Differentiation between intracerebral hemorrhage and ischemic stroke by transcranial color-coded duplex-sonography

Transcranial Duplex Ultrasound as an Outcome Predictor Tool in Spontaneous Intracerebral Hemorrhage

BACKGROUND

To assess the usefulness of transcranial color-coded duplex (TCCD) ultrasound for monitoring intracerebral hemorrhage (ICH) and to analyze its prognostic predictive performance.

METHODS

Prospective observational study of consecutive patients with spontaneous supratentorial ICH admitted to a stroke unit between 2017 and 2020. Clinical characteristics, ICH volume and midline shift (MLS) measured by computed tomography (CT) and TCCD were recorded at first 24 hours and at 2 and 7 days. ICH volume and MLS were correlated with CT and TCCD. Adjusted logistic regression analyses were performed to determine the association with 3-month dependence/death. A receiver operating characteristic analysis was used to identify the MLS cut-off point with the highest predictive value.

RESULTS

Sixty-five patients were included, 23 (35%) women, with a mean age of 67 (standard deviation 15) years and an National Institutes of Health Stroke Scale on admission of 12 (standard deviation 7). Strong positive correlations were observed between CT and TCCD at 24, 48 hours, and 7 days for ICH volume (r = 0.871, r = 0.839, r = 0.700) and moderate positive correlations for MLS (r = 0.658, r = 0.637, r = 0.593). A higher TCCD-MLS at 48 hours was independently associated with greater mortality and a higher TCCD-ICH volume at 48 hours with poorer functional outcomes. MLS ≥7 mm predicted mortality with a sensitivity of 80% and specificity of 99% (area under the curve 0.924).

CONCLUSIONS

TCCD-ICH volume and MLS could be used as predictive markers for dependency and mortality at three months, respectively. TCCD is a useful tool for monitoring patients with supratentorial ICH; however, these findings should be confirmed with larger studies.

Non-Invasive Monitoring of Cerebral Edema Using Ultrasonic Echo Signal Features and Machine Learning

OBJECTIVES

Cerebral edema, a prevalent consequence of brain injury, is associated with significant mortality and disability. Timely diagnosis and monitoring are crucial for patient prognosis. There is a pressing clinical demand for a real-time, non-invasive cerebral edema monitoring method. Ultrasound methods are prime candidates for such investigations due to their non-invasive nature.

METHODS

Acute cerebral edema was introduced in rats by permanently occluding the left middle cerebral artery (MCA). Ultrasonic echo signals were collected at nine time points over a 24 h period to extract features from both the time and frequency domains. Concurrently, histomorphological changes were examined. We utilized support vector machine (SVM), logistic regression (LogR), decision tree (DT), and random forest (RF) algorithms for classifying cerebral edema types, and SVM, RF, linear regression (LR), and feedforward neural network (FNNs) for predicting the cerebral infarction volume ratio.

RESULTS

The integration of 16 ultrasonic features associated with cerebral edema development with the RF model enabled effective classification of cerebral edema types, with a high accuracy rate of 97.9%. Additionally, it provided an accurate prediction of the cerebral infarction volume ratio, with an R2 value of 0.8814.

CONCLUSIONS

Our proposed strategy classifies cerebral edema and predicts the cerebral infarction volume ratio with satisfactory precision. The fusion of ultrasound echo features with machine learning presents a promising non-invasive approach for the monitoring of cerebral edema.

Transcranial Ultrasound in the Neurocritical Care Unit

Ultrasound evaluation of the brain is performed through acoustic windows. Transcranial Doppler has long been used to monitor patients with subarachnoid hemorrhage for cerebral vasospasm. Transcranial color-coded sonography permits parenchymal B-mode imaging and duplex evaluation. Transcranial ultrasound may also be used to assess the risk of delayed cerebral ischemia, screen patients for the presence of elevated intracranial pressure, confirm the diagnosis of brain death, measure midline shift, and detect ventriculomegaly. Transcranial ultrasound should be integrated with other point-of-care ultrasound techniques as an essential skill for the neurointensivist.

Prehospital identification of intracerebral haemorrhage: a scoping review of early clinical features and portable devices

INTRODUCTION

Prehospital identification of intracerebral haemorrhage (ICH) in suspected stroke cases may enable the initiation of appropriate treatments and facilitate better-informed transport decisions. This scoping review aims to examine the literature to identify early clinical features and portable devices for the detection of ICH in the prehospital setting.

METHODS

Three databases were searched via Ovid (MEDLINE, EMBASE and CENTRAL) from inception to August 2022 using prespecified search strategies. One reviewer screened all titles, abstracts and full-text articles for eligibility, while a second reviewer independently screened 20% of the literature during each screening stage. Data extracted were tabulated to summarise the key findings.

