Dislocation of the third ventricle due to space-occupying stroke evaluated by transcranial duplex sonography

TCCD Fusion Imaging to Estimate Intracranial Pressure and Tissue Displacement with Large Hemispheric Infarction

BACKGROUND

Despite breakthroughs in stroke treatment, some patients still experience large infarctions of the cerebral hemispheres resulting in mass effect and tissue displacement. The evolution of mass effect is currently monitored using serial computed tomography (CT) imaging. However, there are patients who are ineligible for transport, and there are limited options for bedside monitoring of unilateral tissue shift.

METHODS

We used fusion imaging for overlaying transcranial color duplex with CT angiography. This method allows overlay of live ultrasound on top of CT or magnetic resonance imaging scans. Patients with large hemispheric infarctions were eligible to participate. Position data from the source files were used and matched with live imaging and correlation to magnetic probes on the patient's forehead and ultrasound probe. Shift of cerebral parenchyma, displacement of the anterior cerebral arteries, basilary artery and third ventricle were analyzed, as well as pressure on the midbrain, and the displacement of the basilar artery on the head were analyzed. Patients received multiple examinations in addition to standard care of treatment with CT imaging.

RESULTS

The sensitivity for diagnosing a shift of 3 mm with fusion imaging was 100%, with a specificity of 95%. No side effects or interactions with critical care equipment were recorded.

CONCLUSIONS

Fusion imaging is an easy method to access and acquire measurements for critical care patients and follow-up of tissue and vascular displacement after stroke. Fusion imaging may be a decisive support for indicating hemicraniectomy.

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.

Application of Transcranial Sonography for the Assessment of Brain Midline Shift in Patients Presenting With Suspected Intracranial Pathology to the Emergency Department of a Tertiary Care Hospital in Central Gujarat, India

BACKGROUND

A shift in midline brain structure indicates raised intracranial pressure (ICP), thereby a sign of compromised perfusion to brain tissues or a mass effect. Early diagnosis can help in planning timely neurosurgical interventions that could prevent further neuron loss. Also, this may aid in neuroprognostication.

OBJECTIVES

The objectives of the study were to find the accuracy of bedside assessment of brain midline shift (MLS) using transcranial sonography (TCS) in comparison to a computed tomography (CT) scan of the brain for patients presenting with suspected intracranial pathology to the emergency department (ED).

METHODS

This prospective observational study was carried out for one year in an ED. A total of 124 patients with suspected intracranial pathology were included in the study. Transtemporal scanning along the orbitomeatal line was performed to image the third ventricle. The distance between the third ventricle and the internal side of the temporal bone was measured on both sides as A and B. The MLS was then calculated using the following formula: midline shift = (A-B)/2. The data were entered and analyzed using a Microsoft Excel worksheet (Microsoft Corp., Redmond, WA).

RESULTS

Out of the total 124 patients enrolled in this study, adequate views for 12 patients were not obtained and, hence, they were excluded from the study. The time to perform a TCS assessment of brain MLS was around 22 minutes (range: 15-30 minutes). In our study, out of 112 analyzed patients, 33 (29.5% of our study) had a significant MLS in the brain (defined by an MLS of more than 5 mm) diagnosed by TCS. Analyzing CT brain results revealed that out of the total 112 patients under study, 27 had a significant brain MLS (24.1% of the total population under study) as defined above.

CONCLUSION

A TCS is a promising alternative to a brain CT in an emergency for brain MLS detection.

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.

POCUS, how can we include the brain? An overview

Point-of-care ultrasound (POCUS) is an essential tool to assess and manage different pathologies in the intensive care unit, and many protocols have been proposed for its application in critical care literature. However, the brain has been overlooked in these protocols.

Brain ultrasonography (BU) is easily available, and it allows a goal-directed approach thanks to its repeatability and immediate interpretation and provides a quick management and real time assessment of patients’ conditions. Based on recent studies, the increasing interest from intensivists, and the undeniable benefits of ultrasound, the main goal of this overview is to describe the main evidence and progresses in the incorporation of BU into the POCUS approach in the daily practice, and thus becoming POCUS-BU. This integration would allow a noninvasive global assessment to entail an integrated analysis of the critical care patients.

