Binocular Optic Nerve Sheath Diameter Research Articles

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.

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.

Assessment of Optic Nerve Sheath Diameter and Its Postoperative Regression among Patients Undergoing Brain Tumor Resection in a Tertiary Care Center.

Introduction Bedside measurement of optic nerve sheath diameter (ONSD) using ultrasonography (USG) is a useful method for detecting raised intracranial pressure (ICP). The primary and main objective of this study is to estimate ONSD among patients with brain tumor and its regression post tumor resection to assess the correlation as well as diagnostic accuracy of the same. Materials and Methods This prospective observational study was performed in a tertiary health care center over a span of 3 months on 68 adults of either sex, out of which 30 were nonneurosurgical patients, taken as control group. Rest 38 were neurosurgical patients posted for brain tumor resection. Normal ONSD in our population was determined by calculating average ONSD using transorbital USG in individuals of control group. ONSD in neurosurgical patients taken as case group was recorded before surgery, intraoperatively immediately post tumor resection, as well as 12 and 24 hours post surgery. These values were analyzed to see the correlation of ONSD with tumor resection. Results The mean (±standard deviation) binocular ONSD in our population was 4.28 ± 0.28 mm. The mean preoperative binocular ONSD in cases using transorbital USG came out to be 5.43 ± 0.37 mm with 88.23% sensitivity and 100% specificity. Postoperatively, transorbital ONSD showed significant regression at 12 and 24 hours as compared with preoperative values ( p -value < 0.05). Conclusion Transorbital ultrasonographic measurement of ONSD could be considered as an indirect indicator of ICP in neurosurgical patients perioperatively. The technique is quick to perform at bedside, feasible in critical patients, and without any harmful effects.

Ultrasound assessment of optic nerve sheath diameter for evaluation of elevated intracranial pressure in patient with head trauma: A comparative study with CT head

Purpose: Increased intracranial pressure (ICP) is complication of traumatic brain injury. Early detection of raised ICP is helpful in timely treatment. Bed side ultrasound of optic nerve sheath is easier for detection of raised intracranial pressure by measuring its diameter. Our aim was to determine whether bedside ultrasound measurement of optic nerve sheath diameter (ONSD) can accurately predict raised intracranial pressure in head injury patients and to calculation of validity of test. Methods and Materials: Total 150 patients with head injury was first examined by ultrasound. The ONSD was measured 3 mm behind the globe perpendicular to long axis of globe in both eyes than mean binocular ONSD was calculated. Diameter more than 5 mm was considered abnormal. CT scan was performed in all patients and result was considered positive for elevated ICP if mid line shift, effacement of sulci, ventricles and cisterns are seen. Results: Out of total 150 patients 61 was female and 89 was male, age was ranging from 23-61 years. 30 patients showed mean binocular ONSD >5mm by ultrasound out of them 26 patients showed positive signs of raised intracranial pressure on CT. Sensitivity and negative predictive value of ultrasound to detect raised ICP was 100%, Specificity was 96.7 % and negative predictive value was 86.6 %. Conclusions: Ultrasound can be used as bed side screening tool to detect raised ICP in ICU patients and head trauma patients especially in hospital with high patient flow in emergency department.

Ultrasonographic measurement of optic nerve sheath diameter to detect raised intracranial pressure in adult head injury patients in the intensive care unit and its correlation with computed tomography scan findings

