Eagle jugular syndrome presenting with intracranial hypertension - Diagnosis and illustration of pathophysiology by multi-modality imaging

Eagle jugular syndrome is an uncommon condition caused by compression of an elongated styloid process onto the internal jugular vein. Its presentation is non-specific but may represent in severe clinical consequences including venous thrombosis and intracranial haemorrhage. Thorough understanding of local anatomy is important in understanding the pathogenesis and establishing the diagnosis. Our case reported here illustrates the use of multimodality imaging, including dynamic Computer tomography manoeuvre, in identifying the site of obstruction and guidance towards successful surgical treatment.

Correlation of the transorbital ultrasonographic optic nerve sheath diameter with intracranial pressure measured intraoperatively in infants with hydrocephalus

OBJECTIVE

Hydrocephalus is a highly significant global public health concern. In infants, it may be associated with a potentially deleterious increase in intracranial pressure (ICP). Currently, the gold standard for accurate monitoring of ICP is an intraventricular ICP monitor, but this method is invasive and expensive. Transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) may provide a noninvasive and cost-effective alternative method for monitoring ICP. The goal of the study was to determine the extent of the correlation between ultrasonographic ONSD and ICP in infants.

METHODS

A prospective observational study of 47 children with hydrocephalus aged ≤ 18 months was performed. The ONSD was measured with a transorbital ultrasound scan, while the intraventricular CSF opening pressure was assessed using a manometer during ventriculoperitoneal shunt insertion. Data were analyzed using SPSS software. The ONSD and ICP measurements were correlated, the receiver operating characteristic (ROC) curve was evaluated, and a sensitivity analysis was performed. Inferences were made using the 0.05 alpha level of significance.

RESULTS

The mean age of the study cohort was 4.8 ± 4.3 months, and 93.6% of patients were infants. The mean ONSD was 4.5 ± 0.7 mm (range 2.9-6.0 mm), and the mean ICP was 19.9 ± 6.5 mm Hg (range 5.2-32.4 mm Hg). Both ONSD and ICP increased with increasing age. The Pearson correlation coefficient revealed a strong positive correlation between ONSD and ICP (r = 0.77, p < 0.001). The ONSD cutoff points were 3.2 mm, 4.0 mm, and 4.6 mm for patients with ICPs of 10 mm Hg, 15 mm Hg, and ≥ 20 mm Hg, respectively. The sensitivity of ONSD was 97.7% (area under the ROC curve 0.99), and for every 14.3-mm Hg increase in ICP, the ONSD increased by 1.0 mm holding age constant.

CONCLUSIONS

ONSD has a strong positive correlation with ICP. Correspondingly, ONSD is highly sensitive in estimating ICP.

Advantages and Pitfalls of the Use of Optical Coherence Tomography for Papilledema

PURPOSE OF REVIEW

Papilledema refers to optic disc swelling caused by raised intracranial pressure. This syndrome arises from numerous potential causes, which may pose varying degrees of threat to patients. Manifestations of papilledema range from mild to severe, and early diagnosis is important to prevent vision loss and other deleterious outcomes. The purpose of this review is to highlight the role of optical coherence tomography (OCT) in the diagnosis and management of syndromes of raised intracranial pressure associated with papilledema.

RECENT FINDINGS

Ophthalmoscopy is an unreliable skill for many clinicians. Optical coherence tomography is a non-invasive ocular imaging technique which may fill a current care gap, by facilitating detection of papilledema for those who cannot perform a detailed fundus examination. Optical coherence tomography may help confirm the presence of papilledema, by detecting subclinical peripapillary retinal nerve fiber layer (pRNFL) thickening that might otherwise be missed with ophthalmoscopy. Enhanced depth imaging (EDI) and swept source OCT techniques may identify optic disc drusen as cause of pseudo-papilledema. Macular ganglion cell inner plexiform layer (mGCIPL) values may provide early signs of neuroaxonal injury in patients with papilledema and inform management for patients with syndromes of raised intracranial pressure. There are well-established advantages and disadvantages of OCT that need to be fully understood to best utilize this method for the detection of papilledema. Overall, OCT may complement other existing tools by facilitating detection of papilledema and tracking response to therapies.  Moving forward, OCT findings may be included in deep learning models to diagnose papilledema.

The Relationship between Lumbar Puncture Opening Pressure and Retinal Nerve Fiber Layer Thickness in the Diagnosis of Idiopathic Intracranial Hypertension: Is a Lumbar Puncture Always Necessary?

OBJECTIVES

Idiopathic intracranial hypertension (IIH), is characterized by elevated intracranial pressure (ICP) without an identified cause. Today, lumbar puncture (LP) is the most common method used for diagnosis by measuring cerebrospinal fluid (CSF) pressure to reflect intracranial pressure. This invasive examination has significant disadvantages, such as complications and negative experiences for patients. Therefore, noninvasive methods for ICP measurement are desired. Optical coherence tomography (OCT) is widely used for the diagnosis and follow-up of IIH patients as it reflects papilledema. The aim of this study is to investigate the relationship between CSF pressure and OCT parameters and the ability of OCT in the diagnostic approach.

METHODS

In our study, patients who were followed up with a diagnosis of IIH with complete neuro-ophthalmological examinations, including visual acuity (VA), visual field, and OCT imaging within 24 hours before lumbar puncture, were retrospectively evaluated. CSF pressure, visual acuity LogMAR, mean deviation of visual fields, retinal nerve fiber layer (RNFL) thickness measured by OCT, and treatment protocols were obtained from our hospital data system.

RESULTS

A total of 42 eyes of 21 patients were enrolled in the study. A statistically significant positive and moderate correlation was found between CSF pressure values and average RNFL thickness ( r =0.507; P =0.001). The same relationship was demonstrated in all 4 quadrants: inferior, superior, nasal, and temporal.

CONCLUSIONS

Increased peripapillary RNFL thickness in optic nerve head OCT may be correlated with increased ICP in IIH patients. A larger number of patients are needed to better understand the correlation between OCT parameters and CSF pressure in patients with IIH.

Transorbital point-of-care ultrasound versus fundoscopic papilledema to support treatment indication for potentially elevated intracranial pressure in children

PURPOSE

To compare transorbital point-of-care ultrasound techniques -optic nerve sheath diameter (US-ONSD) and optic disc elevation (US-ODE)- with fundoscopic papilledema to detect potentially raised intracranial pressure (ICP) with treatment indication in children.

METHODS

In a prospective study, 72 symptomatic children were included, 50 with later proven disease associated with raised ICP (e.g. pseudotumour cerebri, brain tumour, hydrocephalus) and 22 with pathology excluded. Bilateral US-ONSD and US-ODE were quantified by US using a 12-MHz-linear-array transducer. This was compared to fundoscopic optic disc findings (existence of papilledema) and, in 28 cases, invasively measured ICP values.

RESULTS

The sensitivity and specificity of a cut-off value of US-ONSD (5.73 mm) to detect treatment indication for diseases associated with increased ICP was 92% and 86.4%, respectively, compared to US-ODE (0.43 mm) with sensitivity: 72%, specificity: 77.3%. Fundoscopic papilledema had a sensitivity of 46% and a specificity of 100% in this context. Repeatability and observer-reliability of US-ODE examination was eminent (Cronbach's α = 0.978-0.989). Papilledema was detected fundoscopically only when US-ODE was > 0.67 mm; a US-ODE > 0.43 mm had a positive predictive value of 90% for potentially increased ICP.

CONCLUSION

In our cohort, transorbital point-of-care US-ONSD and US-ODE detected potentially elevated ICP requiring treatment in children more reliably than fundoscopy. US-ONSD and US-ODE indicated the decrease in ICP after treatment earlier and more reliably than fundoscopy. The established cut-off values for US-ONSD and US-ODE and a newly developed US-based grading of ODE can be used as an ideal first-line screening tool to detect or exclude conditions with potentially elevated ICP in children.

The "Wrinkle Sign" in Time-of-Flight Magnetic Resonance Venography is a Hallmark of Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is usually caused by sinus stenosis, which manifests in magnetic resonance venography (MRV) as occlusion or intraluminal webbing. We present the case of a 27-year-old patient with IIH, and time-of-flight (TOF) MRV only exhibited a rare "wrinkle sign," which was eventually proved to indicate sinus obstruction. The patient received venting and recovered. The TOF MRV provides a nonradioactive approach to identify IIH patients who potentially need intervention.

Optic Nerve Sheath Diameter Sonography for the Diagnosis of Intracranial Hypertension in Traumatic Brain Injury: A Systematic Review and Meta-Analysis

OBJECTIVES

Timely diagnosis and management of elevated intracranial pressure (ICP) in patients with traumatic brain injury (TBI) can significantly reduce mortality rates. Ultrasound examination of the optic nerve sheath diameter (ONSD) is considered a potential, noninvasive, and effective method for assessing ICP. We conducted a systematic review and meta-analysis of ONSD ultrasound detection and invasive ICP monitoring methods to compare and evaluate the diagnostic accuracy of ONSD ultrasound detection methods for intracranial hypertension (IH) in patients with TBI.

