Pulsatile Tinnitus: Differential Diagnosis and Approach to Management.

PURPOSE OF REVIEW: The purpose of this review is to provide an updated approach to the evaluation and management of pulsatile tinnitus (PT), an uncommon but often treatable subtype of tinnitus. RECENT FINDINGS: Secondary PT can be due to either vascular or non-vascular etiologies, including, but not limited to: neoplasm, arteriovenous malformation or fistula, idiopathic intracranial hypertension, dural venous sinus stenosis, otoacoustic etiologies (e.g., otosclerosis, patulous eustachian tube) and bony defects (e.g., superior semicircular canal dehiscence). Computed tomography (CT) and magnetic resonance imaging (MRI) imaging have comparable diagnostic yield, though each may be more sensitive to specific etiologies. If initial vascular imaging is negative and a vascular etiology is strongly suspected, digital subtraction angiography (DSA) may further aid in the diagnosis. Many vascular etiologies of PT can be managed endovascularly, often leading to PT improvement or resolution. Notably, venous sinus stenting is an emerging therapy for PT secondary to idiopathic intracranial hypertension with venous sinus stenosis. Careful history and physical exam can help establish the differential diagnosis for PT and guide subsequent evaluation and management. Additional studies on the efficacy and long-term outcome of venous sinus stenting for venous stenosis are warranted.

Causes of Pulsatile Tinnitus and Treatment Options.

Pulsatile tinnitus (PT) requires detailed workup to evaluate for an underlying structural cause. With advances in neuroimaging, structural venous abnormalities that can cause PT have becoming increasingly recognized. A number of anomalies, including dural arteriovenous fistulas, idiopathic intracranial hypertension, transverse sinus stenosis, sigmoid sinus wall abnormalities, jugular venous anomalies, and hypertrophied emissary veins, have been implicated in flow disruption and turbulence in the vicinity of auditory structures, resulting in PT. Endovascular treatment options, including stenting, coiling, and embolization with liquid agents, have demonstrated high efficacy and safety. These treatments can lead to symptomatic relief in carefully selected cases.

Endovascular stenting for cerebral venous sinus stenosis secondary to meningioma invasion.

INTRODUCTION: Symptomatic intracranial hypertension (IH) due to venous outflow obstruction secondary to dural venous sinus (DVS) tumoral invasion affects up to 3% of intracranial meningioma patients. The literature regarding endovascular therapies of such patients is limited to a few case reports and a recent single-centre case series. PURPOSE: We describe our single-centre experience of endovascular therapy in patients with clinically symptomatic IH secondary to DVS meningioma invasion. METHODS: We performed a retrospective review of clinical and radiological data of all patients with refractory IH and meningiomas invading the DVS who were referred for possible DVS venoplasty and stenting. Seven endovascular procedures in six female patients were done. Presumed secondarily induced lateral transverse sinus stenosis was also stented in four patients as part of the primary intervention. RESULTS: All patients experienced complete symptomatic resolution at 6-month follow-up. Five patients had no symptom recurrence over a mean follow-up period of 3.5 years. One patient with multiple meningiomas developed recurrent IH 2 years following stenting secondary to in-stent tumour re-invasion. This was re-stented with consequent 6 months post-retreatment symptomatic relief at the time of writing. No procedure-related complications occurred. CONCLUSION: In the setting of DVS stenosis secondary to meningioma invasion, endovascular therapy is a safe and successful therapeutic option with promising mid-term results. The procedure should be considered in cases where complete surgical tumour resection is unlikely or carries a significant risk. If present, secondarily induced stenoses at the lateral ends of the transverse sinuses should also be considered for treatment.

Intensive mannitol slow infusion post-stenting may attenuate stenting-related early adverse effects in patients with cerebral venous sinus stenosis.

AIMS: To analyze intensive slow mannitol poststenting on attenuating stenting-related early adverse effects in cerebral venous sinus stenosis (CVSS). METHODS: This real-world study enrolled subacute or chronic CVSS patients from January 2017 through March 2022 and divided them into DSA only and stenting post-DSA groups. The later group was subdivided into control (without extra mannitol use) and intensive slow mannitol subgroup (immediate extra mannitol 250-500 mL, 2 mL/min infusion post-stenting) after signed informed consent. All data were compared. RESULTS: A total of 95 eligible patients entered into final analysis, in which 37 cases underwent DSA only and 58 cases underwent stenting post-DSA. Finally, 28 patients were entered into intensive slow mannitol subgroup and 30 in control. Stenting group vs. DSA group, HIT-6 scores and WBC counts were higher in the former (both p < 0.001). Intensive slow mannitol subgroup vs. control on the third day post-stenting, a statistically significant reductions were noticed in the former on WBC counts (6.19 ± 1.86 × 109 /L vs. 9.59 ± 2.05 × 109 /L); HIT-6 scores (degree of headache) (40.00 (38.00-40.00) vs. 49.00 (41.75-55.25)) and brain edema surrounding the stent on CT maps (17.86% vs.96.67%), all p < 0.001. CONCLUSIONS: Stenting-related severe headache, inflammatory biomarkers elevation, and brain edema aggravation can be attenuated by intensive slow mannitol infusion.

