Mean Optic Nerve Sheath Diameter Research Articles

Optic nerve sheath measurement to monitor disease activity in giant cell arteritis: a pilot study.

Optic nerve sheath (ONS) enhancement using magnetic resonance imaging of the orbits was observed in patients with giant cell arteritis (GCA). We previously showed that ONS diameter (ONSD) by bedside ultrasound is increased in patient with active GCA. This study aims to assess whether ONSD decreases with clinical remission in patients with GCA. A prospective cohort study was conducted from June 2022 to January 2023. Patients who had an optic nerve ultrasound at GCA diagnosis as part of a previous crosssectional study were eligible. Optic nerve ultrasound was performed by the same investigator at diagnosis and month 3. ONSD (includes the optic nerve and its sheath) and optic nerve diameter (OND) were measured. Descriptive statistics for baseline characteristics and paired sample t-test were performed to assess the mean difference in OND and ONSD between diagnosis and month 3. Nine patients with GCA were included. The median age at disease onset was 79years (interquartile range (IQR) of 79-82years), and 7 patients were males. All patients were in clinical remission at month 3 on prednisone (median dose of 15mg/day, IQR of 10-25mg). The mean ONSD was lower at month 3 (3.76mm) compared to baseline (5.98mm), with a paired mean difference of 2.22mm (95% CI 1.41-3.03mm, p < 0.001). As anticipated, OND measurements did not vary between diagnosis and month 3. ONSD on ultrasound improves after 3 months of therapy in patients with GCA. A longer prospective study is required to determine if ONSD is useful to assess disease activity in GCA. Key Points • ONS ultrasound can identify patients with active GCA. • The ONSD on ultrasound is dynamic and improved after 3months of GCA therapy. • ONS ultrasound may be useful to monitor disease activity in GCA.

Optic Nerve Sheath Measurement on Ultrasound: A Novel Diagnostic Test for Giant Cell Arteritis.

Optic nerve sheath enhancement on magnetic resonance imaging has been reported in patients with giant cell arteritis (GCA), with or without visual manifestations. Whether similar findings can be documented on ultrasound is unknown. Optic nerve ultrasound is a point-of-care, easy to learn, rapid, and noninvasive technique. This study aims to investigate whether optic nerve sheath diameter (ONSD) measured on ultrasound is useful in the diagnosis of active, new-onset GCA. A single-center, diagnostic accuracy study was performed from June to November 2022 on consecutive eligible patients referred for suspected GCA. Optic nerve ultrasound was performed on both eyes. The ONSD (includes the optic nerve and its sheath) and optic nerve diameter (OND) were measured 3 mm behind the ocular globe. The presence or absence of GCA was confirmed clinically 6 months later. Multivariable linear regression, adjusting for age and sex, was used to determine the association between optic nerve ultrasound measures and final GCA diagnosis. Thirty participants were enrolled, including nine participants with a final diagnosis of GCA. Mean ± SD ONSD was 5.98 ± 1.17 mm in patients with GCA and 4.02 ± 0.99 mm in patients without GCA. Mean ONSD was greater by 1.26 mm in patients with GCA (95% confidence interval 0.30-2.21 mm, P = 0.01) compared with those without GCA, adjusting for age and sex. Mean ± SD OND was 2.97 ± 0.46 mm in patients with GCA and 2.47 ± 0.58 mm in patients without GCA. There was no evidence of an association between GCA diagnosis and OND. Patients with GCA had a significantly greater ONSD on ultrasound than patients without GCA. Optic nerve ultrasound may represent a novel, rapid, bedside diagnostic test for GCA. A large prospective study is required to confirm these findings and evaluate whether ONSD can be used as a disease activity biomarker in GCA.

Optic nerve sheath diameter as a non-invasive tool to detect clinically relevant raised intracranial pressure in children: an observational analytical study

BackgroundRaised intracranial pressure (ICP) contributes to approximately 20% of the admissions in the paediatric intensive care unit (PICU) in our setting. Timely identification and treatment of raised ICP is important...