RESULTS

A total of 6803 articles were screened for eligibility, of which 22 studies were included for analysis. Among them, 15 studies reported on early clinical features, while 7 considered portable devices. Associations between age, sex and comorbidities with the presence of ICH varied across studies. However, most studies reported that patients with ICH exhibited more severe neurological deficits (n=6) and higher blood pressure levels (n=11) at onset compared with other stroke and non-stroke diagnoses. Four technologies were identified for ICH detection: microwave imaging technology, volumetric impedance phase shift spectroscopy, transcranial ultrasound and electroencephalography. Microwave and ultrasound imaging techniques showed promise in distinguishing ICH from other diagnoses.

CONCLUSION

This scoping review has identified potential clinical features for the identification of ICH in suspected stroke patients. However, the considerable heterogeneity among the included studies precludes meta-analysis of available data. Moreover, we have explored portable devices to enhance ICH identification. While these devices have shown promise in detecting ICH, further technological development is required to distinguish between stroke subtypes (ICH vs ischaemic stroke) and non-stroke diagnoses.

Transcranial sonography in the critical patient

Transcranial ultrasonography is a non-invasive, bedside technique that has become a widely implemented tool in the evaluation and management of neurocritically ill patients. It constitutes a technique in continuous growth whose fundamentals (and limitations) must be known by the intensivist. This review provides a practical approach for the intensivist, including the different sonographic windows and planes of insonation and its role in different conditions of the neurocritical patients and in critical care patients of other etiologies.

Role of point-of-care ultrasound in critical care and emergency medicine: update and future perspective

Point-of-care ultrasound (POCUS) is a rapidly developing technology that has the potential to revolutionize emergency and critical care medicine. The use of POCUS can improve patient care by providing real-time clinical information. However, appropriate usage and proper training are crucial to ensure patient safety and reliability. This article discusses the various applications of POCUS in emergency and critical care medicine, the importance of training and education, and the future of POCUS in medicine.

Transcranial ultrasonography to detect intracranial pathology: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Transcranial ultrasonography (TCU) can be a useful diagnostic tool in evaluating intracranial pathology in patients with limited or delayed access to routine neuroimaging in critical care or austere settings. We reviewed available literature investigating the diagnostic utility of TCU for detecting pediatric and adult patient's intracranial pathology in patients with intact skulls and reported diagnostic accuracy measures.

METHODS

We performed a systematic review of PubMed^® , Cochrane Library, Embase^® , Scopus^® , Web of Science™, and Cumulative Index to Nursing and Allied Health Literature databases to identify articles evaluating ultrasound-based detection of intracranial pathology in comparison to routine imaging using broad Medical Subject Heading sets. Two independent reviewers reviewed the retrieved articles for bias using the Quality Assessment of Diagnostic Accuracy Studies tools and extracted measures of diagnostic accuracy and ultrasound parameters. Data were pooled using meta-analysis implementing a random-effects approach to examine the sensitivity, specificity, and accuracy of ultrasound-based diagnosis.

RESULTS

A total of 44 studies out of the 3432 articles screened met the eligibility criteria, totaling 2426 patients (Mean age: 60.1 ± 14.52 years). We found tumors, intracranial hemorrhage (ICH), and neurodegenerative diseases in the eligible studies. Sensitivity, specificity, and accuracy of TCU and their 95% confidence intervals were 0.80 (0.72, 0.89), 0.71 (0.59, 0.82), and 0.76 (0.71, 0.82) for neurodegenerative diseases; 0.88 (0.74, 1.02), 0.81 (0.50, 1.12), and 0.94 (0.92, 0.96) for ICH; and 0.97 (0.92, 1.03), 0.99 (0.96, 1.01), and 0.99 (0.97, 1.01) for intracranial masses. No studies reported ultrasound presets.

CONCLUSIONS

TCU has a reasonable sensitivity and specificity for detecting intracranial pathology involving ICH and tumors with clinical applications in remote locations or where standard imaging is unavailable. Future studies should investigate ultrasound parameters to enhance diagnostic accuracy in diagnosing intracranial pathology.

Exploratory study to assess feasibility of intracerebral hemorrhage detection by point of care cranial ultrasound

Background

Limited studies have evaluated the use of ultrasound for detection of intracerebral hemorrhage (ICH) using diagnostic ultrasound Transcranial Doppler machines in adults. The feasibility of ICH detection using Point of care Ultrasound (POCUS) machines has not been explored. We evaluated the feasibility of using cranial POCUS B mode imaging performed using intensive care unit (ICU) POCUS device for ICH detection with a secondary goal of mapping optimal imaging technique and brain topography likely to affect sensitivity and specificity of ICH detection with POCUS.

