Noninvasive methods of detecting increased intracranial pressure. Xu Wen,Gerety Patrick,Aleman Tomas,Swanson Jordan,Taylor Jesse Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery The detection of elevated intracranial pressure (ICP) is of paramount importance in the diagnosis and management of a number of neurologic pathologies. The current gold standard is the use of intraventricular or intraparenchymal catheters; however, this is invasive, expensive, and requires anesthesia. On the other hand, diagnosing intracranial hypertension based on clinical symptoms such as headaches, vomiting, and visual changes lacks sensitivity. As such, there exists a need for a noninvasive yet accurate and reliable method for detecting elevated ICP. In this review, we aim to cover both structural modalities such as computed tomography (CT), magnetic resonance imaging (MRI), ocular ultrasound, fundoscopy, and optical coherence tomography (OCT) as well as functional modalities such as transcranial Doppler ultrasound (TCD), visual evoked potentials (VEPs), and near-infrared spectroscopy (NIRS). 10.1007/s00381-016-3143-x
    The accuracy of transcranial Doppler in excluding intracranial hypertension following acute brain injury: a multicenter prospective pilot study. Rasulo Frank A,Bertuetti Rita,Robba Chiara,Lusenti Francesco,Cantoni Alfredo,Bernini Marta,Girardini Alan,Calza Stefano,Piva Simone,Fagoni Nazzareno,Latronico Nicola Critical care (London, England) BACKGROUND:Untimely diagnosis of intracranial hypertension may lead to delays in therapy and worsening of outcome. Transcranial Doppler (TCD) detects variations in cerebral blood flow velocity which may correlate with intracranial pressure (ICP). We investigated if intracranial hypertension can be accurately excluded through use of TCD. METHOD:This was a multicenter prospective pilot study in patients with acute brain injury requiring invasive ICP (ICPi) monitoring. ICP estimated with TCD (ICPtcd) was compared with ICPi in three separate time frames: immediately before ICPi placement, immediately after ICPi placement, and 3 hours following ICPi positioning. Sensitivity and specificity, and concordance correlation coefficient between ICPi and ICPtcd were calculated. Receiver operating curve (ROC) and the area under the curve (AUC) analyses were estimated after measurement averaging over time. RESULTS:A total of 38 patients were enrolled, and of these 12 (31.6%) had at least one episode of intracranial hypertension. One hundred fourteen paired measurements of ICPi and ICPtcd were gathered for analysis. With dichotomized ICPi (≤20 mmHg vs >20 mmHg), the sensitivity of ICPtcd was 100%; all measurements with high ICPi (>20 mmHg) also had a high ICPtcd values. Bland-Altman plot showed an overestimation of 6.2 mmHg (95% CI 5.08-7.30 mmHg) for ICPtcd compared to ICPi. AUC was 96.0% (95% CI 89.8-100%) and the estimated best threshold was at ICPi of 24.8 mmHg corresponding to a sensitivity 100% and a specificity of 91.2%. CONCLUSIONS:This study provides preliminary evidence that ICPtcd may accurately exclude intracranial hypertension in patients with acute brain injury. Future studies with adequate power are needed to confirm this result. 10.1186/s13054-017-1632-2
    Transcranial Doppler Monitoring of Intracranial Pressure Plateau Waves. Cardim Danilo,Schmidt Bernhard,Robba Chiara,Donnelly Joseph,Puppo Corina,Czosnyka Marek,Smielewski Peter Neurocritical care BACKGROUND:Transcranial Doppler (TCD) has been used to estimate ICP noninvasively (nICP); however, its accuracy varies depending on different types of intracranial hypertension. Given the high specificity of TCD to detect cerebrovascular events, this study aimed to compare four TCD-based nICP methods during plateau waves of ICP. METHODS:A total of 36 plateau waves were identified in 27 patients (traumatic brain injury) with TCD, ICP, and ABP simultaneous recordings. The nICP methods were based on: (1) interaction between flow velocity (FV) and ABP using a "black-box" mathematical model (nICP_BB); (2) diastolic FV (nICP_FV ); (3) critical closing pressure (nICP_CrCP), and (4) pulsatility index (nICP_PI). Analyses focused on relative changes in time domain between ICP and noninvasive estimators during plateau waves and the magnitude of changes (∆ between baseline and plateau) in real ICP and its estimators. A ROC analysis for an ICP threshold of 35 mmHg was performed. RESULTS:In time domain, nICP_PI, nICP_BB, and nICP_CrCP presented similar correlations: 0.80 ± 0.24, 0.78 ± 0.15, and 0.78 ± 0.30, respectively. nICP_FV presented a weaker correlation (R = 0.62 ± 0.46). Correlations between ∆ICP and ∆nICP were better represented by nICP_CrCP and BB, R = 0.48, 0.44 (p < 0.05), respectively. nICP_FV and PI presented nonsignificant ∆ correlations. ROC analysis showed moderate to good areas under the curve for all methods: nICP_BB, 0.82; nICP_FV , 0.77; nICP_CrCP, 0.79; and nICP_PI, 0.81. CONCLUSIONS:Changes of ICP in time domain during plateau waves were replicated by nICP methods with strong correlations. In addition, the methods presented high performance for detection of intracranial hypertension. However, absolute accuracy for noninvasive ICP assessment using TCD is still low and requires further improvement. 10.1007/s12028-016-0356-5
