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Spontaneous intracranial hypotension (SIH) is due to a leakage of CSF lowering the pressure of subarachnoid space, mostly caused by a dural breach or discogenic microspur. Clinical and MRI are usually typical enough to allow diagnosis, while finding the location of the dural breach is challenging. Since some years, CSF venous fistulas have been described as the cause of SIH, and a specific diagnostic and therapeutic path has been proposed. Here we report the first two successfully treated patients in Italy. Both had chronic and non specific symptoms, with severe reduction of quality of life; clinical symptoms improved after endovascular occlusion of the responsible vein. [ABSTRACT FROM AUTHOR]

The article discusses the prenatal diagnosis of Walker-Warburg syndrome (WWS), a rare autosomal recessive disorder affecting the brain, eyes, and muscles. The case study presented involves a child with WWS who exhibited generalized hypotonia, cataracts, and progressive muscular dystrophy leading to death within the second year after birth. The syndrome is associated with defective glycosylation of α-dystroglycan, resulting in neuronal overmigration and impaired muscle cell communication, with similarities to other severe forms of congenital muscular dystrophy. Various prenatal ultrasound and magnetic resonance imaging features are described, including brainstem abnormalities, cerebellar hypoplasia, and lissencephaly. Other malformations associated with WWS, such as corpus callosum agenesis and facial dysmorphism, are also mentioned. [Extracted from the article]

External hydrocephalus (EH) is a recognised sub-type of hydrocephalus associated with macrocephaly in infancy. EH is characterised by the enlargement of subarachnoid spaces (so-called subarachnomegaly) with a normal ventricular system on brain imaging. EH is traditionally considered benign and self-limiting, yet its pathophysiology remains puzzling. Mounting evidence for an association between EH and hydrovenous disorders reshapes our understanding of this condition and its management. To our knowledge, we report the first association between EH and dural arteriovenous fistula (dAVF) in a 17-months-old boy. As dAVF may be a life-threatening condition, early diagnosis and optimal treatment are critical. This case epitomises the intricacies of EH's aetiology and associated conditions requiring careful management. Therefore, we recommend considering MR angiography in EH's workup and long-term follow-up. Our experience supports the ongoing reconsideration of EH's presumed benignity. [ABSTRACT FROM AUTHOR]

Abstract Background Ultrasound (US) is often the first method used to look for brain or cerebrospinal fluid (CSF) space pathologies. Knowledge of normal CSF width values is essential. Most of the available US normative values were established over 20 years ago, were obtained with older equipment, and cover only part of the age spectrum that can be examined by cranial US. This prospective study aimed to determine the normative values of the widths of the subarachnoid and internal CSF spaces (craniocortical, minimal and maximal interhemispheric, interventricular, and frontal horn) for high-resolution linear US probes in neurologically healthy infants and children aged 0–19 months and assess whether subdural fluid collections can be delineated. Methods Two radiologists measured the width of the CSF spaces with a conventional linear probe and an ultralight hockey-stick probe in neurologically healthy children not referred for cranial or spinal US. Results This study included 359 neurologically healthy children (nboys = 178, 49.6%; ngirls = 181, 50.4%) with a median age of 46.0 days and a range of 1–599 days. We constructed prediction plots, including the 5th, 50th, and 95th percentiles, and an interactive spreadsheet to calculate normative values for individual patients. The measurements of the two probes and the left and right sides did not differ, eliminating the need for separate normative values. No subdural fluid collection was detected. Conclusion Normative values for the widths of the subarachnoid space and the internal CSF spaces are useful for evaluating intracranial pathology, especially when determining whether an increase in the subarachnoid space width is abnormal.

Background: Bidirectional reciprocal motion of cerebrospinal fluid (CSF) was quantified using four-dimensional (4D) flow magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) MRI. To estimate various CSF motions in the entire intracranial region, we attempted to integrate the flow parameters calculated using the two MRI sequences. To elucidate how CSF dynamics deteriorate in Hakim's disease, an age-dependent chronic hydrocephalus, flow parameters were estimated from the two MRI sequences to assess CSF motion in the entire intracranial region. Methods: This study included 127 healthy volunteers aged ≥ 20 years and 44 patients with Hakim's disease. On 4D flow MRI for measuring CSF motion, velocity encoding was set at 5 cm/s. For the IVIM MRI analysis, the diffusion-weighted sequence was set at six b-values (i.e., 0, 50, 100, 250, 500, and 1000 s/mm2), and the biexponential IVIM fitting method was adapted. The relationships between the fraction of incoherent perfusion (f) on IVIM MRI and 4D flow MRI parameters including velocity amplitude (VA), absolute maximum velocity, stroke volume, net flow volume, and reverse flow rate were comprehensively evaluated in seven locations in the ventricles and subarachnoid spaces. Furthermore, we developed a new parameter for fluid oscillation, the Fluid Oscillation Index (FOI), by integrating these two measurements. In addition, we investigated the relationship between the measurements and indices specific to Hakim's disease and the FOIs in the entire intracranial space. Results: The VA on 4D flow MRI was significantly associated with the mean f-values on IVIM MRI. Therefore, we estimated VA that could not be directly measured on 4D flow MRI from the mean f-values on IVIM MRI in the intracranial CSF space, using the following formula; e0.2(f−85) + 0.25. To quantify fluid oscillation using one integrated parameter with weighting, FOI was calculated as VA × 10 + f × 0.02. In addition, the FOIs at the left foramen of Luschka had the strongest correlations with the Evans index (Pearson's correlation coefficient: 0.78). The other indices related with Hakim's disease were significantly associated with the FOIs at the cerebral aqueduct and bilateral foramina of Luschka. FOI at the cerebral aqueduct was also elevated in healthy controls aged ≥ 60 years. Conclusions: We estimated pulsatile CSF movements in the entire intracranial CSF space in healthy individuals and patients with Hakim's disease using FOI integrating VA from 4D flow MRI and f-values from IVIM MRI. FOI is useful for quantifying the CSF oscillation. [ABSTRACT FROM AUTHOR]

Background: Ultrasound (US) is often the first method used to look for brain or cerebrospinal fluid (CSF) space pathologies. Knowledge of normal CSF width values is essential. Most of the available US normative values were established over 20 years ago, were obtained with older equipment, and cover only part of the age spectrum that can be examined by cranial US. This prospective study aimed to determine the normative values of the widths of the subarachnoid and internal CSF spaces (craniocortical, minimal and maximal interhemispheric, interventricular, and frontal horn) for high-resolution linear US probes in neurologically healthy infants and children aged 0–19 months and assess whether subdural fluid collections can be delineated. Methods: Two radiologists measured the width of the CSF spaces with a conventional linear probe and an ultralight hockey-stick probe in neurologically healthy children not referred for cranial or spinal US. Results: This study included 359 neurologically healthy children (nboys = 178, 49.6%; ngirls = 181, 50.4%) with a median age of 46.0 days and a range of 1–599 days. We constructed prediction plots, including the 5th, 50th, and 95th percentiles, and an interactive spreadsheet to calculate normative values for individual patients. The measurements of the two probes and the left and right sides did not differ, eliminating the need for separate normative values. No subdural fluid collection was detected. Conclusion: Normative values for the widths of the subarachnoid space and the internal CSF spaces are useful for evaluating intracranial pathology, especially when determining whether an increase in the subarachnoid space width is abnormal. [ABSTRACT FROM AUTHOR]

Choroid plexus hyperplasia (CPH), also known as diffuse villous hyperplasia of choroid plexus, is a rare condition characterized by excessive production of cerebrospinal fluid (CSF), resulting in hydrocephalus. Diagnosing CPH can be challenging due to the absence of clear imaging criteria for choroid plexus hypertrophy and the inability to assess CSF production non-invasively. As a result, many CPH patients are initially treated with a ventriculoperitoneal (VP) shunt, but subsequently require additional surgical intervention due to intractable ascites. In our study, we encountered two CPH patients who presented with significantly enlarged subarachnoid spaces, reduced parenchymal volume, and prominent choroid plexus. Initially, we treated these patients with a VP shunt, but eventually opted for endoscopic choroid plexus cauterization (CPC) to address the intractable ascites. Following the treatment with endoscopic CPC, we observed a gradual reduction in subarachnoid spaces and an increase in parenchymal volume. In cases where bilateral prominent choroid plexus, markedly enlarged subarachnoid spaces, and cortical atrophy are present, CPH should be suspected. In these cases, considering initial treatment with combined endoscopic CPC and shunt may help minimize the need for multiple surgical interventions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: We report a patient with recurrent optic disc pit (ODP) maculopathy after Valsalva's maneuver and discuss its pathophysiology. We also hypothesize the role of Valsalva's maneuver in its genesis. Method: Case report of one patient, male, 12 years old. Results: Serous retinal detachment may occur in association with the ODP, a developmental anomaly of the optic nerve head. Histopathologically, it consists of a dysplastic retina herniation into a pocket extending posteriorly through a defect in the lamina cribrosa into the subarachnoid space. These three different compartments--intraocular space, optic nerve head, and subarachnoid space--and the dynamic interactions among them should be understood as the key factors for the occurrence of ODP-related serous retinal detachment. Conclusion: Based on the possibility that serous retinal detachment secondary to the ODP could be related to the Valsalva's maneuver, we strongly recommend that patients with ODP be advised to avoid intense physical or work activities that may increase abdominal, thoracic, and cerebral pressure and to refrain from playing wind instruments to avoid pretreatment, per treatment, and post-treatment intercurrences. [ABSTRACT FROM AUTHOR]

