Dilated Optic Nerve Sheath in Mucopolysaccharidosis I: Common and Not Necessarily High Intracranial Pressure.
AJNR. American journal of neuroradiology
Hydrocephalus is one of the earliest manifestations of mucopolysaccharidosis I-Hurler syndrome, and delayed treatment of hydrocephalus can lead to neurocognitive delay or even death. Optic nerve sheath diameter has been established as a noninvasive measurement to detect elevated intracranial pressure. This study aimed to establish correlations between optic nerve sheath diameter and opening pressure. Forty-nine MR images and opening pressures in patients with mucopolysaccharidosis I-Hurler syndrome were retrospectively reviewed from 2008 to 2020. The optic nerve sheath diameter was measured 3 mm posterior to the posterior margin of the globe (retrobulbar) and 10 mm anterior to the optic foramen (midpoint segment), and the average was taken between the 2 eyes. Opening pressure was measured with the patient in the lateral decubitus position with controlled end-tidal CO on the same day as the MR imaging. The average retrobulbar optic nerve sheath diameter was 5.33 mm, higher than the previously reported measurement in healthy controls, in patients with idiopathic intracranial hypertension, and there was a positive correlation between age and the optic nerve sheath diameter measured at the retrobulbar or midpoint segment (retrobulbar segment, = 0.27, < .01; midpoint segment, = 0.20, < .01). However, there was no correlation between retrobulbar or midpoint segment optic nerve sheath diameter and opening pressure (retrobulbar segment, = 0.02, = .17; midpoint segment, = 0.03, < .12). This study shows a higher average optic nerve sheath diameter in patients with mucopolysaccharidosis I-Hurler syndrome than in healthy controls regardless of the location of the measurement. However, the degree of optic nerve sheath dilation does not correlate with opening pressure, suggesting that increased optic nerve sheath diameter is an ocular manifestation of mucopolysaccharidosis I-Hurler syndrome itself rather than a marker of elevated intracranial pressure.
10.3174/ajnr.A7755
Ultrasound measurement of optic nerve sheath diameter in a healthy adult Colombian population.
BMC neurology
BACKGROUND:Measurement of the optic nerve sheath diameter (ONSD) provides a rapid, safe, and easy method for detecting increased intracranial pressure (ICP). However, the normal mean and upper limit values may vary according to sex, age, ethnicity, and ultrasound technique. AIM:We aimed to obtain the mean ONSD in a healthy Colombian adult population and to correlate it with demographic and anthropometric measures. METHODS:In a prospective study using a 10-13 MHz linear ultrasound probe, eye transverse diameter (ETD) and ONSD in the transverse (ONSD-TP) and sagittal planes (ONSD-SP) were measured in healthy adult volunteers in Bogota, Colombia. RESULTS:A total of 100 healthy subjects were included, with a mean age of 26,7 ± 8,3 years and 62 women. The mean ETD, ONSD-TP and ONSD-SP was 23.11 mm (95% confidence interval (CI): 22.90 mm-23.32 mm), 3.96 mm (95% CI: 3.85 mm-4.07 mm) and 4.0 mm (95% CI: 3.90 mm-4.11 mm), respectively. The ONSD in both planes ranged from 2.35 mm to 5.20 mm. There was a significant correlation between ONSD-SP and ONSD-TP (p < 0.0001) but no correlation between the ocular measures and demographic or anthropometric variables (p > 0.05). The intraclass correlation between the eyes was statistically significant. CONCLUSION:Our study shows that ultrasound-measured ONSD in healthy adults in Colombia is similar to that found worldwide. An ONSD of 5.5 mm may be considered the upper limit for healthy adults in Colombia. ONSD can be measured in either plane; there is a good correlation between the two eyes; and ONSD is not modified by demographic or anthropometric characteristics.
10.1186/s12883-023-03062-4
Dilated optic nerve sheath by ultrasound predicts mortality among patients with acute intracerebral hemorrhage.
