Systematic review and meta-analysis of MRI signs for diagnosis of idiopathic intracranial hypertension

Magnetic Resonance Imaging Signs of Idiopathic Intracranial Hypertension

Importance

The magnetic resonance imaging (MRI) criteria currently used to diagnose idiopathic intracranial hypertension (IIH) are based on expert opinion and have limited accuracy. Additional neuroimaging signs have been proposed and used with contradictory results; thus, prospective evidence is needed to improve diagnostic accuracy.

Objective

To provide evidence-based, accurate MRI signs for IIH diagnosis.

Design, Setting, and Participants

This prospective cohort study was conducted from January 2018 to May 2021 with 3 validation cohorts at 2 Danish headache centers and with 3 independent international cohorts. Consecutive patients with suspected IIH were enrolled. Eligibility required the clinical suspicion of IIH, age 18 years or older, and written informed consent. The validation cohorts comprised patients with confirmed IIH from Austria and the US, and patients without IIH from the US. Data analysis was performed from December 2021 to August 2023.

Exposure

Standardized diagnostic workup was performed to classify cases according to current criteria, and blinded evaluation of cerebral radiological diagnostics and papilledema was performed.

Main Outcomes and Measures

The primary outcomes were MRI signs associated with IIH as assessed by univariate analyses. An MRI score estimating papilledema was calculated using machine learning. Internal validation of associations with lumbar puncture opening pressure and outcome and external validation of accuracy were performed in 3 cohorts.

Results

Of 192 eligible patients (185 women [96.4%]; median [IQR] age, 28.0 [23.0-35.0] years), 110 were classified as having IIH, 4 as having probable IIH, and 1 as having suspected IIH without papilledema; 77 did not have IIH and served as controls, with corresponding age, sex, and weight. Papilledema at diagnosis was associated with perioptic subarachnoid space distension (56 patients [68.3%] vs 21 patients [41.2%]), posterior globe flattening (53 patients [66.3%] vs 10 patients [21.3%]), optic nerve disc protrusion (35 patients [30.4%] vs 2 patients [2.3%]), and transverse sinus venous stenosis (75 patients [79.8%] vs 29 patients [46.8%]). The papilledema-estimating MRI score showed optimal balance between sensitivity (49%) and specificity (87%) when 2 of the 3 latter signs were present and was associated with the lumbar puncture opening pressure and ophthalmological outcome. The score showed strong diagnostic accuracy in the external validation cohorts (587 patients; area under the receiver operating characteristic curve, 0.86) and outperformed the current (2013) diagnostic MRI criteria.

Conclusions and Relevance

The findings of this cohort study of patients with IIH and controls suggest that an evidence-based MRI score including posterior globe flattening, optic nerve disc protrusion, and transverse sinus stenosis can estimate the presence of papilledema more accurately than the current diagnostic criteria.

The diagnostic value of MRI findings in pediatric idiopathic intracranial hypertension: a case-control study

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a rare medical condition in children. Based on the different radiological findings reported in various studies in pediatric IIH, this study was conducted to determine the diagnostic value of MRI findings in diagnosing IIH in children.

METHODS

In this retrospective study, the medical records of all children aged 1 to 18 years who visited Ghaem Hospital in Mashhad, Iran, between 2012 and 2022 and were diagnosed with IIH were gathered. Forty-nine cases of children with IIH and 48 control cases of children with the first unprovoked seizure with no indications of increased intracranial pressure for comparison were selected. Patient demographic information and MRI findings were extracted. The comparison between different MRI findings in the case and control groups was conducted using statistical tests.

RESULTS

In the case group, the mean diameter of the subarachnoid space expansion around the optic nerve was 5.96 ± 1.21, compared to 4.79 ± 0.33 in the control group, with statistically significant difference (P < 0.001). All the patients with flattening of the posterior globe or transverse sinus stenosis were in the case group, and the frequency of these findings in the case group was significantly higher than in the control group (P < 0.001). The majority of patients (95.5%) classified under category 3 and 4 of empty sella were part of the case group, and the statistical test results indicated a significant difference between the two groups (P < 0.001). The optic nerve sheath diameter cut-off of 5.35 mm, when used for expansion of the subarachnoid space around the optic nerve, with a sensitivity of 82% and a specificity of 100% in diagnosing IIH.

CONCLUSION

The most reliable diagnostic indicators for diagnosing IIH in children are perioptic subarachnoid space expansion with high sensitivity, and posterior globe flattening and transverse sinus stenosis with high specificity.

Dimensions of Arachnoid Bulk Ratio: A Superior Optic Nerve Sheath Index for Intracranial Pressure

Background Discrepancies in the literature regarding optimal optic nerve sheath diameter (ONSD) cutoffs for intracranial pressure (ICP) necessitate alternative neuroimaging parameters to improve clinical management. Purpose To evaluate the diagnostic accuracy of the dimensions of the perineural subarachnoid space to the optic nerve sheath ratio, measured using US, in predicting increased ICP. Materials and Methods In a prospective cohort study from April 2022 to December 2023, patients with suspected increased ICP underwent optic nerve US to determine the dimensions of arachnoid bulk (DAB) ratio and ONSD before invasive ICP measurement. Correlation between the parameters and ICP, as well as diagnostic accuracy, was assessed using area under the receiver operating characteristic curve (AUC) analysis. Results A total of 30 participants were included (mean age, 39 years ± 14 [SD]; 24 female). The DAB ratio and ONSD were significantly larger in participants with increased ICP (38% [0.16 of 0.42] and 14% [0.82 of 6.04 mm], respectively; P < .001). The DAB ratio showed a stronger correlation with ICP than ONSD (rs = 0.87 [P < .001] vs rs = 0.61 [P < .001]). The DAB ratio and ONSD optimal cutoffs for increased ICP were 0.5 and 6.5 mm, respectively, and the ratio had higher sensitivity (100% vs 92%) and specificity (94% vs 83%) compared with ONSD. Moreover, the DAB ratio better predicted increased ICP than ONSD, with a higher AUC (0.98 [95% CI: 0.95, 1.00] vs 0.86 [95% CI: 0.71, 0.95], P = .047). Conclusion An imaging ratio was proposed to predict ICP based on the relative anatomy of the cerebrospinal fluid space, demonstrating more accurate diagnosis of increased ICP and a strong correlation with ICP values, suggesting its potential utility as a neuroimaging marker in clinical settings. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Shepherd in this issue.

Collapse or distention of the perioptic space in children - What does it mean to pediatric radiologists? Comprehensive review of perioptic space evaluation

The perioptic space comprises the subarachnoid space [SAS] of the optic nerve communicating with the SAS of the central nervous system. Pressure variations in the SAS of the central nervous system can be transmitted to the optic papilla through the perioptic space. Variations in the diameter of the perioptic space serve as an important indicator for select intracranial pathologies in the pediatric population. Though the perioptic space can be evaluated using various imaging modalities, MRI is considered highly effective due to its superior soft tissue resolution. With advancement in MR imaging techniques, high-resolution images of the orbits can provide improved visualization of the perioptic space. It is imperative for the pediatric radiologist to routinely assess the perioptic space on brain and orbit MR imaging, as it can prompt exploration for additional features associated with select intracranial pathologies, thus improving diagnostic accuracy. This article reviews basic anatomy of the perioptic space, current understanding of the CSF dynamics between the perioptic space and central nervous system SAS, various imaging modalities utilized in the assessment of the perioptic space, MRI sequences and the optimal parameters of specific sequences, normal appearance of the perioptic space on MR imaging, and various common pediatric pathologies which cause alteration in the perioptic space.

Role of neuroimaging markers on predicting of idiopathic intracranial hypertension

BACKGROUND

The goals of neuroimaging in idiopathic intracranial hypertension (IIH) are the exclusion of mimickers and effective management of disease. In recent studies, several imaging markers have been identified as potential predictors of IIH.

PURPOSE

To investigate the predictive roles of novel radiological markers as the Meckel's cave area, alongside classical radiologic markers in identifying IIH such as the empty sella.

MATERIAL AND METHODS

The patients were classified according to cerebrospinal fluid (CSF) opening pressure as the IIH group and control group. The observational, case-control study included 22 patients with IIH and 22 controls. Groups were compared for presence of empty sella, Meckel's cave area, fat area of posterior neck, fat thickness of scalp, presence of transverse sinus stenosis, and ophthalmic markers, such as increase of optic nerve (ON) sheath diameter.

RESULTS

In the IHH group, higher occurrences of increased ON sheath diameter, ON tortuosity, flattening of the scleral surface, and transverse sinus stenosis were observed (P < 0.001, P < 0.001, P = 0.046, and P = 0.021, respectively). Meckel's cave area and fat area of posterior neck were similar in both groups (P = 0.444 and P = 0.794).

CONCLUSION

Ophthalmic markers and transverse sinus stenosis could be utilized as radiologic features supporting early and precise diagnosis of IIH. However, enlargement of Meckel's cave area and measurements of fatty area of posterior neck are not helpful for diagnosis of IIH.

The additive value of complementing diagnostic idiopathic intracranial hypertension criteria by MRI - an external validation study

BACKGROUND

Recently, diagnostic criteria including a standardized MRI criterion were presented to identify patients suffering from idiopathic intracranial hypertension (IIH) proposing that IIH might be defined by two out of three objective findings (papilledema, ≥ 25 cm cerebrospinal fluid opening pressure (CSF-OP) and ≥ 3/4 neuroimaging signs).

METHODS

To provide independent external validation, we retrospectively applied the proposed diagnostic criteria to our cohort of patients with clinical suspicion of IIH from the Vienna IIH database. Neuroimaging was reevaluated for IIH signs according to standardized definitions by a blinded expert neuroradiologist. We determined isolated diagnostic accuracy of the neuroimaging criterion (≥ 3/4 signs) as well as overall accuracy of the new proposed criteria.

