Sonographic monitoring of midline shift in hemispheric infarctions

Early automated cerebral edema assessment following endovascular therapy: impact on stroke outcome

BACKGROUND

Cerebral edema (CED) is associated with poorer outcome in patients with acute ischemic stroke (AIS). The aim of the study was to investigate the factors contributing to greater early CED formation in patients with AIS who underwent endovascular therapy (EVT) and its association with functional outcome.

METHODS

We conducted a multicenter cohort study of patients with an anterior circulation AIS undergoing EVT. The volume of cerebrospinal fluid (CSF) was extracted from baseline and 24-hour follow-up CT using an automated algorithm. The severity of CED was quantified by the percentage reduction in CSF volume between CT scans (∆CSF). The primary endpoint was a shift towards an unfavorable outcome, assessed by modified Rankin Scale (mRS) score at 3 months. Multivariable ordinal logistic regression analyses were performed. The ∆CSF threshold that predicted unfavorable outcome was selected using receiver operating characteristic curve analysis.

RESULTS

We analyzed 201 patients (mean age 72.7 years, 47.8% women) in whom CED was assessable for 85.6%. Higher systolic blood pressure during EVT and failure to achieve modified Thrombolysis In Cerebral Infarction (mTICI) 3 were found to be independent predictors of greater CED. ∆CSF was independently associated with the probability of a one-point worsening in the mRS score (common odds ratio (cOR) 1.05, 95% CI 1.03 to 1.08) after adjusting for age, baseline mRS, National Institutes of Health Stroke Scale (NIHSS), and number of passes. Displacement of more than 25% of CSF was associated with an unfavorable outcome (OR 6.09, 95% CI 3.01 to 12.33) and mortality (OR 6.72, 95% CI 2.94 to 15.32).

CONCLUSIONS

Early CED formation in patients undergoing EVT was affected by higher blood pressure and incomplete reperfusion. The extent of early CED, measured by automated ∆CSF, was associated with worse outcomes.

Novel advanced imaging techniques for cerebral oedema

Cerebral oedema following acute ischemic infarction has been correlated with poor functional outcomes and is the driving mechanism of malignant infarction. Measurements of midline shift and qualitative assessment for herniation are currently the main CT indicators for cerebral oedema but have limited sensitivity for small cortical infarcts and are typically a delayed sign. In contrast, diffusion-weighted (DWI) or T2-weighted magnetic resonance imaging (MRI) are highly sensitive but are significantly less accessible. Due to the need for early quantification of cerebral oedema, several novel imaging biomarkers have been proposed. Based on neuroanatomical shift secondary to space-occupying oedema, measures such as relative hemispheric volume and cerebrospinal fluid displacement are correlated with poor outcomes. In contrast, other imaging biometrics, such as net water uptake, T2 relaxometry and blood brain barrier permeability, reflect intrinsic tissue changes from the influx of fluid into the ischemic region. This review aims to discuss quantification of cerebral oedema using current and developing advanced imaging techniques, and their role in predicting clinical outcomes.

Assessment of Midline Shift in Postdecompressive Craniectomy Patients in Neurocritical Care: Comparison between Transcranial Ultrasonography and Computerized Tomography

Background

Monitoring and evaluation of intracranial structures remain a fundamental element in the neurointensive care unit. Most used technique to monitor progression is the use of computed tomography (CT) in intracranial hemorrhage (ICH) or stroke. Rapid assessment of brain pathology can be made using CT to analyze the midline shift (MLS), hematoma expansion, and ventricular size, but transferring a patient who is intubated is time and resource-consuming task. Ultrasonography is a noninvasive technique, portable, and has the possibility of fast interpretation.

Aims and Objectives

To measure the brain MLS in decompressive craniectomy patients using transcranial ultrasonography (TCS) and compare the correlation of these results with CT scan measurements of MLS in the same patient.

Materials and Methods

Patients who have undergone decompressive craniectomy due to various reasons like ICH, traumatic brain injury, etc., and have a MLS. Trans cranial ultrasonography was assessed by a single consultant (Neuro Critical Care Intensivist) who was blinded for the CT scan measurement. CT scan measurement of MLS was assessed by a neuroradiologist using standard guidelines, who was blinded for the TCS results of MLS. The finding of a MLS >0.5 cm in the CT scan was considered a significant MLS.

Results

A total of 31 patients were recruited for the study. MLS measured using CT was 0.91 ± 0.67 cm. MLS via TCS was 0.91 ± 0.66 cm. A significant MLS via TCS was found in 77.4%. Intraclass correlation coefficient (ICC) was calculated between CT-MLS and TCS MLS and obtained the value of ICC as 0.996, indicating an almost perfect agreement.

Conclusion

Patients after decompressive craniectomy may present as an ideal candidate to visualize intracerebral anatomy with a high resolution. TCS might be considered as an alternative to CT to measure MLS in decompressive craniectomy patients.

Association Between Post-procedure Cerebral Blood Flow Velocity and Severity of Brain Edema in Acute Ischemic Stroke With Early Endovascular Therapy

Objectives

We aimed to investigate the association between post-procedure cerebral blood flow velocity (CBFV) and severity of brain edema in patients with acute ischemic stroke (AIS) who received early endovascular therapy (EVT).

Methods

We retrospectively included patients with AIS who received EVT within 24 h of onset between February 2016 and November 2021. Post-procedure CBFV of the middle cerebral artery was measured in the affected and the contralateral hemispheres using transcranial Doppler ultrasound. The severity of brain edema was measured using the three-level cerebral edema grading from the Safe Implementation of Thrombolysis in Stroke-Monitoring Study, with grades 2–3 indicating severe brain edema. The Association between CBFV parameters and severity of brain edema was analyzed.

Results

A total of 101 patients (mean age 64.2 years, 65.3% male) were included, of whom 56.3% (57/101) suffered brain edema [grade 1, 23 (22.8%); grade 2, 10 (9.9%); and grade 3, 24 (23.8%)]. Compared to patients with non-severe brain edema, patients with severe brain edema had lower affected/contralateral ratios of systolic CBFV (median 1 vs. 1.2, P = 0.020) and mean CBFV (median 0.9 vs. 1.3, P = 0.029). Multivariate logistic regression showed that severe brain edema was independently associated with affected/contralateral ratios of systolic CBFV [odds ratio (OR) = 0.289, 95% confidence interval (CI): 0.069–0.861, P = 0.028] and mean CBFV (OR = 0.278, 95% CI: 0.084–0.914, P = 0.035) after adjusting for potential confounders.

