Imaging of spontaneous intracerebral hemorrhages by means of transcranial color-coded 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.

Unveiling the potential of ultrasound in brain imaging: Innovations, challenges, and prospects

Within medical imaging, ultrasound serves as a crucial tool, particularly in the realms of brain imaging and disease diagnosis. It offers superior safety, speed, and wider applicability compared to Magnetic Resonance Imaging (MRI) and X-ray Computed Tomography (CT). Nonetheless, conventional transcranial ultrasound applications in adult brain imaging face challenges stemming from the significant acoustic impedance contrast between the skull bone and soft tissues. Recent strides in ultrasound technology encompass a spectrum of advancements spanning tissue structural imaging, blood flow imaging, functional imaging, and image enhancement techniques. Structural imaging methods include traditional transcranial ultrasound techniques and ultrasound elastography. Transcranial ultrasound assesses the structure and function of the skull and brain, while ultrasound elastography evaluates the elasticity of brain tissue. Blood flow imaging includes traditional transcranial Doppler (TCD), ultrafast Doppler (UfD), contrast-enhanced ultrasound (CEUS), and ultrasound localization microscopy (ULM), which can be used to evaluate the velocity, direction, and perfusion of cerebral blood flow. Functional ultrasound imaging (fUS) detects changes in cerebral blood flow to create images of brain activity. Image enhancement techniques include full waveform inversion (FWI) and phase aberration correction techniques, focusing on more accurate localization and analysis of brain structures, achieving more precise and reliable brain imaging results. These methods have been extensively studied in clinical animal models, neonates, and adults, showing significant potential in brain tissue structural imaging, cerebral hemodynamics monitoring, and brain disease diagnosis. They represent current hotspots and focal points of ultrasound medical research. This review provides a comprehensive summary of recent developments in brain imaging technologies and methods, discussing their advantages, limitations, and future trends, offering insights into their prospects.

Transcranial Doppler versus CT angiography: a comparative analysis for the diagnosis of ischaemic cerebrovascular disease

AIMS

To compare the sensitivity, specificity, accuracy, and clinical usefulness of transcranial Doppler (TCD) ultrasound against computed tomography angiography (CTA) for the diagnosis of ischaemic cerebrovascular disease.

METHODS

A total of 1,183 sites (vascular segments) of 169 patients who had been diagnosed with cerebrovascular disease using digital subtraction angiography (DSA) were evaluated by CTA and TCD for the diagnosis of the arterial lesions.

RESULTS

Lesions were identified in 509 sites and 674 sites did not have lesions according to the DSA examination. Each individual site had higher sensitivity, specificity, and accuracy for TCD than those for CTA, respectively. For all sites, TCD had higher true-positive (p=0.0029) and -negative (p=0.0151) values and fewer false-positive and -negative (p<0.0001 for both) values than those of CTA. The sensitivity, specificity, and accuracy of CTA for all sites to detect lesions were 77%, 88%, and 84%, respectively. The same parameters for TCD were 94%, 97%, and 95%, respectively. The beneficial scores for CTA and TCD to detect lesions were 0-0.795 diagnostic confidence and 0-0.91 diagnostic confidence, respectively. Beneficial scores >0.795 and >0.91 indicated a risk of underdiagnosis of lesions at CTA and TCD, respectively.

CONCLUSIONS

Compared with DSA (reference standard) and CTA, the study underscores the use of TCD in cerebrovascular pathology.

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.

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.

Reliability of transcranial sonography for assessment of brain midline shift in adult neurocritical patients: a systematic review and meta-analysis

INTRODUCTION

The aim of this systematic review and meta-analysis was to determine the reliability of transcranial sonography as an alternative to computed tomography for evaluation of brain midline shift in adult neurocritical patients.

EVIDENCE AQUISITION

The PubMed, EMBASE, Cochrane Library, Scopus and Web of Science databases were searched. Original studies evaluating brain midline shift in adult neurocritical patients using both transcranial sonography and computed tomography were eligible. Primary outcome measure was concordance between both methods as quantified in terms of concordance correlation coefficient. Secondary outcome measure was limits of agreement, defined as mean difference between sonography and computed tomography plus and minus 1.96 standard deviations.

EVIDENCE SYNTHESIS

Twelve studies (574 patients, 689 examinations) were eligible. Ten studies (416 patients, 492 examinations) provided adequate data for evaluation of concordance. Pooling of effect sizes showed strong concordance between both methods (concordance correlation coefficient, 0.91; 95% CI, 0.87 to 0.94). Two missing studies were imputed and effect size was adjusted to 0.88 (95% CI, 0.81 to 0.93). Nine studies (442 patients, 571 examinations) provided adequate data for estimation of limits of agreement. Pooling of effect sizes showed a bias of -0.53 mm (95% limits of agreement, -1.22 to 0.16 mm). Four missing studies were imputed and bias was adjusted to -0.68 mm (95% limits of agreement, -1.31 to -0.04 mm).

CONCLUSIONS

Transcranial sonography may serve as reliable alternative to computed tomography for evaluation of brain midline shift in adult neurocritical patients. Both methods have strong concordance with acceptably narrow limits of agreement.