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.

The Effects of Pressure Gradient on Papilledema Improvement After Venous Sinus Stenting in Idiopathic Intracranial Hypertension.

PURPOSE: This study aimed to evaluate the impact of the pressure gradient on papilledema after stenting in patients with idiopathic intracranial hypertension (IIH) patients and venous sinus stenosis (VSS). MATERIALS AND METHODS: In this prospective cohort study, we examined 121 patients with IIH and VSS who underwent stenting. The papilledema Frisen grade at the 1-month follow-up was used as a grouping factor (favorable outcome: 0-1; unfavorable outcome: 2-5). We used multivariable logistic regression modeling to determine independent predictors of favorable outcome. The performance of the prediction model was evaluated using a receiver operating characteristic (ROC) analysis. RESULTS: A total of 96 patients had papilledema grades 0 to 1, and 25 patients had papilledema grades 2 to 5. Patients with the first group had significantly lower gradient pressures preoperatively (15.2 mmHg vs. 21.4 mmHg, p=0.001) and postoperatively (2 mmHg vs. 3.3 mmHg, p=0.002) relative to those in the second group. Multivariate analysis indicated that preoperative pressure gradient (odds ratio [OR] = 1.119; 95% confidence interval [CI] = 1.034-1.211]) and postoperative pressure gradient (OR = 1.498; 95% CI = 1.147-1.957) were independent predictors of favorable outcome. In the ROC analysis, the cut-off pressure gradient for the highest sensitivity (0.44) and specificity (0.874) was 22.75 mmHg, with a Youden's index of 0.314. Survival analysis demonstrated that patients with a preoperative pressure gradient <22.75 mmHg had more rapid improvement of papilledema than did those with a pressure gradient >22.75 mmHg (mean+SD: 2.639+0.382 [95% CI: 1.890-3.388] versus mean+SD: 3.882+0.884 [95% CI: 2.149-5.616]; p=0.004). CONCLUSION: A significant reduction in the pressure gradient appears to be strongly correlated with the success of VSS in patients with IIH. A higher preoperative pressure gradient may reduce stenting efficacy in patients with IIH. CLINICAL IMPACT: Venous sinus stenting has the potential to yield substantial clinical advantages in individuals diagnosed with idiopathic intracranial hypertension with venous sinus stenosis. Nevertheless, a heightened preoperative pressure gradient could lead to less favorable results. Thus, the early adoption of venous sinus stenting is advised to avert additional irreversible clinical deterioration among idiopathic intracranial hypertension patients with venous sinus stenosis.

Cerebral venous sinus stenting in idiopathic intracranial hypertension.

Cerebral venous sinus stenting (CVSS) is a minimally invasive procedure using endovascular stent placement to relieve elevated intracranial pressure secondary to venous sinus stenosis. Increased venous sinus pressure secondary to stenosis is commonly associated with elevated intracranial pressure without intracranial lesions on imaging or idiopathic intracranial hypertension (IIH). While the etiology of IIH remains unknown, stenosis of one or more of the dural sinuses has been implicated as a possible underlying mechanism. The manifestations of IIH include headaches, transient vision loss, pulsatile tinnitus, and neck pain. In this review, we discuss the recent studies that have demonstrated the e!ectiveness of CVSS for patients with IIH and also the indications, technical challenges, potential complications, and emerging developments in CVSS.

Coronary Stent for Right Transverse Venous Sinus Stenosis in a Patient With Symptomatic Idiopathic Intracranial Hypertension.

