of ICP are essential for clinical decision-making and therapeutic strategies. However, the measurement of ICP is constrained by clinical techniques and obtaining the exact values of the ICP has proven challenging. In this study, we propose the first computational model for the simulation of cerebral oedema following acute ischaemic stroke for the investigation of ICP and midline shift (MLS) relationship. The model consists of three components for the simulation of healthy blood flow, occluded blood flow and oedema, respectively. The healthy and occluded blood flow components are utilized to obtain oedema core geometry and then imported into the oedema model for the simulation of oedema growth. The simulation results of the model are compared with clinical data from 97 traumatic brain injury patients for the validation of major model parameters. Midline shift has been widely used for the diagnosis, clinical decision-making, and prognosis of oedema patients. Therefore, we focus on quantifying the relationship between ICP and midline shift (MLS) and identify the factors that can affect the ICP-MLS relationship. Three major factors are investigated, including the brain geometry, blood-brain barrier damage severity and the types of oedema (including rare types of oedema). Meanwhile, the two major types (stress and tension/compression) of mechanical brain damage are also presented and the differences in the stress, tension, and compression between the intraparenchymal and periventricular regions are discussed. This work helps to predict ICP precisely and therefore provides improved clinical guidance for the treatment of brain oedema.

The Anterior Interhemispheric Transcallosal Approach to the Ventricles: How We Do It.

Intraventricular tumors of the lateral and third ventricles are relatively rare, accounting for 1-2% of all primary brain tumors in most large series [1-4]. They can be uniquely challenging to approach due to their deep location, propensity to become large before they are discovered, and association with hydrocephalus [5, 6]. The surgeon's goal is to develop a route to these deep lesions that will cause the least morbidity, provide adequate working space, and achieve a complete resection. This must be performed with minimal manipulation of the neural structures encircling the ventricles, avoiding functional cortical areas, and acquiring early control of feeding vessels [7, 8].

CT-guided spatial normalization of nuclear hybrid imaging adapted to enlarged ventricles: Impact on striatal uptake quantification.

INTRODUCTION: Spatial normalization is a prerequisite step for the quantitative analysis of SPECT or PET brain images using volume-of-interest (VOI) template or voxel-based analysis. MRI-guided spatial normalization is the gold standard, but the wide use of PET/CT or SPECT/CT in routine clinical practice makes CT-guided spatial normalization a necessary alternative. Ventricular enlargement is observed with aging, and it hampers the spatial normalization of the lateral ventricles and striatal regions, limiting their analysis. The aim of the present study was to propose a robust spatial normalization method based on CT scans that takes into account features of the aging brain to reduce bias in the CT-guided striatal analysis of SPECT images. METHODS: We propose an enhanced CT-guided spatial normalization pipeline based on SPM12. Performance of the proposed pipeline was assessed on visually normal [123I]-FP-CIT SPECT/CT images. SPM12 default CT-guided spatial normalization was used as reference method. The metrics assessed were the overlap between the spatially normalized lateral ventricles and caudate/putamen VOIs, and the computation of caudate and putamen specific binding ratios (SBR). RESULTS: In total 231 subjects (mean age ± SD = 61.9 ± 15.5 years) were included in the statistical analysis. The mean overlap between the spatially normalized lateral ventricles of subjects and the caudate VOI and the mean SBR of caudate were respectively 38.40 % (± SD = 19.48 %) of the VOI and 1.77 (± 0.79) when performing SPM12 default spatial normalization. The mean overlap decreased to 9.13 % (± SD = 1.41 %, P < 0.001) of the VOI and the SBR of caudate increased to 2.38 (± 0.51, P < 0.0001) when performing the proposed pipeline. Spatially normalized lateral ventricles did not overlap with putamen VOI using either method. The mean putamen SBR value derived from the proposed spatial normalization (2.75 ± 0.54) was not significantly different from that derived from the default SPM12 spatial normalization (2.83 ± 0.52, P > 0.05). CONCLUSION: The automatic CT-guided spatial normalization used herein led to a less biased spatial normalization of SPECT images, hence an improved semi-quantitative analysis. The proposed pipeline could be implemented in clinical routine to perform a more robust SBR computation using hybrid imaging.

Longitudinal assessment of ventricular volume trajectories in early-stage schizophrenia: evidence of both enlargement and shrinkage.