Materials and methods

After obtaining IRB approval, a blinded investigator performed cranial ultrasound (Fujifilm, Sonosite^® Xporte, transcranial and abdominal presets) through temporal windows on 11 patients with intracerebral pathology within 72 h of last CT/MRI (computed tomography scan/magnetic resonance imaging) brain after being admitted to a neurocritical care unit in Aug 2020 and Nov 2020–Mar 2021. Images were then compared to patient’s CT/MRI to inform topography. Inferential statistics were reported.

Results

Mean age was 57 (28–77 years) and 6/11 were female. Six patients were diagnosed with ICH, 3 with ischemic stroke, 1 subarachnoid hemorrhage, and 1 brain tumor. The sensitivity and specificity of point of care diagnosis of ICH compared to CT/MRI brain was 100% and 50%, respectively. Mean time between ultrasound scan and CT/MRI was 13.3 h (21 min–39 h). Falx cerebri, choroid calcification and midbrain-related artifacts were the most reproducible hyperechoic signals. Abdominal preset on high gain yielded less artifact than Transcranial Doppler preset for cranial B mode imaging. False positive ICH diagnosis was attributed to intracerebral tumor and midbrain-related artifact.

Conclusions

Our exploratory analysis yielded preliminary data on use of point of care cranial ultrasound for ICH diagnosis to inform imaging techniques, cranial topography on B mode and sample size estimation for future studies to evaluate sensitivity and specificity of cranial POCUS in adult patients. This pilot study is limited by small sample size and over representation of ICH in the study. Cranial POCUS is feasible using POCUS machines and may have potential as a screening tool if validated in adequately powered studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13089-022-00289-z.

Ultrasound in postresuscitation care: a narrative review

The efficacy of ultrasound (US) in real-time differential diagnosis and guiding further treatment decisions has been well demonstrated in prearrest conditions and during resuscitation. Evidence is limited regarding the application of US in postresuscitation care. Most of the patients following resuscitation remain comatose, and the requirement for transportation to other examination rooms increases their risk of injury. US can be performed at the bedside with high accessibility and timeliness without radiation. This narrative review provides an overview of current evidence regarding the application of US in identifying the cause of cardiac arrest (CA), hemodynamic monitoring, and prognostication in postresuscitation care. For identifying the cause of CA, cardiac US is mainly used to detect regional wall motion abnormality. However, postarrest myocardial dysfunction would confound the sonographic findings that a combination of electrocardiograms and biomarkers besides the cardiac US could improve the positive predictive value of coronary artery disease. For hemodynamic monitoring, left ventricular outlet tract velocity time integral has the best performance in predicting fluid responsiveness in conjunction with the passive leg raising test. The RUSH protocol assists in determining the subtypes of shock with high sensitivity and specificity in hypovolemic, cardiogenic, or obstructive shock. Evidence regarding the application of US for prognostication is still limited, and further evaluation should be needed.

Factors affecting transtemporal window quality in transcranial sonography

OBJECTIVE

To assess the influencing factors of transtemporal window quality and identify patients suitable for transcranial sonography (TCS) examination in two-dimensional imaging.

METHODS

In this cross-sectional study, TCS was performed in 161 consecutive patients through the temporal bone window (TBW) in the neurology or neurosurgery department. Each patient's sex, age, height, weight, and temporal bone thickness (TBT) were collected. After examination, the patients were divided into two groups: TBW success and TBW failure. The data were statistically compared between the two groups.

RESULTS

Among the studied population, the total TBW success rate was 80.1% (95% confidence interval [CI]: 74-86). The TBW success rate was 91.4% (95% CI: 85-98) in males and 70.9% (95% CI: 61-81) in females (p = .001). Sex (p = .001), age (p = .002), height (p = .047), and TBT (p < .001) showed significant differences between the TBW success and failure groups. In males, only TBT (p = .001) showed a significant difference; in females, age (p < .001) and TBT (p = .003) showed a significant difference. The area under the receiver operating characteristic curve (AUC) of sex, age, and TBT and their combination was 0.686, 0.659, 0.842, and 0.922 (p < .001), respectively. The AUC of the combination of parameters was significantly greater than that of age and sex alone (p = .007; p = .0002) but not greater than that of TBT (p = .090).

CONCLUSIONS

The TBW success rate varied with sex, age, height, and TBT. Males, younger patients, taller patients, and patients with a thinner temporal bone tended to be more suitable for the examination by TCS.

