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Gastroenterology Mar 2021Hepatic encephalopathy (HE) is a serious neurologic complication in patients with liver cirrhosis. Very little is known about the role of the meningeal lymphatic system...
BACKGROUND & AIMS
Hepatic encephalopathy (HE) is a serious neurologic complication in patients with liver cirrhosis. Very little is known about the role of the meningeal lymphatic system in HE. We tested our hypothesis that enhancement of meningeal lymphatic drainage could decrease neuroinflammation and ameliorate HE.
METHODS
A 4-week bile duct ligation model was used to develop cirrhosis with HE in rats. Brain inflammation in patients with HE was evaluated by using archived GSE41919. The motor function of rats was assessed by the rotarod test. Adeno-associated virus 8-vascular endothelial growth factor C (AAV8-VEGF-C) was injected into the cisterna magna of HE rats 1 day after surgery to induce meningeal lymphangiogenesis.
RESULTS
Cirrhotic rats with HE showed significantly increased microglia activation in the middle region of the cortex (P < .001) as well as increased neuroinflammation, as indicated by significant increases in interleukin 1β, interferon γ, tumor necrosis factor α, and ionized calcium binding adaptor molecule 1 (Iba1) expression levels in at least 1 of the 3 regions of the cortex. Motor function was also impaired in rats with HE (P < .05). Human brains of patients with cirrhosis with HE also exhibited up-regulation of proinflammatory genes (NFKB1, IbA1, TNF-α, and IL1β) (n = 6). AAV8-VEGF-C injection significantly increased meningeal lymphangiogenesis (P = .035) and tracer dye uptake in the anterior and middle regions of the cortex (P = .006 and .003, respectively), their corresponding meninges (P = .086 and .006, respectively), and the draining lymph nodes (P = .02). Furthermore, AAV8-VEGF-C decreased microglia activation (P < .001) and neuroinflammation and ameliorated motor dysfunction (P = .024).
CONCLUSIONS
Promoting meningeal lymphatic drainage and enhancing waste clearance improves HE. Manipulation of meningeal lymphangiogenesis could be a new therapeutic strategy for the treatment of HE.
Topics: Animals; Cell Line; Cerebral Cortex; Cisterna Magna; Dependovirus; Disease Models, Animal; Genetic Vectors; Glymphatic System; Hepatic Encephalopathy; Humans; Liver Cirrhosis; Lymphangiogenesis; Male; Microglia; Motor Disorders; Rats; Vascular Endothelial Growth Factor C
PubMed: 33227282
DOI: 10.1053/j.gastro.2020.11.036 -
Clinical Anatomy (New York, N.Y.) Jan 2021The motion of the brain relative to the skull is influenced by the architecture of the subarachnoid space (SAS), and in particular, by the arachnoid trabeculae. In...
INTRODUCTION
The motion of the brain relative to the skull is influenced by the architecture of the subarachnoid space (SAS), and in particular, by the arachnoid trabeculae. In previous studies of these structures, specific shapes were identified. However, the work presented here shows much finer detail of the SAS geometries using SEM and TEM.
MATERIALS AND METHODS
These images were acquired by maintaining the SAS structure of a rat using glutaraldehyde formaldehyde to strengthen the tissues via crosslinking with the biological proteins.
RESULTS
The results showed the detailed shape of five dominant arachnoid trabeculae structures: single strands, branched strands, tree like shapes, sheets, and trabecular networks. Each of these architectures would provide a different response when exposed to a tensile load and would provide different levels of resistance to the flow of the cerebrospinal fluid (CSF) within the SAS.
CONCLUSION
This very detailed level of geometric information will therefore allow more accurate finite element models of the SAS to be developed.