Subarachnoid hemorrhage (SAH) is primarily attributed to the rupture of intracranial aneurysms and is associated with a high incidence of disability and mortality. SAH disrupts the blood‒brain barrier, leading to the release of iron ions from blood within the subarachnoid space, subsequently inducing neuronal ferroptosis. A recently discovered protein, known as ferroptosis suppressor protein 1 (FSP1), exerts anti-ferroptotic effects by facilitating the conversion of oxidative coenzyme Q 10 (CoQ10) to its reduced form, which effectively scavenges reactive oxygen radicals and mitigates iron-induced ferroptosis. In our investigation, we observed an increase in FSP1 levels following SAH. However, the depletion of CoQ10 caused by SAH hindered the biological function of FSP1. Therefore, we created neuron-targeted liposomal CoQ10 by introducing the neuron-targeting peptide Tet1 onto the surface of liposomal CoQ10. Our objective was to determine whether this formulation could activate the FSP1 system and subsequently inhibit neuronal ferroptosis. Our findings revealed that neuron-targeted liposomal CoQ10 effectively localized to neurons at the lesion site after SAH. Furthermore, it facilitated the upregulation of FSP1, reduced the accumulation of malondialdehyde and reactive oxygen species, inhibited neuronal ferroptosis, and exerted neuroprotective effects both in vitro and in vivo. Our study provides evidence that supplementation with CoQ10 can effectively activate the FSP1 system. Additionally, we developed a neuron-targeted liposomal CoQ10 formulation that can be selectively delivered to neurons at the site of SAH. This innovative approach represents a promising therapeutic strategy for neuronal ferroptosis following SAH. Subarachnoid hemorrhage (SAH) is primarily attributed to the rupture of intracranial aneurysms and is associated with a high incidence of disability and mortality. Ferroptosis suppressor protein 1 (FSP1), exerts anti-ferroptotic effects by facilitating the conversion of oxidative coenzyme Q 10 (CoQ10) to its reduced form, which effectively scavenges reactive oxygen radicals and mitigates iron-induced ferroptosis. In our investigation, we observed an increase in FSP1 levels following SAH. However, the depletion of CoQ10 caused by SAH hindered the biological function of FSP1. Therefore, we created neuron-targeted liposomal CoQ10. We find that it effectively localized to neurons at the lesion site after SAH and activated the FSP1/CoQ10 system. This innovative approach represents a promising therapeutic strategy for neuronal ferroptosis following SAH and other central nervous system diseases characterized by disruption of the blood-brain barrier. [Display omitted] [ABSTRACT FROM AUTHOR]

In comparison to other stroke types, subarachnoid hemorrhage (SAH) is characterized by an early age of onset and often results in poor prognosis. The inadequate blood flow at the site of the lesion leads to localized oxygen deprivation, increased level of hypoxia-inducible factor-1α (HIF-1α), and triggers inflammatory responses and oxidative stress, ultimately causing hypoxic brain damage. Despite the potential benefits of oxygen (O 2) administration, there is currently a lack of efficient focal site O 2 delivery following SAH. Conventional clinical O 2 supply methods, such as transnasal oxygenation and hyperbaric oxygen therapy, do not show the ideal therapeutic effect in severe SAH patients. The perfluorocarbon oxygen carrier (PFOC) demonstrates efficacy in transporting O 2 and responding to elevated levels of CO 2 at the lesion site. Through cellular experiments, we determined that PFOC oxygenation serves as an effective therapeutic approach in inhibiting hypoxia. Furthermore, our animal experiments showed that PFOC oxygenation outperforms O 2 breathing, leading to microglia phenotypic switching and the suppression of inflammatory response via the inhibition of HIF-1α. Therefore, as a new type of O 2 therapy after SAH, PFOC oxygenation can effectively reduce hypoxic brain injury and improve neurological function. Subarachnoid hemorrhage primarily arises from the rupture of intracranial aneurysms. The rupture of an aneurysm results in a substantial influx of blood into the subarachnoid space, exerting arterial pressure and accumulating within the cerebral sulcus cerebral pool, thereby forming a hematoma that compresses the brain tissue. Consequently, this compression leads to localized tissue hypoxia, which subsequently triggers excitatory neuroinflammation and oxidative stress. Considering these circumstances, we propose a novel approach utilizing perfluorocarbons following subarachnoid hemorrhage, enhancing oxygenation at the site of the lesion in comparison to conventional O 2 breathing. Perfluorocarbon oxygen carrier oxygenation has been found to have a downregulating effect on HIF-1α, leading to a decrease in the population of M1-type microglia and an increase in the population of M2-type microglia. Additionally, this oxygenation process inhibits inflammatory responses and oxidative stress following subarachnoid hemorrhage, ultimately resulting in an improvement in neurological function. [Display omitted] • HIF-1α mediates hypoxic brain injury after SAH. • We developed a method of supplying oxygen that can be administered intravenously. • Perfluorocarbon oxygen carrier ameliorates hypoxic brain injury by inhibiting HIF-1α. [ABSTRACT FROM AUTHOR]

The human subarachnoid space harbors the cerebrospinal fluid, which flows within a landscape of blood vessels and trabeculae. Functional implications of subarachnoid space anatomy remain far less understood. This study of 75 patients utilizes a cerebrospinal fluid tracer (gadobutrol) and consecutive magnetic resonance imaging to investigate features of early (i.e. within 2-3 h after injection) tracer propagation within the subarachnoid space. There is a time-dependent perivascular pattern of enrichment antegrade along the major cerebral artery trunks; the anterior-, middle-, and posterior cerebral arteries. The correlation between time of first enrichment around arteries and early enrichment in nearby cerebral cortex is significant. These observations suggest the existence of a compartmentalized subarachnoid space, where perivascular ensheathment of arteries facilitates antegrade tracer passage towards brain tissue. Periarterial transport is impaired in subjects with reduced intracranial pressure-volume reserve capacity and in idiopathic normal pressure hydrocephalus patients who also show increased perivascular space size. Functional implications of subarachnoid space anatomy remain unclear. Here, the authors show by human in vivo imaging that an intrathecal tracer propagates antegrade along the major cerebral arteries within a perivascular subarachnoid space facilitating tracer passage towards the brain. [ABSTRACT FROM AUTHOR]

Long thought to be immune privileged, the central nervous system is far from being devoid of local immunity. Subarachnoid hemorrhage (SAH) and traumatic brain injury represent 2 distinct central nervous system injury situations which, while both exposed to external ventricular drains, present different incidences of ventriculostomy-related infection (VRI). We sought to compare VRI incidence and initial cerebrospinal fluid (CSF) inflammatory profiles in these 2 clinical situations. From 2015 to 2020, 227 patients treated for SAH (193) or traumatic brain injury (34) with an external ventricular drain were prospectively included. CSF samples were sent daily for microbiological examination, cell count, and biochemical analysis. VRI was defined as a positive CSF culture associated with CSF profile modifications and clinical signs. Ventriculostomy-related colonization was defined as positive catheter culture at removal. Positive events were defined as VRI and/or ventriculostomy-related colonization. Eleven patients suffered from VRI, with an incidence of 3.6 VRI per 1000 catheter-days. All VRIs occurred among SAH patients without a significant difference. Median duration of drainage was 12 (7–18) days, there were no significant differences for known VRI risk factors. Positive events were significantly higher in SAH patients (20.7% vs. 2.9%, P = 0.013). Inflammatory CSF markers and serum white blood cells were higher in SAH patients. Local inflammatory markers were markedly higher in SAH than in traumatic brain injury. However, positive events were more frequent in SAH. Furthermore, SAH may be a risk factor for VRI. Hypothesis that a primary injury to the subarachnoid space could impair central nervous system immune functions should be explored. [ABSTRACT FROM AUTHOR]