Arquivos de neuro-psiquiatria
BACKGROUND:Intracerebral hemorrhage (ICH) is a deadly disease and increased intracranial pressure (ICP) is associated with worse outcomes in this context. OBJECTIVE:We evaluated whether dilated optic nerve sheath diameter (ONSD) depicted by optic nerve ultrasound (ONUS) at hospital admission has prognostic value as a predictor of mortality at 90 days. METHODS:Prospective multicenter study of acute supratentorial primary ICH patients consecutively recruited from two tertiary stroke centers. Optic nerve ultrasound and cranial computed tomography (CT) scans were performed at hospital admission and blindly reviewed. The primary outcome was mortality at 90-days. Multivariate logistic regression, ROC curve, and C-statistics were used to identify independent predictors of mortality. RESULTS:Between July 2014 and July 2016, 57 patients were evaluated. Among those, 13 were excluded and 44 were recruited into the trial. Their mean age was 62.3 ± 13.1 years and 12 (27.3%) were female. On univariate analysis, ICH volume on cranial CT scan, ICH ipsilateral ONSD, Glasgow coma scale, National Institute of Health Stroke Scale (NIHSS) and glucose on admission, and also diabetes mellitus and current nonsmoking were predictors of mortality. After multivariate analysis, ipsilateral ONSD (odds ratio [OR]: 6.24; 95% confidence interval [CI]: 1.18-33.01; = 0.03) was an independent predictor of mortality, even after adjustment for other relevant prognostic factors. The best ipsilateral ONSD cutoff was 5.6mm (sensitivity 72% and specificity 83%) with an AUC of 0.71 ( = 0.02) for predicting mortality at 90 days. CONCLUSION:Optic nerve ultrasound is a noninvasive, bedside, low-cost technique that can be used to identify increased ICP in acute supratentorial primary ICH patients. Among these patients, dilated ONSD is an independent predictor of mortality at 90 days.
10.1055/s-0043-1775885
Usefulness of optic nerve sheath diameter measurement in hypertensive patients during pregnancy and the puerperium.
The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians
Pre-eclampsia/eclampsia during pregnancy and the puerperium are major risk factors for maternal and perinatal morbidity and mortality worldwide. Early diagnosis followed by appropriate treatment can prevent neurological disorders, considered one of the most serious sequelae of the disease. The detection of increased intracerebral pressure through the use of ocular ultrasonography could be considered an effective method for its diagnosis, since it has the advantage of being a noninvasive technique, easy to perform at the patient's bedside and with a high sensitivity and specificity for the detection of intracranial hypertension.
10.1080/14767058.2023.2187253
Correlation between optic nerve sheath diameter and extracorporeal life support time.
Rivas-Rangel Jorge,García-Arellano Maricela,Marquez-Romero Juan M
Anales de pediatria
INTRODUCTION:The objective of the study was to analyse the correlation between extracorporeal life support (ECLS) and aortic cross-clamp times and optic nerve sheath diameter (ONSD). PATIENTS AND METHODS:Study in a cohort of patients aged 0-15 years that underwent ECLS for cardiac surgery after obtention of signed informed consent. We calculated a sample size of 23 participants. First, we obtained 3 vertical and 3 horizontal measurements of the ONSD for each eye and calculated the mean of both eyes for each measurement to be used in the analysis. The measurements were made at admission and at 6 and 24 h post surgery. We retrieved the ECLS time and the aortic cross-clamp time were from the operative report. RESULTS:We analysed data for 23 participants, 52.2% female, with a median age of 14 months. The median ECLS time was 60 min; the median aortic cross-clamp time was 32 min. The median baseline ONSD was 3.1 mm. ONSD values had increased a median of 0.015 mm at 6 h post surgery (P = .03). We found a positive correlation between ECLS time and ONSD values (r = 0.476, P < 0,05). The ONSD values returned to baseline by 24 h post surgery. None of the patients developed signs or symptoms of increased intracranial pressure. CONCLUSION:Our study found a correlation between ECLS time and ONSD at 24 h post surgery. We found variations in the ONSD even in patients without signs or symptoms of increased ICP. Further research is required to identify the factors related to these variations.
10.1016/j.anpede.2021.02.002
Optic Nerve Sheath Diameter Ultrasound for Raised Intracranial Pressure: A Literature Review and Meta-analysis of its Diagnostic Accuracy.