A 59-year-old woman was referred to the neuro-interventional team with complaints of headache, papilledema, and visual disturbances. Imaging and Lumbar puncture revealed signs consistent with idiopathic intracranial hypertension with stenosis of the right transverse venous sinus. The neurosurgery board chose to treat her with an endovascular approach and stenting. During the procedure, the right jugular vein revealed decreased blood flow. This led to a left jugular vein access through the confluence of venous dural sinuses. However, an incomplete confluence required the catheter to ascend the superior sagittal sinus before descending to the right transverse sinus. The carotid catheter system kept herniating up the SSS, risking rupture. Given the intraoperative findings and the available equipment, a more flexible coronary catheter system was chosen. This catheter device allowed plasty and successful stent deployment. A lumbar puncture was performed, and the patient was discharged. A follow-up MRI at five weeks showed signs of intracranial hypertension improvement and the patient reported Improvement in symptoms. To our knowledge, this is the first time this type of device has been used in this anatomical location for this pathology.

Intracranial venous stenting for idiopathic intracranial hypertension.

INTRODUCTION: There is increasing evidence in the literature to support venous sinus stenting in patients with idiopathic intracranial hypertension who fail first-line therapy. Venous sinus stenting is a safe and successful technique compared with cerebrospinal fluid diversion procedures. This study examines the clinical outcomes of patients post intracranial venous stenting for intracranial hypertension across three tertiary hospitals in Western Australia. METHODS: A retrospective analysis was performed on 83 consecutive patients treated with intracranial venous stenting for IIH at three tertiary hospitals from October 2013 to March 2020. Data were collected from outpatient clinic letters, electronic discharge letters, electronic radiological imaging and procedural reports. RESULTS: 89.2% patients were able to cease Acetazolomide post stenting. 78.3% patients reported resolution of headaches. 84.3% patients demonstrated resolution of their papilloedema. 91.6% patients demonstrated improvement of their visual acuity. Compared with a recent meta-analysis by Satti and Chaudry in 2015, our results demonstrated a higher technical success rate and lower complication rates. CONCLUSION: Our study findings support the paradigm shift from CSF diversion procedures to venous sinus stenting in patients with IIH who fail first-line therapy. Venous sinus stenting has a high technical success rate and significantly lower complication rates than other invasive treatments.

Dynamic interaction between cerebrospinal fluid and sinovenous pressure in idiopathic intracranial hypertension: a case report.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a common neurosurgical condition, and the exact pathophysiology remains elusive. Cerebral sinovenous stenosis (CSS) and the resultant decreased venous outflow have been labelled as a potential contributors to the pathophysiology of IIH. We describe the effect of cerebrospinal fluid (CSF) drainage on sinovenous pressure in a patient with IIH and a radiographic evidence of CSS. CASE DESCRIPTION: A patient in their 40s with a diagnoses of IIH and imaging finding of focal stenosis of the distal left transverse sinus. To assess the nature of the stenosis, we performed venous sinus pressure monitoring with concurrent CSF drainage (5 ml at one minute intervals) through a lumbar drain with continuous mean sinovenous pressures recording. We observed a progressive decline in the pressure recording while draining CSF, after draining 40 ml of CSF, the final pressure gradient recording of the TS-SS trans-stenotic was (7 mm Hg from 27 mm Hg), mean SSS pressure (37 mm Hg from 60 mm Hg), and mean TS pressure (35 mm Hg from 56 mm Hg). The mean SS pressure remained relatively unperturbed. CONCLUSION: Our findings indicate that the cerebral sinovenous pressure response to CSF removal generally conforms to a monophasic exponential decay model.

Association of post-intervention pressure gradient with symptom-free at 6 months in idiopathic intracranial hypertension with venous sinus stenosis treated by stenting.

OBJECTIVE: This study aimed to identify the key factors that might affect the clinical outcome of patients with idiopathic intracranial hypertension (IIH) and Venous sinus stenting (VSS). METHODS: We performed an analysis of a prospectively collected database of patients with IIH and VSS who underwent stenting. The trans-stenotic pressure gradient was measured before and after intervention. In additional, patients' baseline characteristics, procedure details and clinical outcomes at 6-month follow-up (including changes in headache, visual impairment, papilledema, etc.) were recorded. The effects of post-intervention pressure gradient on symptom-free at 6 months were explored using logistic regression analysis, generalized additive model and receiver operator characteristic (ROC) curve. RESULTS: Of 101 patients included in this study, the median pressure gradient across stenosis decreased from 19 mmHg before intervention to 2 mmHg after intervention. At 6 months, symptom-free was observed in 58 cases (57.4%). Multivariable logistic analysis and generalized additive model showed that post-intervention pressure gradient (increased by 1 mmHg) was independently and linearly correlated with symptom-free (OR = 0.79, 95% CI = 0.67-0.94). Moreover, the post-intervention pressure gradient revealed moderate discrimination with an area under ROC curve of 0.68 (95% CI = 0.57-0.78). Similar associations were observed for the disappearance of headache and papilledema, but not for the visual recovery. CONCLUSION: The post-intervention pressure gradient may be a valid and reliable predictor of 6-month clinical outcome in patients with IIH and VSS treated by stenting. Nevertheless, external validation with blinded outcome is still needed to confirm its performance before clinical application.

