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BMJ Open Aug 2017Increased intracranial pressure (ICP) is a significant neurological issue that may lead to permanent neurological sequelae. When evaluating patients with traumatic brain... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Increased intracranial pressure (ICP) is a significant neurological issue that may lead to permanent neurological sequelae. When evaluating patients with traumatic brain injury, it is crucial to identify those with high ICP in order to expedite ICP lowering measures and maintain adequate cerebral perfusion. Several measures are used to recognise patients with increased ICP including CT scan, MRI, ICP monitor, and lumbar puncture (LP). However, these tests can be invasive, associated with radiation exposure, contraindicated, or not readily available. Ultrasonography measurement of the optic nerve sheath diameter (ONSD) is proposed as a non-invasive and quick measure to identify high ICP. The aim of this systematic review and meta-analysis will be to examine the accuracy of ONSD sonography for increased ICP diagnosis.
METHODS AND ANALYSES
We will include published and unpublished randomised controlled trials, observational studies, and abstracts, with no publication type or language restrictions. Search strategies will be designed to peruse the MEDLINE, Embase, Web of Science, WHO Clinical Trials, ClinicalTrials.gov, CINAHL, and the Cochrane Library databases. We will also implement strategies to search grey literature. Two reviewers will independently complete data abstraction and conduct quality assessment. Included studies will be assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. We will construct the hierarchical summary receiver operating characteristic curve for included studies and pool sensitivity and specificity using the bivariate model. We also plan to conduct prespecified subgroup analyses to explore heterogeneity. The overall quality of evidence will be rated using Grading of Recommendations, Assessment, Development and Evaluations (GRADE).
ETHICS AND DISSEMINATION
Research ethics board approval is not required for this study as it draws from published data and raises no concerns related to patient privacy. This review will provide a comprehensive assessment of the evidence on ONSD sonography diagnostic accuracy and is directed to a wide audience. Results from the review will be disseminated extensively through conferences and submitted to a peer-reviewed journal for publication.
PROSPERO REGISTRATION NUMBER
CRD42017055485.
CLINICAL TRIAL NUMBER
Trial registration number is NCT00783809.
Topics: Humans; Intracranial Hypertension; Intracranial Pressure; Optic Nerve; Research Design; Sensitivity and Specificity; Systematic Reviews as Topic; Ultrasonography
PubMed: 28801417
DOI: 10.1136/bmjopen-2017-016194 -
International Journal of Developmental... Feb 2014Developmental abnormalities of optic nerve are the leading cause of child blindness. The goal of this study was to use diffusion tensor imaging (DTI) to characterize the... (Review)
Review
Developmental abnormalities of optic nerve are the leading cause of child blindness. The goal of this study was to use diffusion tensor imaging (DTI) to characterize the optic nerve development of non-human primates during the normal maturation from birth to adulthood. Forty healthy rhesus monkeys aged from 2 weeks to 6 years old were scanned with a clinical 3T scanner. It was demonstrated that the DTI parameters followed an exponential pattern during optic nerve maturation. The time constants of mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (λ∥) and radial diffusivity (λ⊥) were 16, 14, 18 and 15 months in rhesus monkeys, respectively. Significant decrease in RD was observed firstly at 12 months after birth (p<0.05). No significant differences were observed between the left and right optic nerves in any age group. The in vivo imaging results reveal the normal evolution patterns of DTI parameters during optic nerve maturation in primates. The data might be used as a reference in the examination of optic nerve developmental abnormalities or injury in children or preclinical studies.
Topics: Analysis of Variance; Animals; Animals, Newborn; Anisotropy; Decision Making, Computer-Assisted; Diffusion Tensor Imaging; Macaca mulatta; Optic Nerve
PubMed: 23831120
DOI: 10.1016/j.ijdevneu.2013.06.007 -
AJNR. American Journal of Neuroradiology Feb 2019The sensitivity of contrast-enhanced 3D-FLAIR has not been assessed in patients with idiopathic intracranial hypertension. The purpose of this study was to evaluate...