Conclusion

Post-procedure affected/contralateral ratio of CBFV may be a promising predictor of brain edema severity in patients with AIS who received early EVT.

Value of ultrasound fusion imaging in detecting vascular cerebral white matter pathology

BACKGROUND

Transcranial sonography is beside magnetic resonance imaging (MRI) and computed tomography, a well-established imaging method for evaluation of brain parenchyma and already implicated in various neurological disorders as bed-side investigation possibility in clinical routine. The aim of this study was the qualitative assessment detecting vascular white matter hyperintensities (WMHs), with ultrasound fusion-imaging technique (UFI) and to find the optimal location for their visualization in accordance to the grade of WMHs and to possibly providing a standardized protocol for clinical use.

RESULTS

29 patients with WMHs of variable degree quantified according to Fazekas grading scale (n = 13 I; n = 9 II; n = 7 III) and 11 subjects with normal findings on MRI were identified for further analysis. Ultrasound images were analyzed to a standardized protocol and predefined anatomical landmarks. UFI could visualize the MRI-verified WMHs in 147 of 161 localizations (91%). The overall ultrasound detection rate of WMHs increased with higher degree of WMHs burden (I:85%, II:94%, III:97%). The highest sensitivity was achieved at the contralateral central part (CPc) (97%) of the lateral ventricle. The inter-rater analysis between 2 independent raters, who were blinded to the patient's diagnosis and assessed only the B-mode ultrasound images, indicated an 86% agreement with an overall moderate strength of agreement (κ: 0.489, p < 0.0005) for all localizations. The highest accordance within raters was shown at the CPc; 92% (κ: 0.645, p < 0.0005).

CONCLUSIONS

This explorative study describes prospectively the ultrasound detection of periventricular vascular WMHs based on MRI lesions using UFI. Transcranial ultrasound (TCS) could serve as an additional screening opportunity for the detection of incidental WMLs during routine TCS investigations to initiate early vascular risk factor modification in primary prevention.

Ten Good Reasons to Practice Neuroultrasound in Critical Care Setting

In the beginning, cerebral ultrasound (US) was not considered feasible because the intact skull was a seemingly impenetrable obstacle. For this reason, obtaining a clear image resolution had been a challenge since the first use of neuroultrasound (NUS) for the assessment of small deep brain structures. However, the improvements in transducer technologies and advances in signal processing have refined the image resolution, and the role of NUS has evolved as an imaging modality for the brain parenchyma within multiple pathologies. This article summarizes ten crucial applications of cerebral ultrasonography for the evaluation and management of neurocritical patients, whose transfer from and to intensive care units poses a real problem to medical care staff. This also encompasses ease of use, low cost, wide acceptance by patients, no radiation risk, and relative independence from movement artifacts. Bedsides, availability and reliability raised the interest of critical care intensivists in using it with increasing frequency. In this mini-review, the usefulness and the advantages of US in the neurocritical care setting are discussed regarding ten aspects to encourage the intensivist physician to practice this important tool.

Role of Ultrasound in Neurocritical Care

Bedside point of care ultrasound has acquired an extremely significant role in diagnosis and management of neurocritical care, just as it has in other specialties. Easy availability and increasing expertise have allowed the intensivists to use it in a wide array of situations, such as confirming clinical findings as well as for interventional and prognostic purposes. At present, the clinical applications of ultrasonography (USG) in a neurosurgical patient include estimation of elevated intracranial pressure (ICP), assessment of cerebral blood flow (CBF) and velocities, diagnosis of intracranial mass lesion and midline shifts, and examination of pupils, apart from the systemic applications. Transcranial sonography has also found use in the diagnosis of the cerebral circulatory arrest. An increasing number of clinicians are now relying on the use of ultrasound in the neurointensive care unit for neurological as well as non-neurological indications. These uses include the diagnosis of shock, respiratory failure, deep vein thrombosis and performing bedside procedures.

A web based dynamic MANA Nomogram for predicting the malignant cerebral edema in patients with large hemispheric infarction

Background

For large hemispheric infarction (LHI), malignant cerebral edema (MCE) is a life-threatening complication with a mortality rate approaching 80%. Establishing a convenient prediction model of MCE after LHI is vital for the rapid identification of high-risk patients as well as for a better understanding of the potential mechanism underlying MCE.

Methods

One hundred forty-two consecutive patients with LHI within 24 h of onset between January 1, 2016 and August 31, 2019 were retrospectively reviewed. MCE was defined as patient death or received decompressive hemicraniectomy (DHC) with obvious mass effect (≥ 5 mm midline shift or Basal cistern effacement). Binary logistic regression was performed to identify independent predictors of MCE. Independent prognostic factors were incorporated to build a dynamic nomogram for MCE prediction.

Results

After adjusting for confounders, four independent factors were identified, including previously known atrial fibrillation (KAF), midline shift (MLS), National Institutes of Health Stroke Scale (NIHSS) and anterior cerebral artery (ACA) territory involvement. To facilitate the nomogram use for clinicians, we used the “Dynnom” package to build a dynamic MANA (acronym for MLS, ACA territory involvement, NIHSS and KAF) nomogram on web (http://www.MANA-nom.com) to calculate the exact probability of developing MCE. The MANA nomogram’s C-statistic was up to 0.887 ± 0.041 and the AUC-ROC value in this cohort was 0.887 (95%CI, 0.828 ~ 0.934).

Conclusions

Independent MCE predictors included KAF, MLS, NIHSS, and ACA territory involvement. The dynamic MANA nomogram is a convenient, practical and effective clinical decision-making tool for predicting MCE after LHI in Chinese patients.

Sonography of optic nerve sheath diameter identifies patients with middle cerebral artery infarction at risk of a malignant course: a pilot prospective observational study

INTRODUCTION

To assess the value of optic nerve sheath diameter (ONSD) measurements at different time points to predict the malignant evolution in middle cerebral artery (MCA) infarction and to investigate the relationship between ONSD and infarct volume on follow-up computed tomography (CT).