    Invasive and noninvasive means of measuring intracranial pressure: a review. Zhang Xuan,Medow Joshua E,Iskandar Bermans J,Wang Fa,Shokoueinejad Mehdi,Koueik Joyce,Webster John G Physiological measurement Measurement of intracranial pressure (ICP) can be invaluable in the management of critically ill patients. Cerebrospinal fluid is produced by the choroid plexus in the brain ventricles (a set of communicating chambers), after which it circulates through the different ventricles and exits into the subarachnoid space around the brain, where it is reabsorbed into the venous system. If the fluid does not drain out of the brain or get reabsorbed, the ICP increases, which may lead to brain damage or death. ICP elevation accompanied by dilatation of the cerebral ventricles is termed hydrocephalus, whereas ICP elevation accompanied by normal or small ventricles is termed idiopathic intracranial hypertension. OBJECTIVE:We performed a comprehensive literature review on how to measure ICP invasively and noninvasively. APPROACH:This review discusses the advantages and disadvantages of current invasive and noninvasive approaches. MAIN RESULTS:Invasive methods remain the most accurate at measuring ICP, but they are prone to a variety of complications including infection, hemorrhage and neurological deficits. Ventricular catheters remain the gold standard but also carry the highest risk of complications, including difficult or incorrect placement. Direct telemetric intraparenchymal ICP monitoring devices are a good alternative. Noninvasive methods for measuring and evaluating ICP have been developed and classified in five broad categories, but have not been reliable enough to use on a routine basis. These methods include the fluid dynamic, ophthalmic, otic, and electrophysiologic methods, as well as magnetic resonance imaging, transcranial Doppler ultrasonography (TCD), cerebral blood flow velocity, near-infrared spectroscopy, transcranial time-of-flight, spontaneous venous pulsations, venous ophthalmodynamometry, optical coherence tomography of retina, optic nerve sheath diameter (ONSD) assessment, pupillometry constriction, sensing tympanic membrane displacement, analyzing otoacoustic emissions/acoustic measure, transcranial acoustic signals, visual-evoked potentials, electroencephalography, skull vibrations, brain tissue resonance and the jugular vein. SIGNIFICANCE:This review provides a current perspective of invasive and noninvasive ICP measurements, along with a sense of their relative strengths, drawbacks and areas for further improvement. At present, none of the noninvasive methods demonstrates sufficient accuracy and ease of use while allowing continuous monitoring in routine clinical use. However, they provide a realizable ICP measurement in specific patients especially when invasive monitoring is contraindicated or unavailable. Among all noninvasive ICP measurement methods, ONSD and TCD are attractive and may be useful in selected settings though they cannot be used as invasive ICP measurement substitutes. For a sufficiently accurate and universal continuous ICP monitoring method/device, future research and developments are needed to integrate further refinements of the existing methods, combine telemetric sensors and/or technologies, and validate large numbers of clinical studies on relevant patient populations. 10.1088/1361-6579/aa7256
    Prospective Study on Noninvasive Assessment of Intracranial Pressure in Traumatic Brain-Injured Patients: Comparison of Four Methods. Cardim Danilo,Robba Chiara,Donnelly Joseph,Bohdanowicz Michal,Schmidt Bernhard,Damian Maxwell,Varsos Georgios V,Liu Xiuyun,Cabeleira Manuel,Frigieri Gustavo,Cabella Brenno,Smielewski Peter,Mascarenhas Sergio,Czosnyka Marek Journal of neurotrauma Elevation of intracranial pressure (ICP) may occur in many diseases, and therefore the ability to measure it noninvasively would be useful. Flow velocity signals from transcranial Doppler (TCD) have been used to estimate ICP; however, the relative accuracy of these methods is unclear. This study aimed to compare four previously described TCD-based methods with directly measured ICP in a prospective cohort of traumatic brain-injured patients. Noninvasive ICP (nICP) was obtained using the following methods: 1) a mathematical "black-box" model based on interaction between TCD and arterial blood pressure (nICP_BB); 2) based on diastolic flow velocity (nICP_FVd); 3) based on critical closing pressure (nICP_CrCP); and 4) based on TCD-derived pulsatility index (nICP_PI). In time domain, for recordings including spontaneous changes in ICP greater than 7 mm Hg, nICP_PI showed the best correlation with measured ICP (R = 0.61). Considering every TCD recording as an independent event, nICP_BB generally showed to be the best estimator of measured ICP (R = 0.39; p < 0.05; 95% confidence interval [CI] = 9.94 mm Hg; area under the curve [AUC] = 0.66; p < 0.05). For nICP_FVd, although it presented similar correlation coefficient to nICP_BB and marginally better AUC (0.70; p < 0.05), it demonstrated a greater 95% CI for prediction of ICP (14.62 mm Hg). nICP_CrCP presented a moderate correlation coefficient (R = 0.35; p < 0.05) and similar 95% CI to nICP_BB (9.19 mm Hg), but failed to distinguish between normal and raised ICP (AUC = 0.64; p > 0.05). nICP_PI was not related to measured ICP using any of the above statistical indicators. We also introduced a new estimator (nICP_Av) based on the average of three methods (nICP_BB, nICP_FVd, and nICP_CrCP), which overall presented improved statistical indicators (R = 0.47; p < 0.05; 95% CI = 9.17 mm Hg; AUC = 0.73; p < 0.05). nICP_PI appeared to reflect changes in ICP in time most accurately. nICP_BB was the best estimator for ICP "as a number." nICP_Av demonstrated to improve the accuracy of measured ICP estimation. 10.1089/neu.2015.4134