BACKGROUND AND PURPOSE
The sensitivity of contrast-enhanced 3D-FLAIR has not been assessed in patients with idiopathic intracranial hypertension. The purpose of this study was to evaluate whether hyperintensity of the optic nerve/optic nerve head on contrast-enhanced 3D-FLAIR imaging is associated with papilledema in patients with idiopathic intracranial hypertension.
MATERIALS AND METHODS
A retrospective review was conducted from 2012 to 2015 of patients with clinically diagnosed idiopathic intracranial hypertension and age- and sex-matched controls who had MR imaging with contrast-enhanced 3D-FLAIR. Two neuroradiologists graded each optic nerve/optic nerve head on a scale of 0-3. This grade was then correlated with the Frisén Scale, an ophthalmologic scale used for grading papilledema from 0 (normal) to 5 (severe edema). To estimate the correlation between the MR imaging and Frisén scores, we calculated the Kendall τ coefficient.
RESULTS
Forty-six patients (3 men, 43 women) with idiopathic intracranial hypertension and 61 controls (5 men, 56 women) with normal findings on MR imaging were included in this study. For both eyes, there was moderate correlation between the 2 scales (right eye: τ = 0.47; 95% CI, 0.31-0.57; left eye: τ = 0.38; 95% CI, 0.24-0.49). Interreader reliability for MR imaging scores showed high interreader reliability (right eye: κ = 0.76; 95% CI, 0.55-0.88; left eye: κ = 0.87; 95% CI, 0.78-0.94). Contrast-enhanced 3D-FLAIR imaging correlates with the Frisén Scale for moderate-to-severe papilledema and less so for mild papilledema.
CONCLUSIONS
Hyperintensity of the optic nerve/optic nerve head on contrast-enhanced 3D-FLAIR is sensitive for the detection of papilledema in patients with idiopathic intracranial hypertension, which may be useful when prompt diagnosis is crucial.
Topics: Adult; Algorithms; Female; Humans; Imaging, Three-Dimensional; Magnetic Resonance Imaging; Male; Middle Aged; Neuroimaging; Optic Disk; Optic Nerve; Papilledema; Pseudotumor Cerebri; Reproducibility of Results; Retrospective Studies
PubMed: 30679213
DOI: 10.3174/ajnr.A5937 -
Current Eye Research Jul 2020We aimed to characterize the connective tissue microanatomy, elastin abundance, and fiber orientation in the human optic nerve sheath, also known as the optic nerve dura...
PURPOSE/AIM
We aimed to characterize the connective tissue microanatomy, elastin abundance, and fiber orientation in the human optic nerve sheath, also known as the optic nerve dura mater, for correlation with its biomechanical properties.
MATERIALS AND METHODS
Seven whole human orbits aged 4-93 years, and five isolated human optic nerve sheaths aged 26-75 years were formalin fixed, paraffin embedded, coronally sectioned, stained by Masson trichrome and van Gieson's elastin methods, and analyzed quantitatively for elastin fiber abundance and orientation. Elastin area fraction was defined as area stained for elastin divided by total area.
RESULTS
While unilaminar in children, the adult ON sheath exhibited distinct inner and outer layers. Collagen was denser and more compact in the inner layer. Elastin area fraction was significantly greater at 6.0 ± 0.4% (standard error of mean) in the inner than outer layer at 3.6 ± 0.4% ( < 10). Elastin fibers had three predominant orientations: longitudinal, diagonal, and circumferential. Of circumferential fibers, 63 ± 4.7% were in the inner and 37 ± 4.7% in the outer layer ( < 10). Longitudinal and diagonal fibers were uniformly distributed in both layers. Elastin density and sheath thickness increased significantly with age ( < .01).
CONCLUSIONS
The adult human optic nerve sheath is bilaminar, with each layer containing elastin fibers oriented in multiple directions consistent with isotropic properties. Differences in laminar elastin density and orientation may reflect greater tensile loading in the inner than in the outer layer.