METHODS

In a single-center prospective observational study, we recruited patients with MCA infarction and age- and sex-matched controls. Clinical characteristics including NationaI Institutes of Health Stroke Scale (NIHSS) and ONSD measurement were assessed during the first five days after symptom onset. Volumetric analysis of the infarction was performed by a neuroradiologist, who was blinded to results of ONSD measurement and clinical examinations, based on  CT scans.

RESULTS

We enrolled 29 patients with MCA infarction, including 10 with malignant MCA (mMCA) infarction and 14 controls. Mean ONSD on admission was already larger in patients who had developed an mMCA (5.99 ± 0.32 mm) compared to patients with MCA infarction (4.98 ± 0.53 mm; P = 0.003), and to control patients (4.57 ± 0.29 mm; P < 0.001). Correlation was observed between the ONSD mean value bilateral measures per individual and volumetric evaluation of cerebral infarction in the CT scan after one day (r = 0.623; P = 0.002). An ONSD value of 5.6 mm predicted an mMCA with a sensitivity of 100% and specificity of 90% yielding a positive predictive value of 83% and negative predictive value of 100%.

CONCLUSIONS

ONSD measurement might be accurate for the noninvasive detection of increased ICP and for the recognition of patients being likely to develop mMCA.

A nomogram for predicting the in-hospital mortality after large hemispheric infarction

BACKGROUND

Large hemispheric infarction (LHI) is a severe form of stroke with high mortality and disability rates. The purpose of this study was to explore predictive indicators of the in-hospital mortality of LHI patients treated conservatively without decompressive hemicraniectomy.

METHOD

We performed a retrospective study of 187 consecutive patients with LHI between January 1, 2016 to May 31, 2019. The receiver operating curves were preformed to evaluate predictive performance of demographics factors, biomarkers and radiologic characteristics. Significant prognostic factors were combined to build a nomogram to predict the risk of in-hospital death of individual patients.

RESULT

One hundred fifty-eight patients with LHI were finally enrolled, 58 of which died. Through multivariate logistic regression analysis, we identified that independent prognostic factors for in-hospital death were age (adjusted odds ratio [aOR] = 1.066; 95% confidence interval [CI], 1.025-1.108; P = 0.001), midline shift (MLS, aOR = 1.330, 95% CI, 1.177-1.503; P <  0.001), and neutrophil-to-lymphocyte ratio (NLR, aOR = 3.319, 95% CI, 1.542-7.144; P = 0.002). NLR may serve as a better predictor than white blood count (WBC) and neutrophil counts. Lastly, we used all of the clinical characteristics to establish a nomogram for predicting the prognosis, area under the curve (AUC) of this nomogram was 0.858 (95% CI, 0.794-0.908).

CONCLUSION

This study shows that age, MLS, and admission NLR value are independent predictors of in-hospital mortality in patients with LHI. Moreover, nomogram, serve as a precise and convenient tool for the prognosis of LHI patients.

Reduction in Cerebrospinal Fluid Volume as an Early Quantitative Biomarker of Cerebral Edema After Ischemic Stroke

Background and Purpose- Cerebral edema (CED) develops in the hours to days after stroke; the resulting increase in brain volume may lead to midline shift (MLS) and neurological deterioration. The time course and implications of edema formation are not well characterized across the spectrum of stroke. We analyzed displacement of cerebrospinal fluid (ΔCSF) as a dynamic quantitative imaging biomarker of edema formation. Methods- We selected subjects enrolled in a stroke cohort study who presented within 6 hours of onset and had baseline and ≥1 follow-up brain computed tomography scans available. We applied a neural network-based algorithm to quantify hemispheric CSF volume at each imaging time point and modeled CSF trajectory over time (using a piecewise linear mixed-effects model). We evaluated ΔCSF within the first 24 hours as an early biomarker of CED (defined as developing MLS on computed tomography beyond 24 hours) and poor outcome (modified Rankin Scale score, 3-6). Results- We had serial imaging in 738 subjects with stroke, of whom 91 (13%) developed CED with MLS. Age did not differ (69 versus 70 years), but baseline National Institutes of Health Stroke Scale was higher (16 versus 7) and baseline CSF volume lower (132 versus 161 mL, both P<0.001) in those with CED. ΔCSF was faster in those developing MLS, with the majority seen by 24 hours (36% versus 11% or 2.4 versus 0.8 mL/h; P<0.0001). Risk of CED almost doubled for every 10% ΔCSF within 24 hours (odds ratio, 1.76 [95% CI, 1.46-2.14]), adjusting for age, glucose, and National Institutes of Health Stroke Scale. Risk of neurological deterioration (1.6-point increase in National Institutes of Health Stroke Scale at 24 hours) and poor outcome (adjusted odds ratio, 1.34 [95% CI, 1.15-1.56]) was also greater for every 10% increase in ΔCSF. Conclusions- CSF volumetrics provides quantitative evaluation of early edema formation. ΔCSF from baseline to 24-hour computed tomography is a promising early biomarker for the development of MLS and worse neurological outcome.

Early Prediction of Malignant Brain Edema After Ischemic Stroke

Background and Purpose- Malignant brain edema after ischemic stroke has high mortality but limited treatment. Therefore, early prediction is important, and we systematically reviewed predictors and predictive models to identify reliable markers for the development of malignant edema. Methods- We searched Medline and Embase from inception to March 2018 and included studies assessing predictors or predictive models for malignant brain edema after ischemic stroke. Study quality was assessed by a 17-item tool. Odds ratios, mean differences, or standardized mean differences were pooled in random-effects modeling. Predictive models were descriptively analyzed. Results- We included 38 studies (3278 patients) with 24 clinical factors, 7 domains of imaging markers, 13 serum biomarkers, and 4 models. Generally, the included studies were small and showed potential publication bias. Malignant edema was associated with younger age (n=2075; mean difference, -4.42; 95% CI, -6.63 to -2.22), higher admission National Institutes of Health Stroke Scale scores (n=807, median 17-20 versus 5.5-15), and parenchymal hypoattenuation >50% of the middle cerebral artery territory on initial computed tomography (n=420; odds ratio, 5.33; 95% CI, 2.93-9.68). Revascularization (n=1600, odds ratio, 0.37; 95% CI, 0.24-0.57) were associated with a lower risk for malignant edema. Four predictive models all showed an overall C statistic >0.70, with a risk of overfitting. Conclusions- Younger age, higher National Institutes of Health Stroke Scale, and larger parenchymal hypoattenuation on computed tomography are reliable early predictors for malignant edema. Revascularization reduces the risk of malignant edema. Future studies with robust design are needed to explore optimal cutoff age and National Institutes of Health Stroke Scale scores and to validate and improve existing models.