METHODS

We searched the Web of Science, PubMed, and Embase databases to assess the diagnostic accuracy of ONSD sonography for predicting increased ICP. The 2 authors independently extracted the collected data. Simultaneously, the QUADAS-2 tool was used to evaluate the bias risk of each study and conducted random-effects meta-analyses for the accuracy and specificity of diagnosis, and calculated pooled estimates.

RESULTS

Ten studies with 512 patients were included. The diagnostic accuracy of ONSD sonography for IH was revealed as a pooled sensitivity of 0.85 (95% confidence interval [CI], 0.79-0.89) and specificity of 0.88 (95% CI, 0.80-0.93), compared with the invasive ICP monitoring standard for patients with TBI.

CONCLUSIONS

ONSD sonography may be a useful method for predicting increased ICP in adult patients with TBI. Further clinical studies are required to confirm the diagnostic value of ONSD sonography.

MRI signs of intracranial hypertension in morbidly obese and normal-weight individuals

PURPOSE

 Idiopathic intracranial hypertension (IIH) is associated with intracranial abnormalities, although not obligatory, which can be detected with cranial MRI. Obesity is an important risk factor for IIH and a pathogenetic link is suspected but the extent to which these MRI signs are already related to obesity has not yet been examined. We investigated whether IIH-MRI signs are present more often in obese individuals with a BMI > 30 kg/m² than in individuals of normal weight.

MATERIALS AND METHODS

 Brain MRI of 32 obese and 53 normal-weight participants from the Food-Chain-Plus cohort were analyzed for three main signs of IIH: (I) stenosis of the transverse sinus, (II) increased width of the optic nerve sheath, and (III) reduction of pituitary height. In addition, a scoring system for the MRI signs was applied. Furthermore, tortuosity of the optic nerve and flattening of the posterior globe were considered as additional MRI signs.

RESULTS

 Obese participants had a significantly higher MRI score (p < 0.001) than those in the normal-weight cohort, with significant differences in quantitative measurements of cerebral venous sinus stenosis (p < 0.001), widening of the optic nerve sheath (p < 0.05), and flattening of the pituitary gland (p < 0.05) also always being observed more frequently and in a more pronounced manner in the obese group. Furthermore, our findings correlated significantly with BMI and proportionately with hip and waist circumference.

CONCLUSION

 Obese individuals show a significantly higher prevalence of cerebral MRI signs related to IIH. This supports the hypothesis that obesity is a risk factor for possible intracranial hypertension and reinforces the suspicion that obesity is involved in the pathomechanism of IIH.

KEY POINTS

  · Obesity is associated with changes such as those seen in IIH.. · BMI, weight, and body measurements correlate with the expression of MRI signs of IIH.. · To prevent IIH symptoms in obesity, the pathomechanism must be further clarified..

Development of a Randomized Trial Comparing ICP-Monitor-Based Management of Severe Pediatric Traumatic Brain Injury to Management Based on Imaging and Clinical Examination Without ICP Monitoring-Research Algorithms

BACKGROUND AND OBJECTIVES

The efficacy of our current approach to incorporating intracranial pressure (ICP) data into pediatric severe traumatic brain injury (sTBI) management is incompletely understood, lacking data from multicenter, prospective, randomized studies. The National Institutes of Health-supported Benchmark Evidence from Latin America-Treatment of Raised Intracranial Pressure-Pediatrics trial will compare outcomes from pediatric sTBI of a management protocol based on ICP monitoring vs 1 based on imaging and clinical examination without monitoring. Because no applicable comprehensive management algorithms for either cohort are available, it was necessary to develop them.

METHODS

A consensus conference involving the 21 intensivists and neurosurgeons from the 8 trial sites used Delphi-based methodology to formulate management algorithms for both study cohorts. We included recommendations from the latest Brain Trauma Foundation pediatric sTBI guidelines and the consensus-based adult algorithms (Seattle International Brain Injury Consensus Conference/Consensus Revised Imaging and Clinical Examination) wherever relevant. We used a consensus threshold of 80%.

RESULTS

We developed comprehensive management algorithms for monitored and nonmonitored cohort children with sTBI. We defined suspected intracranial hypertension for the nonmonitored group, set minimum number and timing of computed tomography scans, specified minimal age-adjusted mean arterial pressure and cerebral perfusion pressure targets, defined clinical neuroworsening, described minimal requisites for intensive care unit management, produced tiered management algorithms for both groups, and listed treatments not routinely used.

CONCLUSION

We will study these protocols in the Benchmark Evidence from Latin America-Treatment of Raised Intracranial Pressure-Pediatrics trial in low- and middle-income countries. Second, we present them here for consideration as prototype pediatric sTBI management algorithms in the absence of published alternatives, acknowledging their limited evidentiary status. Therefore, herein, we describe our study design only, not recommended treatment protocols.

Development of a Randomized Trial Comparing ICP-Monitor-Based Management of Severe Pediatric Traumatic Brain Injury to Management Based on Imaging and Clinical Examination Without ICP Monitoring-Study Protocol

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) is a major global public health problem. It is a leading cause of death and disability in children and adolescents worldwide. Although increased intracranial pressure (ICP) is common and associated with death and poor outcome after pediatric TBI, the efficacy of current ICP-based management remains controversial. We intend to provide Class I evidence testing the efficacy of a protocol based on current ICP monitor-based management vs care based on imaging and clinical examination without ICP monitoring in pediatric severe TBI.

METHODS

A phase III, multicenter, parallel-group, randomized superiority trial performed in intensive care units in Central and South America to determine the impact on 6-month outcome of children aged 1-12 years with severe TBI (age-appropriate Glasgow Coma Scale score ≤8) randomized to ICP-based or non-ICP-based management.

EXPECTED OUTCOMES

Primary outcome is 6-month Pediatric Quality of Life. Secondary outcomes are 3-month Pediatric Quality of Life, mortality, 3-month and 6-month Pediatric extended Glasgow Outcome Score, intensive care unit length of stay, and number of interventions focused on treating measured or suspected intracranial hypertension.

DISCUSSION

This is not a study of the value of knowing the ICP in sTBI. This research question is protocol-based. We are investigating the added value of protocolized ICP management to treatment based on imaging and clinical examination in the global population of severe pediatric TBI. Demonstrating efficacy should standardize ICP monitoring in severe pediatric TBI. Alternate results should prompt reassessment of how and in which patients ICP data should be applied in neurotrauma care.

A Novel Method for Prediction of Raised Intracranial Pressure Through Automated ONSD and ETD Ratio Measurement From Ocular Ultrasound

The paper presents a novel framework for the prediction of the raised Intracranial Pressure (ICP) from ocular ultrasound images of traumatic patients through automated measurement of Optic Nerve Sheath Diameter (ONSD) and Eyeball Transverse Diameter (ETD). The measurement of ONSD using an ocular ultrasound scan is non-invasive and correlates with the raised ICP. However, the existing studies suggested that the ONSD value alone is insufficient to indicate the ICP condition. Since the ONSD and ETD values may vary among patients belonging to different ethnicity/origins, there is a need for developing an independent global biomarker for predicting raised ICP condition. The proposed work develops an automated framework for the prediction of raised ICP by developing algorithms for the automated measurement of ONSD and ETD values. It is established that the ONSD and ETD ratio (OER) is a potential biomarker for ICP prediction independent of ethnicity and origin. The OER threshold value is determined by performing statistical analysis on the data of 57 trauma patients obtained from the AIIMS, New Delhi. The automated OER is computed and compared with the conventionally measured ICP by determining suitable correlation coefficients. It is found that there is a significant correlation of OER with ICP (r = .81, p ≤ .01), whereas the correlation of ONSD alone with ICP is relatively less (r = .69, p = .004). These correlation values indicate that OER is a better parameter for the prediction of ICP. Further, the threshold value of OER is found to be 0.21 for predicting raised ICP conditions in this study. Scatter plot and Heat map analysis of OER and corresponding ICP reveal that patients with OER ≥ 0.21, have ICP in the range of 17 to 35 mm Hg. In the data available for this research work, OER ranges from 0.17 to 0.35.

Long-term efficacy of venous sinus stenting in the treatment of idiopathic intracranial hypertension

BACKGROUNDS

Previous studies have suggested that cerebral dural sinus stenosis could be a possible underlying cause of idiopathic intracranial hypertension (IIH). Venous sinus stenting (VSS) has emerged as a potential alternative for treating IIH related to dural sinus stenosis. However, most of the documented studies have been conducted in Western countries. In this study, we present the results of 16 Chinese IIH patients who underwent VSS treatment in our single center.

METHODS

We prospectively collected angiographic and manometric data from IIH patients who underwent angioplasty/stenting. All patients had confirmed dural sinus stenosis and had failed maximal medical therapy (MMT). Demographic, clinical, and radiological presentation, as well as long-term follow-up outcomes were collected retrospectively.