    Non-invasive assessment of intracranial pressure. Robba C,Bacigaluppi S,Cardim D,Donnelly J,Bertuccio A,Czosnyka M Acta neurologica Scandinavica Monitoring of intracranial pressure (ICP) is invaluable in the management of neurosurgical and neurological critically ill patients. Invasive measurement of ventricular or parenchymal pressure is considered the gold standard for accurate measurement of ICP but is not always possible due to certain risks. Therefore, the availability of accurate methods to non-invasively estimate ICP has the potential to improve the management of these vulnerable patients. This review provides a comparative description of different methods for non-invasive ICP measurement. Current methods are based on changes associated with increased ICP, both morphological (assessed with magnetic resonance, computed tomography, ultrasound, and fundoscopy) and physiological (assessed with transcranial and ophthalmic Doppler, tympanometry, near-infrared spectroscopy, electroencephalography, visual-evoked potentials, and otoacoustic emissions assessment). At present, none of the non-invasive techniques alone seem suitable as a substitute for invasive monitoring. However, following the present analysis and considerations upon each technique, we propose a possible flowchart based on the combination of non-invasive techniques including those characterizing morphologic changes (e.g., repetitive US measurements of ONSD) and those characterizing physiological changes (e.g., continuous TCD). Such an integrated approach, which still needs to be validated in clinical practice, could aid in deciding whether to place an invasive monitor, or how to titrate therapy when invasive ICP measurement is contraindicated or unavailable. 10.1111/ane.12527
    Transcranial Doppler Systolic Flow Index and ICP-Derived Cerebrovascular Reactivity Indices in Traumatic Brain Injury. Zeiler Frederick A,Cardim Danilo,Donnelly Joseph,Menon David K,Czosnyka Marek,Smielewski Peter Journal of neurotrauma The purpose of our study was to explore relationships between transcranial Doppler (TCD) indices of cerebrovascular reactivity and those derived from intracranial pressure (ICP). Goals included: A) confirming previously described co-variance patterns of TCD/ICP indices, and B) describing thresholds for systolic flow index (Sx; correlation between systolic flow velocity [FVs] and cerebral perfusion pressure [CPP]) associated with outcome. In a retrospective cohort of traumatic brain injury (TBI) patients: with TCD and ICP monitoring, we calculated various continuous indices of cerebrovascular reactivity: A) ICP (pressure reactivity index [PRx]: correlation between ICP and mean arterial pressure [MAP]; PAx: correlation between pulse amplitude of ICP [AMP] and MAP; RAC: correlation between AMP and CPP) and B) TCD (mean flow index [Mx]: correlation between mean flow velocity [FVm] and CPP; Mx_a: correlation between FVm and MAP; Sx: correlation between FVs and CPP; Sx_a: correlation between FVs and MAP; Dx: correlation between diastolic flow velocity [FVd] and CPP; Dx_a: correlation between FVd and MAP). We assessed the relationships via various statistical techniques, including: principal component analysis, agglomerative hierarchal clustering, and k-means cluster analysis (KMCA). We performed sequential χ testing to define thresholds associated with outcome for Sx/Sx_a. Outcome was assessed at 6 months via dichotomized Glasgow Outcome Score (GOS): A) Favorable (GOS 4 or 5) versus Unfavorable (GOS 3 or less), B) Alive versus Dead. We analyzed 410 recordings in 347 patients. All analyses confirmed our previously described co-variance of Sx/Sx_a with ICP-derived indices. Sx displayed thresholds of -0.15 for unfavorable outcome (p < 0.0001) and -0.20 for mortality (p < 0.0001). Sx_a displayed thresholds of +0.05 (p = 0.019) and -0.10 (p = 0.0001) for alive/dead and favorable/unfavorable outcomes. TCD systolic indices are most closely associated with ICP indices. Sx and Sx_a likely provide better approximation of ICP indices, compared with Mx/Mx_a/Dx/Dx_a. Sx provides superior outcome prediction, versus Mx, with defined thresholds. 10.1089/neu.2017.5364
    Decompressive Craniectomy for Traumatic Brain Injury: Postoperative TCD Cerebral Hemodynamic Evaluation. Bor-Seng-Shu Edson,de-Lima-Oliveira Marcelo,Nogueira Ricardo Carvalho,Almeida Kelson James,Paschoal Eric Homero Albuquerque,Paschoal Fernando Mendes Frontiers in neurology There are no studies describing the cerebral hemodynamic patterns that can occur in traumatic brain injury (TBI) patients following decompressive craniectomy (DC). Such data have potentially clinical importance for guiding the treatment. The objective of this study was to investigate the postoperative cerebral hemodynamic patterns, using transcranial Doppler (TCD) ultrasonography, in patients who underwent DC. The relationship between the cerebral circulatory patterns and the patients' outcome was also analyzed. Nineteen TBI patients with uncontrolled brain swelling were prospectively studied. Cerebral blood circulation was evaluated by TCD ultrasonography. Patients and their cerebral hemispheres were categorized based on TCD-hemodynamic patterns. The data were correlated with neurological status, midline shift on CT scan, and Glasgow outcome scale scores at 6 months after injury. Different cerebral hemodynamic patterns were observed. One patient (5.3%) presented with cerebral oligoemia, 4 patients (21%) with cerebral hyperemia, and 3 patients (15.8%) with cerebral vasospasm. One patient (5.3%) had hyperemia in one cerebral hemisphere and vasospasm in the other hemisphere. Ten patients (52.6%) had nonspecific circulatory pattern. Abnormal TCD-circulatory patterns were found in 9 patients (47.4%). There was no association between TCD-cerebral hemodynamic findings and outcome. There is a wide heterogeneity of postoperative cerebral hemodynamic findings among TBI patients who underwent DC, including hemodynamic heterogeneity between their cerebral hemispheres. DC was proved to be effective for the treatment of cerebral oligoemia. Our data support the concept of heterogeneous nature of the pathophysiology of the TBI and suggest that DC as the sole treatment modality is insufficient. 10.3389/fneur.2019.00354