RESULTS

We included patients with IIH (n = 102) and patients without IIH (no-IIH, n = 23). Baseline characteristics were balanced between IIH and no-IIH groups, but papilledema and CSF-OP were significantly higher in IIH. For the presence of ≥ 3/4 MRI signs, sensitivity was 39.2% and specificity was 91.3% with positive predictive value (PPV) of 95.2% and negative predictive value (NPV) 25.3%. Reclassifying our cohort according to the 2/3 IIH definition correctly identified 100% of patients without IIH, with definite IIH and suggested to have IIH without papilledema by Friedman criteria, respectively.

CONCLUSION

The standardized neuroimaging criteria are easily applicable in clinical routine and provide moderate sensitivity and excellent specificity to identify patients with IIH. Defining IIH by 2/3 criteria significantly simplifies diagnosis without compromising accuracy.

The Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome is a syndrome of increased cerebrospinal fluid pressure without ventriculomegaly, mass lesion, or meningeal abnormality. It is either primary (idiopathic intracranial hypertension, IIH) or secondary. A secondary cause is unlikely when adhering to the diagnostic criteria. Permanent visual loss occurs if undetected or untreated, and the associated headaches may be debilitating. Fulminant disease may result in blindness despite aggressive treatment. This study addresses the diagnosis and management of IIH including new insights into the pathobiology of IIH, updates in therapeutics and causes of overdiagnosis.

Foundations of the Diagnosis and Management of Idiopathic Intracranial Hypertension and Pulsatile Tinnitus

Venous sinus stenosis has garnered increasing academic attention as a potential etiology of idiopathic intracranial hypertension (IIH) and pulsatile tinnitus (PT). The complex anatomy of the cerebral venous sinuses and veins plays a crucial role in the pathophysiology of these conditions. Venous sinus stenosis, often found in the superior sagittal or transverse sinus, can lead to elevated intracranial pressure (ICP) and characteristic IIH symptoms. Stenosis, variations in dural venous anatomy, and flow dominance patterns contribute to aberrant flow and subsequent PT. Accurate imaging plays a vital role in diagnosis, and magnetic resonance (MR) venography is particularly useful for detecting stenosis. Management strategies for IIH and PT focus on treating the underlying disease, weight management, medical interventions, and, in severe cases, surgical or endovascular procedures. Recently, venous sinus stenting has gained interest as a minimally invasive treatment option for IIH and PT. Stenting addresses venous sinus stenosis, breaking the feedback loop between elevated ICP and stenosis, thus reducing ICP and promoting cerebrospinal fluid outflow. The correction and resolution of flow aberrances can also mitigate or resolve PT symptoms. While venous sinus stenting remains an emerging field, initial results are promising. Further research is needed to refine patient selection criteria and evaluate the long-term efficacy of stenting as compared to traditional treatments.

Is foramen magnum decompression for acquired Chiari I malformation like putting a finger in the dyke? - A simplistic overview of artificial intelligence in assessing critical upstream and downstream etiologies

Background

Missed diagnosis of evolving or coexisting idiopathic (IIH) and spontaneous intracranial hypotension (SIH) is often the reason for persistent or worsening symptoms after foramen magnum decompression for Chiari malformation (CM) I. We explore the role of artificial intelligence (AI)/convolutional neural networks (CNN) in Chiari I malformation in a combinatorial role for the first time in literature, exploring both upstream and downstream magnetic resonance findings as initial screening profilers in CM-1. We have also put together a review of all existing subtypes of CM and discuss the role of upright (gravity-aided) magnetic resonance imaging (MRI) in evaluating equivocal tonsillar descent on a lying-down MRI. We have formulated a workflow algorithm MaChiP 1.0 (Manjila Chiari Protocol 1.0) using upstream and downstream profilers, that cause de novo or worsening Chiari I malformation, which we plan to implement using AI.

Materials and Methods

The PRISMA guidelines were used for "CM and machine learning and CNN" on PubMed database articles, and four articles specific to the topic were encountered. The radiologic criteria for IIH and SIH were applied from neurosurgical literature, and they were applied between primary and secondary (acquired) Chiari I malformations. An upstream etiology such as IIH or SIH and an isolated downstream etiology in the spine were characterized using the existing body of literature. We propose the utility of using four selected criteria for IIH and SIH each, over MRI T2 images of the brain and spine, predominantly sagittal sequences in upstream etiology in the brain and multiplanar MRI in spinal lesions.

Results

Using MaChiP 1.0 (patent/ copyright pending) concepts, we have proposed the upstream and downstream profilers implicated in progressive Chiari I malformation. The upstream profilers included findings of brain sagging, slope of the third ventricular floor, pontomesencephalic angle, mamillopontine distance, lateral ventricular angle, internal cerebral vein-vein of Galen angle, and displacement of iter, clivus length, tonsillar descent, etc., suggestive of SIH. The IIH features noted in upstream pathologies were posterior flattening of globe of the eye, partial empty sella, optic nerve sheath distortion, and optic nerve tortuosity in MRI. The downstream etiologies involved spinal cerebrospinal fluid (CSF) leak from dural tear, meningeal diverticula, CSF-venous fistulae, etc.

Conclusion

AI would help offer predictive analysis along the spectrum of upstream and downstream etiologies, ensuring safety and efficacy in treating secondary (acquired) Chiari I malformation, especially with coexisting IIH and SIH. The MaChiP 1.0 algorithm can help document worsening of a previously diagnosed CM-1 and find the exact etiology of a secondary CM-I. However, the role of posterior fossa morphometry and cine-flow MRI data for intracranial CSF flow dynamics, along with advanced spinal CSF studies using dynamic myelo-CT scanning in the formation of secondary CM-I is still being evaluated.

Pseudotumor cerebri in the paediatric population: clinical features, treatment and prognosis

INTRODUCTION

Pseudotumor cerebri (PC) in prepubertal patients displays certain characteristics that differentiate it from its presentation at the postpubertal stage. The aim of this study is to describe the characteristics of paediatric patients diagnosed with PC at our centre and to compare them according to their pubertal status.

PATIENTS AND METHODS

We included patients aged between 1 and 18 years who were diagnosed with PC in a tertiary-level hospital between 2006 and 2019 and who met the updated diagnostic criteria for PC. They were classified according to body weight and pubertal status. Subsequently, we analysed results from lumbar punctures, neuroimaging studies, ophthalmological assessments, and treatments received during follow-up.

RESULTS

We included 28 patients, of whom 22 were of prepubertal age and 6 were of postpubertal age. The mean age (standard deviation) was 9.04 (2.86) years. Among the postpubertal patients, 83.3% were boys, 66.7% of whom presented overweight/obesity. In the group of prepubertal patients, 27% were boys, 31.8% of whom were overweight. The most frequent symptoms were headache (89.9%) and blurred vision (42.9%). All patients presented papilloedema, and 21.4% manifested sixth nerve palsy. Possible triggers were identified in 28.6% of cases. Nineteen percent of patients presented clinical recurrence, all of whom were prepubertal patients. Complete clinical resolution was achieved in 55.6% of patients.

CONCLUSION

Prepubertal patients with PC show lower prevalence of obesity, higher prevalence of secondary aetiologies, and higher recurrence rates than postpubertal patients.

Normative body mass-adjusted reference ranges of magnetic resonance imaging signs commonly used in diagnosing idiopathic intracranial hypertension in a healthy standard population

Patients with chronic daily headaches (CDH) are often a diagnostic challenge and frequently undergo neuroimaging. One common underlying cause of CDH is idiopathic intracranial hypertension (IIH). However, certain neuroimaging abnormalities that suggest IIH, such as optic nerve sheath diameters (ONSD), pituitary gland height, and venous sinus diameter, require interpretation due to the absence of established normative values. Notably, intracranial pressure is known to varies with age, sex and weight, further complicating the determination of objectively abnormal findings within a specific patient group. This study aims to assist clinical neuroradiologists in differentiating neuroimaging results in CDH by providing weight-adjusted normative values for imaging characteristics of IIH. In addition to age and BMI we here assessed 1924 population-based T1-weighted MRI datasets of healthy participants for relevant MRI aspects of IIH. Association to BMI was analyzed using linear/logistic regression controlled for age and stratified for sex. ONSD was 4.3 mm [2.8; 5.9]/4.6 mm [3.6; 5.7] and diameter of transverse sinus was 4.67 mm [1.6; 6.5]/4.45 mm [3.0; 7.9]. Height of pituitary gland was 5.1 mm [2.2;8.1]/4.6 mm [1.9;7.1] for female and male respectively. Values generally varied with BMI with regression slopes spanning 0.0001 to 0.05 and were therefor presented as normative values stratified by BMI. Protrusion of ocular papilla, empty sella and transverse sinus occlusion were rare in total. Our data show an association between BMI and commonly used MRI features for diagnosing IIH. We provide categorized normative BMI values for ONSD, pituitary gland height, and transverse sinus diameter. This distinction helps objectively identify potential IIH indicators compared to regular population norms, enhancing diagnostic accuracy for suspected IIH patients. Notably, optic nerve head protrusion, empty sella, and transverse sinus occlusion are rare in healthy individuals, solidifying their importance as imaging markers regardless of BMI.

The role of arachnoid granulations in idiopathic intracranial hypertension

OBJECTIVES

Idiopathic intracranial hypertension (IIH) is a disease defined by elevated intracranial pressure (ICP) without an established etiology. Arachnoid granulations (AG) are conduits for CSF resorption from the subarachnoid space to the venous system. AG have been implicated to play a central role in maintaining CSF homeostasis. We tested the hypothesis that patients with fewer visible AG on MRI are more likely to present with IIH.

METHODS

In this institutional review board (Institutional Review Board)-approved retrospective chart review study, 65 patients with a clinical diagnosis of idiopathic intracranial hypertension were compared to 144 control patients who met inclusion/exclusion criteria. Patients' signs and symptoms pertaining to IIH were obtained through the electronic medical record Brain MR images were reviewed for the number and distribution of AGs indenting the dural venous sinuses. The presence of imaging and clinical findings associated with long standing increased ICP was noted. Propensity score method (with inverse probability weighting technique) was used to compare case and control groups.