RESULTS

A total of 16 patients who underwent VSS were enrolled in the present study. Demographic data revealed a mean age of 40 (range 20-55), with 69% (11/16) being female, and a mean body mass index (BMI) of 27.05 (range 19.18-38.04) kg/m2 . All patients presented with papilledema and visual disturbances. During a median follow-up period of 47.5 months, 93.75% (15/16) of patients reported improvement in symptoms, although only 37.5% (6/16) experienced complete resolution. Headaches, blurred vision, and amaurosis related to increased pressure improved in 100% (8/8), 81.25% (13/16), and 75% (3/4) of patients, respectively. However, one patient suffered cerebral infarction and secondary epilepsy soon after VSS, and another patient had recurrence of symptoms due to stent wall thrombosis 2 years later.

CONCLUSIONS

The significance of venous sinus stenosis in the development of IIH may be undervalued. Our study, based on a Chinese case series, affirms the long-term safety and effectiveness of VSS in treating IIH patients with relatively lower BMI than those from Western countries.

B-mode transorbital ultrasonography for the diagnosis of idiopathic intracranial hypertension: an updated systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis aimed to evaluate the role of B-mode transorbital ultrasonography (TOS) for the diagnosis of idiopathic intracranial hypertension (IIH) in adults.

METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) (1966-May 2022) were searched to identify studies reporting ultrasonographic data about the optic nerve sheath diameter (ONSD) and optic disc elevation (ODE) in adults with IIH compared to subjects without IIH. The quality of the included studies was evaluated by the Newcastle-Ottawa Quality.

RESULTS

Fifteen studies were included (total of 439 patients). The values of ODE ranged from 0.6 to 1.3 mm in patients with IIH. The values of ONSD ranged from 4.7 to 6.8 mm in IIH patients and from 3.9 to 5.7 mm in controls. In IIH patients, the ONSD was significantly higher compared to controls (standardized mean difference: 2.5 mm, 95% confidence interval (CI): 1.6-3.4 mm). Nine studies provided data about the presence of papilledema and the pooled prevalence was 95% (95% CI, 92-97%).

CONCLUSIONS

In adults, the thickness of ONSD and the entity of ODE were significantly associated with IIH. B-mode TOS enables to noninvasively detect increased ICP and should be performed, potentially routinely, in any patient with suspected IIH.

Poor Accuracy of Manually Derived Head Computed Tomography Parameters in Predicting Intracranial Hypertension After Nontraumatic Intracranial Hemorrhage

BACKGROUND

The utility of head computed tomography (CT) in predicting elevated intracranial pressure (ICP) is known to be limited in traumatic brain injury; however, few data exist in patients with spontaneous intracranial hemorrhage.

METHODS

We conducted a retrospective review of prospectively collected data in patients with nontraumatic intracranial hemorrhage (subarachnoid hemorrhage [SAH] or intraparenchymal hemorrhage [IPH]) who underwent external ventricular drain (EVD) placement. Head CT scans performed immediately prior to EVD placement were quantitatively reviewed for features suggestive of elevated ICP, including temporal horn diameter, bicaudate index, basal cistern effacement, midline shift, and global cerebral edema. The modified Fisher score (mFS), intraventricular hemorrhage score, and IPH volume were also measured, as applicable. We calculated the accuracy, positive predictive value (PPV), and negative predictive value (NPV) of these radiographic features for the coprimary outcomes of elevated ICP (> 20 mm Hg) at the time of EVD placement and at any time during the hospital stay. Multivariable backward stepwise logistic regression analysis was performed to identify significant radiographic factors associated with elevated ICP.

RESULTS

Of 608 patients with intracranial hemorrhages enrolled during the study time frame, 243 (40%) received an EVD and 165 (n = 107 SAH, n = 58 IPH) had a preplacement head CT scan available for rating. Elevated opening pressure and elevated ICP during hospitalization were recorded in 48 of 152 (29%) and 103 of 165 (62%), respectively. The presence of ≥ 1 radiographic feature had only 32% accuracy for identifying elevated opening pressure (PPV 30%, NPV 58%, area under the curve [AUC] 0.537, 95% asymptotic confidence interval [CI] 0.436-0.637, P = 0.466) and 59% accuracy for predicting elevated ICP during hospitalization (PPV 63%, NPV 40%, AUC 0.514, 95% asymptotic CI 0.391-0.638, P = 0.820). There was no significant association between the number of radiographic features and ICP elevation. Head CT scans without any features suggestive of elevated ICP occurred in 25 of 165 (15%) patients. However, 10 of 25 (40%) of these patients had elevated opening pressure, and 15 of 25 (60%) had elevated ICP during their hospital stay. In multivariable models, mFS (adjusted odds ratio [aOR] 1.36, 95% CI 1.10-1.68) and global cerebral edema (aOR 2.93, 95% CI 1.27-6.75) were significantly associated with elevated ICP; however, their accuracies were only 69% and 60%, respectively. All other individual radiographic features had accuracies between 38 and 58% for identifying intracranial hypertension.

CONCLUSIONS

More than 50% of patients with spontaneous intracranial hemorrhage without radiographic features suggestive of elevated ICP actually had ICP > 20 mm Hg during EVD placement or their hospital stay. Morphological head CT findings were only 32% and 59% accurate in identifying elevated opening pressure and ICP elevation during hospitalization, respectively.

Retinal microvascular and structural changes in intracranial hypertension patients correlate with intracranial pressure

AIMS

We aimed to evaluate the retinal microvascular and structural changes in intracranial hypertension (IH) patients compared with an age- and sex-matched control group. We also investigated the association between clinical parameters and retinal changes in IH patients.

METHODS

Intracranial hypertension patients were divided into eyes with papilledema (IH-P) and eyes without papilledema (IH-WP). IH patients underwent lumbar puncture to measure intracranial pressure (ICP); visual acuity was performed using the Snellen chart. Optical coherence tomography (OCT) was used to image and measure the retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) while OCT angiography was used to image and measure the superficial vascular complex (SVC) and deep vascular complex (DVC).

RESULTS

Intracranial hypertension patients showed reduced microvascular densities and thinner retinal thicknesses compared with the control group (all p < 0.001). Compared with the control group, IH-P showed reduced microvascular densities and thinner retinal thicknesses (all p < 0.001). IH-P showed reduced SVC density and thinner retinal thicknesses when compared with IH-WP (p = 0.008 for SVC, p = 0.025 for RNFL, and p = 0.018 for GCIPL). ICP correlated with the microvascular densities and GCIPL thickness in IH patients (p = 0.025 for GCIPL, p = 0.004 for SVC, and p = 0.002 for DVC). A significant association of ICP with SVC (p = 0.010) and DVC (p = 0.005) densities were also found in IH-P.

CONCLUSIONS

Given the observed differences in these noninvasive retinal imaging markers, further research into their clinical utility in IH is needed.

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.

Optic Nerve Diameter on Non-Contrast Computed Tomography and Intracranial Hypertension in Patients With Acute Brain Injury: A Validation Study

Intracranial hypertension is a feared complication of acute brain injury that can cause ischemic stroke, herniation, and death. Identifying those at risk is difficult, and the physical examination is often confounded. Given the widespread availability and use of computed tomography (CT) in patients with acute brain injury, prior work has attempted to use optic nerve diameter measurements to identify those at risk of intracranial hypertension. We aimed to validate the use of optic nerve diameter measurements on CT as a screening tool for intracranial hypertension in a large cohort of brain-injured patients. We performed a retrospective observational cohort study in a single tertiary referral Neuroscience Intensive Care Unit. We identified patients with documented intracranial pressure (ICP) measures as part of their routine clinical care who had non-contrast CT head scans collected within 24 h, and then measured the optic nerve diameters and explored the relationship and test characteristics of these measures to identify those at risk of intracranial hypertension. In a cohort of 314 patients, optic nerve diameter on CT was linearly but weakly associated with ICP. When used to identify those with intracranial hypertension (> 20 mm Hg), the area under the receiver operator curve (AUROC) was 0.68. Using a previously proposed threshold of 0.6 cm, the sensitivity was 81%, specificity 43%, positive likelihood ratio 1.4, and negative likelihood ratio 0.45. CT-derived optic nerve diameter using a threshold of 0.6 cm is sensitive but not specific for intracranial hypertension, and the overall correlation is weak.