    Optic nerve sheath diameter: present and future perspectives for neurologists and critical care physicians. Lochner Piergiorgio,Czosnyka Marek,Naldi Andrea,Lyros Epameinondas,Pelosi Paolo,Mathur Shrey,Fassbender Klaus,Robba Chiara Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology BACKGROUND:Estimation of intracranial pressure (ICP) may be helpful in the management of neurological critically ill patients. It has been shown that ultrasonography of the optic nerve sheath diameter (ONSD) is a reliable tool for non-invasive estimation of increased intracranial pressure (ICP) at hospital admission or in intensive care. Less is known about the estimation of increased ICP and usefulness of ONSD in the prehospital setting. The aim of this review was to elucidate both prevailing and novel applications of ONSD for neurologists and critical care physicians. METHODS:In this review, we discuss the technique and the novel approach of ONSD measurement, the clinical applications of ONSD in neurology and critical care patients. RESULTS:ONSD measurement is simple, easy to learn, and has diverse applications. ONSD has utility for ICP measurement in intracranial hemorrhage and ischemic stroke, meningitis and encephalitis, and idiopathic intracranial hypertension (IIH). It is also valuable for lesser known syndromes, where an increase of ICP is postulated, such as acute mountain sickness and posterior reversible encephalopathy syndrome. ONSD changes develop in inflammatory or ischemic optic neuropathies. Some papers demonstrate the usefulness of ONSD studies in symptomatic intracranial hypotension. CONCLUSIONS:ONSD is a safe and low-cost bedside tool with the potential of screening patients who need other neuroimaging and those who may need an invasive measurement of ICP. 10.1007/s10072-019-04015-x
    [Correlation between ultrasonographic optic nerve sheath diameter and intracranial pressure]. Li Z,Zhang X X,Yang H Q,Zhao L P,Jia J P,Sun F,Liu D C [Zhonghua yan ke za zhi] Chinese journal of ophthalmology To evaluate the association of the ultrasonographic optic nerve sheath diameter (ONSD) and intracranial pressure (ICP), and the feasibility of ultrasonographic ONSD in predicting high ICP. A prospective study. The outpatients who planned to measure ICP by lumbar puncture in Department of Neurology, Xuanwu Hospital, Capital Medical University were selected from January 2011 to May 2012. All the retrobulbar ONSD measurement with B-scan ultrasound was performed just before lumbar puncture. When high ICP was defined as ICP more than 200 mmHO(1 mmHO=0.009 8 kPa), the participants were divided into the high ICP group and the normal ICP group. The Pearson correlation coefficient analysis was used to analyze the correlation between ICP and postbulbar ONSD measurements. The difference in ONSD was compared between the high ICP and normal ICP groups with the test. The receiver operating characteristic (ROC) curve was used to calculate the cutoff value of mean ONSD and evaluate the sensitivity and specificity of the method. A total of 130 participants were involved in this study. There were 71 males and 59 females, aged (38±14) years.The mean ICP was (209.84±79.99) mmHO. The mean ONSD was (5.68±0.78) mm in the right eyes, (5.78±0.78) mm in the left eyes, and (5.73±0.71) mm in both eyes. The ICP had a significant correlation with ONSD in the right eyes (0.54, 0.001), ONSD in the left eyes (0.56, 0.001) and ONSD in both eyes (0.60, 0.001), but no correlation with age (0.14, 0.114) and gender (0.20, 0.817). The ONSD in the high ICP group (65) was (6.11±0.66) mm, (6.22±0.56) mm and (6.17±0.50) mm in the right eyes, left eyes, and both eyes, respectively. Compared with the ONSD in the normal ICP group (65), which was (5.26±0.64) mm in the right eyes, (5.34±0.72) mm in the left eyes and (5.30±0.62) mm in both eyes, there was a significantly enlarged ONSD in the high ICP group (=-7.507, -7.778, -8.779, all 0.001). The ROC analysis showed the ONSD of 5.6 mm was the best cutoff value with a sensitivity of 86% and a specificity of 71% for identifying high ICP. There is a significantly positive correlation between ICP and postbulbar ONSD measured by ultrasound. This non-invasive method may be an alternative approach to predicting the ICP value of patients whose ICP measurement via lumbar puncture is at high risk. However, it can not replace the direct ICP measurement with the invasive method. . 10.3760/cma.j.issn.0412-4081.2018.09.009
    Ultrasonography Assessments of Optic Nerve Sheath Diameter as a Noninvasive and Dynamic Method of Detecting Changes in Intracranial Pressure. Wang Li-Juan,Chen Li-Min,Chen Ying,Bao Li-Yang,Zheng Nan-Nan,Wang Yu-Zhi,Xing Ying-Qi JAMA ophthalmology Importance:The crtierion standard method for monitoring intracranial pressure (ICP) can result in complications and pain. Hence, noninvasive, repeatable methods would be valuable. Objective:To examine how ultrasonographic optic nerve sheath diameter (ONSD) correlated with noninvasive and dynamically monitored ICP changes. Design, Setting, and Participants:The ONSD was measured before the lumbar puncture (LP) in 60 patients on admission. Patients with elevated ICP were divided into group 1 (200 < LP ≤ 300 mm H2O) and group 2 (LP > 300 mm H2O). Patients underwent follow-up ONSD and LP measurements within 1 month. We analyzed the correlations between the ONSD and ICP on admission and between the changes in ONSD and ICP, which were the respective changes in ONSD and ICP from admission to follow-up. Main Outcomes and Measures:The ultrasonographic ONSD and ICP were measured on admission and follow-up. The correlations between the ONSD and ICP on admission and between the changes in ONSD and ICP were analyzed using Pearson correlation analyses. Results:For 60 patients (Han nationality; mean [SD] age, 36.2 [12.04] years; 29 [48%] female) on admission, the ONSD and ICP values were strongly correlated, with an r of 0.798 (95% CI, 0.709-0.867; P < .001). Twenty-five patients with elevated ICP who completed the follow-up were included. The mean (SD) ONSD and ICP on admission were 4.50 (0.54) mm and 302.40 (54.26) mm H2O, respectively. The ONSD and ICP values obtained on admission were strongly correlated , with an r of 0.724 (95% CI, 0.470-0.876; P < .001). The mean (SD, range) changes in ICP and ONSD were 126.64 (52.51 mm H2O, 20-210 mm H2O) (95% CI, 106.24-146.07) and 1.00 (0.512 mm, 0.418-2.37 mm) (95% CI, 0.83-1.20), respectively. The change in ONSD was strongly correlated with the change in ICP, with an r of 0.702 (95% CI, 0.425-0.870; P < .001). The follow-up evaluations revealed that the elevated ICP and dilated ONSD had returned to normal, and no evidence of difference was found in the mean ONSDs between group 1 (3.49 mm; 95% CI, 3.34-3.62 mm) and group 2 (3.51 mm; 95% CI, 3.44-3.59 mm) (P = .778) at follow-up. Conclusions and Relevance:The dilated ONSDs decreased along with the elevated ICP reduction. Ultrasonographic ONSD measurements may be a useful, noninvasive tool for dynamically evaluating ICP. 10.1001/jamaophthalmol.2017.6560