Comparison of microcatheter and pressure wire for venous sinus manometric evaluation of patients with idiopathic intracranial hypertension.

BACKGROUND: Venous sinus manometry performed by microcatheter to assess candidacy for venous sinus stenting in patients with idiopathic cranial pressure (IIH) can be tiring, time-consuming and unreliable. Pressure wire is widely used to measure coronary pressure and evaluate coronary stenosis severity, but venous sinus manometry using the pressure guide wire has only been reported in one case, and few studies have examined the accuracy of this approach. OBJECTIVE: To compare venous manometry performed by microcatheter with by pressure wire under awake setting in patients with IIH. METHODS: The manometry results of 30 patients with IIH were recorded by Rebar-27 microcatheter and a pressure wire under awake setting. The mean venous pressures (MVPs) and trans-stenosis pressure gradients were obtained and compared between microcatheter and pressure wire. Paired t-test) were used to evaluate the data between the two groups. RESULTS: MVPs in superior sagittal sinus (SSS) and torcula were slightly higher with microcatheter, though without statistically significant differences (p > 0.05). MVPs in transverse sinus (TS) and sigmoid sinus (SS) were significantly higher with microcatheter (p < 0.05). Trans-stenotic pressure gradient with microcatheter was significantly higher than with pressure wire (p＜0.001). CONCLUSIONS: Intracranial venous pressure measured with the microcatheter and pressure wire showed a moderate difference. Compared with the traditional microcatheter method，the pressure wire is safe, fast and effective method to identify the patient needing intervention.

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 TSmax/TSmin and TSmin sum/SSmin 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.

Elusive Neck Carcinoma Simulating Idiopathic Intracranial Hypertension Due to Jugular Venous Outflow Obstruction - Case Report.

Few cases have been reported of extra-cranial tumours in the neck causing intracranial hypertension due to jugular vein compression and consequent outflow obstruction. We present a case of a patient presenting with transient vision loss due to intracranial hypertension of unidentifiable cause on initial imaging workup. Upon further evaluation, the patient was found to have a neck tumour compressing the right jugular vein with stenosis of the ipsilateral transverse sinus - both contributing to his intracranial hypertension. Atypical patients presenting with symptoms concerning for intracranial hypertension may benefit from imaging below the level of the head to evaluate for extra-cranial causes.

Technical and clinical success after venous sinus stenting for treatment of idiopathic intracranial hypertension using a novel guide catheter for access: Case series and initial multi-center experience.

INTRODUCTION: Venous sinus stenting is a well established alternative to cerebrospinal fluid diversion for the treatment of idiopathic intracranial hypertension (IIH) with associated venous sinus stenosis. During this procedure, distal guide catheter placement within the venous sinuses may be desirable to facilitate stent delivery. We report our initial experience using the TracStar LDP™ (Imperative Care, Campbell, USA, 0.088-inch inner diameter) as the guide catheter for intracranial access during venous sinus stenting. METHODS: A multi-institutional retrospective chart review of a prospectively maintained IRB-approved database was performed. Consecutive patients who underwent venous sinus stenting from 1/1/2020-9/6/2021 for IIH were included. Patient characteristics, procedural details, TracStar distal reach, outcomes, and complications were collected and analyzed. RESULTS: Fifty-eight patients were included. The mean age was 33.8 years and 93.1% of patients were female. Visual changes prompted evaluation in 86.2% of patients. Stent placement was successful in all patients. The TracStar LDP catheter was advanced to the location of stent placement in 97.9% of cases in which it was attempted. The large 0.088-inch inner diameter lumen enabled compatibility with all desired stent sizes ranging from six to 10 millimeters. Gradient pressure across transverse sinus stenosis dropped from an average of 19.5 mmHg pre-procedure to 1.7 mmHg post-stent placement (p < 0.001). Clinical improvement was achieved in 87.9% (51/58) of patients. There were no catheter-related complications. CONCLUSION: The TracStar LDP is a safe and effective access platform for reaching treatment locations in patients who present with idiopathic intracranial hypertension and who are candidates for venous sinus stent placement.