Multimodal monitoring intracranial pressure by invasive and noninvasive means

Although the placement of an intraventricular catheter remains the gold standard method for the diagnosis of intracranial hypertension (ICH), the technique has several limitations including but not limited to its invasiveness. Current noninvasive methods, however, still lack robust evidence to support their clinical use. We aimed to estimate, as an exploratory hypothesis generating analysis, the discriminative power of four noninvasive methods to diagnose ICH. We prospectively collected data from adult intensive care unit (ICU) patients with subarachnoid hemorrhage (SAH), intraparenchymal hemorrhage (IPH), and ischemic stroke (IS) in whom invasive intracranial pressure (ICP) monitoring had been placed. Measures were simultaneously collected from the following noninvasive methods: optic nerve sheath diameter (ONSD), pulsatility index (PI) using transcranial Doppler (TCD), a 5-point visual scale designed for brain Computed Tomography (CT), and two parameters (time-to-peak [TTP] and P2/P1 ratio) of a noninvasive ICP wave morphology monitor (Brain4Care[B4c]). ICH was defined as a sustained ICP > 20 mmHg for at least 5 min. We studied 18 patients (SAH = 14; ICH = 3; IS = 1) on 60 occasions with a mean age of 52 ± 14.3 years. All methods were recorded simultaneously, except for the CT, which was performed within 24 h of the other methods. The median ICP was 13 [9.8-16.2] mmHg, and intracranial hypertension was present on 18 occasions (30%). Median values from the noninvasive techniques were ONSD 4.9 [4.40-5.41] mm, PI 1.22 [1.04-1.43], CT scale 3 points [IQR: 3.0], P2/P1 ratio 1.16 [1.09-1.23], and TTP 0.215 [0.193-0.237]. There was a significant statistical correlation between all the noninvasive techniques and invasive ICP (ONSD, r = 0.29; PI, r = 0.62; CT, r = 0.21; P2/P1 ratio, r = 0.35; TTP, r = 0.35, p < 0.001 for all comparisons). The area under the curve (AUC) to estimate intracranial hypertension was 0.69 [CIs = 0.62-0.78] for the ONSD, 0.75 [95% CIs 0.69-0.83] for the PI, 0.64 [95%Cis 0.59-069] for CT, 0.79 [95% CIs 0.72-0.93] for P2/P1 ratio, and 0.69 [95% CIs 0.60-0.74] for TTP. When the various techniques were combined, an AUC of 0.86 [0.76-0.93]) was obtained. The best pair of methods was the TCD and B4cth an AUC of 0.80 (0.72-0.88). Noninvasive technique measurements correlate with ICP and have an acceptable discrimination ability in diagnosing ICH. The multimodal combination of PI (TCD) and wave morphology monitor may improve the ability of the noninvasive methods to diagnose ICH. The observed variability in non-invasive ICP estimations underscores the need for comprehensive investigations to elucidate the optimal method-application alignment across distinct clinical scenarios.

Automated pupillometry and optic nerve sheath diameter ultrasound to define tuberculous meningitis disease severity and prognosis

BACKGROUND

Tuberculous meningitis (TBM) causes high mortality and morbidity, in part due to raised intracranial pressure (ICP). Automated pupillometry (NPi) and optic nerve sheath diameter (ONSD) are both low-cost, easy-to-use and non-invasive techniques that correlate with ICP and neurological status. However, it is uncertain how to apply these techniques in the management of TBM.

METHODS

We conducted a pilot study enrolling 20 adults with TBM in the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. Our objective was to investigate the relationships between baseline and serial measurements of NPi and ONSD and disease severity and outcome. Serial NPi and ONSD were performed for 30 days, at discharge, and at 3-months, with measurements correlated with clinical progression and outcomes.

RESULTS

ONSD and NPi measurements had an inverse relationship. Higher ONSD and lower NPi values were associated with lower Glasgow coma score. Baseline NPi was a strong predictor 3-month outcome (median NPi 4.55, interquartile range 4.35-4.65 for good outcomes versus 2.60, IQR 0.65-3.95 for poor outcomes, p = 0.002). Pupil inequality (NPi ≥0.7) was also strongly associated with poor 3-month outcomes (p = 0.006). Individual participants' serial NPi and ONSD were variable during initial treatment and correlated with clinical condition and outcome.

CONCLUSION

Pupillometry and ONSD may be used to predict clinical deterioration and outcome from TBM. Future, larger studies are need explore the optimal timing of measurements and to define how they might be used to optimise treatments and improve outcomes from TBM.

Dilated optic nerve sheath by ultrasound predicts mortality among patients with acute intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is a deadly disease and increased intracranial pressure (ICP) is associated with worse outcomes in this context.

OBJECTIVE

We evaluated whether dilated optic nerve sheath diameter (ONSD) depicted by optic nerve ultrasound (ONUS) at hospital admission has prognostic value as a predictor of mortality at 90 days.

METHODS

Prospective multicenter study of acute supratentorial primary ICH patients consecutively recruited from two tertiary stroke centers. Optic nerve ultrasound and cranial computed tomography (CT) scans were performed at hospital admission and blindly reviewed. The primary outcome was mortality at 90-days. Multivariate logistic regression, ROC curve, and C-statistics were used to identify independent predictors of mortality.

RESULTS

Between July 2014 and July 2016, 57 patients were evaluated. Among those, 13 were excluded and 44 were recruited into the trial. Their mean age was 62.3 ± 13.1 years and 12 (27.3%) were female. On univariate analysis, ICH volume on cranial CT scan, ICH ipsilateral ONSD, Glasgow coma scale, National Institute of Health Stroke Scale (NIHSS) and glucose on admission, and also diabetes mellitus and current nonsmoking were predictors of mortality. After multivariate analysis, ipsilateral ONSD (odds ratio [OR]: 6.24; 95% confidence interval [CI]: 1.18-33.01; p = 0.03) was an independent predictor of mortality, even after adjustment for other relevant prognostic factors. The best ipsilateral ONSD cutoff was 5.6mm (sensitivity 72% and specificity 83%) with an AUC of 0.71 (p = 0.02) for predicting mortality at 90 days.

CONCLUSION

Optic nerve ultrasound is a noninvasive, bedside, low-cost technique that can be used to identify increased ICP in acute supratentorial primary ICH patients. Among these patients, dilated ONSD is an independent predictor of mortality at 90 days.

Diagnostic Value of the Combination of Ultrasonographic Optic Nerve Sheath Diameter and Width of Crural Cistern with Respect to the Intracranial Pressure in Patients Treated with Decompressive Craniotomy

BACKGROUND

The monitoring of intracranial pressure (ICP) and detection of increased ICP are crucial because such increases may cause secondary brain injury and a poor prognosis. Although numerous ultrasound parameters, including optic nerve sheath diameter (ONSD), width of the crural cistern (WCC), and the flow velocities of the central retinal artery and middle cerebral artery, can be measured in patients after hemicraniectomy, researchers have yet to determine which of these is better for evaluating ICP. This study aimed to analyze the correlation between ICP and ultrasound parameters and investigate the best noninvasive estimator of ICP.

METHODS

This observational study enrolled 50 patients with brain injury after hemicraniectomy from January 2021 to December 2021. All patients underwent invasive ICP monitoring with microsensor, transcranial, and ocular ultrasound postoperatively. We measured the ONSD including the dura mater (ONSDI), the ONSD excluding the dura mater, the optic nerve diameter (OND), the eyeball transverse diameter (ETD), the WCC, and the flow velocities in the central retinal artery and middle cerebral artery. Then, we calculated the ONSDI-OND (the difference between ONSDI and OND) and ONSDI/ETD (the ratio of ONSDI to ETD). Patients were divided into a normal ICP group (n = 35) and an increased ICP group (≥ 20 mm Hg, n = 15) according to the ICP measurements. Correlations were then assessed between the values of the ultrasound parameters and ICP.

RESULTS

The ONSDI, ONSDI-OND, and ONSDI/ETD were positively associated with ICP (r = 0.455, 0.482, 0.423 and p = 0.001, < 0.001, 0.002, respectively), whereas the WCC was negatively associated with ICP (r = - 0.586, p < 0.001). The WCC showed the highest predictive power for increased ICP (area under the receiver operating characteristic curve [AUC] = 0.904), whereas the ONSDI-OND and ONSDI also presented with acceptable predictive power among the ONSD-related parameters (AUC = 0.831, 0.803, respectively). The cutoff values for increased ICP prediction for ONSDI, ONSDI-OND, and WCC were 6.29, 3.03, and 3.68 mm, respectively. The AUC of the combination of ONSDI-OND and WCC was 0.952 (95% confidence interval 0.896-1.0, p < 0.001).

CONCLUSIONS

The ONSDI, ONSDI-OND, and WCC were correlated with ICP and had acceptable accuracy levels in estimating ICP in patients after hemicraniectomy. Furthermore, WCC showed a higher diagnostic value than ONSD-related parameters, and the combination of ONSDI-OND and WCC was a satisfactory predictor of increased ICP.

Venous sinus stenting for the treatment of acute blindness in a patient with idiopathic intracranial hypertension

We present a case of acute onset of blindness treated with venous sinus stenting in the hyperacute period (24-48 h). The patient had not been diagnosed previously with idiopathic intracranial hypertension and presented at an outside facility with a short history of headache, nausea, vomiting and visual deficits. Initial management included lumbar punctures for pressure relief. Unfortunately, the patient's condition deteriorated and she experienced the rapid onset of blindness. Within 24-48 h of blindness onset, she was transferred to our institution for emergent endovascular stenting of the venous sinuses. The intervention resulted in improvement of symptoms and recovery of visual acuity over a short-term follow-up period.

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.

Emergent cerebral venous stenting: A valid treatment option for fulminant idiopathic intracranial hypertension

BACKGROUND

Fulminant idiopathic intracranial hypertension (FIIH) is characterized by rapid, severe, progressive vision loss and often treated surgically. Cerebral transverse venous stenting (CTVS) is efficacious in IIH patients, but emergent CTVS in FIIH is rarely reported. We present our experience with emergent CTVS in patients with FIIH.