Objective: Spinal extradural arachnoid cysts (SEDC) are rare primary spinal lesions, accounting for less than 1% of all spinal epidural lesions. The literature contains only case reports of this pathology, and treatment remains controversial due to its rarity. Major reported SEDC cases are caused by leaking out of cerebrospinal fluid through a dural defect in the thecal sac forming an extradural cyst. Other reports describe non-communicating SEDC cases where the dural defect was not identified. We report a literature review on SEDC and the case of a 53 year‑old female who presented with type IA extradural cyst with subarachnoid space communication. Methods: Literature review, preoperative imaging and surgical technique. Results: The extradural cyst was excised completely and the dural defect was repaired. After surgical decompression, neurological symptoms gradually recovered. Conclusions: The extradural arachnoid cyst is an uncommon entity. Preoperative imaging is one of the determining elements in orienting the therapeutic management of the SEDCs. The choice of the surgical technique must be the least invasive in order to avoid postoperative complications. Subtotal or complete excision of the cyst, followed by obliteration of the communication stalk and repair of the dural defect is the gold standard treatment. [ABSTRACT FROM AUTHOR]

Introduction: Open-lip-type schizencephaly is characterized by trans-cerebral clefts filled with cerebrospinal fluid (CSF) between the subarachnoid space at the hemisphere surface and the lateral ventricles. Disorders related to CSF retention, including hydrocephalus and arachnoid cysts, have reportedly been associated with open-lip schizencephaly and have induced intracranial hypertension in some cases. However, detailed neuroimaging and surgical treatment findings have rarely been described. Case Presentation: We report 2 cases of open-lip schizencephaly with an expanding CSF-filled cavity overlying the ipsilateral cerebral hemisphere that manifested as signs of intracranial hypertension. Detailed three-dimensional heavily T2-weighted imaging revealed thin borders between the CSF-filled cavity and the subarachnoid space, but no separating structures between the cavity and the lateral ventricle, suggesting that the cavity was directly connected to the lateral ventricle through the schizencephalic cleft but not to the subarachnoid space. Neuroendoscopic observation in case 1 confirmed this finding. Endoscopic fenestration of the cavity to the prepontine cistern was ineffective in case 1. Shunting between the lateral ventricle (case 1) or CSF-filled cavity (case 2) and the peritoneal cavity slightly decreased the size of the CSF-filled cavity. Discussion: We speculate that the thin borders along the margin of the CSF-filled cavity are membranes that previously covered the schizencephalic cleft and are now pushed peripherally. In addition, we believe that the cavity is a ventricular diverticulum protruding through the cleft and that shunting operation is effective against such expanding cavity. Detailed magnetic resonance imaging can be useful for evaluating patients with schizencephaly associated with CSF retention disorders. Established Facts: Open-lip-type schizencephalic clefts directly connect the lateral ventricles and the subarachnoid spaces. Detailed relationship between the clefts and cerebrospinal fluid retention disorders, including hydrocephalus and arachnoid cysts, remains unknown. [ABSTRACT FROM AUTHOR]

Background & Methods: The aim of the study is to evaluate of postdural puncture backache in cases of lscs under subarachnoid block given by resident doctors. Successful identification of the subarachnoid space with one skin puncture and no redirection of the spinal needle was considered as first pass success. The subarachnoid block was given by resident doctor. Results: The mean duration of backache was 2 ± 1.5days. All patients responded to treatment with paracetamol and diclofenac. Factors affecting the incidence of PDPB. The factors did not affect the incidence of PDPB: age (P = 0.606), elective or emergency LSCS (P = 0.324) or parturient in labour (P = 0.709), previous spinal anaesthesia (P = 0.389), body habitus (P = 0.125), bony deformity (P = 0.875), occurrence of paraesthesia (P = 1.000), contact of spinal needle with bone (P = 0.078), duration of surgery (P = 0.058), time to sitting (P = 0.346) and time to ambulation (P = 0.748), occurrence of PDPH (P = 0.628). Conclusion: The incidence of PDPB was 10% in patients undergoing LSCS under subarachnoid block given by resident doctor. The onset of backache was within 24 hour of spinal anaesthesia and the pain was mild to mod intensity and responded to treatment with paracetamol and diclofenac. Factors associated with PDPB included increased weight, poor quality of spinal landmarks, increased number of attempts and spinal needle redirections and occurrence of bloody tap. Association was also noted between PDPB and provider experience. It was noted that the patients who are complaining of backache after subarachnoid block mostly primigravida, unco-operative or obese patients due to poor positioning during SAB given by resident doctors. This resulted in multiple skin punctures, spinal needle redirections, needle passes, first pass failure, change in intervertebral space level, more than 2 attempt by resident doctor, bloody CSF tap taking over by a second provider and the SAB was given by second provider. [ABSTRACT FROM AUTHOR]

"To evaluate the effect of sitting vs left lateral decubitus position during sub-arachnoid block on occurrence of post-dural puncture headache in patients undergoing lower segment caesarean section. Aims and Objectives: The present study was carried out in 200 patients of ASA grade I/II, posted for lower segment caesarean section from October 2023 to March 2024 at People's College of Medical Sciences and Research Centre, Bhopal with aims of: • To find out role of the position of patient in the occurrence of postdural puncture headache. • Incidence of PDPH in sitting position vs left lateral decubitus position. • Onset and duration of PDPH in both positions. • Comparison of ease of technique in both positions. • Haemodynamic parameters of the patients in both positions. Methodology: 200 patients of ASA grade I and II between the ages of 18 and 40 years, who underwent lower segment caesarean section. Patients were randomly divided into two groups: 1. Group A (n=100): Patients given subarachnoid block in sitting position. 2. Group B (n=100): Patients given subarachnoid block in left lateral decubitus position • STATISTICAL ANALYSIS: The categorical data will be presented as numbers % and compared by Chi-square test. The quantitative data will be presented as mean ± standard deviation and compared by Student's t-test (P < 0.05 as statistically significant). • CONCLUSION: It is unclear as to whether the position of the patient during subarachnoid blockade leads to the occurrence of PDPH. The aim of this study was to compare the effect of the sitting and the left lateral decubitus position during subarachnoid blockade on the occurrence and severity of PDPH in the patients. [ABSTRACT FROM AUTHOR]

Leptomeningeal gliomatosis (LG) is characterized by extensive dissemination of neoplastic glial cells in the subarachnoid space either without an intraparenchymal glioma (primary LG or PLG) or secondary to an intraparenchymal glioma (secondary LG or SLG). Given the low frequency of LG in human and veterinary medicine, specific diagnostic criteria are lacking. Here, we describe 14 cases of canine LG that were retrospectively identified from 6 academic institutions. The mean age of affected dogs was 7.3 years and over 90% of patients were brachycephalic. Clinical signs were variable and progressive. Relevant magnetic resonance image findings in 7/14 dogs included meningeal enhancement of affected areas and/or intraparenchymal masses. All affected dogs were euthanized because of the poor prognosis. Gross changes were reported in 12/14 cases and consisted mainly of gelatinous leptomeningeal thickening in the brain (6/12 cases) or spinal cord (2/12 cases) and 1 or multiple, gelatinous, gray to red intraparenchymal masses in the brain (6/12 cases). Histologically, all leptomeningeal neoplasms and intraparenchymal gliomas were morphologically consistent with oligodendrogliomas. Widespread nuclear immunolabeling for OLIG2 was observed in all neoplasms. The absence of an intraparenchymal glioma was consistent with PLG in 3 cases. The remaining 11 cases were diagnosed as SLG. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the 3D U-Net model for automatic segmentation and measurement of cervical spine structures using magnetic resonance (MR) images of healthy adults. Materials and methods: MR images of the cervical spine from 160 healthy adults were collected retrospectively. A previously constructed deep-learning model was used to automatically segment anatomical structures.Segmentation and localization results were checked by experienced radiologists. Pearson's correlation analyses were conducted to examine relationships between patient and image parameters. Results: No measurement was significantly correlated with age or sex. The mean values of the areas of the subarachnoid space and spinal cord from the C2/3 (cervical spine 2-3) to C6/7 intervertebral disc levels were 102.85-358.12 mm² and 53.71-110.32 mm², respectively. The ratios of the areas of the spinal cord to the subarachnoid space were 0.25-0.68. The transverse and anteriorposterior diameters of the subarachnoid space were 14.77-26.56 mm and 7.38-17.58 mm, respectively. The transverse and anterior-posterior diameters of the spinal cord were 9.11-16.02 mm and 5.47-10.12 mm, respectively. Conclusion: A deep learning model based on 3D U-Net automatically segmented and performed measurements on cervical spine MR images from healthy adults, paving the way for quantitative diagnosis models for spinal cord diseases. [ABSTRACT FROM AUTHOR]