Background: Our objective was to evaluate if ultrasonographic measurement of optic nerve sheath diameter can be used for early and accurate diagnosis of raised intracranial pressure as seen in cranial CT scan in patients of traumatic brain injury. Methods: Prospective, observational study. 40 adult traumatic head injury patients with altered sensorium suspected to have elevated intracranial pressure admitted to the ICU. Single optic nerve sheath diameter was measured 3.0 mm behind the globe in each eye, and optic nerve sheath diameter from each eye were averaged to create a binocular optic nerve sheath diameter measurement. A binocular optic nerve sheath diameter or uni-ocular measurement in patients with single eye measurement greater than 5.00 mm was considered abnormal. A CT scan of the head was performed within 2 hrs of USG measurement. The radiologist was blinded to the USG measurement of optic nerve sheath diameter and patient's CT considered to be positive for raised ICP Results: Mean age of the patients was 41.15 years. Mean ONSD recorded was 5.613. Highest ONSD was 6.300 and the lowest was 4.750. CT scan findings of raised ICT were present in 36 patients and mean ONSD was >5.00 mm in all the patients. CT scan finding of raised ICT was not present in 4 patients out of which raised ONSD was present in 1 patient. Hence study showed that USG of ONSD has 100% sensitivity and 75% specificity with a positive predictive value of 97.3% and a negative predictive value of 100%. Conclusions: Bedside ultrasonographic measurement of optic nerve sheath diameter has the potential as a sensitive screening test for elevated intracranial pressure in adult head injury patients in ICU.

Evaluation of bedside sonographic measurement of optic nerve sheath diameter for assessment of raised intracranial pressure in adult head trauma patients

Aim:The aim was to evaluate the use of bedside sonographic measurement of the optic nerve sheath diameter (ONSD) in the assessment of elevated intracranial pressure in patients with head injury coming to the emergency department (ED).Methods:A prospective study of ED patients presenting with a history of acute head injury, an ocular ultrasound was performed for ONSD measurement, followed by a computed tomography (CT) of the brain. Three measurements were taken for each eye, then, the mean binocular ONSD measurement for each patient was obtained to ensure accuracy. A mean bipolar ONSD >5 mm was considered abnormal.Results:A total of 175 patients were considered for the study. Of 175 patients, only 56 (32%) had intracranial pathology detected on CT brain with mean ONSD of 5.7 mm (standard deviation [SD]: 0.59). The mean ONSD for 119 (68%) patients, who had normal CT brain, was 4.5 mm (SD: 0.42). The mean ONSD measured for the right eye was 4.86 mm with SD 0.88, and the mean ONSD for the left eye was 4.90 mm with SD 0.85. When comparing ONSD measurement with CT findings of raised intracranial pressure, the ONSD sensitivity was 87.5% (95% confidence interval [CI]: 85%–96%) and specificity was 94.1% (95% CI: 85%–96%), with a positive predictive value of 87.5% and a negative predictive value of 94.1%. The area under the receiver operator characteristic curve obtained was 0.90 (95% CI: 0.85–0.96).Conclusion:The study has shown a bedside measurement of ONSD through sonography as an efficient tool to assess elevations in intracranial pressure in head injury patients.

Optic nerve sheath diameter asymmetry in healthy subjects and patients with intracranial hypertension.

Ultrasonography of the optic nerve sheath diameter (ONSD) is used for the non-invasive assessment of increased intracranial pressure (ICP). ONSD values are usually obtained by averaging the measurements of the two eyes, but asymmetric ONSD dilation is possible, leading to potentially inaccurate ICP estimation when using binocular averaging. In addition, few data are available about the asymmetry of the ONSD and the use of the maximum ONSD value between eyes for raised ICP detection. The aim of the study was to evaluate the interocular ONSD asymmetry in healthy subjects and patients with intracranial hypertension (IH) by ultrasonography and to investigate whether the maximum ONSD could be as useful as the binocular assessment. Forty healthy subjects and 40 patients with IH (20 with idiopathic intracranial hypertension and 20 with intracerebral hemorrhage) who underwent transorbital sonography were retrospectively enrolled. The prevalence and degree of ONSD asymmetry were compared among groups; ONSD median binocular and maximum values were compared. Forty-two out of 80 subjects (52.5%) showed significant ONSD asymmetry, without significant differences in prevalence among groups (p = 0.28). The median asymmetry was higher in patients than in healthy subjects (0.45mm vs 0.23mm; p = 0.007), without significant differences between the two pathologies (p = 0.58). Both binocular and maximum ONSD measurements were significantly higher in patients with IH than in controls (p < 0.001). Interocular ONSD asymmetry occurs both in healthy subjects and, more consistently, in patients with IH. Both binocular and maximum ONSD may be useful markers for increased ICP detection.