Brain topography on adult ultrasound images: Techniques, interpretation, and image library

BACKGROUND AND PURPOSE

Many studies have explored the possibility of using cranial ultrasound for discerning intracranial pathologies like tumors, hemorrhagic stroke, or subdural hemorrhage in clinical scenarios where computer tomography may not be accessible or feasible. The visualization of intracranial anatomy on B-mode ultrasound is challenging due to the presence of the skull that limits insonation to a few segments on the temporal bone that are thin enough to allow transcranial transmission of sound. Several artifacts are produced by hyperechoic signals inherent in brain and skull anatomy when images are created using temporal windows.

METHODS

While the literature has investigated the accuracy of diagnosis of intracranial pathology with ultrasound, we lack a reference source for images acquired on cranial topography on B-mode ultrasound to illustrate the appearance of normal and abnormal structures of the brain and skull. Two investigators underwent hands-on training in Cranial point-of-care ultrasound (c-POCUS) and acquired multiple images from each patient to obtain the most in-depth images of brain to investigate all visible anatomical structures and pathology within 24 hours of any CT/MRI imaging done.

RESULTS

Most reproducible structures visible on c-POCUS included bony parts and parenchymal structures. Transcranial and abdominal presets were equivalent in elucidating anatomical structures. Brain pathology like parenchymal hemorrhage, cerebral edema, and hydrocephalus were also visualized.

CONCLUSIONS

We present an illustrated anatomical atlas of cranial ultrasound B-mode images acquired in various pathologies in a critical care environment and compare our findings with published literature by performing a scoping review of literature on the subject.

Differentiation Between Ischemic and Hemorrhagic Strokes - A Pilot Study with Transtemporal Investigation of Brain Parenchyma Elasticity Using Ultrasound Shear Wave Elastography

INTRODUCTION

 Ultrasound shear wave elastography is well established in diagnostics of several parenchymatous organs and is recommended by respective guidelines. So far, research about applications in relevant neurological conditions is missing, especially in adults. Here we aimed to examine the method for the differentiation of ischemic (IS) and hemorrhagic strokes (HS) and cerebral mass effects.

MATERIALS & METHODS

 50 patients with a confirmed diagnosis of HS or IS were enrolled in this prospective study. 2D shear wave elastography was performed on the ipsilateral and the contralateral side with a modified acoustic radiation force impulse (ARFI) technique (ElastPQ mode, Philips). Lesion volumetry was conducted based on computed tomography data for correlation with elastography results.

RESULTS

 Elastography measurements (EM) revealed a highly significant difference between IS and HS with mean values of 1.94 and 5.50 kPa, respectively (p < 0.00 001). Mean values of brain tissue on the non-affected side were almost identical (IS 3.38 (SD = 0.63); HS 3.35 (SD = 0.66); p = 0.91). With a sensitivity of 0.98 and a specificity of 0.99, a cut-off value of 3.52 kPa for discrimination could be calculated. There was a significant correlation of mass effect represented by midline shift and EM values on the contralateral side (Pearson correlation coefficient = 0.68, p < 0.0003).

CONCLUSION

 Ultrasound brain parenchyma elastography seems to be a reliable sonographic method for discriminating between large IS and HS and for detecting and tracking conditions of intracerebral mass effects.

Diagnostic value of transcranial ultrasonography for selecting subjects with large vessel occlusion: a systematic review

Introduction

A number of pre-hospital clinical assessment tools have been developed to triage subjects with acute stroke due to large vessel occlusion (LVO) to a specialised endovascular centre, but their false negative rates remain high leading to inappropriate and costly emergency transfers. Transcranial ultrasonography may represent a valuable pre-hospital tool for selecting patients with LVO who could benefit from rapid transfer to a dedicated centre.

Methods

Diagnostic accuracy of transcranial ultrasonography in acute stroke was subjected to systematic review. Medline, Embase, PubMed, Scopus, and The Cochrane Library were searched. Published articles reporting diagnostic accuracy of transcranial ultrasonography in comparison to a reference imaging method were selected. Studies reporting estimates of diagnostic accuracy were included in the meta-analysis.

Results

Twenty-seven published articles were selected for the systematic review. Transcranial Doppler findings, such as absent or diminished blood flow signal in a major cerebral artery and asymmetry index ≥ 21% were shown to be suggestive of LVO. It demonstrated sensitivity ranging from 68 to 100% and specificity of 78–99% for detecting acute steno-occlusive lesions. Area under the receiver operating characteristics curve was 0.91. Transcranial ultrasonography can also detect haemorrhagic foci, however, its application is largely restricted by lesion location.