Topics: Adult; Aged; Aged, 80 and over; Biomechanical Phenomena; Child, Preschool; Dura Mater; Elastic Tissue; Elastin; Humans; Middle Aged; Optic Nerve
PubMed: 32155090
DOI: 10.1080/02713683.2020.1739314 -
The British Journal of Ophthalmology Sep 2000To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after...
AIM
To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide.
METHODS
Domestic pigs were used as experimental animals. Oxygen tension was measured by means of a polarographic electrode in the vitreous 0.5 mm anterior to the optic disc. This entity is called the optic nerve oxygen tension. Intraocular pressure was controlled by a hypodermic needle inserted into the anterior chamber and connected to a saline reservoir.
RESULTS
When the intraocular pressure was clamped at 20 cm H2O optic nerve oxygen tension was 20 (5) mm Hg (n=8). Intravenous administration of dorzolamide caused an increase in optic nerve oxygen tension of 43 (8)% (n=6). Both before and after administration of dorzolamide optic nerve oxygen tension was unaffected by changes in intraocular pressure, as long as this pressure remained below 60 cm H2O. At intraocular pressures of 60 cm H(2)O and below, dorzolamide significantly increased optic nerve oxygen tension.
CONCLUSION
Intravenous administration of 500 mg dorzolamide increases the oxygen tension at the optic nerve head during acute increases in intraocular pressure.
Topics: Animals; Carbonic Anhydrase Inhibitors; Glaucoma; Infusions, Intravenous; Intraocular Pressure; Optic Nerve; Oxygen; Sulfonamides; Swine; Thiophenes
PubMed: 10966963
DOI: 10.1136/bjo.84.9.1045 -
International Journal of Molecular... Nov 2021Human pluripotent stem cell-derived neural progenitor cells (NPCs) have the potential to recover from nerve injury. We previously reported that human placenta-derived...
Human pluripotent stem cell-derived neural progenitor cells (NPCs) have the potential to recover from nerve injury. We previously reported that human placenta-derived mesenchymal stem cells (PSCs) have neuroprotective effects. To evaluate the potential benefit of NPCs, we compared them to PSCs using R28 cells under hypoxic conditions and a rat model of optic nerve injury. NPCs and PSCs (2 × 106 cells) were injected into the subtenon space. After 1, 2, and 4 weeks, we examined changes in target proteins in the retina and optic nerve. NPCs significantly induced vascular endothelial growth factor (Vegf) compared to age-matched shams and PSC groups at 2 weeks; they also induced neurofilaments in the retina compared to the sham group at 4 weeks. In addition, the expression of brain-derived neurotrophic factor (Bdnf) was high in the retina in the NPC group at 2 weeks, while expression in the optic nerve was high in both the NPC and PSC groups. The low expression of ionized calcium-binding adapter molecule 1 (Iba1) in the retina had recovered at 2 weeks after NPC injection and at 4 weeks after PSC injection. The expression of the inflammatory protein NLR family, pyrin domain containing 3 (Nlrp3) was significantly reduced at 1 week, and that of tumor necrosis factor-α (Tnf-α) in the optic nerves of the NPC group was lower at 2 weeks. Regarding retinal ganglion cells, the expressions of Brn3a and Tuj1 in the retina were enhanced in the NPC group compared to sham controls at 4 weeks. NPC injections increased Gap43 expression from 2 weeks and reduced Iba1 expression in the optic nerves during the recovery period. In addition, R28 cells exposed to hypoxic conditions showed increased cell survival when cocultured with NPCs compared to PSCs. Both Wnt/β-catenin signaling and increased Nf-ĸb could contribute to the rescue of damaged retinal ganglion cells via upregulation of neuroprotective factors, microglial engagement, and anti-inflammatory regulation by NPCs. This study suggests that NPCs could be useful for the cellular treatment of various optic neuropathies, together with cell therapy using mesenchymal stem cells.