Topics: Animals; Meninges; Microscopy, Electron; Rats; Rats, Sprague-Dawley; Subarachnoid Space
PubMed: 32519396
DOI: 10.1002/ca.23635 -
Neurosurgical Review Aug 2022Despite advances in cerebrospinal fluid shunting technology, complications remain a significant concern. There are some contradictions about the effectiveness of... (Review)
Review
Despite advances in cerebrospinal fluid shunting technology, complications remain a significant concern. There are some contradictions about the effectiveness of proximal catheter entry sites that decrease shunt failures. We aim to compare efficiency of shunts with ventricular frontal, ventricular occipital, and cisterna magna entry sites. The systemic search was conducted in the database from conception to February 16, 2022 following guidelines of PRISMA. Between 2860 identified articles, 24 articles including 6094 patients were used for data synthesis. The aggregated results of all patients showed that "overall shunt failure rate per year" in mixed hydrocephalus with ventricular frontal and occipital shunts, and cisterna magna shunt (CMS) were 9.0%, 12.6%, and 30.7%, respectively. The corresponding values for "shunt failure rate" due to obstruction were 15.3%, 31.5%, and 10.2%, respectively. The similar results for "shunt failure rate" due to infection were 11.3%, 9.1%, and 27.2%, respectively. The related values for "shunt failure rate" due to overdrainage were 2.9%, 3.9%, and 13.6%, respectively. CMS was successful in the immediate resolution of clinical symptoms. Shunting through an occipital entry site had a greater likelihood of inaccurate catheter placement and location. Contrary to possible shunt failure due to overdrainage, the failure likelihood due to obstruction and infection in pediatric patients was higher than that of mixed hydrocephalus patients. In both mixed and pediatric hydrocephalus, obstruction and overdrainage were the most and least common complications of ventricular frontal and occipital shunts, respectively. The most and least common complications of mixed CMS were infection and obstruction, respectively.
Topics: Cerebrospinal Fluid Shunts; Child; Cisterna Magna; Equipment Failure; Humans; Hydrocephalus; Neurosurgical Procedures
PubMed: 35513737
DOI: 10.1007/s10143-022-01798-0 -
Journal of Magnetic Resonance Imaging :... Sep 2021Prior imaging studies characterizing lumbar arachnoiditis have been based on small sample numbers and have reported inconsistent results.
BACKGROUND
Prior imaging studies characterizing lumbar arachnoiditis have been based on small sample numbers and have reported inconsistent results.
PURPOSE
To review the different imaging patterns of lumbosacral arachnoiditis, their significance, and clinical implications.
STUDY TYPE
Retrospective.
POPULATION
A total of 96 patients (43 women; average age 61.3 years) with imaging findings of arachnoiditis (postsurgical: N = 49; degenerative: N = 29; vertebral fracture: N = 6; epidural and subdural hemorrhage: N = 3, infectious: N= 1; other: N = 8) from January 2009 to April 2018.
FIELD STRENGTH/SEQUENCE
Sagittal and axial T2-weighted Turbo Spin Echo at 1.5 T and 3 T.
ASSESSMENT
Chart review was performed to assess the cause of arachnoiditis, and imaging was reviewed by two musculoskeletal and three neurology radiologists, blinded to the clinical data and to each other's imaging interpretation. Previous classification included a three-group system based on the appearance of the nerve roots on T2-weighted images. A fourth group was added in our review as "nonspecified" and was proposed for indeterminate imaging findings that did not fall into the classical groups. The presence/absence of synechiae/fibrous bands that distort the nerve roots and of spinal canal stenosis was also assessed.
STATISTICAL TESTS
The kappa score was used to assess agreement between readers for both classification type and presence/absence of synechiae.
RESULTS
Postsurgical (51%) and degenerative changes (30%) were the most common etiologies. About 7%-55% of arachnoiditis were classified as group 4. There was very poor classification agreement between readers (kappa score 0.051). There was also poor interreader agreement for determining the presence of synechiae (kappa 0.18) with, however, strong interreader agreement for the presence of synechia obtained between the most experienced readers (kappa 0.89).
DATA CONCLUSION
This study demonstrated the lack of consensus and clarity in the classification system of lumbar arachnoiditis. The presence of synechia has high interreader agreement only among most experienced readers and promises to be a useful tool in assessing arachnoiditis.