Effect of different positive end expiratory pressure levels on optic nerve sheath diameter in patients with or without midline shift who are undergoing supratentorial craniotomy

PurposeIn general, high levels of PEEP application is avoided in patients undergoing craniotomy to prevent a rise in ICP. But that approach would increase the risk of secondary brain injury especially in hypoxemic patients. Because the optic nerve sheath is distensible, a rise in ICP is associated with an increase in the optic nerve sheath diameter (ONSD). The cutoff value for elevated ICP assessed by ONSD is between 5.6 and 6.3 mm. We aimed to evaluate the effect of different PEEP levels on ONSD and compare the effect of different PEEP levels in patients with and without intracranial midline shift.MethodsThis prospective observational study was performed in aged 18–70 years, ASA I–III, 80 patients who were undergoing supratentorial craniotomy. After the induction of general anesthesia, the ONSD’s were measured by the linear transducer from 3 mm below the globe at PEEP values of 0–5–10 cmH2O. The ONSD were compered between patients with (n = 7) and without midline shift (n = 73) at different PEEP values.ResultsThe increases in ONSD due to increase in PEEP level were determined (p < 0.001). No difference was found in the comparison of ONSD between patients with and without midline shift in different PEEP values (p = 0.329, 0.535, 0.410 respectively). But application of 10 cmH2O PEEP in patients with a midline shift increased the mean ONSD value to 5.73 mm. This value is roughly 0.1 mm higher than the lower limit of the ONSD cutoff value.ConclusionsThe ONSD in adults undergoing supratentorial tumor craniotomy, PEEP values up to 5 cmH2O, appears not to be associated with an ICP increase; however, the ONSD exceeded the cutoff for increased ICP when a PEEP of 10 cmH2O was applied in patients with midline shift.

435 Use of Optic Nerve Sheath Diameter in Extraventricular Drain Weaning in Adults With Post-hemorrhagic Hydrocephalus

INTRODUCTION: Optic nerve sheath diameter (ONSD) can be used as a noninvasive measurement of intercranial pressure. Few studies have evaluated the value of ONSD in predicting the need for ventriculoperitoneal shunt (VPS) placement after development of post-hemorrhagic hydrocephalus (PHH) in adults. METHODS: Adult patients 18 years or older, admitted with intracranial hemorrhage and hydrocephalus requiring EVD placement were included in the study. Demographics were recorded. CT imaging of ONSD was measured (mm) upon initial ED visit before EVD placement (pre-EVD), immediately after successful EVD removal (post-EVD), and if applicable, after EVD removal but immediately before VPS placement. Change in ONSD was calculated and groups were stratified by EVD only patients and EVD+VPS patients. RESULTS: Imaging for 30 patients were successfully retrieved and analyzed for bilateral ONSD values at all timepoints. A statistically significant convergence to a normally distributed mean ONSD was found for both groups (EVD and EVD+VPS). Additionally, a statistically significant increase was found in ONSD between the EVD+VPS group compared to the EVD only group. The EVD only group showed a mean EVD placement time of only 14 days (2 weeks) with an average decrease in ONSD (-0.905mm) compared with the EVD+VPS group who had an increase in ONSD at 14-days (+1.089 mm). CONCLUSIONS: Patients with hydrocephalus due to intracranial hemorrhage who went on to require VPS developed an increase in ONSD despite EVD use while patients who were successfully weaned from the EVD developed a decrease in ONSD. ONSD may be a useful adjunct tool to aid in the process of EVD weaning in this patient population.

Ultrasound-guided initial diagnosis and follow-up of pediatric idiopathic intracranial hypertension

BackgroundIdiopathic intracranial hypertension in children often presents with non-specific symptoms found in conditions such as hydrocephalus. For definite diagnosis, invasive intracranial pressure measurement is usually required. Ultrasound (US) of the optic nerve sheath diameter provides a non-invasive method to assess intracranial pressure. Transtemporal US allows imaging of the third ventricle and thus assessment for hydrocephalus.ObjectiveTo investigate whether the combination of US optic nerve sheath and third ventricle diameter can be used as a screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure and exclude hydrocephalus as an underlying pathology. Further, to analyze whether both parameters can be used to monitor treatment outcome.Materials and methodsWe prospectively included 36 children with idiopathic intracranial hypertension and 32 controls. Using a 12-Mhz linear transducer and a 1–4-Mhz phased-array transducer, respectively, optic nerve sheath and third ventricle diameters were determined initially and during the course of treatment.ResultsIn patients, the mean optic nerve sheath diameter was significantly larger (6.45±0.65 mm, controls: 4.96±0.32 mm) and the mean third ventricle diameter (1.69±0.65 mm, controls: 2.99±1.31 mm) was significantly smaller compared to the control group, P<0.001. Optimal cut-off values were 5.55 mm for the optic nerve sheath and 1.83 mm for the third ventricle diameter.ConclusionsThe combined use of US optic nerve sheath and third ventricle diameter is an ideal non-invasive screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure while ruling out hydrocephalus. Treatment can effectively be monitored by repeated US, which also reliably indicates relapse.