    Ultrasonic measurement of optic nerve sheath diameter: a non-invasive surrogate approach for dynamic, real-time evaluation of intracranial pressure. Chen Li-Min,Wang Li-Juan,Hu Yang,Jiang Xiao-Han,Wang Yu-Zhi,Xing Ying-Qi The British journal of ophthalmology The current study aimed to identify whether ultrasonographic measurements of optic nerve sheath diameter (ONSD) could dynamically and sensitively evaluate real-time intracranial pressure (ICP). ONSD measurements were performed approximately 5  min prior to and after a lumbar puncture (LP). A total of 84 patients (mean±SD age, 43.5±14.7 years; 41 (49%) men; 18 patients with elevated ICP) were included in the study. The Spearman correlation coefficients between the two observers were 0.779 and 0.703 in the transverse section and 0.751 and 0.788 in the vertical section for the left and right eyes, respectively. The median (IQR) change in ONSD (ΔONSD) and change in ICP (ΔICP) were 0.11 (0.05-0.21) mm and 30 (20-40) mmHO, respectively, for all participants. With a reduction in cerebrospinal fluid pressure, 80 subjects (95%) showed an immediate drop in ONSD; the median (IQR) decreased from 4.13 (4.02-4.38) mm to 4.02 (3.90-4.23) mm (p<0.001). Significant correlations were found between ONSD and ICP before LPs (r=0.482, p<0.01) and between ΔONSD and ΔICP (r=0.451, p<0.01). Ultrasonic measurement of ONSD can reflect the relative real-time changes in ICP. 10.1136/bjophthalmol-2018-312934
    Assessment of intracranial pressure with ultrasonographic retrobulbar optic nerve sheath diameter measurement. Liu Dachuan,Li Zhen,Zhang Xuxiang,Zhao Liping,Jia Jianping,Sun Fei,Wang Yaxing,Ma Daqing,Wei Wenbin BMC neurology BACKGROUND:Ultrasonograpic retrobulbar optic nerve sheath diameter (ONSD) measurement is considered to be an alternative noninvasive method to estimate intracranial pressure,but the further validation is urgently needed. The aim of the current study was to investigate the association of the ultrasonographic ONSD and intracranial pressure (ICP) in patients. METHODS:One hundred and ten patients whose intracranial pressure measured via lumbar puncture were enrolled in the study. Their retrobulbar ONSD with B-scan ultrasound was determined just before lumber puncture. The correlation between the ICP and the body mass index (BMI), ONSD or age was established respectively with the Pearson correlation coefficient analysis. The discriminant analysis was used to obtain a discriminant formula for predicting ICP with the ONSD、BMI、gender and age. Another 20 patients were recruited for further validation the efficiency of this discriminant equation. RESULTS:The mean ICP was 215.3 ± 81.2 mmHO. ONSD was 5.70 ± 0.80 mm in the right eye and 5.80 ± 0.77 mm in the left eye. A significant correlation was found between ICP and BMI (r = 0.554, p < 0.001), the mean ONSD (r = 0.61, P < 0.001), but not with age (r = -0.131, p = 0.174) and gender (r = 0.03, p = 0.753). Using receiver operating characteristic (ROC) curve analysis, the critical value for the risk mean-ONSD was 5.6 mm from the ROC curve, with the sensitivity of 86.2% and specificity of 73.1%. With 200 mmHO as the cutoff point for a high or low ICP, stepwise discriminant was applied, the sensitivity and specificity of ONSD predicting ICP was 84.5%-85.7% and 86.5%-92.3%. CONCLUSIONS:Ophthalmic ultrasound measurement of ONSD may be a good surrogate of invasive ICP measurement. This non-invasive method may be an alternative approach to predict the ICP value of patients whose ICP measurement via lumbar puncture are in high risk. The discriminant formula, which incorporated the factor of BMI, had similar sensitivity and higher specificity than the ROC curve. 10.1186/s12883-017-0964-5
    Improved diagnostic value of a TCD-based non-invasive ICP measurement method compared with the sonographic ONSD method for detecting elevated intracranial pressure. Ragauskas Arminas,Bartusis Laimonas,Piper Ian,Zakelis Rolandas,Matijosaitis Vaidas,Petrikonis Kestutis,Rastenyte Daiva Neurological research OBJECTIVES:To compare the diagnostic reliability of optic nerve sheath diameter (ONSD) ultrasonography with a transcranial Doppler (TCD)-based absolute intracranial pressure (ICP) value measurement method for detection of elevated ICP in neurological patients. The ONSD method has been only tested previously on neurosurgical patients. METHODS:A prospective clinical study of a non-invasive ICP estimation method based on ONSD correlation with ICP and an absolute ICP value measurement method based on a two-depth TCD technology has recruited 108 neurological patients. Ninety-two of these patients have been enrolled in the final analysis of the diagnostic reliability of ONSD ultrasonography and 85 patients using the absolute ICP value measurement method. All non-invasive ICP measurements were compared with 'Gold Standard' invasive cerebrospinal fluid (CSF) pressure measurements obtained by lumbar puncture. Receiver-operating characteristic (ROC) analysis has been used to investigate the diagnostic value of these two methods. RESULTS:The diagnostic sensitivity, specificity, and the area under the ROC curve (AUC) of the ONSD method for detecting elevated intracranial pressure (ICP >14·7 mmHg) were calculated using a cutoff point of ONSD at 5·0 mm and found to be 37·0%, 58·5%, and 0·57, respectively. The diagnostic sensitivity, specificity, and AUC for the non-invasive absolute ICP measurement method were calculated at the same ICP cutoff point of 14·7 mmHg and were determined to be 68·0%, 84·3%, and 0·87, respectively. CONCLUSIONS:The non-invasive ICP measurement method based on two-depth TCD technology has a better diagnostic reliability on neurological patients than the ONSD method when expressed by the sensitivity and specificity for detecting elevated ICP >14·7 mmHg. 10.1179/1743132813Y.0000000308