The relation of optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in pediatric neurosurgery practice - Part II: Influence of wakefulness, method of ICP measurement, intra-individual ONSD-ICP correlation and changes after therapy

Previous studies correlating ultrasound (US)-based optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in children were performed under general anesthesia. To apply ONSD in daily clinical routine, it is necessary to investigate patients awake. It is furthermore essential for ICP-assessment with ONSD to know if ONSD-ICP correlation varies within individuals. In this study, we report on the influence of wakefulness, method of ICP measurement, intraindividual correlations, and dynamic changes of ONSD and ICP after ICP decreasing therapy. The overall study included 72 children with a median age of 5.2years. US ONSD determination was performed immediately prior to invasive ICP measurement, and the mean binocular ONSD was compared to ICP. In 10 children, a minimum of 3 ONSD/ICP measurements were performed to investigate a correlation within subjects. In 30 children, measurements were performed before and after therapy. Twenty-eight children were investigated awake with an excellent correlation of ONSD and ICP (r = 0.802, p < 0.01). In 10 children, at least three simultaneous ONSD and ICP measurements were performed. The intraindividual correlations were excellent (r = 0.795-1.0) however with strongly differing individual regression curves. The overall correlation within subjects was strong (r = 0.78, p < 0.01). After ICP decreasing therapy, all ONSD values decreased significantly (p < 0.01); however, there was no correlation between ∆ICP and ∆ONSD. Awake investigation does not impair the correlation between ONSD and ICP. Even if there is a good overall ONSD-ICP correlation, every individual has its own distinctive and precise correlation line. The relationship between ONSD and ICP is furthermore not uniform between individuals. Strong ICP decreases can lead to smaller ONSD changes and vice versa. This should be kept in mind when using this technique in the clinical daily routine.

The relation of optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in pediatric neurosurgery practice - Part I: Correlations, age-dependency and cut-off values.

It is assumed that the width of the optic nerve sheath diameter (ONSD) is dependent on intracranial pressure (ICP) and pulsatility and thus constitutes a non-invasively accessible "window" for qualitative assessment of ICP. Data on the correlation to invasively measured ICP in children are scarce and have often been obtained from sedated patients in intensive care unit (ICU) or intraoperatively. We report on a mixed cohort of pediatric neurosurgical patients, ICP and ONSD measurements were available from both sedated and awake children, only a minority from ICU patients. Seventy-two children were investigated. Ultrasound ONSD determination was performed immediately prior to invasive ICP measurement and the mean binocular ONSD was compared with ICP. The investigations were performed in children awake, sedated, or under general anesthesia. In the entire patient cohort, the correlation between ONSD and ICP was good (r = 0.52, p < 0.01). Children > 1year revealed a better correlation (r = 0.63; p < 0.01) and those ≤ 1year did worse (r = 0.21). Infants with open fontanelle had no correlation. In the entire cohort, the best ONSD cut-off value for detecting ICP ≥ 15 and ≥ 20mmHg was 5.28 and 5.57mm (OR 22.5 and 7.2, AUC 0.782 and 0.733). Transorbital ultrasound measurement of ONSD is a reliable non-invasive technique to assess increased ICP in children in every clinical situation; however, the impact of age and fontanelle status needs to be considered. ONSD thresholds enable qualitative first orientation regarding ICP categories with a very satisfying diagnostic accuracy.

Ultrasonography Monitoring of Optic Nerve Sheath Diameter and Retinal Vessels in Patients with Cerebral Hemorrhage.