Better With Ultrasound: Transcranial Doppler

Transcranial Doppler (TCD) ultrasound is a noninvasive method of obtaining bedside neurologic information that can supplement the physical examination. In critical care, this can be of particular value in patients who are unconscious with an equivocal neurologic examination because TCD findings can help the physician in decisions related to more definitive imaging studies and potential clinical interventions. Although TCD is traditionally the domain of sonographers and radiologists, there is increasing adoption of goal-directed TCD at the bedside in the critical care environment. The value of this approach includes round-the-clock availability and a goal-directed approach allowing for repeatability, immediate interpretation, and quick clinical integration. This paper presents a systematic approach to incorporating the highest yield TCD techniques into critical care bedside practice, and includes a series of illustrative figures and narrated video presentations to demonstrate the techniques described.

Whole body ultrasound in the operating room and intensive care unit

Whole body ultrasound can be used to improve the speed and accuracy of evaluation of an increasing number of organ systems in the critically ill. Cardiac and abdominal ultrasound can be used to identify the mechanisms and etiology of hemodynamic instability. In hypoxemia or hypercarbia, lung ultrasound can rapidly identify the etiology of the condition with an accuracy that is equivalent to that of computed tomography. For encephalopathy, ocular ultrasound and transcranial Doppler can identify elevated intracranial pressure and midline shift. Renal and bladder ultrasound can identify the mechanisms and etiology of renal failure. Ultrasound can also improve the accuracy and safety of percutaneous procedures and should be currently used routinely for central vein catheterization and percutaneous tracheostomy.

Brain ultrasonography: methodology, basic and advanced principles and clinical applications. A narrative review

Brain ultrasonography can be used to evaluate cerebral anatomy and pathology, as well as cerebral circulation through analysis of blood flow velocities. Transcranial colour-coded duplex sonography is a generally safe, repeatable, non-invasive, bedside technique that has a strong potential in neurocritical care patients in many clinical scenarios, including traumatic brain injury, aneurysmal subarachnoid haemorrhage, hydrocephalus, and the diagnosis of cerebral circulatory arrest. Furthermore, the clinical applications of this technique may extend to different settings, including the general intensive care unit and the emergency department. Its increasing use reflects a growing interest in non-invasive cerebral and systemic assessment. The aim of this manuscript is to provide an overview of the basic and advanced principles underlying brain ultrasonography, and to review the different techniques and different clinical applications of this approach in the monitoring and treatment of critically ill patients.

Incorporation of Transcranial Doppler into the ED for the neurocritical care patient

INTRODUCTION

In the catastrophic neurologic emergency, a complete neurological exam is not always possible or feasible given the time-sensitive nature of the underlying disease process, or if emergent airway management is indicated. As the neurologic exam may be limited in some patients, the emergency physician is reliant on the assessment of brainstem structures to determine neurological function. Physicians thus routinely depend on advanced imaging modalities to further investigate for potential catastrophic diagnoses. Acquiring these tests introduces the risks of transport as well as delays in managing time-sensitive neurologic processes. A more immediate, non-invasive bedside approach complementing these modalities has evolved: Transcranial Doppler (TCD).

OBJECTIVE

This narrative review will provide a description of scenarios in which TCD may be applicable. It will summarize the sonographic findings and associated underlying pathophysiology in such neurocritical care patients. An illustrated tutorial, along with pearls and pitfalls, is provided.

DISCUSSION

Although there are numerous formalized TCD protocols utilizing four views (transtemporal, submandibular, suboccipital, and transorbital), point-of-care TCD is best accomplished through the transtemporal window. The core applications include the evaluation of midline shift, vasospasm after subarachnoid hemorrhage, acute ischemic stroke, and elevated intracranial pressure. An illustrative tutorial is provided.

CONCLUSIONS

With the wide dissemination of bedside ultrasound within the emergency department, there is a unique opportunity for the emergency physician to utilize TCD for a variety of conditions. While barriers to training exist, emergency physician performance of limited point-of-care TCD is feasible and may provide rapid and reliable clinical information with high temporal resolution.

Point-of-care transcranial Doppler by intensivists

In the unconscious patient, there is a diagnostic void between the neurologic physical exam, and more invasive, costly and potentially harmful investigations. Transcranial color-coded sonography and two-dimensional transcranial Doppler imaging of the brain have the potential to be a middle ground to bridge this gap for certain diagnoses. With the increasing availability of point-of-care ultrasound devices, coupled with the need for rapid diagnosis of deteriorating neurologic patients, intensivists may be trained to perform point-of-care transcranial Doppler at the bedside. The feasibility and value of this technique in the intensive care unit to help rule-in specific intra-cranial pathologies will form the focus of this article. The proposed scope for point-of-care transcranial Doppler for the intensivist will be put forth and illustrated using four representative cases: presence of midline shift, vasospasm, raised intra-cranial pressure, and progression of cerebral circulatory arrest. We will review the technical details, including methods of image acquisition and interpretation. Common pitfalls and limitations of point-of-care transcranial Doppler will also be reviewed, as they must be understood for accurate diagnoses during interpretation, as well as the drawbacks and inadequacies of the modality in general.

Applications of Transcranial Color-Coded Sonography in the Emergency Department

Transcranial color-coded Doppler sonography is a noninvasive bedside ultrasound application that combines both imaging of parenchymal structures and Doppler assessment of intracranial vessels. It may aid in rapid diagnoses and treatment decision making of patients with intracranial emergencies in point-of-care settings. This pictorial essay illustrates the technical aspects and emergency department applications of transcranial color-coded Doppler sonography, and provides some rationale for implementation of this technique into the emergency department practice.