BACKGROUND: Lateral ventricular enlargement represents a canonical morphometric finding in chronic patients with schizophrenia; however, longitudinal studies elucidating complex dynamic trajectories of ventricular volume change during critical early disease stages are sparse. METHODS: We measured lateral ventricular volumes in 113 first-episode schizophrenia patients (FES) at baseline visit (11.7 months after illness onset, SD = 12.3) and 128 age- and sex-matched healthy controls (HC) using 3T MRI. MRI was then repeated in both FES and HC one year later. RESULTS: Compared to controls, ventricular enlargement was identified in 18.6% of patients with FES (14.1% annual ventricular volume (VV) increase; 95%CI: 5.4; 33.1). The ventricular expansion correlated with the severity of PANSS-negative symptoms at one-year follow-up (p = 0.0078). Nevertheless, 16.8% of FES showed an opposite pattern of statistically significant ventricular shrinkage during ≈ one-year follow-up (-9.5% annual VV decrease; 95%CI: -23.7; -2.4). There were no differences in sex, illness duration, age of onset, duration of untreated psychosis, body mass index, the incidence of Schneiderian symptoms, or cumulative antipsychotic dose among the patient groups exhibiting ventricular enlargement, shrinkage, or no change in VV. CONCLUSION: Both enlargement and ventricular shrinkage are equally present in the early stages of schizophrenia. The newly discovered early reduction of VV in a subgroup of patients emphasizes the need for further research to understand its mechanisms.

Adult idiopathic bilateral occlusion of foramen of Monro: Systematic review with illustrative case.

BACKGROUND: Adult idiopathic occlusion of foramen of Monro (AIOFM) is a rare condition that results in hydrocephalus, and bilateral presentation is even rarer. Here we report a case of idiopathic bilateral stenosis of the foramen of Monro in an adult patient and performed a systematic literature review on the current treatment options and outcomes. METHODS: We performed a systematic review of SCOPUS, Science Direct, and PubMed databases in accordance with PRISMA guidelines. Data on demographics, clinical presentation, imaging findings, type of AIOFM, treatment, and outcomes were collected. RESULTS: A total of 22 cases of bilateral AIOFM were identified in the literature, including ours. The median age was 38.5 years (range: 20-53), with no sex predilection. The most common presenting symptoms were headache (n=16, 73%) and vomiting (n=10, 45%). There were 9 cases of Type 1 AIOFM (stenosis) and 13 cases of Type 2 (membrane occlusion). Majority of patients underwent surgical treatment, mostly endoscopic unilateral foraminoplasty and septostomy (59%), followed by ventriculoperitoneal shunt insertion (31%). One patient underwent medical management only to alleviate her presenting symptoms (seizures). The overall outcome was good for majority of patients at a median follow-up of 6 months. CONCLUSION: Bilateral AIOFM is a rare condition that may easily be missed, so neurosurgeons should be cognizant of this disease entity. Identification of the type of AIOFM may guide surgical decision-making. Treatment options include neuroendoscopic procedures such as septostomy and foraminoplasty, and ventriculoperitoneal shunt insertion.

Mri findings, looking behaviour and affect recognition in very preterm children: A pilot study.

Children born very preterm often exhibit atypical gaze behaviors, affect recognition difficulties and are at risk for cerebral white matter damage. This study explored links between these sequalae. In 24 12-year-old children born very preterm, ventricle size using Evans and posterior ventricle indices, and corpus callosum area were used to measure white matter thickness. The findings revealed a correlation between less attention towards the eyes and larger ventricle size. Ventricle and posterior corpus callosum sizes were correlated to affect-recognition proficiency. Findings suggest a link between white matter damage, gaze behavior, and affect recognition accuracy, emphasizing a relation with social perception.

Deep Learning-based Approach for Brainstem and Ventricular MR Planimetry: Application in Patients with Progressive Supranuclear Palsy.