    Evaluation of Optic Nerve Sheath Diameter and Transcranial Doppler As Noninvasive Tools to Detect Raised Intracranial Pressure in Children. Sharawat Indar Kumar,Kasinathan Ananthanarayanan,Bansal Arun,Sahu Jitendra Kumar,Sodhi Kushaljit Singh,Dogra Mangat Ram,Sankhyan Naveen Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies OBJECTIVES:To compare the diagnostic accuracy of the ultrasonography-guided optic nerve sheath diameter with transcranial Doppler-guided middle cerebral artery flow indices against the gold standard invasive intraparenchymal intracranial pressure values in children. DESIGN:A single-center prospective cohort study. SETTING:PICU of a tertiary care teaching hospital in North India. PATIENTS:Eligible children (2-12 yr) are admitted to ICU and are undergoing intracranial pressure monitoring using an intraparenchymal catheter. Observations with a parallel measured intracranial pressure greater than or equal to 20 mm Hg were included as case-observations. Children with an invasive intracranial pressure of less than or equal to 15 mm Hg were taken as neurologic-control-observations and healthy children served as healthy-control-observations. INTERVENTIONS:The horizontal and vertical diameters of the optic nerves were measured, and averages were calculated and compared. Middle cerebral artery flow indices (pulsatility index and resistive index) were measured bilaterally and averages were calculated and compared in the three groups. Twenty-two measurements of optic nerve sheath diameter were assessed by two different observers in quick succession for interrater reliability. MEASUREMENTS AND MAIN RESULTS:A total of 148 observations were performed in 30 children. Four observations were excluded (intracranial pressure between 16 and 19 mm Hg). Of the 144 observations, 106 were case-observations and 38 were neurologic-control-observations. Additional 66 observations were healthy-control-observations. The mean optic nerve sheath diameter was 5.71 ± 0.57 mm in the case-observations group, 4.21 ± 0.66 mm in the neurologic-control-observations group, and 3.71 ± 0.27 mm in the healthy-control-observations group (p < 0.001 for case-observations vs neurologic-control-observations/healthy-control-observations). The mean pulsatility index in case-observations was 0.92 ± 0.41 compared with controls 0.79 ± 0.22 (p = 0.005) and the mean resistive index was 0.56 ± 0.13 in case-observations compared with 0.51 ± 0.09 (p = 0.007) in controls (neurologic-control-observations and healthy-control-observations). For the raised intracranial pressure defined by intracranial pressure greater than or equal to 20 mm Hg, the area under the curve for optic nerve sheath diameter was 0.976, while it was 0.571 for pulsatility index and 0.579 for resistive index. Furthermore, the optic nerve sheath diameter cutoff of 4.0 mm had 98% sensitivity and 75% specificity for raised intracranial pressure, while the pulsatility index value of 0.51 had 89% sensitivity and 10% specificity by middle cerebral artery flow studies. The sensitivity and specificity of 0.40 resistive index value in the raised intracranial pressure were 88% and 11%, respectively. Kendall correlation coefficient between intracranial pressure and optic nerve sheath diameter, pulsatility index, and resistive index was 0.461, 0.148, and 0.148, respectively. The Pearson correlation coefficient between two observers for optic nerve sheath diameter, pulsatility index, and resistive index was 0.98, 0.914, and 0.833, respectively. CONCLUSIONS:Unlike transcranial Doppler-guided middle cerebral artery flow indices, ultrasonography-guided optic nerve sheath diameter was observed to have a good diagnostic accuracy in identifying children with an intracranial pressure of greater than or equal to 20 mm Hg. 10.1097/PCC.0000000000002523
    Optic Nerve Sheath Diameter Ultrasound and the Diagnosis of Increased Intracranial Pressure. Hylkema Christopher Critical care nursing clinics of North America Ultrasound has been used for almost 30 years in a wide variety of clinical applications and environments. From the austerity of battlefields to the labor and delivery ward, ultrasound has the ability to give clinicians real-time, noninvasive diagnostic imaging. Ultrasound by emergency physicians (and all nonradiologists) has become more prevalent and has been used for examinations such as the transcranial Doppler to evaluate for stroke, cardiac function, FAST and EFAST examinations for trauma, and now increased intracranial pressure (ICP) via Optic Nerve Sheath Diameter Ultrasound (ONSD). The ONSD is a valid and reliable indicator of ICP. 10.1016/j.cnc.2015.10.005