Evidence-based guidelines for the management of large hemispheric infarction : a statement for health care professionals from the Neurocritical Care Society and the German Society for Neuro-intensive Care and Emergency Medicine

Large hemispheric infarction (LHI), also known as malignant middle cerebral infarction, is a devastating disease associated with significant disability and mortality. Clinicians and family members are often faced with a paucity of high quality clinical data as they attempt to determine the most appropriate course of treatment for patients with LHI, and current stroke guidelines do not provide a detailed approach regarding the day-to-day management of these complicated patients. To address this need, the Neurocritical Care Society organized an international multidisciplinary consensus conference on the critical care management of LHI. Experts from neurocritical care, neurosurgery, neurology, interventional neuroradiology, and neuroanesthesiology from Europe and North America were recruited based on their publications and expertise. The panel devised a series of clinical questions related to LHI, and assessed the quality of data related to these questions using the Grading of Recommendation Assessment, Development and Evaluation guideline system. They then developed recommendations (denoted as strong or weak) based on the quality of the evidence, as well as the balance of benefits and harms of the studied interventions, the values and preferences of patients, and resource considerations.

[Dislocation syndrome in patients with severe massive ischemic stroke]

OBJECTIVE

To compare the severity of brain dislocation, the rate of its progression according to CT results and clinical signs of dislocation syndrome (DS) in patients with unfavorable form of massive ischemic stroke (MII).

MATERIAL AND METHODS

We analyzed the results of examination and treatment of 114 patients with unfavorable course of MII. Patients were stratified by the type of DS course into two groups: group 1 with unfavorable course (91 patients) and group 2 with favorable course (23 patients). Patients were compared by disease course and outcome as well as by progression rate and severity of brain dislocation. Twenty-seven patients of group 1 underwent decompressive craniectomy (DC).

RESULTS

All patients of group 1 had DS decompensation and, therefore DS course was assessed as unfavorable. All patients of group 1, who received only conservative treatment, died from brain dislocation. In patients treated with DC in addition to conservative treatment, the fatality rate was 48%. In this group, we singled out 3 variants of DS course: fulminant, progressive and delayed. In patients of group 2, the fatality rate was 52%. The patients died from non-cranial complications and DS course in this group was regarded as favorable.

CONCLUSION

In patients with unfavorable course of MII, the risk of fatal outcome from temporal-tentorial impaction is determined both by the severity and progression rate of transverse dislocation of the middle brain structures. DS in patients with unfavorable course of MII can have favorable or unfavorable course. The unfavorable course is characterized by fulminant, progressive or delayed DS progression rate. The unfavorable course of DS is an absolute indication of administration of DC.

Assessment of brain midline shift using sonography in neurosurgical ICU patients

Introduction

Brain midline shift (MLS) is a life-threatening condition that requires urgent diagnosis and treatment. We aimed to validate bedside assessment of MLS with Transcranial Sonography (TCS) in neurosurgical ICU patients by comparing it to CT.

Methods

In this prospective single centre study, patients who underwent a head CT were included and a concomitant TCS performed. TCS MLS was determined by measuring the difference between the distance from skull to the third ventricle on both sides, using a 2 to 4 MHz probe through the temporal window. CT MLS was measured as the difference between the ideal midline and the septum pellucidum. A significant MLS was defined on head CT as >0.5 cm.

Results

A total of 52 neurosurgical ICU patients were included. The MLS (mean ± SD) was 0.32 ± 0.36 cm using TCS and 0.47 ± 0.67 cm using CT. The Pearson’s correlation coefficient (r²) between TCS and CT scan was 0.65 (P <0.001). The bias was 0.09 cm and the limits of agreements were 1.10 and -0.92 cm. The area under the ROC curve for detecting a significant MLS with TCS was 0.86 (95% CI =0.74 to 0.94), and, using 0.35 cm as a cut-off, the sensitivity was 84.2%, the specificity 84.8% and the positive likelihood ratio was 5.56.

Conclusions

This study suggests that TCS could detect MLS with reasonable accuracy in neurosurgical ICU patients and that it could serve as a bedside tool to facilitate early diagnosis and treatment for patients with a significant intracranial mass effect.

Advances in transcranial Doppler clinical applications

IMPORTANCE OF THE FIELD

Diagnostic neurosonology techniques including transcranial Doppler (TCD), transcranial color Doppler imaging (TCDI) and power motion-mode (PMD) TCD provide information about various aspects of cerebrovascular status such as microemboli detection, dynamic autoregulation and long-duration real-time monitoring of flow characteristics. Although most of the information provided cannot be obtained by any other imaging methodology, and is critical in clinical decision-making in the care of various neurovascular diseases, these modalities are widely underutilized. Increasing the familiarity to neurosonological techniques is of crucial importance.

AREAS COVERED IN THIS REVIEW

After briefly reviewing TCD, TCDI and PMD techniques, classical features are summarized and recent developments in the clinical neurosonology applications with specific interest in the neurovascular disorders.

WHAT THE READER WILL GAIN

Practical perspectives of ultrasound evaluation of intracranial arterial status in various neurovascular diseases including sickle cell vasculopathy and vasospasm are reviewed in detail. Pearls on the neurosonological monitoring of acute ischemic stroke and increased intracranial pressure increase is provided. Standards of cerebral microembolism detection, right to left shunts diagnosis and cerebral autoregulation assessment are discussed methodologically. Future perspectives of therapeutic neurosonology including sonothrombolysis, microbubble-ultrasound-mediated gene and drug delivery into the brain, and alteration of the brain-blood barrier permeability are summarized.

TAKE HOME MESSAGE

Suitable with future medicine, neurosonology brings imaging to the bedside, which enables the treating physician to monitor a given intervention in real time. A non-invasive neurosonology-guided treatment of various diseases could be possible in the near future. The first and foremost step in gaining mastery in this very fruitful field is beginning to use it.

Transcranial Doppler ultrasound in neurovascular diseases: diagnostic and therapeutic aspects

Albeit no direct anatomical information can be obtained, neurosonological methods provide real-time determination of velocity, and spectral waveform of blood flow in basal intracranial arteries adds significant benefit to the care of the patients with neurovascular diseases. Several features, such as relative simplicity in terms of interpretation and performance, significantly low cost, totally non-invasiveness, portability, and excellent temporal resolution, make neurosonology increasingly popular tool for evaluation, planning, and monitoring of treatment, and for determining prognosis in various neurovascular diseases. Usefulness of transcranial Doppler in diagnosing/monitoring subarachnoid hemorrhage related vasospasm and sickle cell vasculopathy is already well known. Utility in diagnosis of intracranial arterial stenosis, acute occlusion and recanalization, intracranial hemodynamic effect of the cervical arterial pathologies, intracranial pressure increase, and cerebral circulatory arrest are also well established. Neurosonological determination of vasomotor reactivity, cerebral autoregulation, neurovascular coupling, and micro-embolic signals detection are useful in the assessment of stroke risk, diagnosis of right-to-left shunting, and monitoring during surgery and interventional procedures. Transcranial Doppler is also an evolving ultrasound method with a therapeutic potential such as augmentation of clot lysis and cerebral delivery of thrombolytic or neuroprotective agent loaded nanobubbles in neurovascular diseases. The aim of this study is to give an overview of current usage of the different ultrasound modalities in different neurovascular diseases.