Abstract Background Impaired cerebrospinal fluid (CSF) dynamics is involved in the pathophysiology of neurodegenerative diseases of the central nervous system and the optic nerve (ON), including Alzheimer’s and Parkinson’s disease, as well as frontotemporal dementia. The smallness and intricate architecture of the optic nerve subarachnoid space (ONSAS) hamper accurate measurements of CSF dynamics in this space, and effects of geometrical changes due to pathophysiological processes remain unclear. The aim of this study is to investigate CSF dynamics and its response to structural alterations of the ONSAS, from first principles, with supercomputers. Methods Large-scale in-silico investigations were performed by means of computational fluid dynamics (CFD) analysis. High-order direct numerical simulations (DNS) have been carried out on ONSAS geometry at a resolution of 1.625 μm/pixel. Morphological changes on the ONSAS microstructure have been examined in relation to CSF pressure gradient (CSFPG) and wall strain rate, a quantitative proxy for mass transfer of solutes. Results A physiological flow speed of 0.5 mm/s is achieved by imposing a hydrostatic pressure gradient of 0.37–0.67 Pa/mm across the ONSAS structure. At constant volumetric rate, the relationship between pressure gradient and CSF-accessible volume is well captured by an exponential curve. The ONSAS microstructure exhibits superior mass transfer compared to other geometrical shapes considered. An ONSAS featuring no microstructure displays a threefold smaller surface area, and a 17-fold decrease in mass transfer rate. Moreover, ONSAS trabeculae seem key players in mass transfer. Conclusions The present analysis suggests that a pressure drop of 0.1–0.2 mmHg over 4 cm is sufficient to steadily drive CSF through the entire subarachnoid space. Despite low hydraulic resistance, great heterogeneity in flow speeds puts certain areas of the ONSAS at risk of stagnation. Alterations of the ONSAS architecture aimed at mimicking pathological conditions highlight direct relationships between CSF volume and drainage capability. Compared to the morphological manipulations considered herein, the original ONSAS architecture seems optimized towards providing maximum mass transfer across a wide range of pressure gradients and volumetric rates, with emphasis on trabecular structures. This might shed light on pathophysiological processes leading to damage associated with insufficient CSF flow in patients with optic nerve compartment syndrome.

Objective Syringomyelia is a common central nervous system disease characterized by the dilation of the central canal (CC). Regarding the pathogenesis of syringomyelia, cerebrospinal fluid (CSF) circulation obstruction in the subarachnoid space (SAS) of the spinal cord has been widely accepted. However, clinical and animal studies on obstructing the CSF in SAS failed to form syringomyelia, challenging the theory of SAS obstruction. The precise pathogenesis remains unknown. Methods We utilized an extradural compression rat model to investigate the pathogenesis underlying syringomyelia. Magnetic resonance imaging enabled detection of syringomyelia formation. To assess CSF flow within the SAS, Evans blue was infused into the cisterna magna. Histological analysis allowed morphological examination of the CC. Furthermore, CSF flow through the CC was traced using Ovalbumin Alexa-Flour 647 conjugate (OAF-647). Scanning electron microscopy (SEM) enabled visualization of ependymal cilia. Results The findings showed that the dura mater below the compression segment exhibited lighter coloration relative to the region above the compression, indicative of partial obstruction within the SAS. However, the degree of SAS occlusion did not significantly differ between syringomyelia (SM-Y group) and those without (SM-N group). Intriguingly, hematoxylin and eosin staining and CSF tracing revealed occlusion of the CC accompanied by reduced CSF flow in the SM-Y group compared to SM-N and control groups. SEM images uncovered impairment of ependymal cilia inside the syringomyelia. Conclusion CC occlusion may represent a physiological prerequisite for syringomyelia formation, while SAS obstruction serves to initiate disease onset. The impairment of ependymal cilia appears to facilitate progression of syringomyelia.

Abstract Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4th meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1–3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.

Background: Impaired cerebrospinal fluid (CSF) dynamics is involved in the pathophysiology of neurodegenerative diseases of the central nervous system and the optic nerve (ON), including Alzheimer's and Parkinson's disease, as well as frontotemporal dementia. The smallness and intricate architecture of the optic nerve subarachnoid space (ONSAS) hamper accurate measurements of CSF dynamics in this space, and effects of geometrical changes due to pathophysiological processes remain unclear. The aim of this study is to investigate CSF dynamics and its response to structural alterations of the ONSAS, from first principles, with supercomputers. Methods: Large-scale in-silico investigations were performed by means of computational fluid dynamics (CFD) analysis. High-order direct numerical simulations (DNS) have been carried out on ONSAS geometry at a resolution of 1.625 μm/pixel. Morphological changes on the ONSAS microstructure have been examined in relation to CSF pressure gradient (CSFPG) and wall strain rate, a quantitative proxy for mass transfer of solutes. Results: A physiological flow speed of 0.5 mm/s is achieved by imposing a hydrostatic pressure gradient of 0.37–0.67 Pa/mm across the ONSAS structure. At constant volumetric rate, the relationship between pressure gradient and CSF-accessible volume is well captured by an exponential curve. The ONSAS microstructure exhibits superior mass transfer compared to other geometrical shapes considered. An ONSAS featuring no microstructure displays a threefold smaller surface area, and a 17-fold decrease in mass transfer rate. Moreover, ONSAS trabeculae seem key players in mass transfer. Conclusions: The present analysis suggests that a pressure drop of 0.1–0.2 mmHg over 4 cm is sufficient to steadily drive CSF through the entire subarachnoid space. Despite low hydraulic resistance, great heterogeneity in flow speeds puts certain areas of the ONSAS at risk of stagnation. Alterations of the ONSAS architecture aimed at mimicking pathological conditions highlight direct relationships between CSF volume and drainage capability. Compared to the morphological manipulations considered herein, the original ONSAS architecture seems optimized towards providing maximum mass transfer across a wide range of pressure gradients and volumetric rates, with emphasis on trabecular structures. This might shed light on pathophysiological processes leading to damage associated with insufficient CSF flow in patients with optic nerve compartment syndrome. [ABSTRACT FROM AUTHOR]

Subdural hemorrhages (SDHs) in the pediatric population are associated with a high mortality and morbidity and may present in the context of abusive head trauma. Diagnostic investigations for such cases often include evaluation for rare genetic and metabolic disorders that can have associated SDH. Sotos syndrome is an overgrowth syndrome associated with macrocephaly and increased subarachnoid spaces and rarely with neurovascular complications. Here, we report two cases of Sotos syndrome, one with SDH during infancy who underwent repeated evaluation for suspected child abuse prior to the Sotos syndrome diagnosis and the other with enlarged extra-axial cerebrospinal fluid spaces, demonstrating a possible mechanism for SDH development in this setting. These cases suggest that some individuals with Sotos syndrome may be at elevated risk of developing SDH in infancy and that Sotos syndrome should be on the differential diagnosis during a medical genetics evaluation in cases of unexplained SDH, especially in the setting of macrocephaly. [ABSTRACT FROM AUTHOR]

Although accurate intracranial pressure (ICP) monitoring is essential for the diagnosis and treatment of severe brain diseases, current methods are performed invasively. Therefore, a safe and less invasive ICP measurement is required. The purpose of our study was to develop a simplified cranial cavity model for a better understanding of the relationship between the ICP and the pressure measurement within the dural venous sinus (DVS) to support the validity of using sinus pressure as the surrogate of the ICP. The in-house cranial cavity model had three components: the brain part, the DVS part, and the subarachnoid space (SAS) part. Pressure in other parts was measured when the pressure in the SAS part and, separately, brain part was increased from 0 (baseline) to 50 mmHg at intervals of 10 mmHg. When the pressure in the SAS part was increased from 10 to 50 mmHg at 10 mmHg interval, pressures of both the brain and DVS parts increased without significant difference (all P > 0.05). However, pressures in both the SAS and DVS parts differed while the pressure in the brain part was increased. The pressures in both parts showed about 70% of the increase in the brain part. Nevertheless, the pressures in the SAS and DVS parts were not significantly different (P > 0.05). A simplified in-house cranial cavity model was developed consisting of three compartments to represent the actual intracranial spaces. The pressure measurement within the DVS was feasible to use as a surrogate for the ICP measurement. [ABSTRACT FROM AUTHOR]