Purpose To develop a fast and fully automated deep learning (DL)-based method for the MRI planimetric segmentation and measurement of the brainstem and ventricular structures most affected in patients with progressive supranuclear palsy (PSP). Materials and Methods In this retrospective study, T1-weighted MR images in healthy controls (n = 84) were used to train DL models for segmenting the midbrain, pons, middle cerebellar peduncle (MCP), superior cerebellar peduncle (SCP), third ventricle, and frontal horns (FHs). Internal, external, and clinical test datasets (n = 305) were used to assess segmentation model reliability. DL masks from test datasets were used to automatically extract midbrain and pons areas and the width of MCP, SCP, third ventricle, and FHs. Automated measurements were compared with those manually performed by an expert radiologist. Finally, these measures were combined to calculate the midbrain to pons area ratio, MR parkinsonism index (MRPI), and MRPI 2.0, which were used to differentiate patients with PSP (n = 71) from those with Parkinson disease (PD) (n = 129). Results Dice coefficients above 0.85 were found for all brain regions when comparing manual and DL-based segmentations. A strong correlation was observed between automated and manual measurements (Spearman ρ > 0.80, P < .001). DL-based measurements showed excellent performance in differentiating patients with PSP from those with PD, with an area under the receiver operating characteristic curve above 0.92. Conclusion The automated approach successfully segmented and measured the brainstem and ventricular structures. DL-based models may represent a useful approach to support the diagnosis of PSP and potentially other conditions associated with brainstem and ventricular alterations. Keywords: MR Imaging, Brain/Brain Stem, Segmentation, Quantification, Diagnosis, Convolutional Neural Network Supplemental material is available for this article. © RSNA, 2024 See also the commentary by Mohajer in this issue.

Cerebrospinal Fluid Diversion from the Cisterna Magna in Patients with Idiopathic Intracranial Hypertension and Slit Ventricles: Long-Term Effectiveness, Revision Rates, and Clinical Outcomes.

OBJECTIVE: Idiopathic intracranial hypertension (IIH) is a cerebrospinal fluid (CSF) disorder defect that is frequently treated with CSF shunts. Shunts utilizing the cisterna magna as a proximal reservoir have been described in literature; however, long-term outcomes are unknown. The present study aims to describe the long-term effectiveness, revision rates, and clinical outcomes of this shunt in 14 patients with IIH and slit ventricles. METHODS: A single-center retrospective review of 14 IIH patients treated by cisterna magna shunts was performed. Shunt histories, including revision rate and time until first shunt failure for ventricular, lumbar, and cisterna magna shunts were recorded. "Revision rate" was calculated as the total number of shunt revisions over years of total shunt placement. The average follow-up time was 12.08 years. RESULTS: The mean age at first cisterna magna shunt placement was 18.1 years (6.6-43.3 years) and all patients had radiological evidence of slit ventricles. Cisterna magna shunts improved or resolved clinical symptoms for all 14 patients and had a lower rate of revisions (0.42 revision/year) compared to ventricular (0.72 revision/year) and lumbar (1.30 revision/year) shunts. Of the 11 patients still requiring CSF diversion at the end of the study, eight had functioning shunts that utilized the cisterna magna. CONCLUSIONS: The cisterna magna shunt may be a suitable option for patients with IIH and slit ventricles. Further study is needed to understand the clinical utility of this shunt for the population in which it is indicated.

Prediction of short- and long-term outcomes using pre-operative ventricular size in infants with post-hemorrhagic ventricular dilation.

PURPOSE: Post-hemorrhagic ventricular dilation (PHVD) leads to developmental delays in premature infants, yet the optimal timing of neurosurgical interventions is unknown. Neuroimaging modalities have emerged to delineate injury and follow the progression of PHVD. Fronto-temporal horn ratio (FTHR) is used as a marker of ventricular dilation and can be a standardized tool to direct the timing of neurosurgical intervention. Our study determined a pre-operative FTHR measurement threshold to predict short- and long-term outcomes. METHODS: This is a retrospective cohort study of premature infants with severe intraventricular hemorrhage (IVH) who developed PHVD requiring neurosurgical intervention and were treated in a level IV NICU between 2012 and 2019. Receiver operating characteristic (ROC) curve and area under the curve (AUC) analyses were performed to evaluate the accuracy of pre-operative FTHR for predicting developmental delay. In-hospital outcomes and developmental assessments were analyzed. RESULTS: We reviewed 121 charts of infants with IVH and identified 43 infants with PHVD who required neurosurgical intervention. We found FTHR measurements were an excellent predictor of cognitive and motor delay with an AUC of 0.89 and 0.88, respectively. An average pre-operative FTHR of ≥ 0.67 was also associated with worse lung and feeding outcomes. There was excellent inter-observer reliability of individual components of FTHR measurements. CONCLUSIONS: Early intervention for PHVD is ideal but not always practical. Identification of ventricular size thresholds associated with better outcomes is needed to direct timing of neurosurgical intervention.