    Ultrasonographic measured optic nerve sheath diameter as an accurate and quick monitor for changes in intracranial pressure. Maissan Iscander M,Dirven Perjan J A C,Haitsma Iain K,Hoeks Sanne E,Gommers Diederik,Stolker Robert Jan Journal of neurosurgery OBJECT:Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) is known to be an accurate monitor of elevated intracranial pressure (ICP). However, it is yet unknown whether fluctuations in ICP result in direct changes in ONSD. Therefore, the authors researched whether ONSD and ICP simultaneously change during tracheal manipulation in patients in the intensive care unit (ICU) who have suffered a traumatic brain injury (TBI). MATERIALS:The authors included 18 ICP-monitored patients who had sustained TBI and were admitted to the ICU. They examined the optic nerve sheath by performing ultrasound before, during, and after tracheal manipulation, which is known to increase ICP. The correlation between ONSD and ICP measurements was determined, and the diagnostic performance of ONSD measurement was tested using receiver operating characteristic curve analysis. RESULTS:In all patients ICP increased above 20 mm Hg during manipulation of the trachea, and this increase was directly associated with a dilation of the ONSD of > 5.0 mm. After tracheal manipulation stopped, ICP as well as ONSD decreased immediately to baseline levels. The correlation between ICP and ONSD was high (R(2) = 0.80); at a cutoff of ≥ 5.0 mm ONSD, a sensitivity of 94%, a specificity of 98%, and an area under the curve of 0.99 (95% CI 0.97-1.00) for detecting elevated ICP were determined. CONCLUSIONS:In patients who have sustained a TBI, ultrasonography of the ONSD is an accurate, simple, and rapid measurement for detecting elevated ICP as well as immediate changes in ICP. Therefore, it might be a useful tool to monitor ICP, especially in conditions in which invasive ICP monitoring is not available, such as at trauma scenes. 10.3171/2014.10.JNS141197
    Optic nerve sheath diameter measurement: a means of detecting raised ICP in adult traumatic and non-traumatic neurosurgical patients. Raffiz Mohd,Abdullah Jafri M The American journal of emergency medicine INTRODUCTION:Bedside ultrasound measurement of optic nerve sheath diameter (ONSD) is emerging as a non-invasive technique to evaluate and predict raised intracranial pressure (ICP). It has been shown in previous literature that ONSD measurement has good correlation with surrogate findings of raised ICP such as clinical and radiological findings suggestive of raised ICP. OBJECTIVES:The objective of the study is to find a correlation between sonographic measurements of ONSD value with ICP value measured via the gold standard invasive intracranial ICP catheter, and to find the cut-off value of ONSD measurement in predicting raised ICP, along with its sensitivity and specificity value. METHODS:A prospective observational study was performed using convenience sample of 41 adult neurosurgical patients treated in neurosurgical intensive care unit with invasive intracranial pressure monitoring placed in-situ as part of their clinical care. Portable SonoSite ultrasound machine with 7 MHz linear probe were used to measure optic nerve sheath diameter using the standard technique. Simultaneous ICP readings were obtained directly from the invasive monitoring. RESULTS:Seventy-five measurements were performed on 41 patients. The non-parametric Spearman correlation test revealed a significant correlation at the 0.01 level between the ICP and ONSD value, with correlation coefficient of 0.820. The receiver operating characteristic curve generated an area under the curve with the value of 0.964, and with standard error of 0.22. From the receiver operating characteristic curve, we found that the ONSD value of 5.205 mm is 95.8% sensitive and 80.4% specific in detecting raised ICP. CONCLUSIONS:ONSD value of 5.205 is sensitive and specific in detecting raised ICP. Bedside ultrasound measurement of ONSD is readily learned, and is reproducible and reliable in predicting raised ICP. This non-invasive technique can be a useful adjunct to the current invasive intracranial catheter monitoring, and has wide potential clinical applications in district hospitals, emergency departments and intensive care units. 10.1016/j.ajem.2016.09.044
    Ultrasound non-invasive measurement of intracranial pressure in neurointensive care: A prospective observational study. Robba Chiara,Cardim Danilo,Tajsic Tamara,Pietersen Justine,Bulman Michael,Donnelly Joseph,Lavinio Andrea,Gupta Arun,Menon David K,Hutchinson Peter J A,Czosnyka Marek PLoS medicine BACKGROUND:The invasive nature of the current methods for monitoring of intracranial pressure (ICP) has prevented their use in many clinical situations. Several attempts have been made to develop methods to monitor ICP non-invasively. The aim of this study is to assess the relationship between ultrasound-based non-invasive ICP (nICP) and invasive ICP measurement in neurocritical care patients. METHODS AND FINDINGS:This was a prospective, single-cohort observational study of patients admitted to a tertiary neurocritical care unit. Patients with brain injury requiring invasive ICP monitoring were considered for inclusion. nICP was assessed using optic nerve sheath diameter (ONSD), venous transcranial Doppler (vTCD) of straight sinus systolic flow velocity (FVsv), and methods derived from arterial transcranial Doppler (aTCD) on the middle cerebral artery (MCA): MCA pulsatility index (PIa) and an estimator based on diastolic flow velocity (FVd). A total of 445 ultrasound examinations from 64 patients performed from 1 January to 1 November 2016 were included. The median age of the patients was 53 years (range 37-64). Median Glasgow Coma Scale at admission was 7 (range 3-14), and median Glasgow Outcome Scale was 3 (range 1-5). The mortality rate was 20%. ONSD and FVsv demonstrated the strongest correlation with ICP (R = 0.76 for ONSD versus ICP; R = 0.72 for FVsv versus ICP), whereas PIa and the estimator based on FVd did not correlate with ICP significantly. Combining the 2 strongest nICP predictors (ONSD and FVsv) resulted in an even stronger correlation with ICP (R = 0.80). The ability to detect intracranial hypertension (ICP ≥ 20 mm Hg) was highest for ONSD (area under the curve [AUC] 0.91, 95% CI 0.88-0.95). The combination of ONSD and FVsv methods showed a statistically significant improvement of AUC values compared with the ONSD method alone (0.93, 95% CI 0.90-0.97, p = 0.01). Major limitations are the heterogeneity and small number of patients included in this study, the need for specialised training to perform and interpret the ultrasound tests, and the variability in performance among different ultrasound operators. CONCLUSIONS:Of the studied ultrasound nICP methods, ONSD is the best estimator of ICP. The novel combination of ONSD ultrasonography and vTCD of the straight sinus is a promising and easily available technique for identifying critically ill patients with intracranial hypertension. 10.1371/journal.pmed.1002356