Optic Nerve Sheath MR Imaging Measurements in Patients with Orthostatic Headaches and Normal Findings on Conventional Imaging Predict the Presence of an Underlying CSF-Venous Fistula.

Spontaneous spinal CSF leaks typically cause orthostatic headache, but their detection may require specialized and invasive spinal imaging. We undertook a study to determine the value of simple optic nerve sheath MR imaging measurements in predicting the likelihood of finding a CSF-venous fistula, a type of leak that cannot be detected with routine spine MR imaging or CT myelography, among patients with orthostatic headache and normal conventional brain and spine imaging findings. This cohort study included a consecutive group of patients with orthostatic headache and normal conventional brain and spine imaging findings who underwent digital subtraction myelography under general anesthesia to look for spinal CSF-venous fistulas. The study group consisted of 93 patients (71 women and 22 men; mean age, 47.5 years; range, 17-84 years). Digital subtraction myelography demonstrated a CSF-venous fistula in 15 patients. The mean age of these 8 women and 7 men was 56 years (range, 23-83 years). The mean optic nerve sheath diameter was 4.0 mm, and the mean perioptic subarachnoid space was 0.5 mm in patients with a CSF-venous fistula compared with 4.9 and 1.2 mm, respectively, in patients without a fistula (P < .001). Optimal cutoff values were found at 4.4 mm for optic nerve sheath diameter and 1.0 mm for the perioptic subarachnoid space. Fistulas were detected in about 50% of patients with optic nerve sheath diameter or perioptic subarachnoid space measurements below these cutoff values compared with <2% of patients with optic nerve sheath diameter or perioptic subarachnoid space measurements above these cutoff values. Following surgical ligation of the fistula, optic nerve sheath diameter increased from 4.0 to 5.3 mm and the perioptic subarachnoid space increased from 0.5 to 1.2 mm (P < .001). Concerns about a spinal CSF leak should not be dismissed in patients with orthostatic headache when conventional imaging findings are normal, and simple optic nerve sheath MR imaging measurements can help decide if more imaging needs to be performed in this patient population.

Characterization of Ocular Sonography Findings and their Relationship to Clinical Features from a South Indian Cohort of Idiopathic Intracranial Hypertension.

Idiopathic intracranial hypertension (IIH) typically manifests with headache, accompanied by papilledema and visual loss, and has a higher prevalence in females. In recent years, ocular sonography, particularly, measurement of optic nerve sheath diameter (ONSD), is being investigated for diagnosis of IIH. A total of 35 patients over the age of 18 years, fulfilling the modified Dandy's criteria for diagnosis of IIH were included. Patients underwent assessment with magnetic resonance imaging, lumbar puncture, and ocular sonography to measure ONSD and ocular arterial indices. The mean ONSD values (in centimeters) in the right eye of patients with IIH was 0.57 ± 0.13, while it was 0.48 ± 0.03 in controls. In the left eye, the mean ONSD value (cm) was 0.59 ± 0.13 in patients with IIH and 0.48 ± 0.03 in controls. ONSD was significantly higher in cases compared to controls (P < 0.001, Welch test). Pulsatility index of the central retinal artery was significantly higher in cases compared to controls (P < 0.001, Welch test). Resistance index of the ophthalmic artery was statistically significant (P < 0.005, Welch test). Receiver operating characteristic curve analysis revealed a cutoff value of 5.1 mm on the right side and 5 mm on the left side had a sensitivity and specificity of more than 80% for IIH diagnosis. Our study provides insights into the utility of optic nerve sheath measurements and arterial indices in the diagnosis of IIH in a South Indian cohort. Further research is needed to fully understand the longitudinal relationship of these parameters and treatment outcomes in IIH.

Bedside ultrasonographic evaluation of optic nerve sheath diameter for monitoring of intracranial pressure in traumatic brain injury patients: a cross sectional study in level II trauma care center in India.