Evaluation of the diagnostic accuracy of optic nerve sheath diameter (ONSD) and Doppler indices of central retinal arteries and veins for the detection of increased intracranial pressure (ICP) in intracerebral hemorrhage (ICH) and of the usefulness of a second assessment of these variables in the monitoring of ICH. A total of 46 acute ICH patients with (group 1, n = 25) and without (group 2, n = 21) clinical and radiological computed tomography signs of raised ICP and 40 healthy controls were recruited. The median binocular ONSD and Doppler indices of retinal vessels including resistive index (RI) and retinal venous pulsation (RVP) were compared among groups, both at admission and later during ICH monitoring. Median binocular ONSD showed higher accuracy for the detection of increased ICP (sensitivity and specificity 100%), while Doppler indices were less accurate (sensitivity 48% and specificity 95% for RI; 80% and 62% for RVP). In ICH patients, ONSD was significantly elevated in group 1 both at admission (6.40 mm [interquartile range [IQR]=.70] vs. 4.70 [.40]) and at control time (6.00 [.55] vs. 4.55 [.40]; P<.01), as well as RI (.79 [.11] vs. .77 [.03] and .80 [.06] vs. .75 [.35]; P = .01). RVP was significantly increased in group 1 only at admission (3.20 cm/s [1.05] vs. 2.00 [1.55], P = .02). Median binocular ONSD evaluation showed higher accuracy for the estimation of elevated ICP compared with Doppler indices of retinal vessels. The ONSD enlargement detected in the early phase of ICH persists at control time.

The diagnostic utility of ultrasonographic optic nerve sheath diameter measurement in detecting elevated intracranial pressure: An observer blinded prospective study

Background : The optic nerve sheath diameter (ONSD) has been shown to increase within seconds of raised ICP, which can be measured by ultrasound. Hence, ONSD measurement can be potentially used to indirectly monitor elevated ICP. Methods : A prospective blinded observational study of all children (2-12 years) admitted to PICU undergoing ICP monitoring using intra parenchymal catheter was conducted in PGIMER, Chandigarh from November 2016 to August 2017. The ONSD from both eyes was measured using a 7.5 MHz ultrasound probe on closed eyelids. Horizontal and vertical diameters of both the optic nerves were measured and averages calculated. Repeated measurements were taken at least 3 hours apart. Observations who had measured ICP ≥20 mm Hg at the point of time were included as cases and with measured ICP ≤ 15 mm Hg were included as controls. Results : During the study period, of the total 25 children assessed for eligibility, 21 were enrolled. The median age of the cohort was 70 months. A total 95 observations were taken and the median observations per patient were 3. The total number of the observations included as cases and controls were 65 and 30 respectively. The median ICP was 27 and 7 for observations included as case and controls respectively. Compared to controls, the case group had significantly higher mean right eye ONSD (5.58±0.56 mm vs.4.08±0.55 mm, p<0.0001), mean left eye ONSD (5.61±0.66 mm vs.4.08±0.60 mm, p<0.0001) and mean binocular ONSD (5.60±0.60 mm vs.4.08±0.57 mm, p<0.0001). The spearman rank correlation coefficient of binocular ONSD and ICP was 0.71 (p<0.0005) demonstrating a significant positive correlation. Conclusion : This study demonstrates a strong correlation in between intra-parenchymal measurements of ICP with ONSD measurements and provides support for the use of ONSD measurements as a noninvasive test for elevated ICP.

The relationship between transorbital ultrasound measurement of the optic nerve sheath diameter (ONSD) and invasively measured ICP in children : Part I: repeatability, observer variability and general analysis.