CSF (Cerebro Spinal Fluid) rhinorrhoea occurs when the fluid leaks from subarachnoid space into the nasal cavity. The study aims to find out the prevalence and demographic distribution of CSF leak and to describe the site of the CSF leak along with the management. We did a prospective study on 180 patients admitted with head injury in neurosurgery department, along with the patients who came to ENT department with unilateral nasal discharge during the time period from March 2017 to March 2021. A total of 36 cases of CSF leak were obtained during the time period. The etiology in 18 cases was head injury & the other 18 cases were either due to infectious or nontraumatic causes. In our study, 26(72.22%) patients were aged less than 50 years. Incidence was more among males compared to females. The most common etiology was head injury - 18(50%) patients followed by the spontaneous leak- 16 (44.44%) patients with the most common site as the cribriform plate. Endoscopic repair using a hadad flap was done in most of the patients. Trauma due to head injury is the most common etiology in CSF rhinorrhea with more number of patients aged less than 50 years. Most of the leaks can be repaired successfully with the use of endoscope with excellent illumination & localizing the exact site of the leak. [ABSTRACT FROM AUTHOR]

This article discusses the surgical management and outcomes of pituitary adenomas with subarachnoid invasion. The study analyzed data from 321 patients who underwent an endoscopic endonasal approach for pituitary adenoma resection, and identified 13 patients with subarachnoid invasion. The surgical approach for these tumors involved careful dissection from surrounding neurovascular structures to achieve safe resection. Patients with subarachnoid invasion were more likely to have subtotal tumor resection and require additional treatment, such as medical therapy, radiation, or repeat resection. They also experienced higher rates of intra-operative CSF leak, postoperative diabetes insipidus, post-operative hematomas, and the need for adjuvant interventions. Overall, pituitary adenomas with subarachnoid invasion present unique challenges and require specialized surgical techniques. [Extracted from the article]

Retinal vessels have been good predictive and prognostic imaging biomarkers for systemic or eye diseases. Numerous studies have shown that the two retinal vein occlusion entities may correlate with cardiovascular and cerebrovascular events or primary open-angle glaucoma. This study aims to investigate if there is a disparity in the correlations between branch RVO (BRVO) and central RVO (CRVO) with systemic disorders or POAG, thus explaining the pathogenic difference between BRVO and CRVO. This retrospective case-control study enrolled 59 RVO subjects (118 eyes), including 25 CRVO and 34 BRVO subjects, who received routine eye and brain MRI examinations. The geometric characteristics of the caliber of the retinal and cerebral blood vessels and the optic nerve subarachnoid space width (ONSASW) were measured. Multivariable logistic regression analysis showed that ONSASW at 3 mm behind the globe (p = 0.044) and the relative retinal venular calibers (p = 0.031) were independent risk factors for the CRVO-affected eyes group in comparison with the BRVO-affected eyes group after adjusting for age, duration of hypertension, BMI, and IOP. In the CRVO-affected eyes, narrower relative retinal arteriolar calibers (p = 0.041) and wider relative venular calibers (p = 0.011) were independent risk factors compared with the CRVO-contralateral normal eyes when adjusting for IOP. We concluded that BRVO may be more associated with cerebrovascular diseases, and CRVO may be correlated with primary angle glaucoma. The geometric characteristics difference between the retinal and cerebrovascular may explain the pathological difference between CRVO and BRVO. [ABSTRACT FROM AUTHOR]

Introduction: The nematode Gurltia paralysans is a neglected angio-neurotropic parasite causing chronic meningomyelitis in domestic cats (Felis catus) as well as wild felids of the genus Leopardus in South America. Adult G. paralysans nematodes parasitize the leptomeningeal veins of the subarachnoid space and/ or meningeal veins of the spinal cord parenchyma. The geographic range of G. paralysans encompasses rural and peri-urban regions of Chile, Argentina, Uruguay, Colombia and Brazil. Methods: This case report presents clinical and pathological findings of a G. paralysans-infected cat suffering from severe thrombophlebitis and meningomyelitis resulting in ambulatory paraparesis. Neurological examination of affected cat localized the lesions at the thoracolumbar (T3--L3) and lumbosacral (L4--Cd4) segments. Molecular and morphological characteristics of extracted nematodes from parasitized spinal cord veins confirmed G. paralysans. Additionally, data obtained from a questionnaire answered by cat owners of 12 past feline gurltiosis cases (2014--2015) were here analyzed. Questionnaire collected data on age, gender, geographic location, type of food, hunting behavior, type of prey, and other epidemiological features of G. paralysans-infected cats. Results and Discussion: Data revealed that the majority of cats originated from rural settlements thereby showing outdoor life styles with hunting/predatory behaviors, being in close contact to wild life [i.e. gastropods, amphibians, reptiles, rodents, birds, and wild felids (Leopardus guinia)] and with minimal veterinary assistance. Overall, this neglected angio-neurotropic G. paralysans nematode still represents an important etiology of severe thrombophlebitis and meningomyelitis of domestic cats living in endemic rural areas with high biodiversity of definitive hosts (DH), intermediary (IH), and paratenic hosts (PH). The intention of this study is to generate awareness among veterinary surgeons as well as biologists on this neglected feline neuroparasitosis not only affecting domestic cats but also endangered wild felid species of the genus Leopardus within the South American continent. [ABSTRACT FROM AUTHOR]

Background: The subarachnoid space is continuous with the perivascular compartment in the central nervous system. However, whether the topography and severity of enlarged perivascular spaces (EPVS) correlates with spontaneous subarachnoid hemorrhage (SAH) remains unknown. Based on the underlying arteriopathy distributions, we hypothesized that EPVS in basal ganglia (BGEPVS) are more closely associated with aneurysmal subarachnoid hemorrhage (aSAH) than other SAH without aneurysm. Methods: Magnetic resonance imaging (MRI) scans of 271 consecutive SAH survivors with and without aneurysm were analyzed for EPVS and other markers of imaging data. In the subgroup analysis, we compared the clinical characteristics and EPVS of SAH participants with and without pre-existing known risk factors (hypertension, diabetes, and smoking history) using multivariable logistic regression. Results: Patients with aSAH (n = 195) had a higher severity of BG-EPVS and centrum semiovale EPVS (CSO-EPVS) than those without aneurysm (n = 76). Importantly, BG-EPVS predominance pattern (BG-EPVS>CSO-EPVS) only existed in aSAH survivors rather than other SAH without aneurysm. In the subgroup analysis, interestingly, we also found that a high degree of BG-EPVS showed an independent relationship with aSAH in patients without pre-existing risk factors (e.g., hypertension). Conclusion: In this cohort study, BG-EPVS predominance pattern was associated with aSAH patients compared with those without aneurysm. Moreover, BGEPVS still showed a strong association with aSAH survivors without pre-existing vascular risk factors. Our present study suggested the BG-EPVS as a potential MRI-visible characteristic would shed light on the pathogenesis of glymphatic function at the skull base for aSAH. [ABSTRACT FROM AUTHOR]

The elevation in the optic nerve sheath (ONS) pressure (ONSP) due to microgravity-induced headward fluid shift is the primary hypothesized contributor to SANS. This longitudinal study aims to quantify the axial plane of the optic nerve subarachnoid space area (ONSSA), which is filled with cerebrospinal fluid (CSF) and expands with elevated ONSP during and after head-down tilt (HDT) bed rest (BR). 36 healthy male volunteers (72 eyes) underwent a 90-day strict 6° HDT BR. Without obtaining the pre-HDT data, measurements were performed on days 30, 60, and 90 during HDT and at 6 recovery time points extended to 180-days (R + 180) in a supine position. Portable B-scan ultrasound was performed using the 12 MHz linear array probe binocularly. The measurements of the ONS and the calculation of the ONSSA were performed with ImageJ 1.51 analysis software by two experienced observers in a masked manner. Compared to R + 180, the ONSSA on HDT30, HDT60, and HDT90 exhibited a consistently significant distention of 0.44 mm2 (95% CI: 0.13 to 0.76 mm2, P = 0.001), 0.45 mm2 (95% CI: 0.15 to 0.75 mm2, P = 0.001), and 0.46 mm2 (95% CI: 0.15 to 0.76 mm2, P < 0.001), respectively, and recovered immediately after HDT on R + 2. Such small changes in the ONSSA were below the lateral resolution limit of ultrasound (0.4 mm) and may not be clinically relevant, possibly due to ONS hysteresis causing persistent ONS distension. Future research can explore advanced quantitative portable ultrasound-based techniques and establish comparisons containing the pre-HDT measurements to deepen our understanding of SANS. [ABSTRACT FROM AUTHOR]