Aletreby Waleed,Alharthy Abdulrahman,Brindley Peter G,Kutsogiannis Demetrios J,Faqihi Fahad,Alzayer Waseem,Balhahmar Abdullah,Soliman Ibrahim,Hamido Hend,Alqahtani Saleh A,Karakitsos Dimitrios,Blaivas Michael
Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine
Optic nerve sheath diameter (ONSD) ultrasound is becoming increasingly more popular for estimating raised intracranial pressure (ICP). We performed a systematic review and analysis of the diagnostic accuracy of ONSD when compared to the standard invasive ICP measurement. METHOD:We performed a systematic search of PUBMED and EMBASE for studies including adult patients with suspected elevated ICP and comparing sonographic ONSD measurement to a standard invasive method. Quality of studies was assessed using the QUADAS-2 tool by two independent authors. We used a bivariate model of random effects to summarize pooled sensitivity, specificity, and diagnostic odds ratio (DOR). Heterogeneity was investigated by meta-regression and sub-group analyses. RESULTS:We included 18 prospective studies (16 studies including 619 patients for primary outcome). Only one study was of low quality, and there was no apparent publication bias. Pooled sensitivity was 0.9 [95% confidence intervals (CI): 0.85-0.94], specificity was 0.85 (95% CI: 0.8-0.89), and DOR was 46.7 (95% CI: 26.2-83.2) with partial evidence of heterogeneity. The Area-Under-the-Curve of the summary Receiver-Operator-Curve was 0.93 (95% CI: 0.91-0.95, P < .05). No covariates were significant in the meta-regression. Subgroup analysis of severe traumatic brain injury and parenchymal ICP found no heterogeneity. ICP and ONSD had a correlation coefficient of 0.7 (95% CI: 0.63-0.76, P < .05). CONCLUSION:ONSD is a useful adjunct in ICP evaluation but is currently not a replacement for invasive methods where they are feasible.
10.1002/jum.15732
Optic Nerve Sheath Viscoelastic Properties: Re-Examination of Biomechanical Behavior and Clinical Implications.
Neurocritical care
BACKGROUND:Meta-analyses show a variable relationship between optic nerve sheath diameter (ONSD) and the presence of raised intracranial pressure (ICP). Because optic nerve sheath (ONS) tissue can be deformed, it is possible that ONSD reflects not only the current ICP but also prior deforming biomechanical exposures. In this post hoc analysis of two published data sets, we characterize ONS Young's modulus (E, mechanical stress per unit of strain) and calculate threshold pressure for plastic deformation. METHODS:The authors of two previously published articles contributed primary data for these unique post hoc analyses. Human cadaveric ex vivo measurements of ONSD (n = 10) and luminal distending pressure (range 5 to 65 mm Hg) were used to calculate E and the threshold pressure for plastic deformation. Clinical in vivo measurements of ONSD and ICP during endotracheal tube suction from patients with traumatic brain injury (n = 15) were used to validate the ex vivo cadaveric findings. RESULTS:Ex vivo ONS estimate of E was 140 ± 1.3 mm Hg (mean ± standard error), with evidence of plastic deformation occurring with distending pressure at 45 mm Hg. Similar E (71 ± 10 mm Hg) was estimated in vivo with an average ICP of 34 ± 2 mm Hg. CONCLUSIONS:Ex vivo, ONS plastic deformation occurs at levels of pressure commonly seen in patients with raised ICP, leading to distortion of the ICP-ONSD relationship. This evidence of plastic deformation may illustrate why meta-analyses fail to identify a single threshold in ONSD associated with the presence of raised ICP. Future studies characterizing time-dependent viscous characteristics of the ONS will help determine the time course of ONS tissue biomechanical behavior.
10.1007/s12028-022-01462-x
Optic Nerve Sheath Ultrasound for the Detection and Monitoring of Raised Intracranial Pressure in Tuberculous Meningitis.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
BACKGROUND:Neurological complications of tuberculous meningitis (TBM) often lead to raised intracranial pressure (ICP) resulting in high morbidity and mortality. Measurement of optic nerve sheath diameter (ONSD) by point-of-care ultrasound may aid in the identification of raised ICP in TBM. METHODS:From June 2017 to December 2019, 107 Vietnamese adults with TBM, enrolled in the ACT HIV or LAST ACT trials (NCT03092817, NCT03100786), underwent ONSD ultrasound at ≥1 of days 0, 3, 7, 14, 21, and day ±30 after enrollment. Demographic data, TBM severity grade, HIV coinfection status, and clinical endpoints by 3 months were recorded. ONSD values were correlated with disease severity, baseline brain imaging, cerebrospinal fluid parameters, and clinical endpoints. RESULTS:267 ONSD ultrasound scans were performed in 107 participants over the first 30 days of treatment, with measurements from 0.38-0.74 cm. Paired baseline ONSD and brain imaging were performed in 63 participants. Higher baseline ONSD was associated with more severe disease and abnormal brain imaging (abnormal imaging 0.55 cm vs 0.50 cm normal imaging, P = .01). Baseline median ONSD was significantly higher in participants who died by 3 months (0.56 cm [15/72]) versus participants who survived by 3 months (0.52 cm [57/72]) (P = .02). Median ONSD was higher at all follow-up times in participants who died by 3 months. CONCLUSIONS:Higher ONSD was associated with increased disease severity, brain imaging abnormalities, and increased death by 3 months. ONSD ultrasound has a potential role as a noninvasive, affordable bedside tool for predicting brain pathology and death in TBM.