METHODS

Since 01/2019, an institutional protocol allowed emergent CTVS in FIIH patients with bilateral transverse sinus stenosis and gradient pressure > 15 on digital subtraction angiography (DSA). We retrospectively analyzed a prospective registry of all IIH patients with details of neurological and neuro-ophthalmological assessments before and after treatment, and subjective assessments of headache and tinnitus were made pre-and post-procedure.

RESULTS

259 IIH patients, including 49 who underwent CTVS, were registered. Among them, five female patients met inclusion criteria for FIIH and underwent emergent CTVS. FIIH patients were younger (18.8 ± 1.64 vs 27.7 ± 4.85, p < 0.01), mean BMI was lower (30.8 ± 10.57 vs 34.6 ± 4.3, p < 0.01), and lumbar puncture opening pressure higher (454 ± vs 361 ± 99.4, p < 0.01) than that of IIH patients. They presented with acute visual loss, severe headache, papilledema, significant bilateral transverse sinus stenosis on CT-venography, and mean dominant side gradient pressure of 26.4 ± 6.2 on DSA. CTVS was performed without significant complications, resulting in remarkable improvement in headache, optical coherence tomography, and visual fields within 1 week. At 1-year follow-up (four patients) and 6-month follow-up (1 patient), there was complete resolution of papilledema and headache, and marked improvement in visual acuity.

CONCLUSIONS

In these patients, emergent-CTVS was a safe and effective treatment option for FIIH. Further evaluation is warranted.

Optic Nerve Sheath Point of Care Ultrasound: Image Acquisition

The goal of this protocol is to develop a standardized method for acquiring images of the optic nerve sheath and measuring the optic nerve sheath diameter (ONSD). Diagnostic ultrasound of the ONSD to detect intracranial hypertension has traditionally faced many problems because of methodologic discrepancies. Due to inconsistencies in the measuring techniques, the potential for ONSD to become a non-invasive bedside monitoring tool for ICP has been hampered. However, establishing a transparent, consistent methodology for measuring the ONSD would support its use as a valid and reliable method of identifying intracranial hypertension. This is important as it has both high sensitivity and specificity in acute care settings. This narrative review describes ONSD POCUS image acquisition, including patient positioning, transducer selection, probe placement, the acquisition sequence, and image optimization. Further, visual aids are provided to assist in real-time during image acquisition. This method should be considered for patients for whom there are concerns regarding intracranial hypertension but who do not have an intracranial monitor in place.

Optic nerve sheath diameter correlates to intracranial pressure in spontaneous CSF leak patients

BACKGROUND

Spontaneous cerebrospinal fluid (sCSF) leaks develop from pressure erosion due to idiopathic intracranial hypertension, treatment of which is paramount to preventing recurrence. Direct measurements of intracranial pressure (ICP) for monitoring response to treatment via lumbar drain (LD) or ventriculostomy are invasive and have risks. The objectives of this study are to determine whether ultrasonographic measurements of optic nerve sheath diameter (ONSD) correlate with LD ICP in patients with sCSF leaks undergoing treatment, and whether ONSDs are larger in patients with sCSF leaks than controls.

METHODS

Subjects with sCSF leaks and controls were prospectively recruited. ONSD, sex, and body mass index (BMI) were analyzed. For sCSF leak subjects, ultrasonography was performed at the time of LD opening and each pressure check postoperatively, including the acetazolamide response. In control patients, measurements were obtained at the time of surgery. Pearson's correlation between ONSD and ICP was performed.

RESULTS

Subjects with sCSF leaks (n = 9, age 52.4 ± 9.5, all female) and controls (n = 8, age 60.1 ± 14.8, two females) had significantly different BMIs, 38.4 ± 8.1 vs. 29.2 ± 4.8, t(15) = 2.793, p = 0.014. ONSD was strongly correlated with ICP measurements (r = 0.583, p = 0.002). However, percentage change in ONSD and ICP measurements were more strongly correlated (r = 0.733, p < 0.001). Patients with sCSF leaks had significantly higher ONSDs than controls, 0.63 cm ± 0.044 vs. 0.56 cm ± 0.074, t(15) = 2.329, p = 0.034.

CONCLUSION

ONSD significantly correlated with ICP in sCSF leak patients and was wider in sCSF leak subjects than controls. Ultrasonography has utility in monitoring the ICP response to acetazolamide.

Enhancement of optic nerve sheath on MRI in idiopathic intracranial hypertension(IIH)

OBJECTIVE

Optic nerve sheath(ONS) enhancement in idiopathic intracranial hypertension (IIH) patients has been reported in recent years. In this retrospective observation, we analyzed the clinical characteristics of IIH patients with enhancement of ONS.

METHODS

Eighty-two patients with clinically diagnosed IIH from January 2017 to December 2019 were under observation. Then, based on the presence of contrast-enhancement (CE) in ONS on orbital magnetic resonance image (MRI), the IIH patients were divided into CE-ONS group and no-CE(NCE)-ONS group. Six months follow-up information was also included in the observation study. By comparing clinical data of the two groups of IIH patients, we tried to evaluate whether there is clinical heterogeneity in CE-ONS patients.

RESULT

12 patients were included in CE-ONS group, 10 females and 2 males. 70 patients were included in NCE-ONS group, 56 women and 14 men. We found that patients with CE-ONS had a longer course of disease (median disease duration before diagnosis, 5 months vs. 3months, P<0.01) and more likely had the sign of distension of the perioptic subarachnoid space (DPSS) (58.33 % vs. 24.29 %, P = 0.034). But no significant differences were found in demographic characteristics, clinical symptoms, degree of visual impairment, papilledema, opening pressure(OP) on lumbar puncture and clinical outcomes.

CONCLUSION

As a rare sign on MRI, ONS enhancement can occur in patients with IIH. IIH patients with CE-ONS may have a longer course of disease and more prone to DPSS, but there is no significant difference in clinical manifestations, OP, and clinical outcomes compared with IIH patients without CE-ONS.

Utility of Bedside Ultrasound Measurement of Optic Nerve Sheath Diameter as a Screening Tool for raised Intracranial Pressure in Neurocritical Care Prospective Observational Study

Intracranial pressure (ICP) needs to be monitored in neurocritical patients. There is a need for portable bedside optic nerve ultrasound (ONUS) for early diagnosis to initiate the measures to reduce ICP Objective: To find the utility of bedside ONUS to diagnose raised ICP in neurocritical care. Materials and methods: After approval from the ethical committee, a prospective observational study was conducted. Optic nerve sheath diameter (ONSD) was measured in two groups: control group patients with neurological symptoms but computed tomography (CT)/magnetic resonance imaging (MRI) not suggestive of raised ICP, and second was study group patients with neurological symptoms and CT/MRI suggestive of elevated ICP Result: In patients with normal ICP, the mean ONSD in females was 4.47mm, and in males was 4.66mm. In patients with raised ICP, the mean ONSD in females was 6.45 ± 0.78 mm, and in males was 6.33 ± 0.70 mm. Regarding the correlation between Glasgow coma scale (GCS) and mean ONSD parameters, the coefficient of correlation (R) is 0.14; thus, there is a weak negative correlation. In our study, no difference was observed in raised mean ONSD in patients with different diagnoses. At a cut-off value of &gt;4.8 mm, the sensitivity and specificity are 100% to diagnose raised ICP. Conclusion: Optic nerve sheath diameter (ONSD) is a reliable, rapid bedside screening tool in the Emergency Department/Critical Care/Operation Theatre to diagnose raised ICP. In order to keep a record of trends in ICP, we need to measure ONSD frequently. There was no correlation between GCS and ONSD measurement.

Diagnostic Accuracy of Ocular Ultrasonography in Identifying Raised Intracranial Pressure among Pediatric Population

INTRODUCTION

Role of CT scan, MRI, ophthalmoscopy, direct monitoring by a transducer probe in identifying raised intracranial pressure (ICP) in emergency department is limited. There are few studies correlating elevated optic nerve sheath diameter (ONSD) measured by point of care ultrasound (POCUS) with raised ICP in pediatrics emergencies. We studied the diagnostic accuracy of ONSD, crescent sign, and optic disc elevation in identifying increased ICP in pediatrics.

METHODS

Prospective observational study was done between April 2018 and August 2019 after ethics approval. Out of 125 subjects, 40 patients without clinical features of raised ICP were recruited as external controls and 85 with clinical features of raised ICP as study subjects. Their demographic profile, clinical examination, and ocular ultrasound findings were noted. This was followed by CT scan. Out of 85 patients, 43 had raised ICP (cases) and 42 had normal ICP (disease controls). Diagnostic accuracy of ONSD in identifying raised ICP was evaluated using STATA.

RESULTS

The mean ONSD in case group was 5.5 ± 0.6 mm, 4.9 ± 0.5 mm in disease control group and external control group was 4.8 ± 0.3 mm. Cut-off of ONSD for raised ICP at ≥4.5 mm had a sensitivity and specificity of 97.67% and 10.98%, while ≥5.0 mm showed a sensitivity and specificity of 86.05% and 71.95%. Crescent sign and optic disc elevation had good correlation with increased ICP.