Conclusions

Transcranial ultrasonography might potentially be used for the selection of subjects with acute LVO, to help streamline patient care and allow direct transfer to specialised endovascular centres. It can also assist in detecting haemorrhagic lesions in some cases, however, its applicability here is largely restricted. Additional research should optimize the scanning technique. Further work is required to demonstrate whether this diagnostic approach, possibly combined with clinical assessment, could be used at the pre-hospital stage to justify direct transfer to a regional thrombectomy centre in suitable cases.

Transcranial Color-Coded Sonography for the Detection of Cerebral Veins and Sinuses and Diagnosis of Cerebral Venous Sinus Thrombosis

This study aimed to determine the detection rate of transcranial color-coded sonography (TCCS) of cerebral veins and sinuses and to explore the diagnostic accuracy of TCCS for straight sinus (SS) and transverse sinus (TS) thromboses. The detection rates of cerebral veins and sinuses using TCCS and contrast-enhanced TCCS (CE-TCCS) were analyzed. The diagnostic accuracy of CE-TCCS was evaluated. Median time from symptoms to CE-TCCS was 10 (range, 1-150) d. The detection rate of bilateral basal veins of Rosenthal was 100% by CE-TCCS, followed by right TS (91.89%), SS (88.12%), left TS (74.59%) and vein of Galen (70.27%). Compared with magnetic resonance imaging/magnetic resonance venography, CE-TCCS showed 100% sensitivity and 96.3% specificity for SS thrombosis, 100% and 100% for right TS thrombosis and 100% and 94.4% for left TS thrombosis. In conclusion, CE-TCCS shows high identification rates of cerebral veins and sinuses and a high diagnostic accuracy for SS and TS thrombosis.

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.

Telesonography in emergency medicine: A systematic review

Ultrasound is an efficacious, versatile and affordable imaging technique in emergencies, but has limited utility without expert interpretation. Telesonography, in which experts may remotely support the use of ultrasound through a telecommunications link, may broaden access to ultrasound and improve patient outcomes, particularly in remote settings. This review assesses the literature regarding telesonography in emergency medicine, focussing on evidence of feasibility, diagnostic accuracy and clinical utility. A systematic search was performed for articles published from 1946 to February 2017 using the Cochrane, Medline, EMBASE, and CINAHL databases. Further searches utilising Scopus, Google Scholar, and citation lists were conducted. 4388 titles were identified and screened against inclusion criteria which resulted in the inclusion of 28 papers. These included feasibility, diagnostic accuracy and clinical pilot studies. Study design, methodology and quality were heterogeneous. There was good evidence of feasibility from multiple studies. Where sufficient bandwidth and high quality components were used, diagnostic accuracy was slightly reduced by image transmission. There was evidence of clinical utility in remote hospitals and low-resource settings, although reliability was infrequently reported. Further exploratory research is required to determine minimum requirements for image quality, bandwidth, frame rate and to assess diagnostic accuracy. Clinical trials in remote settings are justifiable. Telecommunication options will depend on local requirements; no one system conveys universal advantages. The methodological quality of research in this field must improve: studies should be designed to minimise bias, and must include details of their methods to allow replication. Analysis of cost effectiveness and sustainability should be provided.

Clinical characteristics and outcomes of patients with stroke admitted to three tertiary hospitals in Zimbabwe: A retrospective one-year study

BACKGROUND

Epidemiological data on stroke in Zimbabwe are scarce and few clinical studies have been performed to date.

METHODS

A retrospective review of the medical records of patients admitted for stroke during the year 2012 was performed at three tertiary hospitals. Sociodemographic data were recorded alongside with comorbidities and outcomes. Scoping over a period of one year using records of patients admitted for stroke helped to quantify and qualify the stroke problem. Descriptive analysis was done using STATA version 13.0.

RESULTS

A total of 450 stroke cases, (63% women) were included in the final analysis. The proportion of stroke cases among the admissions was 0.61%. Mean age of the stroke patients was 61.6±16.8 years (95% CI=60.1; 63.2). Risk factors were hypertension (58.5%), diabetes (18%) and HIV, (14%)). Diagnosis was clinical and 39.4% had a CT scan. Mean length of hospital stay was 8.1±5.6 days with a significance difference noted among hospitals (p<0.001). In-hospital mortality was 24.9%, 95% CI (20.9; 29.0%). Mortality was associated with place of admission (p<0.001). Gender and side of stroke were significantly associated (p<0.001).