Optic nerve sheath diameter (ONSD) is an emerging non-invasive, easily accessible, and possibly useful measurement for evaluating changes in intracranial pressure (ICP). The utilization of bedside ultrasonography (USG) to measure ONSD has garnered increased attention due to its portability, real-time capability, and lack of ionizing radiation. The primary aim of the study was to assess whether bedside USG-guided ONSD measurement can reliably predict increased ICP in traumatic brain injury (TBI) patients. A total of 95 patients admitted to the trauma intensive care unit was included in this cross sectional study. Patient brain computed tomography (CT) scans and Glasgow Coma Scale (GCS) scores were assessed at the time of admission. Bedside USG-guided binocular ONSD was measured and the mean ONSD was noted. Microsoft Excel was used for statistical analysis. Patients with low GCS had higher mean ONSD values (6.4±1.0 mm). A highly significant association was found among the GCS, CT results, and ONSD measurements (P<0.001). Compared to CT scans, the bedside USG ONSD had 86.42% sensitivity and 64.29% specificity for detecting elevated ICP. The positive predictive value of ONSD to identify elevated ICP was 93.33%, and its negative predictive value was 45.00%. ONSD measurement accuracy was 83.16%. Increased ICP can be accurately predicted by bedside USG measurement of ONSD and can be a valuable adjunctive tool in the management of TBI patients.

Measurement of optic nerve sheath diameter on computed tomography for the differentiation of transient ischemic attacks.

The objective of this study was to investigate whether the measurement of mean optic nerve sheath diameter in patients with transient ischemic attack could be used to distinguish between control groups, the acute ischemic stroke group, and subgroups within the acute ischemic stroke category. Retrospectively, the mean optic nerve sheath diameters of patients aged 18 years and older belonging to control, transient ischemic attack, acute ischemic stroke, and subgroups within the acute ischemic stroke category were measured with initial computed tomography conducted in the emergency department. Out of the 773 patients included in the study, 318 (41.1%) were in the control group, 77 (10%) had transient ischemic attack, and 378 (49%) were categorized as stroke patients. The average mean optic nerve sheath diameter was significantly higher in both the stroke and transient ischemic attack groups compared with the control group (p<0.001 for both comparisons). Furthermore, the mean optic nerve sheath diameter in the stroke subgroups was significantly higher than in both the transient ischemic attack and control groups (p<0.001 for all comparisons). In transient ischemic attack patients, the mean optic nerve sheath diameter showed a significant ability to predict transient ischemic attack (AUC=0.913, p<0.001), with a calculated optimal cutoff value of 4.72, sensitivity of 94.8%, and specificity of 73.9%. The mean optic nerve sheath diameter of patients in the transient ischemic attack group was lower compared with those in the stroke subgroups but higher compared with the control group.

Effect of a cervical collar on optic nerve sheath diameter in trauma patients.

As advocated in advanced trauma life support and prehospital trauma life support protocols, cervical immobilization is applied until cervical spine injury is excluded. This study aimed to show the difference in optic nerve sheath diameter (ONSD) between patients with and without a cervical collar using computed tomography (CT). This was a single-center, retrospective study examining trauma patients who presented to the emergency department between January 1, 2021, and December 31, 2021. The ONSD on brain CT of the trauma patients was measured and analyzed to determine whether there was a difference between the ONSD with and without the cervical collar. The study population consisted of 169 patients. On CT imaging of patients with (n=66) and without (n=103) cervical collars, the mean ONSD in the axial plane were 5.43 ± 0.50 mm and 5.04 ± 0.46 mm respectively for the right eye and 5.50 ± 0.52 mm and 5.11 ± 0.46 mm respectively for the left eye. The results revealed an association between the presence of a cervical collar and the mean ONSD, which was statistically significant (P<0.001) for both the right and left eyes. A cervical collar may be associated with increased ONSD. The effect of this increase in the ONSD on clinical outcomes needs to be investigated, and the actual need for cervical collar in the emergency department should be evaluated on a case-by-case basis.