The aim of this study wasto investigate the relationship between optic nerve sheath diameter (ONSD) measurement and invasively measured intracranial pressure (ICP) in children. ONSD measurement was performed prior to invasive measurement of ICP. The mean binocular ONSD measurement was compared to the ICP reading. Physiological variables including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse rate, temperature, respiratory rate and end tidal carbon dioxide (ETCO2) level were recorded at the time of ONSD measurement. Diagnostic accuracy analysis was performed at various ICP thresholds and repeatability, intra- and inter-observer variability, correlation between measurements in different imaging planes as well the relationship over the entire patient cohort were examined in part I of this study. Data from 174 patients were analysed. Repeatability and intra-observer variability were excellent (α = 0.97-0.99). Testing for inter-observer variability revealed good correlation (r = 0.89, p < 0.001). Imaging in the sagittal plane demonstrated a slightly better correlation with ICP (r = 0.66, p < 0.001). The ONSD measurement with the best diagnostic accuracy for detecting an ICP ≥ 20mmHg over the entire patient cohortwas 5.5mm, sensitivity 93.2%, specificity 74% and odds ratio (OR) of 39.3. Transorbital ultrasound measurement of the OSND is a reliable and reproducible technique, demonstrating a good relationship with ICP and high diagnostic accuracy for detecting raised ICP.

Optic Nerve Sheath Diameter Measurement During Diabetic Ketoacidosis: A Pilot Study.

Diabetic ketoacidosis-related cerebral edema (DKA-CE) occurs in up to 1% of children with type 1 diabetes (T1D),1 with approximately 20% displaying neurologic symptoms at presentation.2,3 Similarly, up to 54% have a mild form of subclinical DKA-CE identified by extracellular fluid measurements on magnetic resonance imaging (MRI), which is associated with alterations in neuronal function and cerebral injury on MR spectroscopy.2–6 This suggests that DKA-CE occurs along a continuum, ranging from asymptomatic imaging changes, mild neurologic injury, to cerebral herniation and death. DKA-CE is currently assessed by clinical symptoms and advanced imaging techniques, which have significant cost and limitation. Computed tomography (CT) uses ionizing radiation and can miss nearly 40% of children who ultimately develop DKA-CE.7 MRI is time-consuming, often requires sedation, and may not be available at some centers. Moreover, both CT and MRI require moving critically ill patients out of the intensive care setting. In contrast, point-of-care ocular ultrasound is a relatively low cost, accessible imaging technique that may have the potential to promptly identify DKA-CE through measurement of the optic nerve sheath diameter (ONSD). The sonographic appearance of the ONSD correlates with elevations in intracranial pressure (ICP), which is thought to be due to cerebrospinal fluid accumulation between the dura and optic nerve with the subsequent appearance of swelling.8 ONSD measurement has been used to accurately detect increased ICP in a number of clinical situations,8–10 including pediatric head trauma11 and hydrocephalus.12,13 This method has also been validated in adults using direct measurements of ICP via intrathecal infusion tests,14 lumbar puncture,15 and intracranial monitoring.16 The point at which patients actually progress to subclinical DKA-CE and the minimum duration of preceding symptoms has not been delineated.7 Furthermore, it is currently unclear how the ONSD changes during T1D-related illness or whether ONSD measurement can discriminate stages along the continuum of DKA-CE development, particularly among those with subclinical DKA-CE or those without obvious neurologic symptoms. Therefore, we sought to perform a pilot study among patients with T1D and DKA to determine how ONSD measurements vary during T1D-related illness, and the potential of this tool for discrimination of subclinical DKA-CE. We hypothesized that mean binocular ONSD would increase with illness severity, and would differ among children with DKA, T1D with hyperglycemia, and well-controlled T1D. The association of mean binocular ONSD with DKA-CE risk factors was also examined.

Correlation of measurement of optic nerve sheath diameter with ultrasound and magnetic resonance imaging.