CONCLUSION

ONSD ≥5 mm by POCUS identified raised ICP in pediatric population. Crescent sign and optic disc elevation may function as additional POCUS signs in identifying raised ICP.

Novel application of the Rotterdam CT score in the prediction of intracranial hypertension following severe traumatic brain injury

OBJECTIVE

Severe traumatic brain injury (TBI) is associated with intracranial hypertension (ICHTN). The Rotterdam CT score (RS) can predict clinical outcomes following TBI, but the relationship between the RS and ICHTN is unknown. The purpose of this study was to investigate clinical and radiological factors that predict ICHTN in patients with severe TBI.

METHODS

The authors performed a single-center retrospective review of patients who, between 2018 and 2021, had an intracranial pressure (ICP) monitor placed following TBI. Radiological and clinical characteristics related to the TBI and ICP monitoring were collected. The main outcome of interest was ICHTN, which was a dichotomous outcome (yes or no) defined on a per-patient basis as an ICP > 22 mm Hg that persisted for at least 5 minutes and required an escalation of treatment. ICHTN included both elevated opening pressure on initial monitor placement and ICP elevations later during hospitalization. Multivariate logistic regression was performed to determine variables associated with ICHTN. Diagnostic accuracy was evaluated using the area under the receiver operating characteristic curve (AUROC).

RESULTS

Seventy patients with severe TBI and an ICP monitor were included in this study. There was a predominance of male patients (94.0%), and the mean patient age was 40 years old. Most patients (67%) had an intraparenchymal catheter placed, whereas 33% of patients had a ventriculostomy catheter placed. In the multivariate logistic regression analysis, the RS was an independent predictor of ICHTN (OR 2.0, 95% CI 1.2-3.5, p = 0.014). No instances of ICHTN were observed in patients with an RS of 2 or less and no sulcal effacement. The AUROC of the RS and sulcal effacement was higher than the AUROC of the RS alone for predicting ICHTN (0.76 vs 0.71, p = 0.003, z-test).

CONCLUSIONS

The RS was predictive of ICHTN in patients with severe TBI, and the diagnostic accuracy of the model was improved with the inclusion of sulcal effacement at the vertex on CT of the head. Patients with a low RS and no sulcal effacement are likely at low risk for the development of ICHTN.

Is Lumbar Puncture Needed? - Noninvasive Assessment of ICP Facilitates Decision Making in Patients with Suspected Idiopathic Intracranial Hypertension

PURPOSE

 Idiopathic intracranial hypertension (IIH) usually occurs in obese women of childbearing age. Typical symptoms are headache and sight impairment. Lumbar puncture (LP) is routinely used for both diagnosis and therapy (via cerebrospinal fluid drainage) of IIH. In this study, noninvasively assessed intracranial pressure (nICP) was compared to LP pressure (LPP) in order to clarify its feasibility for the diagnosis of IIH.

MATERIALS AND METHODS

 nICP was calculated using continuous signals of arterial blood pressure and cerebral blood flow velocity in the middle cerebral artery, a method which has been introduced recently. In 26 patients (f = 24, m = 2; age: 33 ± 11 years), nICP was assessed one hour prior to LPP. If LPP was > 20 cmH₂O, lumbar drainage was performed, LPP was measured again, and also nICP was reassessed.

RESULTS

 In total, LPP and nICP correlated with R = 0.85 (p < 0.001; N = 38). The mean difference of nICP-LPP was 0.45 ± 4.93 cmH₂O. The capability of nICP to diagnose increased LPP (LPP > 20 cmH₂O) was assessed by ROC analysis. The optimal cutoff for nICP was close to 20 cmH₂O with both a sensitivity and specificity of 0.92. Presuming 20 cmH₂O as a critical threshold for the indication of lumbar drainage, the clinical implications would coincide in both methods in 35 of 38 cases.

CONCLUSION

 The TCD-based nICP assessment seems to be suitable for a pre-diagnosis of increased LPP and might eliminated the need for painful lumbar puncture if low nICP is detected.

A novel score to estimate thrombus burden and predict intracranial hypertension in cerebral venous sinus thrombosis

BACKGROUND

Current methods to evaluate the severity of cerebral venous sinus thrombosis (CVST) lack patient-specific indexes. Herein, a novel scoring method was investigated to estimate the thrombus burden and the intracranial pressure (ICP) of CVST.

METHODS

In this retrospective study from January 2019 through December 2021, we consecutively enrolled patients with a first-time confirmed diagnosis of CVST by contrast-enhanced magnetic resonance venography (CE-MRV) or computed tomography venography (CTV). In these patients, a comprehensive CVST-Score was established using magnetic resonance black-blood thrombus imaging (MRBTI) to estimate the thrombus burden semi-quantitatively. The relationship between CVST-Score and ICP was explored to assess the potential of using the CVST-score to evaluate ICP noninvasively and dynamically.

RESULTS

A total of 87 patients were included in the final analysis. The CVST-Scores in different ICP subgroups were as follows: 4.29±2.87 in ICP<250mmH₂O subgroup, 11.36±3.86 in ICP =250-330mmH₂O subgroup and 14.99±3.15 in ICP>330mmH₂O subgroup, respectively (p<0.001). For patients with ICP ≤330mmH₂O, the CVST-Score was linearly and positively correlated with ICP (R²=0.53). The receiver operating characteristic (ROC) curves showed the optimal CVST-Score cut-off values to predict ICP ≥250mmH₂O and >330mmH₂O were 7.15 and 11.62, respectively (P<0.001). Multivariate analysis indicated CVST-Score as an independent predictor of ICP ≥250mmH₂O (odds ratio, 2.15; 95% confidence interval, 1.49-3.10; p<0.001).

CONCLUSIONS

A simple and noninvasive CVST-Score can rapidly estimate the thrombus burden and predict the severity of intracranial hypertension in patients with CVST. The CVST-Score can aid in evaluating therapeutic responses and avoiding unnecessary invasive procedures at long-term follow-up.

Non-Invasive Assessment of Intracranial Hypertension in Patients with Traumatic Brain Injury Using Computed Tomography Radiomic Features: A Pilot Study

This study aimed to assess intracranial hypertension in patients with traumatic brain injury non-invasively using computed tomography (CT) radiomic features. Fifty patients from the primary cohort were enrolled in this study. The clinical data, pre-operative cranial CT images, and initial intracranial pressure readings were collected and used to develop a prediction model. Data of 20 patients from another hospital were used to validate the model. Clinical features including age, sex, midline shift, basilar cistern status, and ventriculocranial ratio were measured. Radiomic features-i.e., 18 first-order and 40 second-order features- were extracted from the CT images. LASSO method was used for features filtration. Multi-variate logistic regression was used to develop three prediction models with clinical (CF model), first-order (FO model), and second-order features (SO model). The SO model achieved the most robust ability to predict intracranial hypertension. Internal validation showed that the C-statistic of the model was 0.811 (95% confidence interval [CI]: 0.691-0.931) with the bootstrapping method. The Hosmer Lemeshow test and calibration curve also showed that the SO model had excellent performance. The external validation results showed a good discrimination with an area under the curve of 0.725 (95% CI: 0.500-0.951). Although the FO model was inferior to the SO model, it had better prediction ability than the CF model. The study shows that the radiomic features analysis, especially second-order features, can be used to evaluate intracranial hypertension non-invasively compared with conventional clinical features, given its potential for clinical practice and further research.

Expanding the clinical spectrum of idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP). Although the majority of patients with IIH present classically with headache and papilledema, some patients may have unusual presentations or manifestations. Recent advancements in neuroimaging have facilitated the identification of other presentations associated with IIH. This review provides an overview of the expanding clinical spectrum of IIH.

RECENT FINDINGS

Presentations of IIH that are considered unusual include highly asymmetric or unilateral papilledema, IIH without papilledema, and IIH associated with cranial nerve involvement. These presentations likely reflect differences in the way cerebrospinal fluid (CSF) pressure is transmitted intracranially. Radiological signs of intracranial hypertension are increasingly recognized in patients with IIH and provide further insights into the effects of raised ICP on intracranial structures. Osseous changes in the skull base leading to formation of meningoceles and encephaloceles have been identified in patients with IIH, spontaneous skull base CSF leak, and drug-resistant temporal lobe epilepsy, suggesting a possible association.

SUMMARY

Clinicians should be familiar with the expanding clinical spectrum of IIH and the implications for the management of these presentations.

The Role of Ultrasound in Pediatric Skull Fractures: Determination of Fracture and Optic Nerve Sheath Diameter Measurements

BACKGROUND

The aim of the present study was to determine the accuracy of point-of-care ultrasound (POCUS) for detecting skull fractures and to evaluate sonographic measurements of optic nerve sheath diameter (ONSD) and ONSD/eyeball vertical diameter (EVD) ratios in children with head trauma.

METHODS

Children who presented with local signs of head trauma and underwent cranial computed tomography (CT) were enrolled. The suspected area was examined by POCUS to identify a skull fracture, and then the ONSD at 3 mm posterior to the globe and the EVD were measured. Ratios of ONSD measurement at 3 mm/EVD were reported. All ONSD measurements and ratios were calculated from cranial CT images.