[Non-invasive evaluation of intracranial pressure: how and for whom?]

The invasive monitoring of intracranial pressure is useful in circumstances associated with high-risk of raised intracranial pressure. However the placement of intracranial probe is not always possible and non-invasive assessment of intracranial pressure may be useful, particularly in case of emergencies. Transcranial Doppler measurements allow the estimation of perfusion pressure with the pulsatility index. Recently, new ultrasonographic methods of cerebral monitoring have been developed: the diameter of the optic nerve sheath diameter, a surrogate marker of raised intracranial pressure and the estimation of median shift line deviation.

Consensus recommendations for transcranial color-coded duplex sonography for the assessment of intracranial arteries in clinical trials on acute stroke

BACKGROUND AND PURPOSE

Transcranial color-coded duplex sonography has become a standard diagnostic technique to assess the intracranial arterial status in acute stroke. It is increasingly used for the evaluation of prognosis and the success of revascularization in multicenter trials. The aim of this international consensus procedure was to develop recommendations on the methodology and documentation to be used for assessment of intracranial occlusion and for monitoring of recanalization.

METHODS

Thirty-five experts participated in the consensus process. The presented recommendations were approved during a meeting of the consensus group in October 2008 in Giessen, Germany. The project was an initiative of the German Competence Network Stroke and performed under the auspices of the Neurosonology Research Group of the World Federation of Neurology.

RESULTS

Recommendations are given on how examinations should be performed in the time-limited situation of acute stroke, including criteria to assess the quality of the acoustic bone window, the use of echo contrast agents, and the evaluation of intracranial vessel status. The important issues of the examiners' training and experience, the documentation, and analysis of study results are addressed. One central aspect was the development of standardized criteria for diagnosis of arterial occlusion. A transcranial color-coded duplex sonography recanalization score based on objective hemodynamic criteria is introduced (consensus on grading intracranial flow obstruction [COGIF] score).

CONCLUSIONS

This work presents consensus statements in an attempt to standardize the application of transcranial color-coded duplex sonography in the setting of acute stroke research, aiming to improve the reliability and reproducibility of the results of future stroke studies.

Aggravation of infarct formation by brain swelling in a large territorial stroke: a target for neuroprotection?

OBJECT

In territorial stroke vasogenic edema formation leads to elevated intracranial pressure (ICP) and can cause herniation and death. Brain swelling further impairs collateral blood flow to the ischemic penumbra and causes mechanical damage to adjacent brain structures. In the present study the authors sought to quantify the impact of this space-occupying effect on ischemic lesion formation.

METHODS

Wistar rats were assigned to undergo bilateral craniectomy or a sham operation and then were subjected to temporary middle cerebral artery occlusion (MCAO) for 90 minutes. A clinical evaluation and 7-T MR imaging studies were performed 5 and 24 hours after MCAO. The absolute brain water content was determined at 24 hours by using the wet/dry method.

RESULTS

Bilateral craniectomy before MCAO led to a drastic reduction in lesion volume at both imaging time points (p < 0.0001). Ischemic lesion volume was 2.7- and 2.3-fold larger in sham-operated animals after 5 and 24 hours, respectively. Clinical scores were likewise better in rats that had undergone craniectomy (p < 0.05). After 24 hours the midline shift differed significantly between the 2 groups (p < 0.001), but not after 5 hours. The relation between brain water content and ischemic lesion volume as well as the T2 relaxation time within the infarcted area was not different between the groups (p > 0.05).

CONCLUSIONS

The data indicated that collateral damage caused by the space-occupying effect of a large MCA territory stroke contributes seriously to ischemic lesion formation. The elimination of increased ICP thus must be regarded as a highly neuroprotective measure, rather than only a life-saving procedure to prevent cerebral herniation. Further clinical trials should reveal the neuroprotective potential of surgical and pharmacological ICP-lowering therapeutic approaches.

Midline-shift corresponds to the amount of brain edema early after hemispheric stroke--an MRI study in rats

Vasogenic brain edema formation is a serious complication in hemispheric stroke. Its space-occupying effect can lead to midline-shift (MLS), cerebral herniation, and death. Clinical studies indicate that quantification of MLS can predict cerebral herniation and subsequent death at early time-points, even before clinical deterioration becomes apparent. The present experimental study was designed to determine the relation between MLS, absolute edema volume, lesion size, and clinical findings in a rat stroke model. Middle cerebral artery-occlusion was performed in 24 rats using the suture technique. Clinical evaluation and magnetic resonance imaging (MRI) (Bruker PharmaScan 7.0T) was performed 24 hours later. Lesion volume, the volume-increase within the affected hemisphere (%HEV), and MLS were quantified on T2-weighted images. The absolute increase of hemispheric water content (DeltaH2O) was determined in a subgroup using the wet-dry method (n=12). MLS correlated significantly with the total amount of brain edema (magnetic resonance imaging study: r=0.82; P<0.01; wet-dry analysis r=0.80; P<0.01). MLS correlated only moderately with T2-lesion volume (r=0.55; P<0.01). No significant correlation could be detected between MLS and clinical scores (r=0.26; P>0.05). MLS thus quantitatively reflects the amount of vasogenic brain edema within the affected hemisphere at early time-points. MLS quantification can be regarded as an easily assessable and valid global quantitative parameter for brain edema and thus might facilitate the surgical and nonsurgical management of edema in acute stroke patients.

Third ventricle midline shift due to spontaneous supratentorial intracerebral hemorrhage evaluated by transcranial color-coded sonography

OBJECTIVE

We aimed to assess the clinical usefulness of the third ventricle midline shift (MLS) evaluated by transcranial color-coded sonography (TCCS) in acute spontaneous supratentorial intracerebral hemorrhage (ICH).