Background and Aims: Analysis to correlate the measurements of optic nerve sheath diameter (ONSD) obtained by using ultrasound to magnetic resonance imaging (MRI) techniques in order to establish the accuracy of ocular sonography as a noninvasive modality for detecting raised intracranial pressure (ICP). Materials and Methods: A prospective, observational study was performed in 100 cases of adult meningoencephalitis patients admitted to Intensive Care Unit in whom MRI was performed for neurodiagnosis. ONSD was measured in such patients, 3 mm behind the globe in each eye. A mean binocular ONSD >4.6 mm in female and 4.8 mm in male was taken as cut-off values for diagnosing raised ICP. This was compared with ONSD measured on T2-weighted MRI image measured 3 mm behind the globe. The reading obtained from both the methods were compared with Bland-Altman analysis for correlation and the findings were tabulated. Results: The mean ONSD values measured with ultrasonography (USG) and MRI for female were 5.48 ± 0.43 mm and 5.68 ± 0.44 mm and for male were 5.40 ± 0.37 mm and 5.56 ± 0.38 mm, respectively. The mean age of the female and male was 53.90 ± 17.84 and 56.06 ± 15.67 years, respectively. On comparing ultrasound with MRI-derived ONSD values, we found acceptable agreement between both methods for measurements at a depth of 3 mm ( r = 0.02, P Conclusion: In our study, we have found a good correlation between ocular USG and MRI of ONSD. The study has shown agreement with the fact that ocular sonography can be used as a noninvasive tool for detecting raised ICP with accuracy.

The diagnostic performance of ultrasonographic optic nerve sheath diameter and color Doppler indices of the ophthalmic arteries in detecting elevated intracranial pressure

ObjectivesTo assess the diagnostic accuracy of ultrasonographic optic nerve sheath diameter (ONSD) measurement and color Doppler indices of the ophthalmic arteries in detecting elevated intracranial pressure (ICP). Patients and methodsA total 60 patients with (cases, n=30) and without (controls, n=30) acute clinical and computed tomographic findings of elevated ICP due to intracranial mass/hemorrhage were recruited from a teaching hospital. The mean binocular and maximum ultrasonographic ONSDs, as well as the mean binocular Doppler ultrasound waveform indices of the ophthalmic arteries including pulsatility index (PI), resistive index (RI), end-systolic velocity (ESV), peak systolic velocity (PSV) and end-diastolic velocity (EDV) were compared between the two groups. ResultsCompared to controls, the case group had significantly higher mean binocular ONSD (5.48±0.52mm vs. 4.09±0.22mm, p<0.001), maximum ONSD (5.63±0.55mm vs. 4.16±0.23mm, p<0.001), mean PI (1.53±0.16 vs. 1.45±0.20, p=0.01), and mean RI (0.76±0.07 vs. 0.73±0.04, p=0.01). The mean EDV, in contrast, was significantly higher in controls (8.55±3.09m/s vs. 7.17±2.61m/s, p=0.01). The two groups were comparable for the mean PSV (30.73±7.93m/s in cases vs. 32.27±10.39m/s in controls, p=0.36). Among the mentioned variables, the mean binocular ONSD was the most accurate parameter in detecting elevated ICP (sensitivity and specificity of 100%, cut-off point=4.53mm). The Doppler indices were only moderately accurate (sensitivity: 56.7−60%, specificity: 63.3−76.7%). ConclusionWhile the ultrasonographic mean binocular ONSD (>4.53mm) was completely accurate in detecting elevated ICP, color Doppler indices of the ophthalmic arteries were of limited value.

Optic nerve sonography: A noninvasive means of detecting raised intracranial pressure in a resource-limited setting.