CONCLUSIONS

The sociodemographic characteristics mirrored findings from elsewhere. Mean age was higher than reported for Zimbabwe in the nineties and lately for Malawi. Majority of patients were female, elderly and hypertensive in line with findings from other countries. Presence of HIV is supported by recent studies from Malawi and South Africa. The relationship between gender and side affected needs further research. There is need to standardise acute care through proper diagnosis to reduce mortality. There is need to support caregivers post-discharge. Data-handling is poor and there is limited capacity for Sub Saharan Africa hospitals to provide optimal stroke care. This may have long term implications on the outcome of survivors and caregivers. There is need of vigilance in acute stroke care.

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.

Combining transcranial ultrasound with intelligent communication methods to enhance the remote assessment and management of stroke patients: Framework for a technology demonstrator

With over 150,000 strokes in the United Kingdom every year, and more than 1 million living survivors, stroke is the third most common cause of death and the leading cause of severe physical disability among adults. A major challenge in administering timely treatment is determining whether the stroke is due to vascular blockage (ischaemic) or haemorrhage. For patients with ischaemic stroke, thrombolysis (i.e. pharmacological ‘clot-busting’) can improve outcomes when delivered swiftly after onset, and current National Health Service Quality Improvement Scotland guidelines are for thrombolytic therapy to be provided to at least 80 per cent of eligible patients within 60 min of arrival at hospital. Thrombolysis in haemorrhagic stroke could severely compound the brain damage, so administration of thrombolytic therapy currently requires near-immediate care in a hospital, rapid consultation with a physician and access to imaging services (X-ray computed tomography or magnetic resonance imaging) and intensive care services. This is near impossible in remote and rural areas, and stroke mortality rates in Scotland are 50 per cent higher than in London. We here describe our current project developing a technology demonstrator with ultrasound imaging linked to an intelligent, multi-channel communication device − connecting to multiple 2G/3G/4G networks and/or satellites − in order to stream live ultrasound images, video and two-way audio streams to hospital-based specialists who can guide and advise ambulance clinicians regarding diagnosis. With portable ultrasound machines located in ambulances or general practices, use of such technology is not confined to stroke, although this is our current focus. Ultrasound assessment is useful in many other immediate care situations, suggesting potential wider applicability for this remote support system. Although our research programme is driven by rural need, the ideas are potentially applicable to urban areas where access to imaging and definitive treatment can be restricted by a range of operational factors.

Transcranial doppler and near infrared spectroscopy in the perioperative period

PURPOSE OF REVIEW

Maintenance of adequate blood flow and oxygen to the brain is one of the principal endpoints of all surgery and anesthesia. During operations in general anesthesia, however, the brain is at particular risk for silent ischemia. Despite this risk, the brain still remains one of the last monitored organs in clincial anesthesiology.

RECENT FINDINGS

Transcranial Doppler (TCD) sonography and near-infrared spectroscopy (NIRS) experience a revival as these noninvasive technologies help to detect silent cerebral ischemia. TCD allows for quantification of blood flow velocities in basal intracranial arteries. TCD-derived variables such as the pulsatility index might hint toward diminished cognitive reserve or raised intracranial pressure. NIRS allows for assessment of regional cerebral oxygenation. Monitoring should be performed during high-risk surgery for silent cerebral ischemia and special circumstances during critical care medicine. Both techniques allow for the assessment of cerebrovascular autoregulation and individualized management of cerebral hemodynamics.

SUMMARY

TCD and NIRS are noninvasive monitors that anesthesiologists apply to tailor cerebral oxygen delivery, aiming to safeguard brain function in the perioperative period.

Prediction and observation of post-admission hematoma expansion in patients with intracerebral hemorrhage

Post-admission hematoma expansion in patients with intracerebral hemorrhage (ICH) comprises a simultaneous major clinical problem and a possible target for medical intervention. In any case, the ability to predict and observe hematoma expansion is of great clinical importance. We review radiological concepts in predicting and observing post-admission hematoma expansion. Hematoma expansion can be observed within the first 24 h after symptom onset, but predominantly occurs in the early hours. Thus capturing markers of on-going bleeding on imaging techniques could predict hematoma expansion. The spot sign observed on computed tomography angiography is believed to represent on-going bleeding and is to date the most well investigated and reliable radiological predictor of hematoma expansion as well as functional outcome and mortality. On non-contrast CT, the presence of foci of hypoattenuation within the hematoma along with the hematoma-size is reported to be predictive of hematoma expansion and outcome. Because patients tend to arrive earlier to the hospital, a larger fraction of acute ICH-patients must be expected to undergo hematoma expansion. This renders observation and radiological follow-up investigations increasingly relevant. Transcranial duplex sonography has in recent years proven to be able to estimate hematoma volume with good precision and could be a valuable tool in bedside serial observation of acute ICH-patients. Future studies will elucidate, if better prediction and observation of post-admission hematoma expansion can help select patients, who will benefit from hemostatic treatment.