The use of transcranial ultrasound and clinical assessment to diagnose ischaemic stroke due to large vessel occlusion in remote and rural areas

Rapid endovascular thrombectomy, which can only be delivered in specialist centres, is the most effective treatment for acute ischaemic stroke due to large vessel occlusion (LVO). Pre-hospital selection of these patients is challenging, especially in remote and rural areas due to long transport times and limited access to specialist clinicians and diagnostic facilities. We investigated whether combined transcranial ultrasound and clinical assessment (“TUCA” model) could accurately triage these patients and improve access to thrombectomy. We recruited consecutive patients within 72 hours of suspected stroke, and performed non-contrast transcranial colour-coded ultrasonography within 24 hours of brain computed tomography. We retrospectively collected clinical information, and used hospital discharge diagnosis as the “gold standard”. We used binary regression for diagnosis of haemorrhagic stroke, and an ordinal regression model for acute ischaemic stroke with probable LVO, without LVO, transient ischaemic attacks (TIA) and stroke mimics. We calculated sensitivity, specificity, positive and negative predictive values and performed a sensitivity analysis. We recruited 107 patients with suspected stroke from July 2017 to December 2019 at two study sites: 13/107 (12%) with probable LVO, 50/107 (47%) with acute ischaemic stroke without LVO, 18/107 (17%) with haemorrhagic stroke, and 26/107 (24%) with stroke mimics or TIA. The model identified 55% of cases with probable LVO who would have correctly been selected for thrombectomy and 97% of cases who would not have required this treatment (sensitivity 55%, specificity 97%, positive and negative predictive values 75% and 93%, respectively). Diagnostic accuracy of the proposed model was superior to the clinical assessment alone. These data suggest that our model might be a useful tool to identify pre-hospital patients requiring mechanical thrombectomy, however a larger sample is required with the use of CT angiogram as a reference test.

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.

Correct Outcome Prognostication via Sonographic Volumetry in Supratentorial Intracerebral Hemorrhage

Introduction: The intracerebral hemorrhage (ICH)-score is used for estimation of patients' prognosis. The hemorrhage volume calculated from computed tomography (CT) contributes as one main factor. Several studies have proven that dimensions of an ICH may be displayed sufficiently by transcranial sonography (TCS). Yet, the adequacy of ICH-volumetry via TCS in calculating the ICH-score and its use as prognostic tool has not been studied.

Methods: Forty consecutive patients with supratentorial ICH diagnosed via CT were included in this prospective observational pilot study. 45 examination-series via CT and TCS were done in order to perform an ICH-volumetry and calculate the ICH-score. Volume was calculated using the ABC/2 estimation. Results of both imaging techniques were compared regarding quantification of ICH- volume and correct prognostication. A modified Rankin Scale (mRS)-score of 0–3 points was valued as good outcome.

Results: The imaging techniques did not show a difference in volumetry (p = 0.794) and TCS derived hemorrhage volume correlated significantly with ICH-volume measured on CT-scans. Calculated ICH-scores also did not differ (p = 0.323). Patients with an ICH-score larger than 2 points were predicted to experience a poor outcome at discharge with mRS 4–6 points, and the prognostication of the outcome was correct. Patients with a good outcome showed a smaller ICH-volume (11.2 ± 9.1ml) than patients with a poor outcome (38.2 ± 41.2 ml; p = 0.002).

Conclusion: Volumetry in supratentorial ICH via TCS is feasible and the prognostication with the ICH-score based on its results is comparable to CT-imaging and sufficient.

Sonographic-Assisted Catheter-Positioning in Intracerebral Hemorrhage

Introduction: Intracerebral structures and pathologies such as intracerebral hemorrhages (ICH) can be displayed sufficiently by transcranial sonography (TCS). In some patients with ICH clot evacuation via surgery or catheter drainage to reduce secondary parenchymal injuries may be necessary. We hypothesized that bedside-placement of drainage-catheters, which is a minimal invasive evacuation-technique complicated by a higher rate of catheter misplacement can be optimized via TCS.

Methods: Eleven consecutive ICH-patients diagnosed via computertomography (CT) were included in this prospective observational pilot study. All patients were examined via TCS, firstly in order to illustrate the hematoma, secondly to optimize catheter placement. Catheter placement was primarily validated via CT.

Results: The TCS-depiction of ICH-extension was optimal in 10 patients; one patient showed a partially insufficient transtemporal bone window. Catheter positioning could be traced and adapted correctly via TCS-examination in all patients. Follow-up CT-scans confirmed TCS-description of catheter-positioning in all patients without any complications. Reduction of symptoms and ICH-volumes confirmed effectiveness of treatment.

Conclusions: The illustration of ICH and the drainage-placement is possible via TCS in a cost- and time-efficient way.

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.

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.

3-D transcranial ultrasound imaging with bilateral phase aberration correction of multiple isoplanatic patches: a pilot human study with microbubble contrast enhancement

With stroke currently the second-leading cause of death globally, and 87% of all strokes classified as ischemic, the development of a fast, accessible, cost-effective approach for imaging occlusive stroke could have a significant impact on health care outcomes and costs. Although clinical examination and standard computed tomography alone do not provide adequate information for understanding the complex temporal events that occur during an ischemic stroke, ultrasound imaging is well suited to the task of examining blood flow dynamics in real time and may allow for localization of a clot. A prototype bilateral 3-D ultrasound imaging system using two matrix array probes on either side of the head allows for correction of skull-induced aberration throughout two entire phased array imaging volumes. We investigated the feasibility of applying this custom correction technique in five healthy volunteers with Definity microbubble contrast enhancement. Subjects were scanned simultaneously via both temporal acoustic windows in 3-D color flow mode. The number of color flow voxels above a common threshold increased as a result of aberration correction in five of five subjects, with a mean increase of 33.9%. The percentage of large arteries visualized by 3-D color Doppler imaging increased from 46% without aberration correction to 60% with aberration correction.

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.