Objective:The aim was to assess the use of optic nerve sonography (ONS) as a quick, noninvasive diagnostic test tool for detecting raised the intracranial pressure (ICP).Materials and Methods:A prospective blinded observational study was conducted at Obafemi Awolowo University Teaching Hospitals Complex (OAUTHC), Ile-Ife, Nigeria. The study population consisted of 160 adult patients referred to the radiology department for cranial computed tomography (CT) scan. There were 80 subjects and 80 controls. Optic nerve sheath diameter (ONSD) was measured by a radiologist using a 7.5 Megahertz ultrasound probe while cranial CT was reviewed by other radiologists blinded to the ONSD.Results:Sixty-nine subjects (86.3%) had intracranial space occupying lesions (SOL) with cranial CT confirmed features of increased ICP, mean binocular ONSD of 5.7 ± 0.59 mm while 11 (13.7%) had intracranial SOL without any cranial CT evidence of increased ICP, mean binocular ONSD of 4.8 ± 0.39 mm. The difference of mean ONSD of the two groups was statistically significant (P = 0.0001). The controls had a mean binocular ONSD of 4.5 ± 0.22 mm and the difference in mean binocular ONSD for subjects with raised ICP and the controls were also statistically significant (P = 0.0001). A cut-off value of 5.2 mm (sensitivity 81.2% [95% confidence interval (CI): 69.9–89.6], specificity 100% [95% CI: 71.5–100]) was obtained from the receiver operator characteristics curve as the mean binocular ONSD that best predicts raised ICP confirmed by at least a sign on cranial CT.Conclusions:Optic nerve sonography can differentiate between normal and elevated ICP and may serve as a useful screening tool in resource-limited practice.

Noninvasive intracranial pressure monitoring via optic nerve sheath diameter for robotic surgery in steep Trendelenburg position.

Background:Recent reports of increased intracranial pressure (ICP) due to steep Trendelenburg (ST) position causing neurological deterioration, decreased regional cerebral oxygen saturation and postoperative visual loss after robotic urological and gynecological surgeries led us to consider a simple technique of ICP monitoring. Ours is one of the first instances reported of quantitative noninvasive measurement of increase in ICP with ST position by serial measurement of binocular optic nerve sheath diameter (ONSD) in patients undergoing robot assisted urological and gynecological oncosurgery. We tested whether ONSD values rose to above the upper limits of normal and for what length of time they remained elevated.Materials and Methods:Prospective, randomized, interventional, parallel group, active control study conducted on 252 American Society of Anesthesiologists I and II patients. ONSD was measured using 7.5 MHz linear ultrasound probe in supine and Trendelenburg positions.Statistics:Student's t-test to compare the inter-group mean ONSD and the repetitive t-test for intra-group analysis.Result:Comparison of the mean ONSD values of both groups yielded a 2-tailed significance P <0.01 at all compared time points intra- and post-operatively. In Group-O (open surgery; supine position), the baseline mean bilateral ONSD was 4.36 mm, which did not show any statistically significant change throughout open surgery and postoperative period. On de-docking the robot, 6.2 mm was the mean ONSD value in Group-R (robotic group) while 4.3 mm was the corresponding value in control Group-O.Conclusion:ONSD evaluation is a simple, quick, safe, readily available, reliable, cost effective, noninvasive, potential standard of care for screening and monitoring of patients undergoing robotic surgery in ST position.

Correlation of measurement of optic nerve sheath diameter using ultrasound with magnetic resonance imaging.

Background and Aims:Analysis to correlate the measurements of optic nerve sheath diameter (ONSD) obtained by using ultrasound to magnetic resonance imaging (MRI) techniques in order to establish the accuracy of ocular sonography as a noninvasive modality for detecting raised intracranial pressure (ICP).Materials and Methods:A prospective, observational study was performed in 100 cases of adult meningoencephalitis patients admitted to Intensive Care Unit in whom MRI was performed for neurodiagnosis. ONSD was measured in such patients, 3 mm behind the globe in each eye. A mean binocular ONSD >4.6 mm in female and 4.8 mm in male was taken as cut-off values for diagnosing raised ICP. This was compared with ONSD measured on T2-weighted MRI image measured 3 mm behind the globe. The reading obtained from both the methods were compared with Bland–Altman analysis for correlation and the findings were tabulated.Results:The mean ONSD values measured with ultrasonography (USG) and MRI for female were 5.48 ± 0.43 mm and 5.68 ± 0.44 mm and for male were 5.40 ± 0.37 mm and 5.56 ± 0.38 mm, respectively. The mean age of the female and male was 53.90 ± 17.84 and 56.06 ± 15.67 years, respectively. On comparing ultrasound with MRI-derived ONSD values, we found acceptable agreement between both methods for measurements at a depth of 3 mm (r = 0.02, P < 0.001).Conclusion:In our study, we have found a good correlation between ocular USG and MRI of ONSD. The study has shown agreement with the fact that ocular sonography can be used as a noninvasive tool for detecting raised ICP with accuracy.