Head to toe ultrasound: a narrative review of experts' recommendations of methodological approaches

Critical care ultrasonography (US) is widely used by intensivists managing critically ill patients to accurately and rapidly assess different clinical scenarios, which include pneumothorax, pleural effusion, pulmonary edema, hydronephrosis, hemoperitoneum, and deep vein thrombosis. Basic and advanced critical care ultrasonographic skills are routinely used to supplement physical examination of critically ill patients, to determine the etiology of critical illness and to guide subsequent therapy. European guidelines now recommend the use of US for a number of practical procedures commonly performed in critical care. Full training and competence acquisition are essential before significant therapeutic decisions are made based on the US assessment. However, there are no universally accepted learning pathways and methodological standards for the acquisition of these skills.Therefore, in this review, we aim to provide a methodological approach of the head to toe ultrasonographic evaluation of critically ill patients considering different districts and clinical applications.

Accuracy of bedside bidimensional transcranial ultrasound versus tomodensitometric measurement of the third ventricle

BACKGROUND AND PURPOSE

To evaluate the accuracy of transcranial duplex sonography (TCS) for measuring the diameter of the third ventricle (DTV) and the brain midline shift (MLS), as compared to cerebral CT.

METHODS

Single-center retrospective study including 177 patients admitted to the neurological intensive care unit (NICU). We studied the correlation between TCS and CT measurements of DTV and MLS using a Bland-Altman analysis. The best threshold of DTV to diagnose acute hydrocephalus was evaluated with a receiver operating characteristic (ROC) analysis.

RESULTS

We analyzed 177 pairs of CT-TCS measurements for DTV and 165 for MLS. The mean time interval between CT and TCS was 87 ± 73 minutes. Median DTV measurement on CT was 4 ± 3 mm, and 5 ± 3 mm by TCS. Median MLS on CT was 2 ± 3 mm, and 2 ± 4 mm by TCS. The Pearson correlation coefficient (r² ) was .96 between TCS and CT measurements (p < .001). The Bland-Altman analysis found a proportional bias of 0.69 mm for the DTV with a limit of agreement ranging between -3.04 and 2.53 mm. For the MLS, the proportional bias was 0.23 mm with limits of agreements between -3.5 and 3.95. The area under the ROC curve was .97 for the detection of hydrocephalus by DTV on TCS, with a best threshold of 5.72 mm (Sensitivity [Se] = 92% Specificity [Sp] = 92.1%).

CONCLUSIONS

TCS seems to be a reliable and accurate bedside technique for measuring both DTV and MLS, which might allow detection of acute hydrocephalus among NICU patients.

Brain Ultrasonography Consensus on Skill Recommendations and Competence Levels Within the Critical Care Setting

BACKGROUND

To report a consensus on the different competency levels for the elaboration of skill recommendations in performing brain ultrasonography within the neurocritical care setting.

METHODS

Four brain ultrasound experts, supported by a methodologist, performed a preselection of indicators and skills based on the current literature and clinical expertise. An international panel of experts was recruited and subjected to web-based questionnaires according to a Delphi method presented in three separate rounds. A pre-defined threshold of agreement was established on expert subjective opinions, > 84% of votes was set to support a strong recommendation and > 68% for a weak recommendation. Below these thresholds, no recommendation reached.

RESULTS

We defined four different skill levels (basic, basic-plus, pre-advanced, advanced). Twenty-five experts participated to the full process. After four rounds of questions, two items received a strong recommendation in the basic skill category, three in the advanced, twelve in the basic-plus, and seven in the pre-advanced. Two items in the pre-advanced category received a weak recommendation and three could not be collocated and were excluded from the list.

CONCLUSIONS

Results from this consensus permitted stratification of the different ultrasound examination skills in four levels with progressively increasing competences. This consensus can be useful as a guide for beginners in brain ultrasonography and for the development of specific training programs within this field.