Topics: Animals; Axons; Cell Survival; Cell- and Tissue-Based Therapy; Disease Models, Animal; Female; Humans; Nerve Regeneration; Neural Stem Cells; Optic Nerve; Optic Nerve Diseases; Optic Nerve Injuries; Pluripotent Stem Cells; Pregnancy; Rats; Retinal Ganglion Cells
PubMed: 34830410
DOI: 10.3390/ijms222212529 -
Veterinary Ophthalmology Sep 2012Optical coherence tomography (OCT) is a noninvasive, noncontact imaging technique capable of producing high-resolution images of the retina and optic nerve. These images... (Review)
Review
Optical coherence tomography (OCT) is a noninvasive, noncontact imaging technique capable of producing high-resolution images of the retina and optic nerve. These images provide information that is useful for following the progression and/or resolution of posterior segment disease. Rapid advances in OCT technology allow the acquisition of increasingly detailed images, approaching the original goal of providing in vivo histopathology. Increases in scan acquisition speeds and axial resolution enhance the clinical diagnostic value of this modality. Adapting instrumentation designed for use in human patients for use in animals can be challenging. Each species has a unique set of adjustments that need to be made but it is possible to obtain reproducible, high-quality OCT images in a variety of animals, including rodents, dogs, cats, pigs, and monkeys. Deriving quantitative measurements from OCT instruments is hindered by software algorithm errors in detecting the edges of the distinct retinal layers. These segmentation errors occur in scans of human eyes as well in other species and arise with similar frequency with each of the different OCT instruments. Manual segmentation methods to derive optic nerve head and other structural indices have been developed for several species.
Topics: Animals; Optic Nerve; Retina; Retinal Diseases; Tomography, Optical Coherence
PubMed: 22805095
DOI: 10.1111/j.1463-5224.2012.01045.x -
Sensors (Basel, Switzerland) May 2023The present manuscript introduces an investigation of the structural and functional changes in the optic nerve in patients undergoing glaucoma treatment by comparing...
The present manuscript introduces an investigation of the structural and functional changes in the optic nerve in patients undergoing glaucoma treatment by comparing optical coherence tomography (OCT) measurements and RETeval system parameters. For such a purpose, 140 eyes were examined at the Ophthalmology Clinic of the "Elpis" General Hospital of Athens between October 2022 and April 2023. A total of 59 out of 140 eyes were from patients with early glaucoma under treatment (case group), 63 were healthy eyes (control group) and 18 were excluded. The experimental measurements were statistically analyzed using the SPSS software package. The main outcomes are summarized below: (i) there was no statistical difference between the right and left eye for both groups, (ii) statistical differences were found between age interval subgroups (30-54 and 55-80 years old) for the control group, mainly for the time response part of the RETeval parameters. Such difference was not indicated by the OCT system, and (iii) a statistical difference occurred between the control and case group for both OCT (through the retinal nerve fiber layer-RNFL thickness) and the RETeval parameters (through the photopic negative response-PhNR). RNFL was found to be correlated to b-wave (ms) and W-ratio parameters. In conclusion, the PhNR obtained by the RETeval system could be a valuable supplementary tool for the objective examination of patients with early glaucoma.
Topics: Humans; Tomography, Optical Coherence; Optic Disk; Retina; Optic Nerve; Glaucoma
PubMed: 37177707
DOI: 10.3390/s23094504 -
Transactions of the American... 1991
Review
Topics: Animals; Blood Flow Velocity; Demyelinating Diseases; Disease Models, Animal; Growth Substances; Guinea Pigs; Humans; Male; Myelin Sheath; Oligodendroglia; Optic Disk; Optic Nerve; Optic Nerve Diseases
PubMed: 1808820
DOI: No ID Found -
Annals of Saudi Medicine 2023
Topics: Humans; Ultrasonography; Optic Nerve
PubMed: 37270683
DOI: 10.5144/0256-4947.2023.196