Additional predictive value of optic nerve sheath diameter for neurological prognosis after cardiac arrest: a prospective cohort study

BackgroundThe goal is to estimate the additional value of ultrasonographic optic nerve sheath diameter (ONSD) measurement on days 1–3, on top of electroencephalography (EEG), pupillary light reflexes (PLR), and somatosensory evoked potentials (SSEP), for neurological outcome prediction of comatose cardiac arrest patients. We performed a prospective longitudinal cohort study in adult comatose patients after cardiac arrest. ONSD was measured on days 1–3 using ultrasound. Continuous EEG, PLR, and SSEP were acquired as standard care. Poor outcome was defined as cerebral performance categories 3–5 at 3–6 months. Logistic regression models were created for outcome prediction based on the established predictors with and without ONSD. Additional predictive value was assessed by increase in sensitivity for poor (at 100% specificity) and good outcome (at 90% specificity).ResultsWe included 100 patients, 54 with poor outcome. Mean ONSD did not differ significantly between patients with good and poor outcome. Sensitivity for predicting poor outcome increased by adding ONSD to EEG and SSEP from 25% to 41% in all patients and from 27% to 50% after exclusion of patients with non-neurological death.ConclusionsONSD on days 1–3 after cardiac arrest holds potential to add to neurological outcome prediction.Trialregistration: clinicaltrials.gov, NCT04084054. Registered 10 September 2019, https://www.clinicaltrials.gov/study/NCT04084054.

Optic nerve sheath diameter and severity of central nervous infection

Background Central nervous system (CNS) infection affects the brain, and can cause cerebral edema, increased intracranial pressure (ICP), cerebral herniation, and death. Measurement of the optic nerve sheath diameter (ONSD) by ultrasound is a new, non–invasive examination to predict ICP, with high sensitivity and specificity.Objective To analyze for a possible association between ONSD measured by ultrasonographic examination and severity of CNS infection.&#x0D; Methods This cross–sectional study was performed in the Pediatric Department of Hasan Sadikin Hospital, Bandung, West Java. Subjects were chosen by consecutive sampling. We measured ONSD, examined clinical manifestations, as well as performed a cerebrospinal fluid (CSF) study and imaging of CNS infection. Data analysis was done by paired T–test and one–way ANOVA, followed by Tukey test on significant variables.&#x0D; Results Subjects consisted of 32 children with CNS infection. The most common clinical symptoms were fever, decreased consciousness, and nuchal rigidity. Bivariate analysis revealed strong positive associations between ONSD and Glasgow Coma Scale (GCS), increased protein levels in CSF, and type of CNS infection.&#x0D; Conclusion Larger ONSD is significantly associated with lower GCS, increases CSF protein, and particular CNS infections. The ONSD is also associated with meningitis tuberculosis grade III, with a higher mean ONSD of both eyes compares to other CNS infections. Hence, the higher the ONSD, the more severe the degree of CNS infection.

Automation of ultrasonographic optic nerve sheath diameter measurement using convolutional neural networks.

Ultrasonographic optic nerve sheath (ONS) diameter is a noninvasive intracranial pressure (ICP) surrogate. ICP is monitored invasively in specialized intensive care units. Noninvasive ICP monitoring is important in less specialized settings. However, noninvasive ICP monitoring using ONS diameter (ONSD) is limited by the need for experts to obtain and perform measurements. We aim to automate ONSD measurements using a deep convolutional neural network (CNN) with a novel masking technique. We trained a CNN to reproduce masks that mark the ONS. The edges of the mask are defined by an expert. Eight models were trained with 1000 epochs per model. The Dice-similarity-coefficient-weighted averaged outputs of the eight models yielded the final predicted mask. Eight hundred and seventy-three images were obtained from 52 transorbital cine-ultrasonography sessions, performed on 46 patients with brain injuries. Eight hundred and fourteen images from 48 scanning sessions were used for training and validation and 59 images from four sessions for testing. Bland-Altman and Pearson linear correlation analyses were used to evaluate the agreement between CNN and expert measurements. Expert ONSD measurements and CNN-derived ONSD estimates had strong agreement (r = 0.7, p < .0001). The expert mean ONSD (standard deviation) is 5.27mm (0.43) compared to CNN mean estimate of 5.46mm (0.37). Mean difference (95% confidence interval, p value) is 0.19mm (0.10-0.27mm, p = .0011), and root mean square error is 0.27mm. A CNN can learn ONSD measurement using masking without image segmentation or landmark detection.

Effect of Tourniquet Deflation on Intracranial Pressure Measured by Ultrasound of the Optic Nerve Sheath Diameter in Patients Undergoing Orthopedic Surgery Under Spinal Anesthesia: An Observational Study.