RESULTS

In the control group, the number of AG indenting the dural venous sinuses on MRI (NAG) was lower in women compared to men when matched for age (20-45 yo) and BMI (>30 kg/m2). The NAG was lower in 20-45 yo females in the IIH group as compared to the 20-45 yo females in the control group. This statistically significant difference persists when controlled for BMI. In contrast, the NAG in >45 yo females in the IIH group trended higher compared to the >45 yo females in the control group.

CONCLUSION

Our results suggest that alterations in arachnoid granulations could play a role in the development of IIH.

Transverse Venous Sinus Stenosis in Patients With Nasal Cerebrospinal Fluid Leak and Idiopathic Intracranial Hypertension

OBJECTIVE

Spontaneous nasal cerebrospinal fluid (CSF) leaks are frequently linked to idiopathic intracranial hypertension (IIH). The objectives of our study were: (1) to determine the rate of transverse venous sinus stenosis (TVSS) in patients with spontaneous nasal CSF leak and in patients with IIH without CSF (controls), and (2) to study the correlation between spontaneous nasal CSF leak and brain imaging features.

STUDY DESIGN

A multicenter retrospective case-control study.

SETTING

Six French tertiary hospitals.

METHODS

Patients with spontaneous nasal CSF leaks and patients with IIH without nasal CSF leaks (controls) were included. The transverse venous sinus patency was analyzed by magnetic resonance imaging to identify possible stenosis or hypoplasia.

RESULTS

Thirty-two patients with spontaneous nasal CSF leaks and 32 controls were included. TVSS was significantly more frequent in patients with spontaneous nasal CSF leaks than in controls (p = .029). Univariate analysis indicated that TVSS (odds ratio, OR: 4.2; 95% confidence interval, CI [1.352-14.915]; p = .017) and arachnoid granulations (OR: 3; 95% CI [1.065-8.994]; p = .042) were risk factors for spontaneous nasal CSF leak. In multivariate analysis, TVSS and arachnoid granulations were independent risk factors of nasal CSF leak (OR: 5.577, 95% CI [1.485-25.837], p = .016; and OR: 4.35, 95% CI [1.234-17.756], p = .029, respectively).

CONCLUSION

This multicenter case-control study shows that TVSS is an independent risk factor for CSF leak in patients with IIH. Stenosis management by interventional radiology may be proposed postoperatively to increase the success of IIH surgical treatment or preoperatively to reduce the need for surgery.

Interthalamic Adhesion: Can it be used to Diagnose Idiopathic Intracranial Hypertension?

OBJECTIVE

This retrospective study aimed at determining the dimension of the interthalamic adhesion (ITA) in patients with the idiopathic intracranial hypertension (IIH) for assisting in preoperative radiologic diagnosis.

METHODS

The study universe consisted of magnetic resonance images of 20 patients with IIH (age: 22.70 ± 4.04 years, sex: 14 females and 6 males) and 20 normal subjects (age 22.30± 2.94 years, sex: 14 females and 6 males). To determine the morphology of ITA, its height (vertical diameter) and width (horizontal diameter) were measured on the coronal and axial planes, respectively.

RESULTS

The height and width of ITA in IIH were measured as 2.58 ± 0.71 mm (range: 1.40-4.20 mm) and 2.73 ± 0.77 mm (range: 1.70-4.40 mm), respectively. Its height and width in controls were measured as 4.99 ± 1.04 mm (range: 2.70-6.30 mm) and 4.92 ± 1.11 mm (range: 2.60-6.50 mm), respectively. ITA height and width in IIH was significantly smaller compared with controls (P < 0.001). For an arbitrary cutoff of 3.85 mm, the sensitivity of the height of ITA was 85% with 95% specificity. For an arbitrary cutoff of 4.45 mm, the sensitivity of the width of ITA was 75% with 100% specificity.

CONCLUSIONS

The height and width of ITA are approximately 50% smaller in IIH than controls; therefore alterations in the dimension of ITA may be a valuable radiologic sign for the diagnosis of IIH.

The role of optic nerve sheath ultrasonography in increased intracranial pressure: A systematic review and meta analysis

OBJECTIVES

To review the optimal diagnostic cut-off of ultrasonographic optic nerve sheath diameter (ONSD) in the diagnosis of increased intracranial pressure (IICP).

METHODS

A systematic search was conducted of available studies assessing the use of ONSD ultrasonography in patients with suspected IICP. Meta-analysis of diagnostic accuracy of ultrasonographic ONSD was performed using a bivariate model of random effects to summarize pooled sensitivity and specificity. A summary receiver operating characteristics (SROC) curve was plotted. Accuracy measures associated with ONSD cut-off and predefined covariates were investigated with meta-regression.

RESULTS

We included 38 studies, comprising a total of 2824 patients. A total of 21 studies used invasive techniques as a reference standard estimation of IICP and meta-analysis revealed a pooled sensitivity of 0.90 (95% CI 0.85-0.93) and specificity of 0.87 (95% CI 0.80-0.91). Optimal ONSD cut-off values ranged between 4.1 mm and 7.2 mm. Meta-regression analysis showed that ONSD cut-off values of 5.6 to 6.3 mm were associated with higher pooled specificity compared to cut-off values of 4.9 to 5.5 mm (0.93, 95% CI 0.85-0.97 vs. 0.78, 95% CI 0.65-0.87; p = 0.036).

CONCLUSIONS

Ultrasonography of ONSD shows a high diagnostic accuracy for IICP, with high pooled sensitivity and specificity. Additionally, larger cut-off values seem to significantly increase specificity without compromising sensitivity, which support their use as optimal ONSD cut-off. The overall high sensitivity of ultrasonographic ONSD suggests its usefulness as a screening tool for IIC, which may provide an estimate of when invasive methods are warranted.

CLINICAL RELEVANCE

ONSD ultrasonography is a fast and cost-effective method with a high diagnostic accuracy to detect IICP. The optimum ONSD cut-off hasn't been established before, but we suggest the 5.6 to 6.3 mm range as the best for the diagnosis of IICP.

MRI features to aid the identification of lateral temporal bone cephaloceles

OBJECTIVES

To evaluate ancillary MRI features which may aid the identification of lateral temporal bone cephaloceles (LTBCs).

METHODS

A retrospective cohort study analysed patients with MRI evidence of surgically confirmed spontaneous LTBCs as defined by intracranial contents traversing the tegmen tympani or mastoideum. Cases were identified from radiology and surgical databases. Two observers analysed three-dimensional T 2W temporal bone and whole brain imaging according to a priori criteria by consensus, with emphasis on the relationship of any adjacent cerebrospinal fluid (CSF) cleft to the defect. The contents, location, and clinical features of the LTBCs were recorded.

RESULTS

Eighteen patients (11 female, 7 male; mean age 59.3 years, age range 42-86 years) with 20 surgically confirmed spontaneous LTBCs (2 bilateral;16 unilateral) were evaluated. A temporal lobe sulcus or other CSF cleft extending to or traversing the defect was identified in 19/20 (95%) cases. Isointense CSF tympanomastoid signal was present in 41.2% cases, whilst superior semi-circular canal dehiscence was found in 40% of cephaloceles. At least two MRI features of idiopathic intracranial hypertension were seen in 38.9% patients. Cephaloceles were most commonly centred on the tegmen tympani (55%). Meningoencephaloceles were present in 95% cases.

CONCLUSION

A temporal lobe sulcus or CSF cleft extending to or traversing the defect may aid the identification of LTBCs. Isointense CSF tympanomastoid signal, superior semi-circular canal dehiscence and MRI features of idiopathic intracranial hypertension are only present in under half of LTBCs.

ADVANCES IN KNOWLEDGE

The study details novel ancillary MRI features of LTBCs which may aid their identification.

Impact of rater experience and referral question on detecting magnetic resonance imaging features of idiopathic intracranial hypertension

BACKGROUND AND PURPOSE

In idiopathic intracranial hypertension (IIH), magnetic resonance imaging (MRI) features are promising diagnostic markers, but the impact of rater experience and the specific referral question is unknown.

METHODS

From the Vienna Idiopathic Intracranial Hypertension database, patients were included with definitive IIH and routine cranial MRI performed during diagnostic work-up. Frequencies of partial empty sella (ES), optic nerve sheath distension (ONSD), optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) were compared in three settings: (i) real-world rating, (ii) junior neuroradiologist without special IIH training and (iii) senior neuroradiologist with experience in IIH imaging (gold standard).

RESULTS

Magnetic resonance imaging scans of 84 IIH patients (88% female, mean age 33.5 years) were evaluated. By gold standard, ONSD was the most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.4%) and PGF (23.8%). Compared to the gold standard, IIH features were described significantly less frequently in routine MRI reports (ONSD 28.6%, ONT 13.1%, PGF 4.8%, TSS 42.9%, p < 0.01 respectively) except for ES (42.9%, p = 0.9). A specific referral question regarding IIH increased detection rates in routine reports, but rates remained significantly lower than by gold standard. In contrast, a rating by a neuroradiologist without special training produced significantly higher frequencies of ONSD (81.0%, p < 0.01) and ONT (60.7%, p < 0.01) but not of ES (47.6%), PGF (29.8%) and TSS (68.1%).

CONCLUSIONS

Idiopathic intracranial hypertension MRI features are underestimated in routine MRI reports and partly overcalled by less experienced neuroradiologists, driven by features less well known or methodologically difficult. Reevaluation of MRI scans by an experienced rater (and to a lesser degree a specific referral question) improves diagnostic accuracy.

A rare finding of bilateral facial canal meningoceles involving the tympanic segment in suspected idiopathic intracranial hypertension

Meningoceles are a common radiological feature found in cases of idiopathic intracranial hypertension (IIH). Rarely, they can affect the facial canal within the petrous temporal bone, leading to symptoms such as facial nerve palsy, hearing loss or meningitis. This is the first case report that describes bilateral facial canal meningoceles involving the tympanic segment of the canal. Prominent Meckel's caves were also seen on MRI, a feature commonly associated with IIH.