EVIDENCE LEVEL
3 TECHNICAL EFFICACY: Stage 2.
Topics: Arachnoiditis; Female; Humans; Lumbar Vertebrae; Magnetic Resonance Imaging; Middle Aged; Reproducibility of Results; Retrospective Studies
PubMed: 33644967
DOI: 10.1002/jmri.27583 -
World Neurosurgery Aug 2023Microsurgical dissection of arachnoid cisterns requires a combination of anatomic knowledge and microsurgical skill. The latter relies on experience and microsurgical...
BACKGROUND
Microsurgical dissection of arachnoid cisterns requires a combination of anatomic knowledge and microsurgical skill. The latter relies on experience and microsurgical dexterity, which depend on visual identification of cisternal microvasculature. We describe a novel standardized operative sequence to allow for bloodless arachnoid dissection when cisternal anatomy is challenging.
METHODS
We used the reported technique in 1928 cases over the past 5 years (2018-2022). The outer arachnoid was incised to enter the cisternal space. A cotton pledget was placed in contact with an inner membrane and gently pushed laterally and superficially with the suction cannula at medium suction power. When the arachnoid membranes dried, arachnoid trabeculae were cut and microvasculature were released at the convexity of their loops and gently transposed off the dissection trajectory. The same principle was used to release parent and perforating arteries from the aneurysm dome.
RESULTS
The microcisternal drainage technique enabled safe and efficient access through adhered arachnoid in all cases. A complex anterior communicating artery aneurysm in a 52-year-old lady demonstrated the use of the microcisternal drainage technique during access through the pericallosal cistern. This technique was used in all cases where cisternal dissection was needed.
CONCLUSIONS
The microcisternal drainage technique uses deliberate and strategic suction, dynamic retraction, and nuanced scissor cuts to enable precise and bloodless microdissection of adherent arachnoid cisterns. This technique combines common neurosurgical maneuvers in a novel standardized sequence to improve efficiency and safety during arachnoid dissection.
Topics: Female; Humans; Middle Aged; Subarachnoid Space; Arachnoid; Microsurgery; Intracranial Aneurysm; Drainage
PubMed: 37105274
DOI: 10.1016/j.wneu.2023.04.087 -
AJNR. American Journal of Neuroradiology Feb 2022The arachnoid membranes are projections of connective tissue in the subarachnoid space that connect the arachnoid mater to the pia mater. These are underappreciated and... (Review)
Review
The arachnoid membranes are projections of connective tissue in the subarachnoid space that connect the arachnoid mater to the pia mater. These are underappreciated and largely unrecognized by most neuroradiologists despite being found to be increasingly important in the pathogenesis, imaging, and treatment of communicating hydrocephalus. This review aims to provide neuroradiologists with an overview of the history, embryology, histology, anatomy, and normal imaging appearance of these membranes, as well as some examples of their clinical importance.
Topics: Arachnoid; Consciousness; Humans; Pia Mater; Radiology; Subarachnoid Space
PubMed: 34711549
DOI: 10.3174/ajnr.A7309 -
Journal of Neuro-ophthalmology : the... Sep 2023Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system and is typically diagnosed through visualization of the cysts in the...
BACKGROUND
Neurocysticercosis (NCC) is the most common parasitic infection of the central nervous system and is typically diagnosed through visualization of the cysts in the cerebral parenchyma by neuro-imaging. However, neuro-imaging may not detect extraparenchymal neurocysticercosis (EPNCC), which is a rare manifestation of the disease involving the subarachnoid, meningeal, and intraventricular spaces. We report 2 cases of extraparenchymal neurocysticercosis, and discuss the diagnostic challenges and management of this entity.
METHODS
Two cases were identified through clinical records.
RESULTS
Both patients had an insidious onset with slow progression of disease, and presented with papilledema and cerebrospinal fluid (CSF) eosinophilia. One case was diagnosed with spinal cord biopsy. The other was diagnosed with CSF serology and next-generation sequencing-based pathogen analysis. Both patients were treated with ventriculoperitoneal shunt, systemic antiparasitic agents, and immunosuppression.
CONCLUSIONS
EPNCC is less common than parenchymal NCC. A high level of clinical suspicion is required given its rarity, long incubation period, and slow progression. Diagnosis and treatment can be challenging and requires a multidisciplinary approach.