Background: CSF has long been accepted to circulate throughout the subarachnoid space, which lies between the arachnoid and pia maters of the meninges. How the CSF interacts with the cellular components of the developing postnatal meninges including the dura, arachnoid, and pia of both the meninges at the surface of the brain and the intracranial meninges, prior to its eventual efflux from the cranium and spine, is less understood. Here, we characterize small and large CSF solute distribution patterns along the intracranial and surface meninges in neonatal rodents and compare our findings to meningeal CSF solute distribution in a rodent model of intraventricular hemorrhage-posthemorrhagic hydrocephalus. We also examine CSF solute interactions with the tela choroidea and its pial invaginations into the choroid plexuses of the lateral, third, and fourth ventricles. Methods: 1.9-nm gold nanoparticles, 15-nm gold nanoparticles, or 3 kDa Red Dextran Tetramethylrhodamine constituted in aCSF were infused into the right lateral ventricle of P7 rats to track CSF circulation. 10 min post-1.9-nm gold nanoparticle and Red Dextran Tetramethylrhodamine injection and 4 h post-15-nm gold nanoparticle injection, animals were sacrificed and brains harvested for histologic analysis to identify CSF tracer localization in the cranial and spine meninges and choroid plexus. Spinal dura and leptomeninges (arachnoid and pia) wholemounts were also evaluated. Results: There was significantly less CSF tracer distribution in the dura compared to the arachnoid and pia maters in neonatal rodents. Both small and large CSF tracers were transported intracranially to the arachnoid and pia mater of the perimesencephalic cisterns and tela choroidea, but not the falx cerebri. CSF tracers followed a similar distribution pattern in the spinal meninges. In the choroid plexus, there was large CSF tracer distribution in the apical surface of epithelial cells, and small CSF tracer along the basolateral surface. There were no significant differences in tracer intensity in the intracranial meninges of control vs. intraventricular hemorrhage-posthemorrhagic hydrocephalus (PHH) rodents, indicating preserved meningeal transport in the setting of PHH. Conclusions: Differential CSF tracer handling by the meninges suggests that there are distinct roles for CSF handling between the arachnoid-pia and dura maters in the developing brain. Similarly, differences in apical vs. luminal choroid plexus CSF handling may provide insight into particle-size dependent CSF transport at the CSF-choroid plexus border. [ABSTRACT FROM AUTHOR]

Low-pressure hydrocephalus (LPH) is a serious disease characterized by ventricular dilatation and clinical signs of intracranial hypertension, although the pressure of the cerebrospinal fluid (CSF) in the cerebral ventricles is below the normal range. The pathophysiology of LPH remains complex and not fully understood, but it seems that a combination of mechanisms involving isolation of the ventricular system from the subarachnoid space, changes in brain tissue elasticity and compliance, and increased brain tissue permeability may play a key role. The diagnosis of LPH should be considered in patients with clinical signs of intracranial hypertension and ventricular dilatation on imaging with preserved patent CSF drainage and normal pressure settings. Treatment of LPH includes temporary therapy to ensure patient stabilization with external ventricular drainage and gradual weaning from drainage with the use of increasing intracranial pressure. Permanent treatment includes endoscopic ventriculostomy of the third ventricle and implantation of a shunt with a low differential pressure setting. The choice of the type of shunt may be individualized; only the lumbo-peritoneal type is not recommended. It should be emphasized that recognition and proper treatment of LPH are crucial, as improper treatment can lead to fatal consequences. Despite the ongoing challenges in the diagnosis and treatment of LPH, it is important that the disease is well known to the professional community. [ABSTRACT FROM AUTHOR]

Idiopatic normal pressure hydrocephalus (iNPH) is a progressive neurologic syndrome featured by the triad of gait disturbance, mental deterioration and urinary incontinence, associated with ventriculomegaly and normal cerebrospinal fluid (CSF) pressure. The clinical presentation may be atypical or incomplete, or mimicked by other diseases, so conventional neuroradiologic imaging plays an important role in defining this pathology. iNPH pathophysiologic mechanisms have not yet been fully elucidated, although several studies have demonstrated the involvement of the glymphatic system, a highly organized fluid transport system, the malfunction of which is involved in the pathogenesis of several disorders including normotensive hydrocephalus. Recent studies have shown how crucial in the diagnosis of this pathology is the definition of morphologic biomarkers, such as ventricular enlargement disproportionate to cerebral atrophy and associated ballooning of frontal horns; periventricular hyperintensities; and corpus callosum thinning and elevation, with callosal angle <90 degrees. Another interesting feature that is becoming a well-recognized factor to look for and useful for the diagnosis of iNPH is disproportionately enlarged subarachnoid space hydrocephalus, which includes enlarged ventricles, tight high-convexity and medial surface subarachnoid spaces, and expanded Sylvian fissures. A correct choice of MRI sequences is important for a proper characterization identification of others diseases that may underlie this pathology. Magnetic resonance imaging allows us to evaluate CSF flow, enabling us to define qualitative and quantitative parameters necessary for the purpose of accurate iNPH diagnosis. iNPH can represent a real diagnostic challenge; a proper correlation among clinical features, traditional MRI, and CSF dynamics analysis can lead to a correct diagnosis. [ABSTRACT FROM AUTHOR]

Giant pituitary adenomas (>4 cm, GPAs) have presented great challenges to surgeons because the residual tumor in the subarachnoid space can cause hemorrhage or vessel injury following apoplexy. This study aimed to investigate the factors limiting surgical success in endoscopic skull base surgery (ESS) for GPAs. ESS was performed on 67 consecutive patients with GPAs from 2010 to 2020. We retrospectively analyzed the clinical and radiologic features and surgical outcomes. Correlations between the tumor characteristics and extent of resection were statistically presented with odds ratios (ORs). Preoperative visual and hormonal impairments were present in 59 (88.1%) and 55 patients (82.1%), respectively. Gross total resection (GTR) was achieved in 58.2% of patients, and the tumor remained on the lateral side of the subarachnoid space or the cavernous sinus when complete resection failed. The tumor volume, maximal diameter, multilobulated shape, cavernous sinus invasion, posterior fossa extension, and extent of suprasellar lateral extension of tumors were significantly correlated with incomplete resection. In tumors with subarachnoid lateral extension, greater distances from the medial wall of the proximal cavernous internal carotid artery to the most lateral tumor significantly increased the risk of incomplete resection for the suprasellar lateral portion of the tumor, with an OR of 1.21. Considerable surgical planning in ESS for GPAs is crucial for complete resection and patient safety. We elucidated that lateral extension of tumors in the subarachnoid space hindered the surgical success of the suprasellar portion of the tumor. [ABSTRACT FROM AUTHOR]

Purpose: Idiopathic intracranial hypertension (IIH) is a clinical syndrome that mimics brain tumors with increased intracranial pressure. The present study is designed to investigate the diagnostic criteria of magnetic resonance imaging (MRI) and the severity of cerebrospinal fluid (CSF) pressure to understand the relationship and frequency of these criteria with the level of CSF pressure. Methods: The present cross-sectional study was conducted on children diagnosed with IIH between the years 2011 and 2020, who were admitted to the pediatric neurology department of Ghaem Hospital, Mashhad, Iran. Clinical manifestations and imaging findings of the patients were recorded through a checklist. Results: Forty-nine patients were included in the study; 27 (55.1%) were male, and 22 (44.9%) were female. The average CSF pressure was 40.64±20.63 cmH2O. The mean diameter distension of the perioptic subarachnoid space was 6.02±1.21 mm. Six (10.8%) patients had unilateral transverse sinus stenosis with an average CSF pressure of 20.47±36.80 cmH2O and 11 (21.4%) patients had bilateral transverse sinus stenosis with an average pressure of 48.22±21.04 cmH2O. In 22 (44.89%) patients, flattening of the posterior globe with the CSF pressure of 48.80±17.94 cmH2O was reported. Twenty-four (49%) patients had optic nerve tortuosity, with an average CSF pressure of 46.52±20.33 cmH2O. Among the diagnostic criteria, the pressure had a significant relationship with the flattening of the posterior globe (P<0.022). Conclusion: Since MRI is a non-invasive method for examining IIH, the findings of this study may aid in diagnosing and monitoring these patients. [ABSTRACT FROM AUTHOR]