The expanding spectrum of idiopathic intracranial hypertension

Once considered a rare and often difficult diagnosis in the era predating routine MRI, idiopathic intracranial hypertension has become an everyday concern in ophthalmology and neurology clinics where, especially in the latter, essentially every young overweight woman with headaches is initially presumed to have IIH. Has the diagnosis of IIH become too easy, and are we over-diagnosing IIH in this period of an accelerating obesity crisis? Or are we actually missing cases of IIH because they do not fit the classic clinical profile? We think it is both: at the same time IIH is being diagnosed in excess in obese women without papilledema, often resulting in unnecessary procedures, inappropriate treatment and even iatrogenic complications, the spectrum of this disorder is expanding to include a broad array of clinical presentations that involve multiple specialists beyond just the ophthalmologist and neurologist.

MRI features of idiopathic intracranial hypertension are not prognostic of visual and headache outcome

BACKGROUND

In idiopathic intracranial hypertension (IIH), certain MRI features are promising diagnostic markers, but whether these have prognostic value is currently unknown.

METHODS

We included patients from the Vienna-Idiopathic-Intracranial-Hypertension (VIIH) database with IIH according to Friedman criteria and cranial MRI performed at diagnosis. Presence of empty sella (ES), perioptic subarachnoid space distension (POSD) with or without optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) was assessed and multivariable regression models regarding visual outcome (persistent visual impairment/visual worsening) and headache outcome (headache improvement/freedom of headache) were fitted.

RESULTS

We included 84 IIH patients (88.1% female, mean age 33.5 years, median body mass index 33.7). At baseline, visual impairment was present in 70.2% and headache in 84.5% (54.8% chronic). Persistent visual impairment occurred in 58.3%, visual worsening in 13.1%, headache improvement was achieved in 83.8%, freedom of headache in 26.2%. At least one MRI feature was found in 78.6% and 60.0% had ≥3 features with POSD most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.0%) and PGF (23.8%). In multivariable models, there was no association of any single MRI feature or their number with visual impairment, visual worsening, headache improvement or freedom. Visual impairment at baseline predicted persistent visual impairment (odds ratio 6.3, p<0.001), but not visual worsening. Chronic headache at baseline was significantly associated with lower likelihood of headache freedom (odds ratio 0.48, p=0.013), but not with headache improvement.

CONCLUSIONS

MRI features of IIH are neither prognostic of visual nor headache outcome.

Dural sinus narrowing in patients with spontaneous anterior skull base cerebrospinal fluid leak

Objectives

Current evidence suggests a link between idiopathic intracranial hypertension (IIH) and spontaneous cerebrospinal fluid (sCSF) leak, as well as between IIH and dural venous sinus (DVS) narrowing. However, there are limited data linking DVS narrowing and sCSF leak. This study aims to determine the prevalence of DVS narrowing in patients with sCSF leak.

Methods

A retrospective review of all patients with sCSF leak that presented to a tertiary academic center from 2008 to 2019. Preoperative imaging was independently reviewed by two neuroradiologists to evaluate for DVS narrowing. Available literature was used to estimate the prevalence of DVS narrowing in the general population to allow for comparison. Data were analyzed using Exact binomial test.

Results

Analysis of 25 patients with appropriate imaging revealed the majority were women (21/25, 84%) with a mean age of 51.89 years (SD 13.96). The majority of these patients were found to have narrowing of the DVS (20/25, 80%). In patient with sCSF leaks, there was a significantly higher proportion of patients with DVS narrowing compared with published literature examining this condition in the general population (80% vs. 40%, CI 0.59-0.93, p < .001).

Conclusion

The prevalence of DVS narrowing in patients with sCSF leaks is substantial and likely greater than the general population. Moreover, there appears to be narrowing in most patients with sCSF leak. Preoperative radiological evaluation of the DVS using MR venography may be useful in patients with sCSF leaks as DVS stenosis may be an underdiagnosed etiology. Further study is needed to evaluate this.

Level of Evidence

IV.

Diagnosis of idiopathic intracranial hypertension: A proposal for evidence-based diagnostic criteria

BACKGROUND

Based on expert opinion, abducens nerve palsy and a neuroimaging criterion (≥3 neuroimaging signs suggestive of elevated intracranial pressure) were added to the diagnostic criteria for idiopathic intracranial hypertension. Our objective was to validate this.

METHODS

This prospective study included patients with new-onset idiopathic intracranial hypertension for a standardized work-up: interview, neuro-ophthalmological exam, lumbar puncture, neuroimaging. Neuroimaging was evaluated by a blinded neuroradiologist.

RESULTS

We included 157 patients classified as idiopathic intracranial hypertension (56.7%), probable idiopathic intracranial hypertension (1.9%), idiopathic intracranial hypertension without papilledema (idiopathic intracranial hypertension-without papill edema; 0%), suggested idiopathic intracranial hypertension-without papill edema (4.5%), or non-idiopathic intracranial hypertension (36.9%). Moderate suprasellar herniation was more common in idiopathic intracranial hypertension than non-idiopathic intracranial hypertension (71.4% versus 47.4%, p < 0.01), as was perioptic nerve sheath distension (69.8% versus 29.3%, p < 0.001), flattening of the globe (67.1% versus 11.1%, p < 0.001) and transverse sinus stenosis (60.2% versus 18.9%, p < 0.001). Abducens nerve palsy was of no diagnostic significance. Sensitivity of ≥3 neuroimaging signs was 59.5% and specificity was 93.5%.

CONCLUSION

Moderate suprasellar herniation, distension of the perioptic nerve sheath, flattening of the globe and transverse sinus stenosis were associated with idiopathic intracranial hypertension. We propose that idiopathic intracranial hypertension can be defined by two out of three objective findings (papilledema, opening pressure ≥25 cm cerebrospinal fluid and ≥3 neuroimaging signs).

Presumptive Idiopathic Intracranial Hypertension Based on Neuroimaging Findings: A Referral Pattern Study

BACKGROUND

Radiologic findings of intracranial hypertension (RAD-IH) are common in idiopathic intracranial hypertension (IIH) patients. Paralleling the increasing rates of obesity, the burden of IIH is growing. Urgent neuro-ophthalmology consultations for possible IIH in patients with incidentally detected RAD-IH are increasing, with many patients receiving unnecessary lumbar punctures (LPs) and treatments. This retrospective observational study aimed to determine the prevalence of neuro-ophthalmology consultations for RAD-IH, rate of funduscopic examination by referring providers, prevalence of papilledema, outcomes after neuro-ophthalmic evaluation, and rates of misdiagnosis.

METHODS

Records of 1,262 consecutive new patients seen in one neuro-ophthalmology clinic from January 2019 to January 2020 were reviewed. We identified patients who were: 1) referred with concern for IIH because of findings of RAD-IH; 2) referred for "papilledema"; 3) referred with a diagnosis of IIH; and 4) referred for spontaneous cranial cerebrospinal fluid (CSF) leaks. In addition to basic demographic profiles for all groups, detailed information was collected for patients referred solely for RAD-IH, including referral patterns, prior history of IIH, previous LPs, prior medical or surgical treatment(s), risk factors for increased intracranial pressure (ICP), presenting symptoms, radiologic features observed on neuroimaging, and final disposition. When available, the neuroimaging was reviewed by an expert neuroradiologist.

RESULTS

Of 1,262 consecutive new patients, 66 (5%) were referred specifically for RAD-IH; most referrals came from neurologists (58%); 8/66 (12%) patients had papilledema; 16/66 (24%) patients had prior LP and 13/66 (20%) were already treated based on MRI findings; and 22/66 (33%) patients had ≤2 RAD-IH. Only 34/66 (52%) of patients referred for RAD-IH had prior funduscopic examinations. We confirmed papilledema in 26/82 (32%) patients referred for "papilledema." Only 29/83 (35%) patients referred with a diagnosis of IIH had active papilledema, and 3/16 (19%) patients with spontaneous CSF leaks had papilledema. In total, 247/1,262 (20%) new patients were referred to our clinic over 1 year with concern for IIH, among whom only 66 (27%) were confirmed to have active IIH with papilledema.

CONCLUSIONS

One in 5 new patient referrals seen in our neuro-ophthalmology clinic were referred because of concern for increased ICP, but only 1/4 had active papilledema. Most patients referred for isolated RAD-IH do not have papilledema, many having undergone unnecessary LPs and treatments. The burden of these "rule-out IIH" consultations is overwhelming and will only continue to increase with the concurrent rise of obesity and IIH, straining the already limited neuro-ophthalmologic resources available in the US.

Efficacy of Dural Sinus Quantitative Measurements in Idiopathic Intracranial Hypertension : A Practical Diagnostic Feature

BACKGROUND AND PURPOSE

This study aimed to investigate the potential contribution of quantitative measurements of dural venous sinuses to the diagnosis of idiopathic intracranial hypertension (IIH) and the relationship between IIH and dural venous sinus dimensions on 3D post-gadolinium T1-weighted magnetic resonance (MR) images.

MATERIAL AND METHODS

A total of 129 individuals (57 IIH patients and 72 controls) who complained of headache and underwent both magnetic resonance venography (MRV) and precontrast/postcontrast 3D T1-weighted MR imaging between 2018 and 2021 were included in this retrospective study. Dural venous sinus and jugular vein diameters were measured in all cases using post-gadolinium 3D T1 TFE images. The presence of transverse sinus (TS) hypoplasia and occipital sinus variation, the number and size of arachnoid granulations in the TS, and the presence of brain parenchymal herniation were also evaluated. Cut-off values that maximized accurate diagnosis of IIH were established on the receiver operating characteristic curve. The sensitivity and specificity of the diagnosis of IIH based on quantitative measurements of the dural sinus were calculated.

RESULTS

The ratios of the maximum to minimum TS diameters and the minimum TS diameters to minimum sigmoid sinus (SS) diameters were significantly higher in IIH patients than in the control group (p < 0.001). The diagnostic sensitivity and specificity values of TS_max/TS_min and TS_{min sum}/SS_{min sum} parameters for the detection of IIH were 84.2%, 84.7% and 83.3%, 84.2%, respectively.