Optic nerve sheath diameter as a marker for evaluation and prognostication of intracranial pressure in Indian patients: An observational study.

Background and Aims:The aim was to evaluate efficacy of optic nerve sheath diameter (ONSD) by ultrasound as a noninvasive method for detecting raised intracranial pressure (ICP) in intensive care unit, to compare with computed tomography/magnetic resonance imaging (MRI) findings of raised ICP and to prognosticate ONSD value with treatment.Materials and Methods:We conducted a prospective, observational study on 101 adults by including 41 healthy individuals in group A as control and 60 patients in group B admitted with fever, headache, vomiting, and altered sensorium. We examined them in supine position using 10 MHz linear array probe on closed eyelid. ONSD was measured 3 mm behind the globe in each eye. A mean binocular ONSD > 4.6 mm in female and 4.8 mm in male was considered abnormal. Midline shift, edema, effacement or ONSD > 5.0 mm on T2 MRI suggestive of elevated ICP was used to evaluate ONSD accuracy.Results:Group A mean ONSD was 4.6 mm in females and 4.8 mm in males. Group B mean ONSD for 17 females was 5.103 ± 0.6221 mm (P = 0.002) and for 43 males 5.081 ± 0.5799 mm (P = 0.032). Radiological sign of raised ICP was confirmed in 35 patients (females = 11 and males = 24) with high ONSD value. Sensitivity of detecting raised ICP by ONSD was 84.6% in females and 75% in males while specificity was 100% in both genders. Out of 25 patients without radiological signs of raised ICP 10 patients showed high ONSD (females = 4.735 mm and males = 4.907 mm). ONSD was well prognosticated with treatment modalities.Conclusion:Bedside ocular ultrasonography for measuring ONSD can be used an early test for diagnosing raised ICP as it is a noninvasive, cost effective bedside test, which can be repeated for re-evaluation.

English

Study objective: The objective of the present study is to determine whether a bedside ultrasonographic measurement of optic nerve sheath diameter and optic fundus examination can accurately predict the computed tomographic (CT) findings of elevated intracranial pressure in adult head injury patients in the emergency department (ED). METHODS: We conducted a prospective, blinded observational study on adult ED patients with suspected intracranial injury with possible elevated intracranial pressure. Exclusion criteria were age younger than 18 years or obvious ocular trauma. All patients underwent fundus examination by a single examiner immediate and after 6 hours of admission. Using a 7.5-MHz ultrasonographic probe on the closed eyelids, a single optic nerve sheath diameter was measured 3 mm behind the globe in each eye. A mean binocular optic nerve sheath diameter greater than 5.00 mm was considered abnormal. Cranial CT findings of shift, edema, or effacement suggestive of elevated intracranial pressure were used to evaluate optic nerve sheath diameter accuracy. RESULTS: 200 patients were studied during the study period of 2 years from 2011-2012. Average age was 38 years, and mean Glasgow Coma Scale score was 9. 22 patients with an optic nerve sheath diameter of 5.6 mm or more had CT findings that correlated with elevated intracranial pressure. The sensitivity for the ultrasonography in detecting elevated intracranial pressure was 100% (95% confidence interval (CI) 68% to 100%) and specificity was 63% (95% CI 50% to 76%). Fundus examination in these 22 patients found to have poor correlation with the CT findings of elevated intracranial pressure with low sensitivity of 64% (95% confidence interval (CI) 56% to 80%) and specificity of only 64% (95% CI 50% to 76%). CONCLUSION: Bedside ED optic nerve sheath diameter ultrasonography has potential as a sensitive screening test for elevated intracranial pressure in adult head injury. However fundus examination was not found to be sensitive screening test in these conditions.