Comparative MRI analysis of the forebrain of three sauropsida models.

The study of the brain by magnetic resonance imaging (MRI) allows to obtain detailed anatomical images, useful to describe specific encephalic structures and to analyze possible variabilities. It is widely used in clinical practice and is becoming increasingly used in veterinary medicine, even in exotic animals; however, despite its potential, its use in comparative neuroanatomy studies is still incipient. It is a technology that in recent years has significantly improved anatomical resolution, together with the fact that it is non-invasive and allows for systematic comparative analysis. All this makes it particularly interesting and useful in evolutionary neuroscience studies, since it allows for the analysis and comparison of brains of rare or otherwise inaccessible species. In the present study, we have analyzed the prosencephalon of three representative sauropsid species, the turtle Trachemys scripta (order Testudine), the lizard Pogona vitticeps (order Squamata) and the snake Python regius (order Squamata) by MRI. In addition, we used MRI sections to analyze the total brain volume and ventricular system of these species, employing volumetric and chemometric analyses together. The raw MRI data of the sauropsida models analyzed in the present study are available for viewing and downloading and have allowed us to produce an atlas of the forebrain of each of the species analyzed, with the main brain regions. In addition, our volumetric data showed that the three groups presented clear differences in terms of total and ventricular brain volumes, particularly the turtles, which in all cases presented distinctive characteristics compared to the lizards and snakes.

Endoscopic Ventricular Lavage in Pediatric Pyogenic Cerebral Ventriculitis Associated with Shunt: Outcomes and Technical Notes.

OBJECTIVE: Pyogenic cerebral ventriculitis (PCV) is a rare infectious entity characterized by a potent inflammatory reaction of the ventricular ependyma, which in most cases leads to death. We aim to present the technical note and protocol, based on our center's 10-year experience of the use of endoscopic ventricular lavage (EVL) in pediatric patients with PCV and ventricular peritoneal shunt. METHODS: For this study, all pediatric patients (<16 years) with VP shunts and PCV who were treated with EVL between January 2012 and January 2022 were included. RESULTS: Thirty-four pediatric patients with ventriculitis were analyzed. The median age was 6 years, with 61.7% being male. Most consultations occurred on Day 2 of symptoms. Fever (38.2%) and altered consciousness (26.5%) were the most common initial symptoms. Early ventriculitis was observed in 67.7% of patients. Pathogen identification in the initial cerebrospinal fluid sample was 70.6%, while samples from ventricular peritoneal shunt yielded 23.53% and catheter culture 79.4%. Gram-positive bacteria, mainly S.epidermidis (44.1%), was the most commonly isolated agent. EVL was performed in 73.5% on the second or third day. Reinfection occurred in 23.5%, and 26.5% of patients died. Concordance analysis showed 85.3% agreement between LP and catheter tip samples. Functionality improved, with 55.88% achieving a Lansky score of 90. Early ventriculitis was associated with better Lansky scores. CONCLUSION: EVL can be a useful tool in the management of PCV in cases with VP shunts. Our study suggests a higher chance of isolating an infection-causing germ in the catheter tip culture specimen compared to the cerebrospinal fluid culture. However, future studies with a larger number of patients, or multicentric studies are required for further analysis.

Validating the accuracy of real-time phase-contrast MRI and quantifying the effects of free breathing on cerebrospinal fluid dynamics.