CONCLUSION

Practical measurements from multiplanar T1 sequences can be useful for both quantitative assessment and overcoming misinterpretation due to anatomical variation.

Intracranial computed tomography histogram analysis detects changes in the setting of elevated intracranial pressure and normal imaging

BACKGROUND

Patients with idiopathic intracranial hypertension (IIH) have elevated intracranial pressure (ICP) of unclear etiology. This study evaluated the ability of quantitative intracranial Hounsfield unit (HU) histogram analysis to detect pathophysiological changes from elevated ICP in the setting of a normal head CT.

METHODS

Retrospective analysis of non-contrast-enhanced head CT images of IIH patients and matched controls. Following skull stripping, total intracranial CT voxels within the range of 0-70 HU were divided into seven 10 HU bins. A measurement of total intracranial HU was also calculated for each patient. Imaging studies for IIH patients were reviewed for features of IIH including transverse sinus stenosis (TSS). Histogram measures were compared between IIH and control groups and correlated with imaging and clinical data.

RESULTS

Fourteen IIH patients with CSF opening pressure ≥25 cm water, and 31 age-, sex-, and ethnicity-matched controls were included. Compared to controls, IIH patients had a significantly greater proportion of voxels in the 40-50, 50-60, and 60-70 HU bins (p = 0.003, 0.001, and 0.003, respectively) but similar proportion in the 0-10 HU range. Severity of TSS significantly correlated with total intracranial HU measures. 50-60 HU and 60-70 HU bins demonstrated high AUCs of 0.81 and 0.80, respectively, in differentiating IIH from normal status.

CONCLUSION

Idiopathic intracranial hypertension patients have a greater proportion of high intracranial HU voxels representing blood volume, which may be explained by TSS causing venous congestion. The pattern provides further insights into the pathophysiology of IIH and may be useful for detecting elevated ICP in the setting of normal head CT imaging.

Features of Idiopathic Intracranial Hypertension on MRI With MR Elastography: Prospective Comparison With Control Individuals and Assessment of Postintervention Changes

BACKGROUND. Understanding of dynamic changes of MRI findings in response to intracranial pressure (ICP) changes in idiopathic intracranial hypertension (IIH) is limited. Brain stiffness, as assessed by MR elastography (MRE), may reflect changes in ICP. OBJECTIVE. The purpose of this study was to compare pituitary height, ventricular size, and brain stiffness between patients with IIH and control individuals and to evaluate for changes in these findings in patients with IIH after interventions to reduce ICP. METHODS. This prospective study included 30 patients (28 women, two men; median age, 29.9 years) with IIH and papilledema and 21 control individuals (21 women, 0 men; median age, 29.1 years), recruited from January 2017 to July 2019. All participants underwent 3-T brain MRI with MRE; patients with IIH underwent additional MRI examinations with MRE after acute intervention (lumbar puncture with normal closing pressure; n = 11) and/or chronic intervention (medical management or venous sinus stenting with resolution or substantial reduction in papilledema; n = 12). Pituitary height was measured on sagittal MP-RAGE images. Ventricular volumes were estimated using unified segmentation, and postintervention changes were assessed by tensor-based morphometry. Stiffness pattern score and regional stiffness values were estimated from MRE. RESULTS. In patients with IIH, median pituitary height was smaller than in control individuals (3.1 vs 4.9 mm, p < .001) and was increased after chronic (4.0 mm, p = .05), but not acute (2.3 mm, p = .50), intervention. Ventricular volume was not different between patients with IIH and control individuals (p = .33) and did not change after acute (p = .83) or chronic (p = .97) intervention. In patients with IIH, median stiffness pattern score was greater than in control individuals (0.25 vs 0.15, p < .001) and decreased after chronic (0.23, p = .11) but not acute (0.25, p = .49) intervention. Median occipital lobe stiffness was 3.08 kPa in patients with IIH versus 2.94 kPa in control individuals (p = .07) and did not change after acute (3.24 kPa, p = .73) or chronic (3.10 kPa, p = .83) intervention. CONCLUSION. IIH is associated with a small pituitary and increased brain stiffness pattern score; both findings may respond to chronic interventions to lower ICP. CLINICAL IMPACT. The "partially empty sella" sign and brain stiffness pattern score may serve as dynamic markers of ICP in IIH.

Evaluation of Clinical Findings with MRI Venography in Patients with Idiopatic Intracranial Hypertension

OBJECTIVES

To evaluate clinical data and Magnetic Resonance Venography (MRV) findings together in patients with idiopathic intracranial hypertension (IIH).

MATERIALS AND METHODS

In this retrospective study between January 2009 and February 2021, conventional MRI and MRV examinations were performed on 30 patients who were admitted to the neurology service of Erciyes University Medical Faculty with the pre-diagnosis of IIH, cerebrospinal fluid (CSF) pressure was measured in these patients to confirm the diagnosis of IIH. Transverse Sinus Stenosis Ratio (TS SR), Superior Sagittal Sinus (SSS) diameter, Sinus Rectus (SR) diameter, Stenosis Segment Length (SSL) were studied.

RESULTS

High CSF pressure was detected in 22 of 30 patients with IIH pre-diagnosis. CSF pressure was normal in 8 cases. TS SR was compared in all groups, right TS SR 0.63 ± 0.16, Left TS SR 0.55 ± 0.16 in the patient group with IIH, right TS SR 0.55 ±0.16 in the CSF pressure normal patient group, Right TS SR 0.28 ± 0.07 Left TS SR 0.31 ± 0.07 in the control group Right TS SR It was 0.28 ± 0.09, Sol TS SR was 0.30 ± 0.07.

CONCLUSION

Before LP, the cranial venous system must be monitored. TS SR and CSF pressure are directly proportional. The stenosis rate is important for IIH rather than SSL.

[Idiopathic intracranial hypertension: From physiopathological mechanisms to therapeutic decision]

Clinical features include visual disturbances, headaches, and pulsatile tinnitus that can be associated with reduced quality of life, and a risk of irreversible visual impairment in some cases. Obese women of childbearing age represent the main at-risk population, and the incidence of the disease is increasing because of rising prevalence of obesity worldwide. In addition, an imbalance in sex hormones is reported as a contributing risk factor. The pathophysiology of idiopathic intracranial hypertension involves a disturbance of the evacuation pathway of intracranial fluids caused by the increase in intracranial venous pressure. Brain imaging is useful for diagnosis with several signs including bilateral stenosis of the transverse sinuses that plays a major role in the pathogenesis of the disease by creating a positive feedback loop that increases intracranial venous hypertension and contributes to clinical manifestations. Treatment aims to relieve symptoms and prevent permanent visual impairment. Drug therapies including acetazolamide and topiramate have moderate effectiveness. Among invasive treatments, transverse sinus stenting seems to be the most interesting option to consider in drug-resistant patients. Weight loss remains essential to achieve a sustainable improvement by reducing central venous pressure. Future randomized trials are expected to reach a consensus on this treatment.

Accuracy and reliability of magnetic resonance imaging in the diagnosis of idiopathic intracranial hypertension

PURPOSE

To determine the diagnostic utility of brain magnetic resonance imaging (MRI) findings in patients with idiopathic intracranial hypertension (IIH) and to investigate the significance of evaluating radiological findings together with neurological and ophthalmological data in the diagnosis of IIH.

MATERIALS AND METHODS

All consecutive patients diagnosed with IIH in our tertiary neuro-ophthalmology center between January 1, 2018 and March 15, 2020, were included in the study. The clinical, radiological, and ophthalmological findings of IIH patients were compared with the control group with similar demographic characteristics.

RESULTS

A total of 98 patients, 49 cases and 49 controls, were included in the study. Lateral ventricular index had the highest area under the curve (AUC) value (0.945) for prediction of disease group followed by sella height category (AUC = 0.915) and optic nerve tortuosity (AUC = 0.855) According to the multivariate model we developed, caudate index (OR = 0.572, 95% CI 0.329-0.996), lateral ventricle index (OR = 3.969, 95% CI 1.851-8.509) and bilateral optic nerve tortuosity (OR = 22,784, 95% CI 2.432-213.450) were significant predictors for disease group.

CONCLUSION

Tortuosity in the optic nerve, lateral ventricular index and caudate index can be used as MRI parameters supporting the diagnosis of IIH in clinically suspicious cases. A holistic approach to the clinical and radiological findings of the cases in the diagnosis of IIH can prevent overdiagnosis and enable early correct diagnosis.

Expansion of the Foramen Ovale in Patients With Cerebrospinal Fluid Leak or Encephalocele

OBJECTIVE

Spontaneous cerebrospinal fluid (CSF) leaks are associated with elevated intracranial pressure and idiopathic intracranial hypertension (IIH). Skull base erosion and widening of the foramen ovale have been reported in patients with IIH. This study sought to investigate changes in the size of the foramen ovale and foramen spinosum in patients with IIH, spontaneous CSF leak, and encephalocele.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary care academic medical center.

PATIENTS

Adult patients treated from 2014 to 2018 with computed tomographic imaging of the head and who were diagnosed with IIH, encephalocele, or CSF leak.

INTERVENTION

Two blinded observers measured the long and short axes of the foramen ovale and foramen spinosum on axial computed tomographic images. Measurements were used to calculate the approximate elliptical cross-sectional area of the foramina.

MAIN OUTCOME MEASURES

Length, width, and area of the foramen ovale and foramen spinosum.

RESULTS

A total of 264 patients were identified meeting the inclusion criteria and were placed into three groups. There were 170 patients with IIH, 48 with spontaneous CSF leak or encephalocele (CSF/E group), and 46 with traumatic or iatrogenic CSF leak (control group). Mean foramen ovale short axis (4.85 ± 1.00 mm) and cross-sectional area (30.17 ± 9.25 mm2) in the CSF/E group were significantly increased compared with measurements in patients with IIH or the control groups. Foramen ovale size was positively correlated with age in the CSF/E group. No significant difference in foramen spinosum size was found.

CONCLUSION

Skull base defect resulting in spontaneous CSF leak or encephalocele is associated with enlargement of the foramen ovale on axial computed tomography.