Diastolic blood pressure predicts enlarged vertebral venous plexus and intracranial pressure in patients with bilateral transverse sinus stenosis.

Background: Bilateral transverse sinus stenosis (BTSS) is associated with intracranial hypertension. Enlarged vertebral venous plexus (EVVP) refers to a compensation mechanism against elevated intracranial pressure (ICP) in patients with BTSS. This study aims to investigate the influencing factors of EVVP. Methods: Patients with BTSS were prospectively recruited from the neurology department and neurosurgery department of Xuanwu Hospital Capital Medical University from January 2020 to December 2021. Results: A total of 37 patients were enrolled with a mean age of 45.42 ± 15.64 years. Women tend to be more susceptible to BTSS. The most common co-morbid disease was hypertension. The most common clinical manifestations were visual disorders, headaches, and tinnitus. BMI and DBP were significantly higher in BTSS patients without EVVP than those with EVVP. Multivariate analysis revealed that diastolic blood pressure (DBP) was negatively correlated with EVVP. In addition, a positive correlation between DBP and the ICP was also observed. A DBP of 81.5 mmHg was calculated as the cutoff value for the presence of EVVP. BTSS patients with DBP ≤ 81.5 mmHg had a higher incidence of EVVP and a lower ICP compared to those with DBP > 81.5 mmHg. Conclusions: DBP was identified as an independent predictor of EVVP. DBP was lower (≤81.5 mmHg) in patients with EVVP and therefore was associated with a lower ICP in patients with BTSS.

Life-threatening idiopathic intracranial hypertension: the role of venous sinus stenting.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a clinical syndrome characterised by raised intracranial pressure with no discernible aetiology. It is relatively rare in children and its demographic features may differ from those of adults. The relationship between IIH and venous sinus stenosis (VSS) is well known. As VSS plays an important role in the pathophysiology, treatments have been developed aimed at improving venous blood outflow in refractory IIH. In the last two decades, venous sinus stenting has emerged as a treatment option in cases where stenosis is documented. METHODS AND RESULTS: The scientific literature on paediatric cases of IIH and its treatment with venous sinus stenting was analysed. We present the case of a 6-year-old girl with a life-threatening presentation of IIH, who was treated with transverse sinus stenting and a lumboperitoneal shunt. We summarise the characteristic of paediatric stenting cases reported and review the literature focusing on the main aspects of venous sinus stenting. CONCLUSION: VSS stenting could be a treatment tool for the acute presentation of IIH with severe symptoms and VSS plus an elevated trans-stenotic pressure gradient. However, in some cases, additional surgical treatment may be necessary.

Safety and efficacy comparison between OACs plus single antiplatelet and dual antiplatelet therapy in patients with cerebral venous sinus stenosis poststenting.

BACKGROUND AND PURPOSE: The present strategies regarding poststent management for cerebral venous sinus stenosis (CVSS) are inconsistent. Herein, we compared the safety and efficacy of oral anticoagulants (OACs) plus single antiplatelet therapy and dual antiplatelet therapy for CVSS poststenting. METHODS: A real-world observational study conducted from January 2009 through October 2019 enrolled patients who were diagnosed with CVSS and received stenting. Patients were divided into two groups according to the management they received poststenting. Group 1: OACs plus a single antiplatelet agent (clopidogrel 75 mg or aspirin 100 mg) and Group 2: dual antiplatelet therapy (clopidogrel 75 mg plus aspirin 100 mg). The safety (such as major or minor bleeding or venous thrombosis) and efficacy (the incidences of cerebral venous sinus restenosis, intrastent thrombosis, or stent displacement) of the two groups were compared. RESULTS: There were a total of 110 eligible patients in the final analysis, including 79 females and 31 males with a mean age of 43.42 ± 13.23 years. No major bleeding or venous thrombosis occurred in either of the two groups. Two minor bleeding events occurred in group 2 (one with subcutaneous bleeding points in both lower limbs, another with submucosal bleeding in the mouth), whereas no bleeding events occurred in Group 1. In addition, at the 1-year follow-up, one case of intraluminal restenosis and two cases of in-stent thrombi occurred in Group 2, while none occurred in Group 1. Neither stenosis at stent-adjacent segments nor stent migration was detected in either group during the 1-year following stent placement. CONCLUSION: OACs plus single antiplatelet therapy and dual antiplatelet therapy alone are both safe and efficacious management strategies after CVSS stent placement. The former may have more advantages than the latter for inhibiting intrastent thrombosis. However, further research by larger, multicenter clinical trials is needed.

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.

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.