Introduction: Baricity determines the spread of local anaesthetic agent in the cerebrospinal fluid. Hyperbaric bupivacaine was widely used for sub-arachnoid blockade. Levobupivacaine is S-enantiomer of racemic bupivacaine. There are studies where isobaric levobupivacaine is converted to hyperbaric form by adding dextrose solution. Recently there is availability of preformed hyperbaric levobupivacaine with 8% glucose. Aims and objectives: We have done this study with primary objective to compare the sensory and motor blockade characteristics of preformed hyperbaric levobupivacaine with hyperbaric bupivacaine, after subarachnoid block, among the patients posted for infraumblical surgeries. Secondary objective is to compare the haemodynamic stability and post-operative analgesia duration. Methods and methodology: This is a prospective, randomized, controlled, double blinded clinical trial. 200 patients posted for infraumblical surgeries were randomly allocated in two groups. Group-B and Group-L received preformed HB and HB respectively with 0.2 ml buprenorphine. Sensory and motor blockade characteristics, analgesia duration and patients with hypotension were noted down. Result: There was no statistical significant difference in the sensory and motor blockade characteristics between HB and HL like sensory onset time (HB-111.9± 49.75 s; HL-111.9± 49.75 s; P=0.789); motor onset time (HB-128.87± 78.13 s; HL 123.76± 87.83 s; P=0.664); maximum sensory level attained (HB-7.04± 1.59 and HL-7.16± 1.58; P=0.594); time taken for maximum sensory block (HB-365.6± 108.6 s; HL-361.95±97.86 s; P=0.803) and maximum motor blockade (HB-451±133.7 s; HL-450.95± 121.86 s; P=0.997). Post-operative analgesia duration (HB-249.55±70.7 min; HL-270.7±92.9 min, P=0.072) and patients with hypotension were HB-19% and HL-17% was also not statistically significant (P=0.713). Conclusion: Preformed HL with buprenorphine is also a safe and better choice for spinal anaesthesia in infraumblical surgeries like HB because of its similar sensory blockade, motor blockade and haemodynamic effects as with preformed HB with buprenorphine. [ABSTRACT FROM AUTHOR]

Introduction: Spinal Anaesthesia (SA) has stood as the most favoured and dependable technique in regional anaesthesia for the past century. However, despite its widespread use, there are instances of occasional SA failure. Currently, there is no straightforward, cost-effective, and easily administered real-time test-aside from the positive aspiration of Cerebrospinal Fluid (CSF)-that can reliably confirm the deposition of local anaesthetic in the subarachnoid space. Aim: To evaluate the predictive value of subjective sensations (warmth/tingling/numbness) during the administration of SA for enhancing success rates. Materials and Methods: A prospective observational study preceeded the recruitment of 500 patients for this investigation. Following the confirmation of CSF aspiration upon injecting the SA drug, Bupivacaine, patients were queried about the sensations of warmth and/or tingling numbness in the lower limb, saddle part, and inner thighs. This assessment was conducted at 30 seconds and one minute after injection. Additionally, patients were asked to report any increase in the area and/or intensity of these sensations. The adequacy of SA was determined by achieving a sensory block upto the desired dermatome level and reaching a Bromage scale score of IV. Evaluations were performed at two minutes, five minutes, 10 minutes, and 15 minutes from the initiation of SA. Results: The population, predominantly ASA Class-I (60%) and II (40%), exhibited a median age of 45 years, with 54% being male. Intraoperative vital signs, including Heart Rate (HR), Systolic Blood Pressures (SBP), and Diastolic Blood Pressures (DBP), showed a consistent declining trend post-SA administration. Efficacy assessments revealed that Bromage Grade-IV was achieved in 99% of patients at 15 minutes. Notably, subjective sensations of warmth, tingling, and/or numbness proved to be robust predictors of successful SA, with a 218-fold increased likelihood. The diagnostic model demonstrated a high sensitivity of 98%, specificity of 85%, and a Positive Predictive Value (PPV) exceeding 99%. Conclusion: This study highlights the crucial role of warmth, tingling, and numbness as reliable indicators for successful SA, supported by a robust 97% success rate. Incorporating these patient-reported sensations in assessments provides a practical and accessible approach to improve the efficacy of SA procedures. [ABSTRACT FROM AUTHOR]

Background: CSF dynamics are disturbed in chronic hydrocephalus (NPH). We hypothesise that these alterations reflect a disturbance of intracranial compliance. The aim of our study is to investigate the variations in intracranial hydrodynamics in NPH after ventricular shunt surgery. Patients and method: We included 14 patients with definite NPH. All patients improved after ventriculoperitoneal shunting. The patients underwent an analysis of intracranial haemodynamics by phase-contrast MRI (pcMRI) preoperatively, at 6 months postoperatively, and at 1 year postoperatively. We analysed the dynamics of intraventricular CSF at the level of the aqueduct of Sylvius (SVAQU) and CSF at the level of the high cervical subarachnoid spaces (SVCERV). We calculated the ratio between SVAQU and SVCERV, called CSFRATIO, which reflects the participation of intraventricular pulsatility in overall intracranial CSF pulsatility. Results: SVAQU significantly (p = 0.003) decreased from 240 ± 114 μL/cc to 214 ± 157 μL/cc 6 months after shunt placement. Six months after shunt placement, SVCERV significantly (p = 0.007) decreased from 627 ± 229 μL/cc to 557 ± 234 μL/cc. Twelve months after shunt placement, SVCERV continued to significantly (p = 0.001) decrease to 496 ± 234 μL/cc. CSFRATIO was not changed by surgery. Conclusions: CSF dynamics are altered by shunt placement and might be a useful marker of the shunt's effectiveness—especially if pressure values start to rise again. The detection of changes in CSF dynamics would require a reference postoperative pcMRI measurement for each patient. [ABSTRACT FROM AUTHOR]

Background: Epidermoid cysts (ECs) are rare benign tumors arising from epidermal cells, associated with congenital abnormalities or acquired through trauma, surgery, or lumbar punctures. They represent <1% of all intraspinal tumors and may be associated with limited dorsal myeloschisis (LDM). Case Description: A 7-year-old neurologically intact male had a dorsal skin mass since birth located posteriorly in the midline of the inferior thoracic spine. The mass was palpable, painless, mobile, vascularized, and could be transilluminated. Thoracic magnetic resonance imaging showed an extensive intradural extramedullary cystic lesion extending from D6 to D8 that did not enhance with contrast, accompanied by a subcutaneous fluid collection at D8-D9 communicating with the subarachnoid space. The patient underwent gross total resection of the lesion, pathologically confirmed as an EC. The postoperative course was uneventful, with no recurrence 1 year postoperatively. Conclusion: LDM may be associated with ECs. Early diagnosis and surgical resection of these lesions are essential for favorable outcomes. [ABSTRACT FROM AUTHOR]

Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4th meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1–3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations. [ABSTRACT FROM AUTHOR]

Normal pressure hydrocephalus (NPH) patients had altered white matter tract integrities on diffusion tensor imaging (DTI). Previous studies suggested disproportionately enlarged subarachnoid space hydrocephalus (DESH) as a prognostic sign of NPH. We examined DTI indices in NPH subgroups by DESH severity and clinical symptoms. This retrospective case–control study included 33 NPH patients and 33 age-, sex-, and education-matched controls. The NPH grading scales (0–12) were used to rate neurological symptoms. Patients with NPH were categorized into two subgroups, high-DESH and low-DESH groups, by the average value of the DESH scale. DTI indices, including fractional anisotropy, were compared across 14 regions of interest (ROIs). The high-DESH group had increased axial diffusivity in the lateral side of corona radiata (1.43 ± 0.25 vs. 1.72 ± 0.25, p = 0.04), and showed decreased fractional anisotropy and increased mean, and radial diffusivity in the anterior and lateral sides of corona radiata and the periventricular white matter surrounding the anterior horn of lateral ventricle. In patients with a high NPH grading scale, fractional anisotropy in the white matter surrounding the anterior horn of the lateral ventricle was significantly reduced (0.36 ± 0.08 vs. 0.26 ± 0.06, p = 0.03). These data show that DESH may be a biomarker for DTI-detected microstructural alterations and clinical symptom severity. [ABSTRACT FROM AUTHOR]

Leptomeningeal metastases/diseases (LMDs) are a late-stage complication of solid tumor or hematologic malignancies. LMD is spread of cancer cells to the layers of the leptomeninges (pia and arachnoid maters) and subarachnoid space seen in 3 to 5% of cancer patients. It is a disseminated disease which carries with it significant neurologic morbidity and mortality. Our understanding of disease pathophysiology is currently lacking; however, advances are being made. As our knowledge of disease pathogenesis has improved, treatment strategies have evolved. Mainstays of treatment such as radiotherapy have changed from involved-field radiotherapy strategies to proton craniospinal irradiation which has demonstrated promising results in recent clinical trials. Systemic treatment strategies have also improved from more traditional chemotherapeutics with limited central nervous system (CNS) penetration to more targeted therapies with better CNS tumor response. Many challenges remain from earlier clinical detection of disease through improvement of active treatment options, but we are getting closer to meaningful treatment. [ABSTRACT FROM AUTHOR]