MRI findings differentiating tonsillar herniation caused by idiopathic intracranial hypertension from Chiari I malformation

PURPOSE

Some patients with idiopathic intracranial hypertension (IIH) have cerebellar tonsillar herniation ≥ 5 mm mimicking Chiari malformation I (CMI), which can result in misdiagnosis and unjustified treatment. Our purpose was to identify IIH patients with tonsillar herniation ≥ 5 mm (IIH_TH) and compare with CMI patients to assess imaging findings that could distinguish the two conditions.

METHODS

Ninety-eight patients with IIH, 81 patients with CMI, and 99 controls were retrospectively assessed. Two neuroradiologists blindly reviewed MR images. IIH_TH patients were compared with CMI patients and controls regarding the extent of tonsillar herniation (ETH), bilateral transverse sinus stenosis (BTSS), hypophysis-sella ratio (HSR), and bilateral tortuosity of optic nerve (BTON).

RESULTS

13/98 (13.2%) IIH patients had tonsillar herniation ≥ 5 mm (IIH_TH) and were significantly younger and had higher BMI compared with CMI patients and controls. ETH was significantly less in the IIH_TH than CMI (6.5 ± 2.4 mm vs. 10.9 ± 4.4 mm; p < 0.001). BTSS and HSR < 0.5 were more common in IIH_TH than CMI (p < 0.001 and p = 0.003, respectively). No differences were seen between CMI and controls. BTON was significantly more common in IIH_TH compared to control (p = 0.01) but not to the CMI (p = 0.36). Sensitivity and specificity to differentiate IIH_TH from CMI were 69.2% and 96.1% for BTSS and 69.2% and 75.3% for HSR < 0.5.

CONCLUSION

The presence of BTSS and/or HSR < 0.5 in patients with ETH ≥ 5 mm should suggest further evaluation to exclude IIH before considering CMI surgery.

Cerebral Venous Outflow Implications in Idiopathic Intracranial Hypertension-From Physiopathology to Treatment

In this review, we provide an update on the pathogenesis, diagnosis, and management of adults with idiopathic intracranial hypertension (IIH) and implications of the cerebral venous system, highlighting the progress made during the past decade with regard to mechanisms of the venous outflow pathway and its connection with the cerebral glymphatic and lymphatic network in genesis of IIH. Early diagnosis and treatment are crucial for favorable visual outcomes and to avoid vision loss, but there is also a risk of overdiagnosis and misdiagnosis in many patients with IIH. We also present details about treatment of intracranial hypertension, which is possible in most cases with a combination of weight loss and drug treatments, but also in selected cases with surgical interventions such as optic nerve sheath fenestration, cerebral spinal fluid (CSF) diversion, or dural venous sinus stenting for some patients with cerebral venous sinus stenosis, after careful analysis of mechanisms of intracranial hypertension, patient clinical profile, and method risks.

Population-Based Evaluation of Indirect Signs of Increased Intracranial Pressure

BACKGROUND

The Mayo Clinic Study of Aging (MCSA) is a unique prospective study that systematically evaluates the normal aging population and includes many participants undergoing both MRI and lumbar puncture (LP). Using MCSA date, we aimed to determine the prevalence of indirect signs of raised intracranial pressure (ICP) on MRI and whether these correlate with LP opening pressure (OP). This is a large-scale study that evaluates how often indirect signs of increased ICP occur in a normal population.

METHODS

MCSA participants who had an MRI within 3 months of an LP with recorded OP were included in the study. MRIs were reviewed for indirect signs of raised ICP, including pituitary to sella (P/S) ratio, cerebellar tonsillar ectopia, and optic nerve sheath diameter (ONSD). These signs were evaluated for correlations with OP and influences from body mass index (BMI) and obstructive sleep apnea (OSA).

RESULTS

Five hundred ninety-seven MCSA patients were identified who underwent both LP and MRI. Two hundred sixty (43.6%) were women. The median age was 70.7 years (range 32.6-92.7). Median OP was 152 mm H2O (range 60-314 mm H2O), with 91 (15.2%) participants having an OP ≥ 200 mm H2O. Empty or partially empty sella was seen in 81 (12.8%) of the cohort. The P/S ratio decreased with increasing OP (r = -0.3, P < 0.001). There was a weak correlation between OP and average ONSD (r = 0.184, P = 0.01), which was no longer significant when accounting for age, gender, and BMI (partial r2 = 0.014, P = 0.097). There was no correlation between OP and cerebellar tonsillar ectopia. OSA was associated with increased ONSD (P = 0.004), but this did not remain statistically significant after accounting for age, gender, and BMI (P = 0.085).

CONCLUSION

Smaller pituitary gland size correlated with increasing OP. This suggests that ICP is a continuum with some normal individuals demonstrating asymptomatic radiologic signs of raised ICP.

MRI and MR angiography evaluation of pulsatile tinnitus: A focused, physiology-based protocol

BACKGROUND AND PURPOSE

Pulsatile tinnitus (PT) is the subjective sensation of a pulse-synchronous sound, most often due to a cerebrovascular etiology. PT can severely impact quality of life and may indicate a life-threatening process, yet a timely and accurate diagnosis can often lead to effective treatment. Clinical assessment with a history and physical examination can often suggest a diagnosis for PT, but is rarely definitive. Therefore, PT should be evaluated with a comprehensive and targeted radiographic imaging protocol. MR imaging provides a safe and effective means to evaluate PT. Specific MR sequences may be used to highlight different elements of cerebrovascular anatomy and physiology. However, routine MR evaluation of PT must comply with economic and practical constraints, while effectively capturing both common and rarer, life-threatening etiologies of PT.

METHODS

In this state-of-the-art review, we describe our institutional MR protocol for evaluating PT.

RESULTS

This protocol includes the following dedicated sequences: time-of-flight magnetic resonance angiography; arterial spin labeling; spoiled gradient recalled acquisition in the steady state; time-resolved imaging of contrast kinetics; diffusion weighted imaging, and 3-dimensional fluid-attenuated inversion recovery.

CONCLUSIONS

We describe the physiologic and clinical rationale for including each MR sequence in a comprehensive PT imaging protocol, and detail the role of MR within the broader evaluation of PT, from clinical presentation to treatment.

Diagnostic performance of neuroimaging in suspected idiopathic intracranial hypertension

The diagnostic utility of neuroradiologic signs associated with idiopathic intracranial hypertension (IIH) for the evaluation of patients presenting with papilloedema remains yet to be elucidated. This multicentre retrospective cohort study assessed consecutive patients presenting with suspected papilloedema to Auckland District Health Board (NZ) and Stanford University Medical Centre (US), between 2005 and 2019, undergoing magnetic resonance imaging and venography (MRI/MRV) or computed tomography and venography (CT/CTV) prior to lumbar puncture assessment for diagnostic suspicion of IIH. Data were collected regarding demographic, clinical, radiologic, and lumbar puncture parameters, and the diagnosis of IIH was determined according to the Friedman criteria for primary pseudotumor cerebri syndrome. A total of 204 participants (174 females; mean ± SD age 29.9 ± 12.2 years) were included, and 156 (76.5%) participants fulfilled the diagnostic criteria for IIH. The presence of any IIH-associated radiologic sign on MRI/MRV demonstrated a sensitivity (95% CI) of 74.8% (65.8%-82.0%) and specificity (95% CI) of 94.7% (82.7%-98.5%), while radiologic signs on CT/CTV exhibited a sensitivity (95% CI) of 61.0% (49.9%-71.2%) and specificity (95% CI) of 100.0% (83.2%-100.0%). In summary, the modest sensitivities of radiologic signs of IIH would support the routine use of lumbar puncture assessment following neuroimaging to secure the diagnosis. However, the high specificities might lend limited support for the judicious deferment of lumbar puncture assessment among typical IIH demographic patients who consent to the inherent small risk of missed pathology, which has been proposed by some clinicians.

Pediatric Intracranial Hypertension: A Spotlight on Imaging, the Idiopathic Intracranial Hypertension Treatment Trial, and COVID-19 Associated Cases

Primary intracranial hypertension (PIH) is characterized by clinical signs of increased intracranial pressure, papilledema, elevated opening pressure, and absence of mass lesion, hydrocephalus, or meningeal enhancement on neuroimaging. Visual changes are a common presenting feature and if untreated there is risk of irreversible vision loss. There have been recent proposed changes to the criteria for PIH along with studies looking at the differences in imaging characteristics between adult and pediatric PIH. The presence of transverse sinus stenosis alone was highly sensitive and specific for pediatric PIH. The Idiopathic Intracranial Hypertension Treatment Trial was an adult, multicenter study that examined the use of acetazolamide and weight loss on the course of PIH. The study confirmed many previously held beliefs including the most common presenting symptom in PIH is headache. Most patients present with bilateral papilledema with 58.2% of patients having symmetric Frisen scale grading and within one grade in 92.8%. Although diplopia is a common reported symptom, very few have evidence of cranial nerve palsy. Male gender, high-grade papilledema, and decreased visual acuity at presentation are risk factors for treatment failure. Acetazolamide use is associated with mild metabolic acidosis. During acetazolamide treatment, monitoring for hypokalemia or aplastic anemia is not recommended. Monitoring transaminases in the titration phase of treatment should be considered due to a case of transaminitis and pancreatitis with elevated lipase. Newer case reports have also seen associations of secondary intracranial hypertension with concurrent COVID-19 infection and MIS-C.

Evolution of MRI Findings in Patients with Idiopathic Intracranial Hypertension after Venous Sinus Stenting

BACKGROUND AND PURPOSE

The correlation between imaging findings and clinical status in patients with idiopathic intracranial hypertension is unclear. We aimed to examine the evolution of idiopathic intracranial hypertension-related MR imaging findings in patients treated with venous sinus stent placement.