    Non-invasive Intracranial Pressure Assessment in Brain Injured Patients Using Ultrasound-Based Methods. Robba Chiara,Cardim Danilo,Tajsic Tamara,Pietersen Justine,Bulman Michael,Rasulo Frank,Bertuetti Rita,Donnelly Joseph,Xiuyun Liu,Czosnyka Zofia,Cabeleira Manuel,Smielewski Peter,Matta Basil,Bertuccio Alessandro,Czosnyka Marek Acta neurochirurgica. Supplement BACKGROUND:Non-invasive measurement of intracranial pressure (ICP) can be invaluable in the management of critically ill patients. Invasive measurement of ICP remains the "gold standard" and should be performed when clinical indications are met, but it is invasive and brings some risks. In this project, we aim to validate the non-invasive ICP (nICP) assessment models based on arterious and venous transcranial Doppler ultrasonography (TCD) and optic nerve sheath diameter (ONSD). METHODS:We included brain injured patients requiring invasive ICP monitoring (intraparenchymal or intraventricular). We assessed the concordance between ICP measured non-invasively with arterious [flow velocity diastolic formula (ICP) and pulsatility index (PI)], venous TCD (vPI) and ICP derived from ONSD (nICP) compared to invasive ICP measurement. RESULTS:Linear regression showed a positive relationship between nICP and ICP for all the methods, except PIv. ICP showed the strongest correlation with invasive ICP (r = 0.61) compared to the other methods (ICP, r = 0.26, p value = 0.0015; PI, r = 0.19, p value = 0.02, vPI, r = 0.056, p value = 0.510). The ability to predict intracranial hypertension was highest for ICP (AUC = 0.91; 95% CI, 0.85-0.97 at ICP > 20 mmHg), with a sensitivity and specificity of 85%, followed by ICP (AUC = 0.67; 95% CI, 0.54-0.79). CONCLUSIONS:Our results demonstrate that among the non-invasive methods studied, ONSD showed the best accuracy in the detection of ICP. 10.1007/978-3-319-65798-1_15
    The value of bedside ocular ultrasound assessment of optic nerve sheath diameter in the detection of increased intracranial pressure in patients presenting to the emergency room with headache. Canakci Y,Koksal O,Durak V A Nigerian journal of clinical practice Introduction:Headache is one of the most important complaints in emergency room (ER) admissions, and the rate of the increase in intracranial pressure in these cases should not be overlooked. This study was performed to investigate the value of the measurement of optic nerve sheath diameter (ONSD) by ocular ultrasound in ER patients with the complaint of headache and increase in intracranial pressure regarding this. Materials and Methods:: A total of 100 patients who applied to the ER with the complaint of headache were included in this prospective study. Fifty patients with increased ONSD (≥5 mm) and 50 patients with normal ONSD (<5 mm) were obtained. ONSD measurements were performed with 7.5-10 MHz linear probe and closed-eye technique. In addition to this, all patients underwent cranial computerized tomography (CT) examinations, and CT results were compared with the results of the ocular ultrasound. Results:The median right and left ONSD values were detected to be 4.3 mm (3.6-5.5 mm) and 4.4 mm (3.6-5.6 mm) in patients whose cranial CT results were within normal limits. However, the median right and left ONSD values were detected to be 5.5 mm (5.1-6.3 mm) and 5.5 mm (5.1-6.4 mm) in patients whose cranial CT examination results were abnormal. In all cases with abnormal CT findings, the right and the left ONSD measurements were significantly higher (P < 0.001). Furthermore, ONSD value in the ipsilateral side with the lesion was significantly higher than the contralateral side (P < 0.001). Conclusion:Bedside ocular ultrasound is a noninvasive and easily applicable method in ER for the detection and evaluation of intracranial hypertension with headache. 10.4103/njcp.njcp_119_17
    Ultrasound measurements versus invasive intracranial pressure measurement method in patients with brain injury: a retrospective study. Zhou Jing,Li Jing,Ye Tiantian,Zeng Yanrong BMC medical imaging BACKGROUND:The invasive method for intracranial pressure measurement is 'gold standard' but not always feasible because the intraventricular catheter/ intraparenchymal micro transducer used in the measurement of intracranial pressure measurement may cause complications. Imaging modalities with clinical examination protocol have a lack of specificity and accuracy. The objective of the study was to compare the accuracy of diagnostic parameters of ultrasound measurements in patients with brain injury underwent invasive intracranial pressure measurement method. METHODS:Data of invasive intracranial pressure measurement method and ultrasound measurements of 185 patients with brain injury who required admission diagnosis were included in the analysis. Pearson correlation was tested for diagnostic parameters. Logistical regression analysis was performed for diagnostic parameters of death patients to evaluate independent parameter of mortality. RESULTS:Straight sinus flow velocities, middle cerebral artery flow velocities, and optic nerve sheath diameter were correlated with intracranial pressure (p < 0.0001 for all). Arterial blood pressure (p = 0.127) and middle cerebral artery pulsatility index (p = 0.06) were not correlated with intracranial pressure. A total of 47 patients died during the study period. Intracranial pressure (p = 0.015) and optic nerve sheath diameter (p = 0.035) were found to be independent predictor of mortality. CONCLUSIONS:Ultrasound measurement especially optic nerve sheath diameter can be successfully used instead of invasive intracranial pressure measurement method in patients with brain injury. LEVEL OF EVIDENCE:III. 10.1186/s12880-019-0354-0