Echography in brain imaging in intensive care unit: State of the art

Transcranial sonography (TCS) is an ultrasound-based imaging technique, which allows the identification of several structures within the brain parenchyma. In the past it has been applied for bedside assessment of different intracranial pathologies in children. Presently, TCS is also used on adult patients to diagnose intracranial space occupying lesions of various origins, intracranial hemorrhage, hydrocephalus, midline shift and neurodegenerative movement disorders, in both acute and chronic clinical settings. In comparison with conventional neuroimaging methods (such as computed tomography or magnetic resonance), TCS has the advantages of low costs, short investigation times, repeatability, and bedside availability. These noninvasive characteristics, together with the possibility of offering a continuous patient neuro-monitoring system, determine its applicability in the monitoring of multiple emergency and non-emergency settings. Currently, TCS is a still underestimated imaging modality that requires a wider diffusion and a qualified training process. In this review we focused on the main indications of TCS for the assessment of acute neurologic disorders in intensive care unit.

Ultrasound-based imaging in neurocritical care patients: a review of clinical applications

OBJECTIVE

To analyze the diagnostic, monitoring, and procedural applications of ultrasound (US) imaging in neurocritical care (NCC) patients.

METHOD

US imaging has been extensively validated in various subset of critically ill patients, but not specifically in the NCC population. We reviewed the clinical applications of US imaging for heart, vascular, brain, and lung evaluation and for possible procedural uses in NCC patients. Major neurosurgical books, journals, testimonials, authors' personal experience, and scientific databases were analyzed.

RESULTS

Cardiac US imaging provides accurate information at NCC arrival to stratify risk factors, including presence of atrial septal defect/patent formen ovale, abnormal ventricular function, or pericardial effusion, and to monitor cardiac anatomy and function during the NCC stay for guiding goal-directed therapy. Vascular US in NCC patients has three especially relevant indications: to screen anatomy and flow in extracranial supra-aortic arteries, to diagnose deep vein thrombosis, and to optimize the safety of central venous catheterization. Brain US has important clinical applications in the NCC, including transcranial Doppler and emerging techniques for cerebral blood flow evaluation with contrast-enhanced US imaging. Lung US, as demonstrated in other intensive care unit patients, provides accurate diagnosis of anatomical and functional abnormalities and enables diagnosis of pleural effusion, pneumothorax, lung consolidation, pulmonary abscess and interstitial-alveolar syndrome, and lung recruitment/derecruitment. US imaging can effectively guide percutaneous tracheostomy.

CONCLUSION

In conclusion, US imaging is an important diagnostic tool that provides real-time information at the bedside to stratify risk, monitor for complications, and guide invasive procedures in NCC patients.

Usefulness of transcranial echography in patients with decompressive craniectomy: a comparison with computed tomography scan

OBJECTIVE

To assess the agreement between computed tomography and transcranial sonography in patients after decompressive craniectomy.

DESIGN

Prospective study.

SETTING

The medical intensive care unit of a university-affiliated teaching hospital.

PATIENTS

Thirty head-injured patients consecutively admitted to the intensive care unit of "A. Gemelli" Hospital who underwent decompressive craniectomy were studied. Immediately before brain cranial tomography, transcranial ultrasonography was performed.

MEASUREMENTS AND MAIN RESULTS

The mean difference between computed tomography and echography in measuring the dislocation of midline structures was 0.3 ± 1.6 mm (95% confidence interval 0.2-0.9 mm; intraclass correlation coefficient, 0.979; p < .01). An excellent correlation was found between computed tomography and transcranial sonography in assessing volumes of hyperdense lesions (intraclass correlation coefficient, 0.993; p < .01). Lesions that appear hypodense on computed tomography scan were divided in ischemic and late hemorrhagic. No ischemic lesion was localized on echography; a poor correlation was found between computed tomography and echography in assessing the volume of late hemorrhagic lesions (intraclass correlation coefficient, 0.151; p = .53). A quite good correlation between transcranial ultrasonography and computed tomography was found in measuring lateral ventricles width (intraclass correlation coefficient, 0.967; p < .01). Sensitivity and specificity of transcranial ultrasonography in comparison with computed tomography to detect the position of intracranial pressure catheter was 100% and 78%.

CONCLUSIONS

Echography may be a valid option to computed tomography in patients with decompressive craniectomy to assess the size of acute hemorrhagic lesions, to measure midline structures and the width of lateral ventricles, and to visualize the tip of the ventricular catheter.