Labyrinthitis ossificans is the formation of pathological new bone within the membranous labyrinth of the inner ear due to various local and systemic pathologies. Most commonly it occurs as a sequelae of meningitis spreading to the labyrinth, from the subarachnoid space via the cochlear aqueduct and the internal auditory canal. We are comparing three different etiological presentations of labyrinthitis ossificans; namely, tympanogenic, meningitic, and traumatic, together with their management in the light of recent advances. [ABSTRACT FROM AUTHOR]

Key Clinical Message: In patients with appropriate epidemiological risk factors, neurocysticecosis should be considered as part of the differential diagnosis of suprasellar or parasellar mass lesions. As neuroimaging findings can be nonspecific, serology may be helpful, but when still in doubt, brain biopsy, and histopathology may be necessary to make the correct diagnosis. Neurocysticercosis (NCC) is a well‐documented central nervous system helminth infection that is, frequently observed in developing countries. Known sites of NCC infection include the highly vascular gray‐white matter junction, basal cistern, brain parenchyma, subarachnoid space, ventricular system, and spinal cord. This case highlights an uncommon yet intriguing site of NCC infection within the suprasellar area, which presented with similar clinical and imaging characteristics as suprasellar masses or lesions. The 44‐year‐old female initially complained of headaches and nausea that persisted for 5 years and progressed to vision problems and short‐term memory loss. A craniopharyngioma was initially suspected, based on imaging findings of a partially calcified suprasellar tumor. However, cysticercosis was confirmed by histopathology and serological testing positive for Cysticercus IgG antibodies. The patient was successfully treated with albendazole and tapering doses of steroids, which improved her presenting symptoms and resolved prior imaging findings. This case serves as a reminder to consider NCC in the differential diagnosis of sellar and suprasellar masses or lesions, particularly when an epidemiologic risk factor is present. [ABSTRACT FROM AUTHOR]

Background: The study aimed to investigate the effects of spinal anaesthesia on patients with hypotension and bradycardia. The procedure was uneventful, with no conversions from spinal to general anaesthesia. The study found significant variations in pulse rate after spinal and during GB handling in group S, which may be due to vagal stimulation or hemodynamic response to laryngoscopy and intubation. Bradycardia was an expected side effect due to rapid peritoneal stretch and vagal stimulation in laparoscopic cholecystectomy operations. The incidence of bradycardia was 11.43% and 2.86% in group S and group G, respectively. Aim and objectives: Hypotension and bradycardia were easily managed with inj. Mephentermine and inj. Atropine, respectively. Pre-anaesthetic hydration with 10ml/kg of ringer lactate prevented repeated hypotension occurrences. The decrease in pulse rate and BP in group S was due to the residual analgesic effect of local anaesthetic in subarachnoid space. Methods: Shore tip pain was a significant intraoperative problem caused by the irritation of the subdiaphragmatic area with CO2. Previous studies have shown that maintaining intraabdominal pressure below 10 mmHg reduces right shoulder pain and respiratory distress due to diaphragm irritation. However, the study's high intraabdominal pressure created during pneumoperitoneum affected hemodynamic values negatively and contributed to shoulder pain. Results: The surgical team was satisfied with sufficient abdominal relaxation during the operation in spinal anaesthesia. However, further studies with a larger sample size may be conducted to support observations. All patients in the spinal anaesthesia group remained awake and oriented at the end of surgery, with a smooth transition of pain in the postoperative period. Avoidance of GA and opioids contributed to the lack of deterioration in cognitive function. [ABSTRACT FROM AUTHOR]

Purpose: To quantify the T1 and T2 values of CSF in the subarachnoid space (SAS) at 3 T and interpret them in the context of water exchange between CSF and brain tissues. Methods: CSF T1 was measured using inversion recovery, and CSF T2 was assessed using T2‐preparation. T1 and T2 values in the SAS were compared with those in the frontal horns of lateral ventricles, which have less brain‐CSF exchange. Phantom experiments were performed to examine whether there were spatial variations in T1 and T2 that were unrelated to brain‐CSF exchange. Simulations were conducted to investigate the relationship between the brain‐CSF exchange rate and the apparent T1 and T2 values of SAS CSF. Results: The CSF T1 and T2 values were 4308.7 ± 146.9 ms and 1885.5 ± 67.9 ms, respectively, in the SAS and were 4454.0 ± 187.9 ms and 2372.9 ± 72.0 ms in the frontal horns. The SAS CSF had shorter T1 (p = 0.006) and T2 (p < 0.0001) than CSF in the frontal horns. Phantom experiments showed negligible (< 6 ms for T1; < 1 ms for T2) spatial variations in T1 and T2, suggesting that the T1 and T2 differences between SAS and frontal horns were largely attributed to physiological reasons. Simulations revealed that faster brain‐CSF exchange rates lead to shorter apparent T1 and T2 of SAS CSF. However, the experimentally observed T2 difference between SAS and frontal horns was greater than that attributable to typical exchange effect, suggesting that the T2 shortening in SAS may reflect a combined effect of exchange and deoxyhemoglobin susceptibility. Conclusion: Quantification of SAS CSF relaxation times may be useful to assess the brain‐CSF exchange. [ABSTRACT FROM AUTHOR]

The occurrence of early brain injury (EBI) significantly contributes to the unfavorable prognosis observed in patients with subarachnoid hemorrhage (SAH). During the process of EBI, a substantial quantity of iron permeates into the subarachnoid space and brain tissue, thereby raising concerns regarding its metabolism. To investigate the role and metabolic processes of excessive iron in neurons, we established both in vivo and in vitro models of SAH. We substantiated that ferritinophagy participates in iron metabolism disorders and promotes neuronal ferroptosis using an in vivo model, as detected by key proteins such as ferritin heavy chain 1, glutathione peroxidase 4, autophagy related 5, nuclear receptor coactivator 4 (NCOA4), LC3B, and electron microscopy results. By interfering with NCOA4 expression in vitro and in vivo, we confirmed the pivotal role of elevated NCOA4 levels in ferritinophagy during EBI. Additionally, our in vitro experiments demonstrated that the addition of oxyhemoglobin alone did not result in a significant upregulation of NCOA4 expression. However, simultaneous addition of oxyhemoglobin and hypoxia exposure provoked a marked increase in NCOA4 expression and heightened ferritinophagy in HT22 cells. Using YC-1 to inhibit hypoxia signaling in in vitro and in vitro models effectively attenuated neuronal ferroptosis. Collectively, we found that the hypoxic microenvironment during the process of EBI exaggerates iron metabolism abnormalities, leading to poor prognoses in SAH. The findings also offer a novel and potentially effective foundation for the treatment of SAH, with the aim of alleviating hypoxia. [ABSTRACT FROM AUTHOR]

Background Endovascular therapy has revolutionized the treatment of cerebral aneurysms in recent years and decades. So-called intrasaccular devices (i.e., Woven EndoBridge [WEB], MicroVention, Aliso Viejo, California, United States; or Contour, Cerus Neurovascular, Fremont, California, United States) are a promising endovascular technology, especially for wide-based aneurysms. However, long-term outcome data are currently particularly scarce for Contour and strategies for failed Contour cases are lacking. Here, we report the feasibility of microsurgical clipping after failed Contour device embolization. Methods Feasibility of microsurgical clipping after failed aneurysm embolization with a Contour intrasaccular device was assessed in a patient. Results We present the case of a 36-year-old male patient diagnosed with Hunt and Hess grade 1 subarachnoid hemorrhage from an anterior communicating artery aneurysm. The ruptured aneurysm was initially treated with the Contour device. After 3 months, angiographic imaging showed a clear aneurysm residual deemed not endovascularly accessible. The patient was then successfully clipped using microsurgical techniques. The patient was discharged with no neurologic abnormalities. Conclusion After thorough bibliographical research, this presents the first published case report of microsurgical clipping after failed embolization with Contour. The main insights gained after clipping were that the Contour does not significantly disturb or hinder clipping. In contrast to coils in aneurysms to be clipped, the Contour can be easily compressed by the clip blades and does not have to be removed. In addition, the Contour had not migrated into the subarachnoid space and there was no abnormal scarring. Clipping appears to be a reasonable treatment strategy for failure of embolization with Contour if endovascular means are not suitable. [ABSTRACT FROM AUTHOR]