RESULTS

There were 112 children enrolled in the study. The sensitivity and specificity of POCUS for skull fractures was 93.7% (95% confidence interval [CI], 82.8-98.6) and 96.8% (95% CI, 89.1-99.6), whereas the positive predictive value was 95.7% (95% CI, 85.1-98.8), and the negative predictive value was 95.3% (95% CI, 87.3-98.4). There was high agreement between POCUS and CT for identifying skull fractures (κ, 0.90 [±0.04]). In the group without elevated intracranial pressure findings on CT, patients with space-occupying lesions (SOLs) had higher sonographic ONSD measurements and ratios (P < 0.001) compared with cases without SOLs.

CONCLUSIONS

When used with clinical decision rules to minimize the risk for clinically important traumatic brain injury, POCUS seems to be a promising tool to detect skull fractures and calculate ONSD measurements and rates to predict the risk for SOLs and perform further risk stratification of children with minor head trauma.

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.

The role of sonographic optic nerve sheath diameter measurements in pediatric head trauma

PURPOSE

To determine the accuracy of bedside sonographic measurements of optic nerve sheath diameter (ONSD) and ONSD/eyeball transverse (ETD) diameter ratios to predict space-occupying lesions (SOLs) or elevated intracranial pressure (ICP) in pediatric head trauma.

METHODS

Children who presented to the emergency department with head trauma and underwent cranial computed tomography (CT) were enrolled and examined by ocular ultrasonography (US), and the ONSD was measured at 3 mm posterior to the globe and ETD were measured. Ratios of ONSD at 3 mm/ETD were calculated. All ONSD measurements and ratios were calculated from cranial CT images.

RESULTS

Subjects with elevated ICP had increased ONSD measurements and ratios. To predict elevated ICP, the AUC for ONSD at 3 mm was 0.956 (95% CI 0.896-1). At a cut-off level of 5.1 mm, the sensitivity and specificity of ONSD 3 mm values for elevated ICP were 92.9% and 94.0%. For the ONSD 3 mm/ETD ratio, it was 0.980 (95% CI 0.959-1). At a cut-off level of 0.22, the sensitivity and specificity were 100% sensitivity and 88.0%. All sonographic ONSD measurements and ratios were significantly correlated with readings calculated from cranial CT images.

CONCLUSION

Sonographic ONSD measurements and ratios were found to be quite sensitive to detect elevated ICP on cranial CT images. Additionally, there was a significant correlation between measurements calculated by ocular US and cranial CT scans. Bedside ocular US seems to be a promising and useful tool to determine ICP in children with head trauma.

[Clinical value of bedside transcranial doppler ultrasound in assessing intracranial pressure in critically ill pediatric patients with nervous system disease]

OBJECTIVES

To study the value of bedside transcranial doppler (TCD) in evaluating the level of intracranial pressure (ICP) in critically ill pediatric patients with nervous system disease in the pediatric intensive care unit (PICU).

METHODS

A prospective analysis was performed on the critically ill pediatric patients with nervous system disease who were admitted to the PICU of Shengjing Hospital, China Medical University, from November 2020 to November 2021. Bedside TCD was performed on all patients, and pulsatility index (PI) was calculated. Bedside lumbar puncture was performed to measure ICP. A Pearson correlation analysis was used to assess the correlation between PI and ICP. The receiver operating characteristic (ROC) curve was used to assess the value of PI in the diagnosis of elevated ICP (≥20 mm Hg).

RESULTS

A total of 56 children were included in the study. The top three primary diseases were intracranial infection (24 children, 43%), traumatic brain injury (TBI) (11 children, 20%), and cerebrovascular disease (5 children, 9%). The Pearson correlation analysis showed that PI was positively correlated with ICP (r=0.536, P<0.001). The subgroup analysis based on primary disease showed that in the TBI group, PI was positively correlated with ICP (r=0.655, P=0.029), while no significant correlation between PI and ICP was observed in the intracranial infection group (r=0.324, P=0.122). The ROC curve analysis showed that PI had an area under the curve of 0.828 (95%CI: 0.677-0.979) in predicting ICP≥20 mm Hg, with a sensitivity of 83.3% and a specificity of 79.5% at the optimal cut-off value of 1.255.

CONCLUSIONS

TCD technology for ICP monitoring can predict the change in ICP in critically ill pediatric patients with nervous system disease, suggesting it is useful for treatment options and prognosis evaluation.

Noticable Findings in Cranial MRI of the Patients with Idiopathic Intracranial Hypertension

OBJECTIVES

Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure. We investigated the optic nerve, Meckel's cavity, internal carotid artery (ICA) and pituitary findings of IIH by Cranial Magnetic Resonance Imaging (MRI).

METHODS

Cranial MRI images of 35 adult patients with IIH and 35 adult subjects with normal cranial MRI results (control) were evaluated. Optic nerve diameter (OND), optic nerve sheat diameter (ONSD), OND/ONSD ratio, ON tortuosity, ON protrusion, posterior scleral flattening, ICA transverse diameter, CSF distance in Meckel's cavity and ICA transverse diameter/CSF distance in Meckel's cavity ratio, and pituitary gland measurements (height and transverse dimension; and Optic chiasm- pituitary gland distance) were measured.

RESULTS

OND and ONSD of the IIH group were significantly higher than those of the control groups at anterior and posterior measurements (p < 0.05). OND/ONSD ratio of the IIH group was lower at anterior measurement; and higher at the posterior measurement than the control group (p < 0.05). Right ICA transverse diameter and bilateral CSF distance in Meckel's cavity of the IIH group were higher than those of the control. Optic chiasm- pituitary gland distance of the IIH group was significantly higher than that of the control group (p < 0.05).

CONCLUSION

OND/ONSD ratio is different in anterior and posterior measurements. So we recommend measuring OND and ONSD separately in IIH patients to use in the clinical practice. Similarly, optic chiasm-pituitary gland distance is also another point to note for IIH patients on MRI. Our paper adds new approach to IIH in terms of OND/ONSD ratio.

Role of the optic nerve sheath diameter in the assessment of the effectiveness of decompressive surgery after malignant middle cerebral artery infarction

BACKGROUND

After a case of stroke, intracranial pressure (ICP) must be measured and monitored, and the gold standard method for that is through an invasive technique using an intraventricular or intraparenchymal device. However, The ICP can also be assessed through a non-invasive method, comprised of the measurement of the optic nerve sheath diameter (ONSD) through ultrasound (US).

OBJECTIVE

To evaluate the ICP of patients who underwent wide decompressive craniectomy after middle cerebral artery (MCA) infarction via preoperative and postoperative ONSD measurements.

METHODS

A total of 17 patients, aged between 34 and 70 years, diagnosed with malignant MCA infarction with radiological edema and mid-line shift, who underwent decompressive surgery, were eligible. From the records, we collected data on age, sex, preoperative and postoperative Glasgow Coma Scale (GCS) scores, National Institutes of Health Stroke Scale (NIHSS) score, the degree of disability in the preoperative period and three months postoperatively through the scores on the Modified Rankin Scale (MRS), and the preoperative and postoperative midline shift measured by computed tomography (CT) scans of the brain.

RESULTS

Preoperatively, the mean GCS score was of 8 (range: 7.7-9.2), whereas it was found to be of 12 (range 10-14) on the first postoperative day (p = 0.001). The mean preoperative NIHSS score was of 21.36 ± 2.70 and, on the first postoperative day, it was of 5.30 ± 0.75 (p < 0.001). As for the midline shift, the mean preoperative value was of 1.33 ± 0.75 cm, and, on the first postoperative day, 0.36 ± 0.40 cm (p < 0.001). And, regarding the ONSD, the mean preoperative measurement was of 5.5 ± 0.1 mm, and, on the first postoperative day, it was of 5 ± 0.9 mm (p < 0.001).

CONCLUSION

The ocular US measurement of the ONSD for the preoperative and postoperative monitoring of the ICP seems to be a practical and useful method.

Non-invasive intracranial pressure assessment using shear-wave elastography in neuro-critical care patients

OBJECTIVE

To determine if Young's modulus of the optic nerve (ON) structure as measured by shear-wave elastography can suggest changes in intracranial pressure (ICP) in neuro-critical care patients.

MATERIALS AND METHODS

Thirty-one healthy volunteers and twenty-two neuro-critical care patients were enrolled. ON sheath (ONS) diameter (ONSD) values and Young's modulus measurements of volunteers were collected in a calm state and during a Valsalva maneuver (VM). Ultrasound measurements and ICP values of patients were collected on operation day and at 24 and 48 h after the operation; measurements were thereafter assigned to three groups: severely elevated (ICP greater than 22 mmHg), mildly elevated (ICP = 14-22 mmHg), and normal (ICP ≤ 13 mmHg).