Topics: Humans; Neurocysticercosis; Magnetic Resonance Imaging; Ventriculoperitoneal Shunt; Subarachnoid Space; Central Nervous System
PubMed: 36637411
DOI: 10.1097/WNO.0000000000001782 -
Acta Neurochirurgica Sep 2019Because of the restricted volume of the cisternal space, proper patient positioning on the operating table is of utmost importance during surgery by retrosigmoid... (Review)
Review
BACKGROUND
Because of the restricted volume of the cisternal space, proper patient positioning on the operating table is of utmost importance during surgery by retrosigmoid approaches. Three positions are commonly used: supine, with the head rotated to the side contralateral to the lesion; the semi-sitting position; and the park bench position. Each position has advantages and disadvantages, and the surgeon should choose the one best suited to the individual patient and the pathology to be treated.
METHODS
We describe a modified park bench position that we call the Dormeuse position.
CONCLUSION
The Dormeuse position guarantees decrease in the posterior fossa pressure and allows optimal neural and vascular manipulation and control of any aspect of the cerebellopontine angle.
Topics: Cerebellopontine Angle; Cisterna Magna; Cranial Fossa, Posterior; Humans; Neurosurgical Procedures; Patient Positioning
PubMed: 31324984
DOI: 10.1007/s00701-019-04013-0 -
Revue Medicale de Liege Sep 2020We report the case of a 28-year-old male admitted to the emergency department for generalized seizure. A brain computed tomography (CT) revealed a ruptured dermoid cyst...
We report the case of a 28-year-old male admitted to the emergency department for generalized seizure. A brain computed tomography (CT) revealed a ruptured dermoid cyst of the supra-tentorial stage (multiple drop-shaped fat structures were found in the subarachnoid space, basal cisterns and in ventricular system). An additional magnetic resonance imaging (MRI) was conducted to confirm the CT findings.
Topics: Adult; Dermoid Cyst; Humans; Magnetic Resonance Imaging; Male; Rupture, Spontaneous; Subarachnoid Space; Tomography, X-Ray Computed
PubMed: 32909404
DOI: No ID Found -
Clinical Radiology Oct 2021To evaluate the reliability of synthetic magnetic resonance imaging (SyMRI) for detecting complications associated with subarachnoid haemorrhage (SAH), such as ischaemic...
AIM
To evaluate the reliability of synthetic magnetic resonance imaging (SyMRI) for detecting complications associated with subarachnoid haemorrhage (SAH), such as ischaemic lesions, hydrocephalus, or bleeding complications.
MATERIALS AND METHODS
Twenty patients with SAH, who underwent a conventional brain MRI and a SyMRI on a 3 T MRI machine. Comparable conventional and synthetic T2-weighted fluid attenuated inversion recovery (FLAIR) images were acquired. The presence of ischaemic lesions, hydrocephalus, extra-axial blood collections as well as the volumes of grey matter (GMv), white matter (WMv), and cerebrospinal (CSFv) were compared. The acquisition times of both sequences was also analysed.
RESULTS
The concordance between the two techniques was excellent for the detection of ischaemic lesions and extra-axial collections (kappa = 0.80 and 0.88 respectively) and good for the detection of hydrocephalus (kappa = 0.69). No significant differences were detected in the number of ischaemic lesions (p=0.31) or in the Evans index (p=0.11). The WMv and CSFv measures were also similar (p=0.18 and p=0.94, respectively), as well as the volume of ischaemic lesions (p=0.79). Compared to conventional MRI, the SyMRI acquisition time was shorter regardless of the number of sections (32% and 6% time reduction for 4 or 3 mm section thickness, respectively).
CONCLUSIONS
SyMRI allows the detection of potential complications of SAH in a similar way to conventional MRI with a shorter acquisition time.
Topics: Female; Humans; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; Prospective Studies; Reproducibility of Results; Subarachnoid Hemorrhage; Subarachnoid Space
PubMed: 34193343
DOI: 10.1016/j.crad.2021.05.021