MATERIALS AND METHODS

Thirteen patients with idiopathic intracranial hypertension (median age, 26.9 years) were assessed for changes in the CSF opening pressure, transstenotic pressure gradient, and symptoms after venous sinus stent placement. Optic nerve sheath diameter, posterior globe flattening and/or optic nerve protrusion, empty sella, the Meckel cave, tonsillar ectopia, the ventricles, the occipital emissary vein, and subcutaneous fat were evaluated on MR imaging before and 6 months after venous sinus stent placement. Data are expressed as percentages, medians, or correlation coefficients (r) with P values.

RESULTS

Although all patients showed significant reductions of the CSF opening pressure (31 versus 21 cm H₂O; P = .005) and transstenotic pressure gradient (22.5 versus 1.5 mm Hg; P = .002) and substantial improvement of clinical symptoms 6 months after venous sinus stent placement, a concomitant reduction was observed only for posterior globe involvement (61.5% versus 15.4%; P = .001), optic nerve sheath diameter (6.8  versus 6.1 mm; P < .001), and subcutaneous neck fat (8.9  versus 7.4 mm; P = .001). Strong correlations were observed between decreasing optic nerve sheath diameters and improving nausea/emesis (right optic nerve sheath diameter, r =  0.592, P = .033; left optic nerve sheath diameter, r = 0.718, P = .006), improvement of posterior globe involvement and decreasing papilledema (r = 0.775, P = .003), and decreasing occipital emissary vein diameter and decreasing headache frequency (r = 0.74, P = .035). Decreasing transstenotic pressure gradient at 6 months strongly correlated with decreasing empty sella (r = 0.625, P = .022) and regressing cerebellar ectopia (r = 0.662, P = .019).

CONCLUSIONS

Most imaging findings persist long after normalization of intracranial pressure and clinical improvement. However, MR imaging findings related to the optic nerve may reflect treatment success.

MR findings suggestive of idiopathic intracranial hypertension in 117 patients with spontaneous cerebrospinal fluid rhinorrhea

PURPOSE

The purpose of this study is to document the prevalence of MR findings suggestive of idiopathic intracranial hypertension (IIH) in patients undergoing endoscopic repair of spontaneous CSF rhinorrhea (SCSFR).

METHODS

In a retrospective study, MR images of 117 consecutive patients who had undergone endoscopic repair of SCSFR were evaluated for features suggestive of IIH (empty sella, widened optic nerve sheath, tortuous optic nerve, flattened posterior globe, and enlarged Meckel's cave). Pituitary height was used to diagnose partial and complete empty sella. MR images were independently evaluated by two of the authors without knowledge of the clinical findings. Consensus method was used to resolve differences between the two evaluators.

RESULTS

Empty or partially empty sella was diagnosed in the MR of 105 (89.7%) patients. In 38/105 (36.2%) patients with empty/partial empty sella, no additional MR findings were present. In 43/105 (41%) patients, one or more of the MR features with high specificity for diagnosis of IIH (flattened posterior globe and enlarged Meckel's cave) were seen. In the other 24 (22.9%) additional MR findings, less specific for IIH (widened optic nerve sheath, tortuous optic nerve) were noted. Papilledema was seen in 11 of 60 (18.3%) patients who underwent funduscopic examination. All patients with papilledema had empty/partial empty sella, and 9/11 (81.8%) had an additional MR finding suggestive of IIH.

CONCLUSION

The majority of patients with SCSFR have MR imaging features of IIH. These imaging features should be a major component of previously published modified diagnostic criteria for IIH in patients with SCSFR.

Neuroimaging Features of Intracranial Hypertension in Pediatric Patients With New-Onset Idiopathic Seizures, a Comparison With Patients with Confirmed Diagnosis of Idiopathic Intracranial Hypertension: A Preliminary Study

A cutoff value of 6.0 mm for optic nerve sheath dilation may be used as a screening imaging marker to suspect elevated opening pressure with specificity of 88% in pediatric patients with new-onset idiopathic seizures.

Sensitivity and specificity of neuroimaging signs in patients with idiopathic intracranial hypertension

BACKGROUND

The primary role of neuroimaging in idiopathic intracranial hypertension (IIH) is to exclude secondary causes of raised intracranial pressure. Recently, a few imaging markers have been described which may suggest diagnosis of IIH in atypical cases. We carried out this study to assess the prevalence and accuracy of these neuroimaging signs in predicting the diagnosis of IIH.

METHODS

Eighty treatment-naive patients with IIH and 30 controls were recruited as per a predefined criterion. Magnetic resonance imaging (MRI) brain with detailed sella imaging was done in all patients.

RESULTS

The most common abnormality noted was optic nerve tortuosity in 82.5% of patients, followed by posterior scleral flattening in 80%, perioptic subarachnoid space (SAS) dilatation in 73.8% and partial empty sella in 68.8% of patients. The presence of optic nerve tortuosity was the most sensitive sign on neuroimaging, though the highest specificity was seen for posterior scleral flattening and perioptic SAS dilatation. The presence of more than three neuroimaging features correlated with severity of vision loss.

CONCLUSION

In suggestive clinical scenarios, posterior scleral flattening, perioptic SAS dilatation and optic nerve tortuosity are highly sensitive and specific signs in IIH. This study also highlights the utility of MRI as a valuable tool for prognosis of visual outcome in patients with IIH.

Neuro-Ophthalmic Manifestations of Mollaret Meningitis

ABSTRACT

Mollaret meningitis (MM) refers to benign recurrent aseptic meningitis usually following herpes simplex virus 2 (HSV-2) infection. Neuro-ophthalmic manifestations associated with MM are rarely reported. We present a case of recurrent HSV-2 meningitis with the neuro-ophthalmic presentation of papilledema and sixth nerve palsy. To our knowledge, this is the first such description in the English language ophthalmic literature.

Atypical idiopathic intracranial hypertension presenting as cyclic vomiting syndrome: a case report

Background

Idiopathic intracranial hypertension is a disorder of increased intracranial pressure in the absence of cerebrospinal outflow obstruction, mass lesion, or other underlying cause. It is a rare phenomenon in prepubertal children and is most typically found in women of childbearing age. The classic presentation consists of headaches, nausea, vomiting, and visual changes; however, children present more atypically. We report a case of idiopathic intracranial hypertension in an otherwise healthy, 4-year-old child with atypical symptoms resembling those of cyclic vomiting syndrome.

Case presentation

A 4-year-old Caucasian, otherwise healthy, male child presented to our emergency department with episodic intermittent early-morning vomiting occurring once every 1–3 weeks without interepisodic symptoms, starting 10 months prior. With outpatient metabolic, autoimmune, endocrine, allergy, and gastroenterology work-up all unremarkable, he was initially diagnosed with cyclic vomiting syndrome. Discovery of mild optic nerve sheath distension on magnetic resonance imaging of the brain 10 months after symptom onset led to inpatient admission and a lumbar puncture notable for an opening pressure of 47 mmHg, with normal cell count and protein levels. He had no changes in visual acuity or optic disc edema on dilated fundoscopic examination. The patient was started on acetazolamide, with resolution of episodic emesis at his last follow-up visit 12 weeks after discharge.

Conclusions

Idiopathic intracranial hypertension presents atypically in prepubescent children, with about one-fourth presenting asymptomatically, and only 13–52% presenting with “classic” symptoms. With a prevalence of only 0.6–0.7 per 100,000, much remains unknown regarding the underlying pathophysiology in this demographic. Cyclic vomiting syndrome, however, has a much higher prevalence in this age group, with a prevalence of 0.4–1.9 per 100. It is thought to be an idiopathic, periodic disorder of childhood, often linked to neurological conditions such as abdominal migraines, epilepsy, mitochondrial disorders, and structural lesions such as chiari malformation and posterior fossa tumors. While cyclic vomiting syndrome is thought to have a benign course, untreated idiopathic intracranial hypertension can have long-term detrimental effects, such as visual loss or even blindness. We present a case of idiopathic intracranial hypertension presenting with symptoms resembling cyclic vomiting syndrome in a 4-year-old child, diagnosed 10 months after initial onset of symptoms. We aim to demonstrate the need for a high level of clinical suspicion and the need for further investigation into underlying pathophysiology in this vulnerable population.

The significance of ONSD, ONSD/ETD ratio, and other neuroimaging parameters in idiopathic intracranial hypertension

Background: The measurement of the optic nerve sheath diameter (ONSD) has been suggested to be used in the evaluation of intracranial pressure of several etiologies. However, its potential utility in the clinical evaluation of patients with idiopathic intracranial hypertension (IIH) needs to be clarified.Methods: We recruited all the IIH patients who had been admitted to our neurology clinics and had a cranial MRI before lumbar puncture investigation. A control group of patients with migraine was also included. Studies were reviewed blindly by a radiologist, and ONSD and ONSD/ eyeball transverse diameter (ETD) for both eyes were measured.Results: Ultimately, we have enrolled 50 patients with IIH and 53 migraineurs. The right ONSD values were higher in the IIH group (p = 0.024) whereas the values of ONSD/ETD were found to be both higher in the IIH group (right: p = 0.006, left: p = 0.043). The ROC curve demonstrated an area under the curve of 0.620 (95% CI = 0.508 to 0.731) for ONSD, and it was 0.642 for ONSD/ETD. Using a cut-off of 6.3 mm, ONSD had the following performance characteristics: sensitivity 18%, specificity 81%.Conclusions: The ONSD and ONSD/ETD values may be utilizable in the evaluation processes of IIH patients; however, they do not solely reach sufficient discriminative accuracy. The potential significance of these parameters in rather monitoring the IIH patients may constitute a strictly crucial topic of interest for future research.

Venous sinus stenting after repair of skull base spontaneous cerebrospinal fluid leaks: A single-center retrospective cohort series with case-control analysis

BACKGROUND

Management of idiopathic intracranial hypertension (IIH) is recommended after surgical repair of spontaneous cerebrospinal fluid leaks (sCSF-leaks) of the skull base for prevention of recurrence.

PURPOSE

To assess the feasibility of venous sinus stenting, a treatment commonly used for the treatment of IIH associated with intracranial venous sinus stenosis (VSS), after sCSF-leaks closure.