METHODS

Consecutive patients with acute (<24 hours after symptom onset) ICH were recruited for this TCCS study. Sonographic measurement of MLS and the pulsatility index (PI) of the middle cerebral arteries were compared with head computed tomographic (CT) data, including MLS, and hematoma volume. Poor functional outcome at 30 days after stroke onset was defined as modified Rankin scale greater than 2.

RESULTS

There were 51 patients with spontaneous supratentorial ICH who received CT and TCCS studies within a 12-hour window. Correlation between MLS by TCCS (mean +/- SD, 3.2 +/- 2.6 mm) and CT (3.0 +/- 2.4 mm) was high (gamma = 0.91; P < .01). There was also a good linear correlation between hematoma volume and MLS by TCCS (gamma = 0.81; P < .01). Compared with ICH volume less than 25 mL, those with greater volume had more severe MLS and a higher PI of the ipsilateral middle cerebral artery (P < .001). Midline shift by TCCS was more sensitive and specific than the PI in detecting large ICH (accuracy = 0.82 if MLS > or = 2.5 mm), and it was also a significant predictor of poor outcome (odds ratio, 2.09 by 1-mm increase; 95% confidence interval, 1.06-4.13).

CONCLUSIONS

Midline shift may be measured reliably by TCCS in spontaneous supratentorial ICH. Our study also showed that MLS on TCCS is a useful and convenient method to identify patients with large ICH and hematoma expansion and to predict short-term functional outcome.

Multiplanar transcranial ultrasound imaging: standards, landmarks and correlation with magnetic resonance imaging

The purpose of this study was to define a standardized multiplanar approach for transcranial ultrasound (US) imaging of brain parenchyma based on matched data from 3-D US and 3-D magnetic resonance imaging (MRI). The potential and limitations of multiple insonation planes in transverse and coronal orientation were evaluated for the visualization of intracranial landmarks in 60 healthy individuals (18 to 83 years old, mean 41.4 years) with sufficient temporal bone windows. Landmarks regularly visualized even in moderate sonographic conditions with identification rates of >75% were mesencephalon, pons, third ventricle, lateral ventricles, falx, thalamus, basal ganglia, pineal gland and temporal lobe. Identification of medulla oblongata, fourth ventricle, cerebellar structures, hippocampus, insula, frontal, parietal and occipital lobes was more difficult (<75%). We hypothesize that multiplanar transcranial US images, with standardized specification of tilt angles and orientation, not only allow comparison with other neuroimaging modalities, but may also provide a more objective framework for US monitoring of cerebral disease than freehand scanning.

Current concepts in neurocritical care

The current concepts in neurocritical care including advancement in therapeutic interventions and monitoring modalities are covered for four entities: stroke, subarachnoid hemorrhage, traumatic brain injury and spinal cord injury. Although therapies were mainly supportive in the past, acute ischemic stroke may now be treated with tissue plasminogen activator if inclusion and exclusion criteria are met. The management of subarachnoid hemorrhage including cerebral vasospasm is discussed in detail. Traumatic brain injury and spinal cord injury with prevention of secondary injury to limit further sequelae are also covered. Medical complications which increase morbidity and mortality are also presented.

Management of large hemispheric strokes in the neurological intensive care unit

BACKGROUND

Patients with large hemispheric strokes frequently develop neurologic deterioration secondary to cerebral edema. Despite supportive care in the intensive care unit and traditional forms of therapy for cerebral edema, they have a high morbidity and mortality. New forms of therapy are being investigated to improve outcome in these patients.

REVIEW SUMMARY

This article begins with a discussion of the clinical and radiologic features of large hemispheric strokes. The role of increased intracranial pressure in neurologic deterioration and the predictors of outcome in these patients are reviewed. The various therapeutic options for management of cerebral edema in these patients, including the role of osmotic therapy, hypothermia, and hemicraniectomy, are explored.

CONCLUSIONS

Neurologic deterioration in patients with large hemispheric strokes necessitates admission to the intensive care unit for management of the airway, blood pressure, and cerebral edema. New promising therapies, such as hemicraniectomy and hypothermia, need to be further evaluated to define their role in the management of these patients.

Intracranial venous hemodynamics in patients with midline dislocation due to postischemic brain edema

BACKGROUND AND PURPOSE

Cerebral venous pressure is governed by intracranial pressure, cerebral perfusion pressure, and venous outflow resistance. Therefore, changes in venous flow velocities are to be expected because of changes in intracranial pressure and brain tissue dislocation in patients with ischemic stroke and space-occupying brain edema.

METHODS

In 21 prospectively recruited patients with middle cerebral artery stroke and postischemic edema, flow velocities in the basal veins, the vein of Galen, the straight sinus, and the P2 segment of the posterior cerebral artery were recorded every 0.9+/-0.5 days during the first 5 days after symptom onset with the use of transcranial color-coded duplex sonography. The midline shift of the third ventricle was determined by B-mode imaging.

RESULTS

We observed an initial increase of flow velocity in the basal vein ipsilateral to the lesion, followed by a significant decrease within 5 days after symptom onset and with increasing midline shift in patients with brain herniation. In the straight sinus, flow velocity showed a biphasic U-shaped response to increasing dislocation of the third ventricle, with an initial decrease followed by an increase in the course of mass movement (midline shift 1 to 1.5 cm). A steep increase of flow velocity in the vein of Galen took place with a midline shift >1.5 cm. In the survivors these changes could not be observed. Flow velocity in the P2 segment of the posterior cerebral artery followed a typical course in neither the fatal cases nor the survivors.

CONCLUSIONS

Monitoring of flow velocities in the basal cerebral veins and in the straight sinus can provide additional pathophysiological information in patients with space-occupying brain edema after acute stroke.

Clinical application of transcranial colour-coded duplex sonography--a review

Transcranial colour-coded duplex sonography (TCCS) is a new and non-invasive ultrasound application that combines both imaging of intracranial vessels and parenchymal structures at a high spatial resolution. This manuscript reviews the clinical applications of TCCS with focus on its diagnostic abilities in acute stroke patients. Furthermore, new experimental imaging techniques are discussed.