10.1093/cid/ciaa1823
Optic nerve sheath diameter measurement by ultrasound: Evaluation of a standardized protocol.
Pansell Jakob,Bell Max,Rudberg Peter,Friman Ola,Cooray Charith
Journal of neuroimaging : official journal of the American Society of Neuroimaging
BACKGROUND AND PURPOSE:Treatment of elevated intracranial pressure (ICP) is central to neurocritical care, but not all patients are eligible for invasive ICP-monitoring. A promising noninvasive option is ultrasound measurement of the optic nerve sheath diameter (ONSD). However, meta-analyses of ONSD for elevated ICP show wide confidence intervals. This might be due to baseline variations, inter-rater variability, and varying measurement methods. No standardized protocol has been validated. Corrections for eyeball diameter (ED) and optic nerve diameter (OND) may compensate for baseline variations. We evaluated a protocol and compared two different measurement methods for ONSD ultrasound. METHODS:Two operators, blinded to each other's measurements, measured ONSD, ED, and OND twice in 20 patients. ONSD was measured with two different methods in use: internal (ONSDint) or external (ONSDext) of the dura mater. Intra-class correlation (ICC) was calculated for inter-rater and intra-rater reliability. RESULTS:ICCs for inter-rater reliability of ONSDext and ONSDint (95% confidence interval) were 0.96 (0.93, 0.98) and 0.88 (0.79, 0.94), respectively. ICCs for intra-rater reliability of ONSDext and ONSDint were 0.97 (0.94, 0.99) and 0.93 (0.87, 0.96), respectively. There was no significant bias or difference in intra-rater reliability between operators. CONCLUSIONS:ONSD can be measured with an excellent inter- and intra-rater reliability and low risk of inter-rater bias, when using this protocol. ONSDext yields a higher inter- and intra-rater reliability than ONSDint. Corrections for ED and OND can be performed reliably.
10.1111/jon.12936
Extracorporeal Circulation and Optic Nerve Ultrasound: A Pilot Study.
Medicina (Kaunas, Lithuania)
: Cardiopulmonary bypass (CPB) is an extracorporeal circuit that provides surgical access to an immobile and bloodless area, allowing for technical and procedural advances in cardiothoracic surgery. CBP can alter the integrity of the blood-brain barrier and cause changes in intracranial pressure (ICP) postoperatively. Optical nerve sheath diameter (ONSD) measurement is among the alternative non-invasive methods for ICP monitoring. In this study, we aimed to evaluate the optic nerve sheath diameter measurements under the guidance of ultrasonography for ICP changes during the extracorporeal circulation process. : The study population included 21 patients over 18 years of age who required extracorporeal circulation. Demographic data of the patients, such as age, gender, comorbidity, American Society of Anesthesiologists (ASA) classification and reason for operation (coronary artery disease or mitral or aortic valve disease) were recorded. The ONSD was measured and evaluated before the extracorporeal circulation (first time) and at the 30th minute (second time), 60th minute (third time) and 90th minute (fourth time) of the extracorporeal circulation. Non-invasive ICP (ICP ONSD) values were calculated based on the ONSD values found. : The mean ONSD values measured before the extracorporeal circulation of the patients were found to be 4.13 mm (3.8-4.6) for the right eye and 4.36 mm (4.1-4.7) for the left eye. Calculated nICPONSD values of 11.0 mm Hg (1.0-21.0) for the right eye and 10.89 mm Hg (1.0-21.0) for the left eye were found. It was observed that there was a significant increase in the ONSD and nlCPONSD values recorded during the extracorporeal circulation of all patients compared to the baseline values ( < 0.005). : During extracorporeal circulation, ultrasound-guided ONSD measurement is an easy, inexpensive and low-complication method that can be performed at the bedside during the operation to monitor ICP changes.
10.3390/medicina59030445
Optic Nerve Sheath Diameter Measured by Point-of-Care Ultrasound and MRI.