Impaired Cerebral Autoregulation in a Case of Severe Acute Encephalitis

The status of cerebral autoregulation (CA) is an important prognostic factor for acute head trauma, but the role of CA in patients with acute encephalitis has not been previously discussed. We present the case of a 30-year-old woman with severe acute encephalitis who underwent craniectomy for intractable increased intracranial pressure (ICP). Preoperatively, adjustments of blood pressure (BP) with simultaneous recording of changes in cerebral blood flow velocity with transcranial Doppler indicated increased ICP and impaired CA. Postoperatively, ICP declined remarkably but CA remained impaired when the relationship between spontaneous fluctuation of mean BP and ICP was analyzed. Increased ICP recurred again within 24 hours of the decompression surgery and caused death of the patient. We propose that evaluating the status of CA could be of prognostic importance in patients with severe encephalitis.

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.

Management of Ischemic Stroke in the Next Decade: Stroke Centers of Excellence

Stroke has been increasingly recognized as an important and expensive medical and societal problem during the past 10 years. Currently, organized stroke care is delivered to the American population in only a few cities and hospitals that provide an efficient system for rapid transportation, diagnosis, treatment, and rehabilitation. The Brain Attack Coalition (BAC) has recently proposed the concepts of stroke centers of excellence (akin to trauma level I centers), primary stroke centers, and comprehensive stroke center. The U.S. government, with the Paul Coverdell National Acute Stroke Registry and the Stroke Treatment and Ongoing Prevention Act of 2003, further supports these concepts. Herein, a discussion of the influence that the BAC, the Paul Coverdell National Acute Stroke Registry, and the Stroke Treatment and Ongoing Prevention Acts of 2001 and 2003 will have on the future of stroke therapy in this country during the next 10 years is presented. Also discussed are the elements that are crucial to organized stroke care and the formation of stroke centers of excellence. These include triage and diagnosis in the field, transportation, triage and imaging in the emergency department, prompt transfer to a dedicated stroke unit with focused care, rehabilitation, manpower, prevention and research, reimbursement issues, and politics. The importance of multidisciplinary collaboration on the professional and societal levels and, finally, government- and private sector-sponsored research are also presented.

Cerebral Angiography in the Assessment of Acute Cerebral Ischemia: Guidelines and Recommendations

Catheter-based cerebral angiography remains an essential tool for evaluating patients with acute cerebral ischemia. Noninvasive vascular imaging techniques have yet to achieve the accuracy and wide availability necessary for this purpose. Angiography is rarely indicated when patients present within the short 3-hour time window for treatment with intravenous alteplase. For the many patients who present later in their course, however, angiography is useful for the accurate evaluation of the cerebral vasculature. In addition, angiography serves as the foundation for the endovascular therapies that may be performed to treat acute ischemic stroke beyond the 3-hour time window.

Sonographic imaging of foramen ovale electrodes

OBJECTIVE

In patients with medically intractable partial epilepsy of mesiotemporal origin, video electroencephalographic monitoring with foramen ovale electrodes is necessary to plan neurosurgical interventions. Imaging of these electrodes after implantation hitherto required conventional radiography, magnetic resonance imaging, or computed tomography of the skull. These methods are expensive. Therefore, the aim of our work was to show the capability of more cost-effective transcranial B-mode sonography for visualization of the electrodes.

METHODS

In this pilot study, a 42-year-old female patient with implanted foramen ovale electrodes was examined transtemporally with a 2-MHz sector transducer to visualize the intracranially implanted electroencephalographic recording device.

RESULTS

Foramen ovale electrodes could be detected easily in the patient, and bedside monitoring of explantation was possible.

CONCLUSIONS

We were able to show the applicability of transcranial B-mode sonography for visualization of foramen ovale electrodes in preoperative electroencephalographic monitoring of patients with epilepsy. Further evaluation of this method in additional patients will follow.

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 color Doppler sonography in the emergency diagnosis of middle cerebral artery occlusion in a patient after head injury

The purpose of this report is to highlight the utility of transcranial color Doppler sonography (TCCDS) in the emergency diagnosis of an ischemic stroke in a 64-year-old patient after head injury. An emergency CT identified a subdural hematoma, subarachnoid hemorrhage, a brain contusion and edema. The patient's status deteriorated after admission, and a second CT revealed an intracerebral hematoma and marked mass effect. Transcranial color sonography revealed no flow in the ipsilateral middle and anterior cerebral arteries, which was consistent with ischemic stroke. This case demonstrates that transcranial color Doppler sonography performed early after head injury may be useful in detecting associated occlusion of cerebral vessels.