Background Orthopedic surgeries of the lower extremities frequently require exsanguination and the use of pneumatic tourniquets. However, the deflation of the tourniquet is accompanied by predominant metabolic changes such as an increase in PaCO2. Prior studies have reported the existence of a correlation between tourniquet deflation and an increase in intracranial pressure in patients undergoing surgery under general anesthesia. However, there is a dearth of literature demonstrating such relationships among patients undergoing surgery under subarachnoid block in the Indian setting. The present research was conducted to study the variations in intracranial pressure after the deflation of the tourniquet by measuring the optic nerve sheath diameter (ONSD) using ultrasound among patients undergoing orthopedic surgery of the lower limb under spinal anesthesia at a tertiary care hospital in eastern India. Methodology After obtaining clearance from the Institutional Ethics Committee, this prospective observational study was conducted among 45 patients undergoing orthopedic surgeries of the lower limb using a pneumatic tourniquet. Changes in intracranial pressure following tourniquet deflation were recorded by measuring ONSD by ultrasound in these patients. Heart rate (HR), mean arterial pressure (MAP), SpO2, EtCO2, and ONSD were noted 15 minutes before administration of subarachnoid block (T0), just before tourniquet deflation (T1) and at 5, 10, and 15 minutes after tourniquet deflation (T5, T10, and T15, respectively). Results The ONSD varied significantlyat each point of observation (p < 0.05). The ONSDs at 5 and 10 minutes after the deflation of the tourniquet were significantly greater than that at T0 (p = 0.002). EtCO2 showed a significant increase compared to baseline values at every point of observation intraoperatively whereas MAP showed a significant decrease (p < 0.05).For all parameters (ONSD, HR, systolic blood pressure, diastolic blood pressure, MAP, and EtCO2), the most significant change in observation was noted at T10, i.e., 10 minutes after the deflation of the tourniquet. Conclusions The significant findingin thisstudy was that the ONSD measurements recorded by ultrasound were increased after the deflation of the tourniquet and that this change can be attributed to an increase in EtCO2. However, the results obtained cannot be validated outside the present research owing to the observational nature of the study and limited sample size. Thus, it is difficult to arrive at a definitive conclusion. Further large-scale multicentric studiesmaybe needed to substantiate the findings of thisstudy.

Optic Nerve Sheath Diameter: A Cross-Sectional Study of Ultrasonographic Measurement in Healthy Black South African Adults.

Ultrasonographic optic nerve sheath diameter (ONSD) measurement is an accurate, portable, and non-invasive method of detecting raised intracranial pressure that can also reflect dynamic, real-time changes in intracranial pressure fluctuations. Various studies have shown the mean range of ONSD to vary greatly across different population groups. This study aimed to determine the mean ONSD in healthy Black South African adults. In this cross-sectional study, healthy black South African adult participants underwent optic nerve sheath ultrasound of the right eye, with the diameter being measured at 3 mm behind the retina in two different planes. The average of the two measurements was used to find the mean optic nerve sheath diameter. This measurement was compared to that found in a Canadian adult population, and the effect of age, gender, and co-morbidities on ONSD was assessed. A total of 99 participants were included in this study, of which 39 were male and 60 were female. The mean ONSD was found to be 5.1 mm (SD ± 0.33). This value was significantly higher than the mean ONSD observed in the Canadian population (p < 0.001). There was no significant difference found between the mean ONSD in males and females (p = 0.652), and both age and presence of co-morbidities were not found to significantly correlate with ONSD. (p = 0.693 and p = 0.974, respectively).

Correlation Between Optic Nerve Sheath Diameter at Initial Head CT and the Rotterdam CT Score.

Introduction Intracranial findings on imaging have long been used in assessing the severity of traumatic brain injury (TBI); the Rotterdam CT scoring (RCTS) is a more recent tool. Estimating the optic nerve sheath diameter (ONSD) at computed tomography (CT) can be another valuable predictor of the severity of the injury, especially as both ONSD and the RCTS are proven to be independent predictors of raised intracranial pressure (ICP).The study objective was to determine the correlation between ONSD at initial head CT and RCTS. Material and methods We observed 40 consecutive confirmed TBI cases at their initial head CT examinations in the emergency department for ONSD and the presence of other intracranial findings necessary to derive RCTS. The data were prospectively collected and analyzed, with statistical significance set at p ≤0.05 at 95% CI. Results The mean ONSD positively correlated with the Rotterdam CT score (r=0.368, p=0.019). A cut-off value of 6.83 mm was extrapolated from the receiver operator characteristic (ROC) curve as the mean binocular ONSD that best predicted severe RCTS (≥4) (sensitivity: 73.3%, specificity: 80%, positive predictive value: 68.7%, negative predictive value: 83.3%). The area under the curve (AUC) was 0.780 (p=0.003). Binary logistic regression analysis revealed an odd ratio (OR) of 11.000(95% CI: 2.438-49.627; p=0.002). Conclusion TBI patients with high RCTS have wide mean binocular ONSD. Those with average binocular ONSD above the cut-off value are likelier to have severe TBI. With the documented good correlation, ONSDmay become very useful in informing the clinical decision for sequential CT scans in TBI patients and, therefore, reducing the cumulative radiation burden from needless exposures. Furthermore, the non-invasive nature of its assessment will have more clinical relevance in resource-limited settings, where the skills and equipment for ICP monitoring are either not readily available or too expensive to be used routinely.