Shokoohi Hamid,Pyle Matthew,Kuhl Evan,Loesche Michael A,Goyal Aakshit,LeSaux Maxine A,Boniface Keith S,Taheri M Reza
Journal of neuroimaging : official journal of the American Society of Neuroimaging
BACKGROUND AND PURPOSE:Ultrasound (US) measurement of the optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) is a method frequently used to screen for an increased intracranial pressure. The aim of this study was to assess the accuracy of US measurements of ONSD and OND, when compared to magnetic resonance imaging (MRI) measurements as the criterion standard. METHODS:In this prospective, single-institution study, orbital US was performed for those patients requiring an emergent brain MRI. ONSD and OND of both eyes were measured in the axial and coronal planes in straight gaze by US. ONSD and OND from brain and orbital MRI were measured by two neuroradiologists. Correlation and agreement between readings were assessed using Pearson's correlations. RESULTS:Eighty-two patients met inclusion criteria. The mean axial and coronal ONSD in the MRI examinations was 5.6 and 5.7 mm at 3-5.9 mm behind the globe, respectively. The mean ONSD from the US measurements was 6.22 and 5.52 mm in the axial and coronal planes, respectively. The mean OND in US examinations was 4.31 mm (axial) and 3.68 mm (coronal). Axial versus coronal measurements of ONSD had a modest correlation in US assessment with an r of .385 (P < .001) but there were no correlations between any of the US and MRI measurements. CONCLUSIONS:In measuring ONSD and OND, US measurements showed a modest correlation between axial and coronal measurements, but no concordance was found between US and MRI in our setting.
10.1111/jon.12764
Optic Nerve Sheath Diameter Point-of-Care Ultrasonography Quality Criteria Checklist: An International Consensus Statement on Optic Nerve Sheath Diameter Imaging and Measurement.
Critical care medicine
OBJECTIVES:To standardize optic nerve sheath diameter (ONSD) point-of-care ultrasonography (POCUS) and improve its research and clinical utility by developing the ONSD POCUS Quality Criteria Checklist (ONSD POCUS QCC). DESIGN:Three rounds of modified Delphi consensus process and three rounds of asynchronous discussions. SETTING:Online surveys and anonymous asynchronous discussion. SUBJECTS:Expert panelists were identified according to their expertise in ONSD research, publication records, education, and clinical use. A total of 52 panelists participated in the Delphi process. INTERVENTIONS:None. MEASUREMENTS AND MAIN RESULTS:Three Delphi rounds and three asynchronous discussion rounds generated consensus on quality criteria (QC). This started with 29 QC in addition to other QC proposed by expert panelists. The QC items were categorized into probe selection, safety, body position, imaging, measurement, and research considerations. At the conclusion of the study, 28 QC reached consensus to include in the final ONSD POCUS QCC. These QC were then reorganized, edited, and consolidated into 23 QC that were reviewed and approved by the panelists. CONCLUSIONS:ONSD POCUS QCC standardizes ONSD ultrasound imaging and measurement based on international consensus. This can establish ONSD ultrasound in clinical research and improve its utility in clinical practice.
10.1097/CCM.0000000000006345
Using Optic Nerve Sheath Diameter for Intracranial Pressure (ICP) Monitoring in Traumatic Brain Injury: A Scoping Review.
Neurocritical care
INTRODUCTION:Neuromonitoring represents a cornerstone in the comprehensive management of patients with traumatic brain injury (TBI), allowing for early detection of complications such as increased intracranial pressure (ICP) [1]. This has led to a search for noninvasive modalities that are reliable and deployable at bedside. Among these, ultrasonographic optic nerve sheath diameter (ONSD) measurement is a strong contender, estimating ICP by quantifying the distension of the optic nerve at higher ICP values. Thus, this scoping review seeks to describe the existing evidence for the use of ONSD in estimating ICP in adult TBI patients as compared to gold-standard invasive methods. MATERIALS AND METHODS:This review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews, with a main search of PubMed and EMBASE. The search was limited to studies of adult patients with TBI published in any language between 2012 and 2022. Sixteen studies were included for analysis, with all studies conducted in high-income countries. RESULTS:All of the studies reviewed measured ONSD using the same probe frequency. In most studies, the marker position for ONSD measurement was initially 3 mm behind the globe, retina, or papilla. A few studies utilized additional parameters such as the ONSD/ETD (eyeball transverse diameter) ratio or ODE (optic disc elevation), which also exhibit high sensitivity and reliability. CONCLUSION:Overall, ONSD exhibits great test accuracy and has a strong, almost linear correlation with invasive methods. Thus, ONSD should be considered one of the most effective noninvasive techniques for ICP estimation in TBI patients.