MATERIALS AND METHODS

A single-center cohort series of consecutive patients who underwent sCSF-leak closure was retrospectively analyzed. Stenting was considered either for leak recurrence or in prophylactic manner after repair in patients with VSS as confirmed by cerebral venous imaging. Leak recurrence, need for new repair or adjunctive treatment of IIH, meningitis, and stenting complications were determined at the last follow-up. Cases who had prophylactic stenting were compared to historical controls before stenting option.

RESULTS

Twenty-two patients had intracranial venous stenting after sCSF-leak closure. Their median age was 58 years (Q1=45; Q3=68), BMI=31 kg.m^-2 (Q1=27; Q3=36), and female rate=85%. The overall rate of successful repair after stenting was 95% (95% CI = 87-100%) at a median follow-up of 2.4 years (Q1=1.2; Q3=3.3). Adjunctive treatment for IIH was needed in 4 patients (4/22, 18%) including 2 patients without leak recurrence. No meningitis, permanent morbidity or mortality was observed after stenting. Compared to 18 controls, cases had significantly less recurrence (P = 0.03), and a trend for less adjunctive treatment for IIH (P = 0.06).

CONCLUSIONS

Our study suggests that stenting might be a valid option for prevention of sCSF-leak recurrences after repair in patients with intracranial venous sinus stenosis.

Pseudotumor cerebri in the paediatric population: clinical features, treatment and prognosis

INTRODUCTION

Pseudotumor cerebri (PC) in prepubertal patients displays certain characteristics that differentiate it from its presentation at the postpubertal stage. The aim of this study is to describe the characteristics of paediatric patients diagnosed with PC at our centre and to compare them according to their pubertal status.

PATIENTS AND METHODS

We included patients aged between 1 and 18 years who were diagnosed with PC in a tertiary-level hospital between 2006 and 2019 and who met the updated diagnostic criteria for PC. They were classified according to body weight and pubertal status. Subsequently, we analysed results from lumbar punctures, neuroimaging studies, ophthalmological assessments, and treatments received during follow-up.

RESULTS

We included 28 patients, of whom 22 were of prepubertal age and 6 were of postpubertal age. The mean age (standard deviation) was 9.04 (2.86) years. Among the postpubertal patients, 83.3% were boys, 66.7% of whom presented overweight/obesity. In the group of prepubertal patients, 27% were boys, 31.8% of whom were overweight. The most frequent symptoms were headache (89.9%) and blurred vision (42.9%). All patients presented papilloedema, and 21.4% manifested sixth nerve palsy. Possible triggers were identified in 28.6% of cases. Nineteen percent of patients presented clinical recurrence, all of whom were prepubertal patients. Complete clinical resolution was achieved in 55.6% of patients.

CONCLUSION

Prepubertal patients with PC show lower prevalence of obesity, higher prevalence of secondary aetiologies, and higher recurrence rates than postpubertal patients.

Etiology, pathogenesis and management of idiopathic intracranial hypertension, and role of optic canal size in asymmetric papilledema: A review

Idiopathic intracranial hypertension (IIH) is characterized by raised intracranial pressure of unknown origin that primarily afflicts obese women of childbearing age. There are several treatment options, but currently there are none that are effective for the entire affected population. The lack of a universally effective treatment is related to an incomplete understanding of the etiology of the condition and the lack of a well-defined pathophysiological mechanism for the disease process. Classically, IIH has been thought of as a diagnosis of exclusion once radiographical imaging has ruled out all other causes of elevated intracranial pressure. Today, we know that imaging does capture subtle changes, and might provide keys to finally understand the pathogenesis of IIH so that a definitive treatment can be discovered or developed. Recently, advancements in radiography, optical coherence tomography, and electroretinography have shown promise for the future of IIH evaluation. A topic within IIH imaging that has recently sparked interest is the possibility that the severity of papilledema may have an association with the size of the optic canal. In this article, we also discuss the recent studies on the relationship between asymmetric papilledema and optic canal size.

The Diagnostic Accuracy of Noninvasive Methods to Measure the Intracranial Pressure: A Systematic Review and Meta-analysis

BACKGROUND

Although invasive monitoring is the standard method for intracranial pressure (ICP) measurement, it is not without potential for serious complications. Noninvasive methods have been proposed as alternatives to invasive ICP monitoring. The study aimed to investigate the diagnostic accuracy of the currently available noninvasive methods for intracranial hypertension (ICH) monitoring.

METHODS

We searched 5 databases for articles evaluating the diagnostic accuracy of noninvasive methods in diagnosing ICH in PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase. The quantitative analysis was conducted if there were at least 2 studies evaluating a specific method. The accuracy measures included the sensitivity, specificity, likelihood ratios, and diagnostic odds ratio.

RESULTS

We included 134 articles. Ultrasonographic optic nerve sheath diameter (US ONSD) had high diagnostic accuracy (estimated sensitivity of 90%; 95% confidence interval [CI], 87-92, estimated specificity of 88%; 95% CI, 84-91) while the magnetic resonance imaging (MRI) ONSD had estimated sensitivity of 77%; 95% CI, 64-87 and estimated specificity of 89%; 95% CI, 84-93, and computed tomography (CT) ONSD had estimated sensitivity of 93%; 95% CI, 90-96 and estimated specificity of 79%; 95% CI, 56-92. All MRI signs had a very high estimated specificity ranging from 90% to 99% but a low estimated sensitivity except for sinus stenosis which had high estimated sensitivity as well as specificity (90%; 95% CI, 75-96 and 96%; 95% CI, 91-99, respectively). Among the physical examination signs, pupillary dilation had a high estimated specificity (86%; 95% CI, 76-93). Other diagnostic tests to be considered included pulsatility index, papilledema, transcranial Doppler, compression or absence of basal cisterns, and ≥10 mm midline shift. Setting the cutoff value of ICH to ≥20 mm Hg instead of values <20 mm Hg was associated with higher sensitivity. Moreover, if the delay between invasive and noninvasive methods was within 1 hour, the MRI ONSD and papilledema had a significantly higher diagnostic accuracy compared to the >1 hour subgroup.

CONCLUSIONS

Our study showed several promising tools for diagnosing ICH. Moreover, we demonstrated that using multiple, readily available, noninvasive methods is better than depending on a single sign such as physical examination or CT alone.

A Unique Subset: Idiopathic Intracranial Hypertension Presenting as Spontaneous CSF Leak of the Anterior Skull Base

Introduction Spontaneous cerebrospinal fluid (CSF) leaks represent a unique clinical presentation of idiopathic intracranial hypertension (IIH), lacking classical features of IIH, including severe headaches, papilledema, and markedly elevated opening pressures.

Methods Following a single-institution retrospective review of patients undergoing spontaneous CSF leak repair, we performed a literature review of spontaneous CSF leak in patients previously undiagnosed with IIH, querying PubMed.

Results Our literature review yielded 26 studies, comprising 716 patients. Average age was 51 years with 80.8% female predominance, and average body mass index was 35.5. Presenting symptoms included headaches (32.5%), visual disturbances (4.2%), and a history of meningitis (15.3%). Papilledema occurred in 14.1%. An empty sella was present in 77.7%. Slit ventricles and venous sinus stenosis comprised 7.7 and 31.8%, respectively. CSF leak most commonly originated from the sphenoid sinus (41.1%), cribriform plate (25.4%), and ethmoid skull base (20.4%). Preoperative opening pressures were normal at 22.4 cm H2O and elevated postoperatively to 30.8 cm H2O. 19.1% of patients underwent shunt placement. CSF leak recurred after repair in 10.5% of patients, 78.6% involving the initial site. A total of 85.7% of these patients were managed with repeat surgical intervention, and 23.2% underwent a shunting procedure.

Conclusion Spontaneous CSF leaks represent a distinct variant of IIH, distinguished by decreased prevalence of headaches, lack of visual deficits, and normal opening pressures. Delayed measurement of opening pressure after leak repair may be helpful to diagnose IIH. Permanent CSF diversion may be indicated in patients exhibiting significantly elevated opening pressures postoperatively, refractory symptoms of IIH, or recurrent CSF leak.

Neuroimaging in Children with Ophthalmological Complaints: A Review

Pediatric patients are commonly referred to imaging following abnormal ophthalmological examinations. Common indications include papilledema, altered vision, strabismus, nystagmus, anisocoria, proptosis, coloboma, and leukocoria. Magnetic resonance imaging (MRI) of the brain and orbits (with or without contrast material administration) is typically the imaging modality of choice. However, a cranial CT scan is sometimes initially performed, particularly when MRI is not readily available. Familiarity with the various ophthalmological conditions may assist the radiologist in formulating differential diagnoses and proper MRI protocols afterward. Although MRI of the brain and orbits usually suffices, further refinements are sometimes warranted to enable suitable assessment and accurate diagnosis. For example, the assessment of children with sudden onset anisocoria associated with Horner syndrome will require imaging of the entire oculosympathetic pathway, including the brain, orbits, neck, and chest. Dedicated orbital scans should cover the area between the hard palate and approximately 1 cm above the orbits in the axial plane and extend from the lens to the midpons in the coronal plane. Fat-suppressed T2-weighted fast spin echo sequences should enable proper assessment of the globes, optic nerves, and perioptic subarachnoid spaces. Contrast material should be given judiciously, ideally according to clinical circumstances and precontrast scans. In this review, we discuss the major indications for imaging following abnormal ophthalmological examinations.

Idiopathic intracranial hypertension: a review of diagnosis and management

With the increasing prevalence of obesity, the incidence of idiopathic intracranial hypertension (IIH) is rising. Headache and threat to vision are the predominant features and the principal cause of morbidity and reduced quality of life. Identification of papilloedema must prompt urgent investigation to exclude any underlying cause and management should be multi-disciplinary, focusing on protecting vision and reducing headache burden. Weight loss is the most effective and only disease modifying treatment for IIH but surgical interventions may need to be considered in some patients. Whilst optic nerve sheath fenestration and CSF diversion have established roles in protecting vision, there is increasing interest in venous sinus stenting and bariatric surgery as additional interventions that may have efficacy in the treatment of this condition.