BACKGROUND: Understanding of the cerebrospinal fluid (CSF) circulation is essential for physiological studies and clinical diagnosis. Real-time phase contrast sequences (RT-PC) can quantify beat-to-beat CSF flow signals. However, the detailed effects of free-breathing on CSF parameters are not fully understood. This study aims to validate RT-PC's accuracy by comparing it with the conventional phase-contrast sequence (CINE-PC) and quantify the effect of free-breathing on CSF parameters at the intracranial and extracranial levels using a time-domain multiparametric analysis method. METHODS: Thirty-six healthy participants underwent MRI in a 3T scanner for CSF oscillations quantification at the cervical spine (C2-C3) and Sylvian aqueduct, using CINE-PC and RT-PC. CINE-PC uses 32 velocity maps to represent dynamic CSF flow over an average cardiac cycle, while RT-PC continuously quantifies CSF flow over 45-seconds. Free-breathing signals were recorded from 25 participants. RT-PC signal was segmented into independent cardiac cycle flow curves (Qt) and reconstructed into an averaged Qt. To assess RT-PC's accuracy, parameters such as segmented area, flow amplitude, and stroke volume (SV) of the reconstructed Qt from RT-PC were compared with those derived from the averaged Qt generated by CINE-PC. The breathing signal was used to categorize the Qt into expiratory or inspiratory phases, enabling the reconstruction of two Qt for inspiration and expiration. The breathing effects on various CSF parameters can be quantified by comparing these two reconstructed Qt. RESULTS: RT-PC overestimated CSF area (82.7% at aqueduct, 11.5% at C2-C3) compared to CINE-PC. Stroke volumes for CINE-PC were 615 mm³ (aqueduct) and 43 mm³ (spinal), and 581 mm³ (aqueduct) and 46 mm³ (spinal) for RT-PC. During thoracic pressure increase, spinal CSF net flow, flow amplitude, SV, and cardiac period increased by 6.3%, 6.8%, 14%, and 6%, respectively. Breathing effects on net flow showed a significant phase difference compared to the other parameters. Aqueduct-CSF flows were more affected by breathing than spinal-CSF. CONCLUSIONS: RT-PC accurately quantifies CSF oscillations in real-time and eliminates the need for cardiac synchronization, enabling the quantification of the cardiac and breathing components of CSF flow. This study quantifies the impact of free-breathing on CSF parameters, offering valuable physiological references for understanding the effects of breathing on CSF dynamics.

Frequency of brain ventricular enlargement among patients with diabetes mellitus.

AIMS: To determine the prevalence of dilated ventricles and concomitant high blood glucose measures. METHODS: We retrieved blood glucose measures from the emergency department database and selected a subgroup of individuals having both the radiological marker Evans' index (EI) values and blood glucose measures. RESULTS: Out of 1221 consecutive patients submitted to axial Computed Tomography scans, a blood glucose measure was detected in 841 individuals. 176 scans (21 %) showed an EI > 0.30. According to the blood glucose categorization, diabetic patients were 104 (12 %), 25 of them (24 %) were dilated (mean EI 0.33). The age difference between dilated and not-dilated ventricles is about ten years in not-diabetic participants, whereas it is five years in diabetic participants. The age difference between dilated and not-dilated ventricles is about 10 years in diabetic men, whereas it zero in diabetic women. CONCLUSIONS: Pathological ventricular enlargement is more frequent in men and in the elderly. In diabetic patients (especially women), the cerebral ventricles enlarge faster than in non-diabetic individuals. Age, sex, and diabetes may interact in determining how cerebral ventricle size changes over time, especially in diabetic women, making routine brain imaging advisable in these patients after the age of 70 years.

The prepontine block and its relevance for the development and treatment of hydrocephalus.

OBJECTIVE: Pulsatile CSF flow patterns include flow through the ventricles to the subarachnoid space and cisterns and from the infra- to the supratentorial subarachnoid space. In this study, we demonstrate how an obstruction at the level of the prepontine space may lead to obstructive hydrocephalus with specific radiological characteristics, as well as the implications for treatment options. METHODS: We retrospectively collected data of patients who underwent surgery between February 2010 and December 2022 for hydrocephalus secondary to a suspected prepontine block. One additional patient diagnosed with prepontine block who did not undergo surgery was also included. We excluded patients with a background of previous unrelated neurosurgical procedures or CNS infections. RESULTS: Six children and two adults were included. Three presented with hydrocephalus on imaging, without any other underlying pathology. Five had a suprasellar arachnoid cyst, with its lower border abating the pons and occluding the spinal subarachnoid space (SAS). All cases had an open aqueduct on T2 sagittal sequences, as well as an infracerebellar or retrocerebellar CSF collection. In most cases, a horizontal web was identified in the prepontine region. Seven cases were treated with an endoscopic fenestration. One patient subsequently underwent a shunt surgery. All the operated children reached normal developmental milestones after surgery. CONCLUSIONS: This paper describes a rather small series of cases where clear obstruction was observed at the level of the prepontine subarachnoid space. We believe this anatomical subtlety adds to a better understanding of CSF pathways and the role of ETV in treating hydrocephalus, focusing on a small subgroup of patients without a clear obstruction.