Transcranial sonography of brain tumors in the adult: an in vitro and in vivo study

BACKGROUND

Few reports indicate the potential of transcranial sonography (TCS) in detecting human brain tumors.

METHODS

With an Agilent Sonos 2500 ultrasound device, the authors studied 4 brain tumor phantoms and compared the findings with magnetic resonance imaging (MRI). TCS was performed on 40 patients with intracranial tumors in a follow-up design. Sonographic tumor volume and affection of the ventricular system were compared with MRI findings.

RESULTS

The authors found a good correlation between TCS and MRI volumetry in the in vitro study. TCS showed good intraobserver and interobserver reliability. A new volumetric formula for TCS measurement was determined. TCS detection rate of brain tumors in vivo was 40%. When the investigators were given access to radiological findings, the rate of tumor identification was 80%. Despite a sufficient acoustic window, 40% of gliomas grade II and III were not detected. One glioblastoma was not identified owing to an insufficient temporal acoustic window. Tumor volumes measured with MRI and TCS correlated well. MRI volumes exceeded TCS volumes by 41%. In the postoperative examinations (mean = 8 days postoperative, n = 15), the resection cavity was displayed as hyperechogenic. It appeared impossible to differentiate between residual tumor tissue and normal repair mechanisms or blood. In the follow-up examination (mean = 99 days postoperative, n = 15) in 5 patients, neither MRI nor TCS showed tumor regrowth. Ten patients had residual tumors that were detected by sonography.

CONCLUSIONS

The value of TCS for the diagnostics of brain tumors is at present limited. Once the tumor has been identified, sonographic results match well with those of MRI.

Sonographic monitoring of midline shift in space-occupying stroke: an early outcome predictor

BACKGROUND AND PURPOSE

Transcranial color-coded duplex sonography (TCCS) allows bedside imaging of intracranial hemodynamics and parenchymal structures. It provides reliable information regarding midline shift (MLS) in space-occupying hemispheric stroke. We studied the value of MLS measurement to predict fatal outcome at different time points after stroke onset.

METHODS

Forty-two patients with acute, severe hemispheric stroke were enrolled. Cranial computed tomography (CCT) and extracranial duplex sonography were performed on admission. TCCS was carried out 8+/-3, 16+/-3, 24+/-3, 32+/-3, and 40+/-3 hours after stroke onset. Lesion size was determined from follow-up CCT.

RESULTS

Twelve patients died as the result of cerebral herniation (group 1); 28 survived (group 2). Two patients received decompressive hemicraniectomy and were therefore excluded from further evaluation. MLS was significantly higher in group 1 as early as 16 hours after onset of stroke. Specificity and positive predictive values for death caused by cerebral herniation of MLS >/=2.5, 3.5, 4.0, and 5.0 mm after 16, 24, 32, and 40 hours were 1.0.

CONCLUSIONS

TCCS helps to estimate outcome as early as 16 hours after stroke onset and thus facilitates identification of patients who are unlikely to survive without decompressive craniectomy. Because of its noninvasive character and bedside suitability, sonographic monitoring of MLS might be a useful tool in management of critically ill patients who cannot undergo repeated CCT scans.

Transcranial colour-coded sonography for the bedside evaluation of mass effect after stroke

Repeated cranial computerized tomography scan examination in patients with elevated intracranial pressure is time consuming and requires patient transportation. We prospectively evaluated the diagnostic value of transcranial duplex sonography as a bedside tool for detection of the mass effect after space-occupying ischemic stroke and brain haemorrhage and for evaluating the width and dislocation of the ventricular system and the dislocation of brain mid-line structures. We used transcranial duplex sonography in 21 consecutive patients with space-occupying ischemic middle cerebral artery infarction and brain haemorrhage. The transcranial duplex sonography examinations were performed within 2 h before or after corresponding follow-up cranial computerized tomography scans. We measured the third ventricular width as a parameter for infratentorial and the mid-line shift for supratentorial space-occupying effect. In all patients, mid-line structures could be identified by transcranial duplex sonography. Significant third ventricular dilation was found subsequently in most patients with infratentorial mass effect, and mid-line shift occurred in all patients with supratentorial space-occupying lesions, respectively. The mean difference (absolute values) between transcranial duplex sonography and cranial computerized tomography measurements was 0.8 mm for the ventricular width (standard deviation 1 mm) and 1.1 mm for the mid-line shift (standard deviation: 1.46 mm), with a tendency for these parameters to be underestimated at higher values using transcranial duplex sonography. The linear correlation coefficients were R = 0.97 and R = 0.94, respectively. Transcranial duplex sonography appears to be a sufficiently reliable bedside method for evaluating the width and the lateral displacement of the third ventricle, as validated by cranial computerized tomography scan. Thus, it may be suitable for monitoring the space-occupying effect of both supra- and infratentorial strokes during treatment on critical care and stroke units.

Transcranial sonography of the brain parenchyma: comparison of B-mode imaging and tissue harmonic imaging

Transcranial color-coded Duplex sonography (TCCS) has been used for the identification of cerebrovascular disorders. Recently, its value in the diagnosis of disorders of the brain parenchyma has been proposed. The object of this study was to determine systematically the echo pattern of the brain parenchyma and to compare conventional B-mode imaging with tissue harmonic imaging (THI). Transcranial sonography (TCS) was performed in 54 healthy individuals through the temporal bone window using conventional B-mode imaging and THI by two experienced investigators. Identification rates for several brain structures were assessed, and the quality of depiction of each method was graded semiquantitatively. In addition, several parts of the ventricular system and the basal cerebral cisterns were measured. Four subjects did not have an adequate bone window for transcranial examination. In the remaining people, the bone window was assessed to be adequate (59%) or excellent (33%). In the majority (> 80%), TCS allowed an unequivocal identification of various brain structures. Inter-rater variability of the assessments of tissue echogenicity and measurements of the ventricular width were found to be low for several structures (e.g., brainstem, thalamus, or 3rd ventricle). The echo pattern of brain tissue in THI is identical to that described for B-mode imaging. Using THI, contours of brain structures were typically visualized more clearly and the reproducibility of measurements was more consistent. In our experience, insonation of the contralateral lobes was limited when depths were higher than 12 cm using THI. In conclusion, TCS allowed the sonographic examination of the brain parenchyma in the majority of our subjects. THI substantially improves the identification of parenchymal structures when the depth is below 12 cm.