10.1007/s12028-023-01884-1
Optic nerve sheath diameter measured sonographically as non-invasive estimator of intracranial pressure: a systematic review and meta-analysis.
Robba Chiara,Santori Gregorio,Czosnyka Marek,Corradi Francesco,Bragazzi Nicola,Padayachy Llewellyn,Taccone Fabio Silvio,Citerio Giuseppe
Intensive care medicine
PURPOSE:Although invasive intracranial devices (IIDs) are the gold standard for intracranial pressure (ICP) measurement, ultrasonography of the optic nerve sheath diameter (ONSD) has been suggested as a potential non-invasive ICP estimator. We performed a meta-analysis to evaluate the diagnostic accuracy of sonographic ONSD measurement for assessment of intracranial hypertension (IH) in adult patients. METHODS:We searched on electronic databases (MEDLINE/PubMed, Scopus, Web of Science, ScienceDirect, Cochrane Library) until 31 May 2018 for comparative studies that evaluated the efficacy of sonographic ONSD vs. ICP measurement with IID. Data were extracted independently by two authors. We used the QUADAS-2 tool for assessing the risk of bias (RB) of each study. A diagnostic meta-analysis following the bivariate approach and random-effects model was performed. RESULTS:Seven prospective studies (320 patients) were evaluated for IH detection (assumed with ICP > 20 mmHg or > 25 cmHO). The accuracy of included studies ranged from 0.811 (95% CI 0.678‒0.847) to 0.954 (95% CI 0.853‒0.983). Three studies were at high RB. No significant heterogeneity was found for the diagnostic odds ratio (DOR), positive likelihood ratio (PLR) and negative likelihood ratio (NLR), with I < 50% for each parameter. The pooled DOR, PLR and NLR were 67.5 (95% CI 29‒135), 5.35 (95% CI 3.76‒7.53) and 0.088 (95% CI 0.046‒0.152), respectively. The area under the hierarchical summary receiver-operating characteristic curve (AUHSROC) was 0.938. In the subset of five studies (275 patients) with IH defined for ICP > 20 mmHg, the pooled DOR, PLR and NLR were 68.10 (95% CI 26.8‒144), 5.18 (95% CI 3.59‒7.37) and 0.087 (95% CI 0.041‒0.158), respectively, while the AUHSROC was 0.932. CONCLUSIONS:Although the wide 95% CI in our pooled DOR suggests caution, ultrasonographic ONSD may be a potentially useful approach for assessing IH when IIDs are not indicated or available (CRD42018089137, PROSPERO).
10.1007/s00134-018-5305-7
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
Transcranial Doppler and Optic Nerve Sonography.
Rasulo Frank A,Bertuetti Rita
Journal of cardiothoracic and vascular anesthesia
Transcranial Doppler is a bedside procedure that measures linear cerebral blood flow velocity (CBFV) and the pulsatility index through the intracranial circulation. Transcranial color-coded duplex Doppler (TCCD) provides both CBFV and B-mode functions. In this review they are both referred to as brain ultrasound TCCD. Brain ultrasound can be applied in various environments, including out-of-hospital, emergency room, surgery, intensive care, and ward settings. The most common neurologic disease processes evaluated with TCCD are subarachnoid hemorrhage, traumatic brain injury, and ischemic and hemorrhagic stroke. However, TCCD also is used outside the neuroenvironment for diseases such as sickle cell anemia or for cerebral hemodynamic assessment during the cardiovascular perioperative period. In these applications, TCCD can be used for the detection of cerebral vessel occlusion, estimation of cerebrovascular reactivity, right-to-left cardiac shunts, noninvasive estimation of cerebral perfusion and intracranial pressure, optic nerve sheath diameter, midline shift, hydrocephalus, and the presence of foreign objects. Finally, TCCD has a high accuracy in confirming total cerebral circulatory arrest and has been used as an ancillary test to support clinical diagnosis of brain death. Other indications for TCCD include assessment of collateral blood flow and embolization during carotid endarterectomy, assessment of patterns and extent of collateral circulation in severe stenosis or occlusion, assessment of patent foramen ovale/paradoxical embolism, assessment of arteriovenous malformations and studying their supply arteries and flow patterns, assessment of noncardiac right-to-left shunts, assessment of severe stenosis in the arteries of the circle of Willis, and assessment of vertebral artery dissection.
10.1053/j.jvca.2019.03.040