RESULTS

ONSD and Young's modulus for the ON and ONS of volunteers during VM were higher than those in the calm state (all P < 0.001). In contrast to ONSD, Young's modulus for ON and ONS did not correlate with age, body mass index, or sex. The best cutoff values of Young's modulus for ON for predicting elevated and severely elevated ICP were 16.67 kPa and 22.74 kPa, respectively. Accordingly, the sensitivity values were 96.7% and 88.9%, and the specificity values were 86.1% and 73.7%, which had the same diagnostic performance as ONSD.

CONCLUSION

Young's modulus of the ON accurately reflects changes in ICP. It is not confounded by age, sex, or body mass index compared to ONSD.

Clinical and Radiological Profile of 122 Cases of Idiopathic Intracranial Hypertension in a Tertiary Care Centre of India: An Observational Study

BACKGROUND

Idiopathic intracranial hypertension (IIH) is well-described entity in literature. However, large studies on clinical and radiological profile are still very few from the Indian subcontinent.

AIMS

To analyze the clinical and radiological profile of IIH and correlation of various clinical and radiological parameters with papilledema and CSF opening pressure.

SETTING AND DESIGN

Hospital-based observational, descriptive study.

MATERIALS AND METHODS

This study analyzed 122 patients admitted in the department of Neurology (from January 2014 to December 2018) for detailed history, clinical examination, and neuroimaging. CSF manometry and routine CSF analysis were done. All participants met the modified Dandy criteria. Patients with secondary causes of raised ICP and primary ocular pathology were excluded.

STATISTICAL ANALYSIS USED

Descriptive statistics and Chi-square test.

RESULTS

Among 122 cases 86 (70.49%) were females. The mean age was 33 years. 62 (50.82%) cases were obese. Headache was the most common symptom (114/122; 93.44%). Bilateral papilledema was noted in 114 (93.44%) cases. Higher grades of papilledema had a correlation with higher CSF opening pressure. Empty sella was the most common radiological finding (100/122; 81.97%). All radiological findings except empty sella had a correlation with higher CSF opening pressure.

CONCLUSION

IIH typically affects obese females of childbearing age group. However, it is not uncommon in the nonobese and male sex. Obesity may not be a dominant risk factor for the development of IIH in the Indian subcontinent. Cases with normal BMI and male sex with clinical features of raised intracranial pressure and normal neuroimaging should also be evaluated for IIH. Cases with refractory headache and empty sella on MRI should be evaluated for IIH.

Optic Nerve Sheath Diameter Ultrasound for Raised Intracranial Pressure: A Literature Review and Meta-analysis of its Diagnostic Accuracy

Optic nerve sheath diameter (ONSD) ultrasound is becoming increasingly more popular for estimating raised intracranial pressure (ICP). We performed a systematic review and analysis of the diagnostic accuracy of ONSD when compared to the standard invasive ICP measurement.

METHOD

We performed a systematic search of PUBMED and EMBASE for studies including adult patients with suspected elevated ICP and comparing sonographic ONSD measurement to a standard invasive method. Quality of studies was assessed using the QUADAS-2 tool by two independent authors. We used a bivariate model of random effects to summarize pooled sensitivity, specificity, and diagnostic odds ratio (DOR). Heterogeneity was investigated by meta-regression and sub-group analyses.

RESULTS

We included 18 prospective studies (16 studies including 619 patients for primary outcome). Only one study was of low quality, and there was no apparent publication bias. Pooled sensitivity was 0.9 [95% confidence intervals (CI): 0.85-0.94], specificity was 0.85 (95% CI: 0.8-0.89), and DOR was 46.7 (95% CI: 26.2-83.2) with partial evidence of heterogeneity. The Area-Under-the-Curve of the summary Receiver-Operator-Curve was 0.93 (95% CI: 0.91-0.95, P < .05). No covariates were significant in the meta-regression. Subgroup analysis of severe traumatic brain injury and parenchymal ICP found no heterogeneity. ICP and ONSD had a correlation coefficient of 0.7 (95% CI: 0.63-0.76, P < .05).

CONCLUSION

ONSD is a useful adjunct in ICP evaluation but is currently not a replacement for invasive methods where they are feasible.

The magnetic resonance imaging assessment of optic nerve sheath diameter in pediatric acute liver failure patients

OBJECTIVE

To evaluate the diagnostic value of optic nerve sheath diameter (ONSD) using brain MRI in the pretransplantation period in the pediatric acute liver failure patients, and correlate the ONSD with clinical grade of hepatic encephalopathy (HE) and MRI findings.

PATIENTS AND METHODS

Forty acute liver failure patients and 40 control group patients were retrospectively analyzed. The high signal intensities in T2W (T2-weighted image), FLAIR (Fluid Attenuated Inversion Recovery) and DWI (diffusion-weighted imaging) sequences were evaluated and ONSD was measured. The patients were grouped first into 5 according to their West Haven score, and HE grade 0 and grade 1 were accepted as low grade HE, HE grade 2, 3 and 4 were accepted as high grade HE. The patients were grouped to 2 according to the MRI findings as low grade and high grade MRI group.

RESULTS

The mean value of ONSD was 6.0 ± 1.80 and 4.94 ± 1.27 in the all patients and in the control group, respectively. There was statistically significant difference between both the ONSD and the low grade-high grade HE groups (p=0.01), and between the ONSD and the low grade-high grade MRI groups (p<0.001).

CONCLUSIONS

Although high ONSD values do not make the diagnosis of cerebral edema, it may cause suspicion in the early period. MRI can be helpful in the diagnoses of increased intracranial pressure like ultrasound. Our study is the first study to compare ONSD and MRI findings in addition to HE grades. The widespread use of MRI in children in recent years may help determine the normal range of ONSD values.

Noninvasive Detection of Intracranial Hypertension by Novel Ultrasound Time-Harmonic Elastography

OBJECTIVE

A method for measuring intracranial pressure (ICP) noninvasively has long been sought after in neurology and neurosurgery. Treatment failure in individuals presenting with unspecific symptoms such as headache, gait disturbance, or visual impairment occurring in response to increased ICP can lead to irreversible brain injury, progressive disability, and death. Guidelines for diagnostic ICP measurement recommend intracranial placement of pressure tip catheters or lumbar puncture (LP) despite their invasiveness and possible complications. As ICP fluctuations are closely associated with changes in brain stiffness, ultrasound elastography could be a valid method to detect ICP noninvasively and with short examination times.

MATERIALS AND METHODS

In this pilot study, we have investigated the use of time-harmonic shear waves, introduced into the brain by an external shaker, and measured in real-time by transtemporal ultrasound, for deducing a noninvasive imaging marker sensitive to elevated ICP. To this end, we developed cerebral ultrasound time-harmonic elastography for the noninvasive quantification of shear wave speed (SWS) as a surrogate marker of cerebral stiffness in a short examination time of a few minutes.

RESULTS

We found that SWS in patients enrolled for LP with confirmed intracranial hypertension was 1.81 ± 0.10 m/s, distinguishing them from healthy volunteers with excellent diagnostic accuracy (1.55 ± 0.08 m/s; P < 0.001; area under the curve, 0.99). Interestingly, values in symptomatic patients decreased to normal stiffness immediately after LP (1.56 ± 0.06 m/s, P < 0.001). Moreover, invasively measured opening pressure correlated with SWS measured before LP and liquid volume drained through the spinal tap with the SWS difference between the 2 measurements.

CONCLUSIONS

Collectively, our results suggest a tight link between cerebral stiffness and ICP and demonstrate that intracranial hypertension can be detected noninvasively within short examination times, opening avenues for diagnostic applications of cerebral ultrasound time-harmonic elastography in neurology and emergency medicine.

Recognition of intracranial hypertension using handheld optical coherence tomography in children (RIO Study): a diagnostic accuracy study protocol

INTRODUCTION

Paediatric intracranial hypertension (IH) is a rare but serious condition that can pose deleterious effects on the brain and vision. Estimating intracranial pressure (ICP) in children is difficult. Gold standard direct ICP measurement is invasive and carries risk. It is impractical to routinely perform direct ICP measurements over time for all children at risk of IH. This study proposes to assess the diagnostic accuracy of handheld optical coherence tomography (OCT), a non-invasive ocular imaging method, to detect IH in children.

METHODS AND ANALYSIS

This is a prospective study evaluating the diagnostic accuracy of handheld OCT for IH in at risk children. Inclusion criteria include clinical and/or genetic diagnosis of craniosynostosis, idiopathic intracranial hypertension, space occupying lesion or other conditions association with IH and age 0-18 years old. Exclusion criteria include patients older than 18 years of age and/or absence of condition placing the child at risk of IH. The primary outcome measures are handheld OCT and 48-hour ICP assessments, which will be used for diagnostic accuracy testing (sensitivity, specificity, positive predictive value, negative predictive value and accuracy). Main secondary outcome measures include visual acuity, fundoscopic examination, contrast sensitivity, visual field testing and visual evoked potentials, wherever possible.

ETHICS AND DISSEMINATION

Ethical approval was granted for this study by the East Midlands Nottingham 2 Research Ethics committee (UOL0348/IRAS 105137). Our findings will be disseminated through presentation at relevant meetings, peer-reviewed publication and via the popular media.

TRIAL REGISTRATION NUMBER

ISRCTN52858719.