Evaluation of Optic Nerve Sheath Diameter Measurement in the Management of Patients Admitted to the Emergency Department with Head Trauma

Objective: Ultrasonographic measurements of optic nerve sheath diameter is associated with increased intracranial pressure. Intracranial pressure measurements are usually performed on critical areas or intensive care unit patients. The effect of ultrasonographic measurement of optic nerve sheath diameter in predicting pathology or the need for surgery in mild or moderate head trauma has not been evaluated. In our study, we compared ultrasonographic optic nerve sheath diameter measurements with cranial computed tomography (CT) findings and clinical outcomes of patients with head trauma. Materials and methods: Patients with head trauma admitted to the emergency department who were diagnosed with mild, moderate, and severe brain injury were selected for this retrospective study. The optic nerve sheath diameters were measured by ultrasonography. The findings were compared with the outcome and cranial tomography characteristics of the patients. Results: Of the 58 patients admitted to the emergency department with head trauma, mild traumatic brain injury was most common. Hospitalization or operation was required in 51.7% of the patients (30 patients). The mean optic nerve sheath diameter was 4.96 ± 1.02 mm (3.1–7.3 mm) on the right and 4.92 ± 1.02 mm (3.3–7.8) on the left. Optic nerve sheath diameter of 5 mm or more were statistically significant in predicting hospitalization, the presence of pathology, and increased intracranial pressure on cranial CT (P &lt; 0.05). Conclusion: Optic nerve sheath diameters of patients with moderate and mild head trauma may provide information about the need for hospitalization or surgery and can be used as a triage criterion in determining the need for monitoring and follow-up and imaging priorities.

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.

SONOGRAPHIC MEASUREMENT OF OPTIC NERVE SHEATH DIAMETER TODETECT FINDINGS OF INCREASED INTRACRANIAL PRESSURE IN ADULT HEAD INJURY PATIENTS IN EMERGENCY DEPARTMENT OF TERTIARY CARE HOSPITAL

Introduction:Raised intracranial pressure (ICP)is important to determine in traumatic &amp; non-traumatic neurological and neurosurgical patients as it may cause signicant neurological deterioration due to secondary brain damage. Intra cranial pressure means exerted by uids such as cerebrospinal uid (CSF) inside the skull and on the brain tissue. So, a quick evaluation of increased ICP is important for the management of patients with traumatic brain injury (TBI) to allow timely intervention to decrease the ICP and maintain adequate cerebral perfusion. Aims: The aim was to evaluate use of bedside sonographic measurement of optic nerve sheath diameter (ONSD) to detect ndings of increased intracranial pressure in adult head injury patients in Emergency department. Methods: This prospective study was conducted at Emergency Medicine department of Mahatma Gandhi medical college &amp; Hospital, Jaipur. Total 108 adult head injury patientswith suspected raised ICPwere included in this study. Bedside ultrasound was done for ONSD measurement, followed by a computed tomography (CT) of brain. Mechanism of injury, GCS, TBI classication, clinical featuresof increased ICP, mean ONSD of both eyes by USG and brain CT ndings of increased ICP were recorded.A mean bipolar ONSD &gt; 5mm was considered abnormal. Result: Present study found Moderate head injury (57.4 %) as most common head injury. Mean ONSD in right eye was 5.964 with SD 0.822 and mean ONSD in left eye was 5.957 with SD 0.822.Total mean ONSD was &gt;5mm was found in 84.25 % patients. Raised ICP features was present in 82.4 % CT brain.GCS score was inversely correlated with mean ONSD. Conclusion: We concluded that thesonographic measurement of optic nerve sheath diameter has excellent diagnostic accuracy to predict increased intracranial pressure in adult head injury patients in Emergency department