Bedside Sonographic Duplex Technique as a Monitoring Tool in Patients after Decompressive Craniectomy: A Single Centre Experience

Background and objectives: Bedside sonographic duplex technique (SDT) may be used as an adjunct to cranial computed tomography (CCT) to monitor brain-injured patients after decompressive craniectomy (DC). The present study aimed to assess the value of SDT in repeated measurements of ventricle dimensions in patients after DC by comparing both techniques. Materials and Methods: Retrospective assessment of 20 consecutive patients after DC for refractory intracranial pressure (ICP) increase following subarachnoid hemorrhage (SAH), bleeding and trauma which were examined by SDT and CCT in the context of routine clinical practice. Whenever a repeated CCT was clinically indicated SDT examinations were performed within 24 hours and correlated via measurement of the dimensions of all four cerebral ventricles. Basal cerebral arteries including pathologies such as vasospasms were also evaluated in comparison to selected digital subtraction angiography (DSA). Results: Repeated measurements of all four ventricle diameters showed high correlation between CCT and SDT (right lateral r = 0.997, p < 0.001; left lateral r = 0.997, p < 0.001; third r = 0.991, p < 0.001, fourth ventricle r = 0.977, p < 0.001). SDT performed well in visualizing basal cerebral arteries including pathologies (e.g., vasospasms) as compared to DSA. Conclusions: Repeated SDT measurements of the dimensions of all four ventricles in patients after DC for refractory ICP increase delivered reproducible results comparable to CCT. SDT may be considered as a valuable bedside monitoring tool in patients after DC.

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.

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.

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.

Speckle Tracking in Transcranial Ultrasound Allows Noninvasive Analysis of Pulsation Patterns of the Third Ventricle

Cerebrospinal fluid (CSF) flow is sensitive to many cerebral disorders. We aimed to develop a noninvasive bedside method to detect physiological and pathological CSF phenomena by measuring pulsation patterns of the third ventricle. By transcranial B-mode ultrasound, electrocardiography (ECG)-gated video loops of the third ventricle were acquired. "Speckle tracking" software was used to quantify the relative change of its width. We conducted measurements of nine cardiac cycles in 11 healthy subjects in sitting and in supine position during Valsalva maneuver to investigate the influence of an increased intracranial pressure on the relative deformation of the third ventricle. In one patient with occlusive hydrocephalus, 19 cardiac cycles were measured in sitting position before and after removal of a tumorous obstruction of the aqueduct of Sylvius. Healthy subjects expressed a pulse-related increased width of the third ventricle ([Formula: see text]: +5.69, 95% confidence interval [CI] = [4.38, 7.00]). No significant difference was found between the sitting and the supine position in healthy adults. In the preoperative state of occlusive hydrocephalus, we found a negative, pulse-related deformation ([Formula: see text]: -1.86, 95% CI = [-2.15, -1.58]) with delayed onset. After surgery, the deformation pattern resembled that of our healthy controls. The difference between pre- and postoperative condition was significant (p < 0.001). Transcranial B-mode sonography can be used to record small movements of the sidewalls of the third ventricle. This noninvasive bedside method is suitable to assess CSF pulsatility within the third ventricle and might be able to distinguish between physiological and pathological flows.

Transcranial Doppler ultrasound in neurocritical care

Multimodality monitoring is a common practice in caring for neurocritically ill patients, and consists mainly in clinical assessment, intracranial pressure monitoring and using several imaging methods. Of these imaging methods, transcranial Doppler (TCD) is an interesting tool that provides a non-invasive, portable and radiation-free way to assess cerebral circulation and diagnose and follow-up (duplex method) intracranial mass-occupying lesions, such as hematomas and midline shift. This article reviews the basics of TCD applied to neurocritical care patients, offering a rationale for its use as well as tips for practitioners.

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.

Comparison between Brain Computed Tomography Scan and Transcranial Sonography to Evaluate Third Ventricle Width, Peri-Mesencephalic Cistern, and Sylvian Fissure in Traumatic Brain-Injured Patients

Introduction

Transcranial color-coded duplex sonography (TCCS) may help guide multimodal monitoring in the neurocritical setting. It may provide indirect information about intracranial hypertension, such as midline shift, third ventricle width, and peri-mesencephalic cistern obliteration. We aim to assess the agreement between brain computed tomography scan (CT scan) and TCCS in traumatic brain injury (TBI) patients.

Methods

In this retrospective cross-sectional observational study, TCCS was performed within 6 h before a brain CT scan. Only the first CT and TCCS after ICU admission were included. The agreement between the CT scan and TCCS was assessed by Bland–Altman plots and evaluating the intraclass correlation coefficient.

Results

Overall, 15 consecutive patients were included (80% male, 42 ± 23 years of age, Glasgow Coma Score 5 [4,6]). The mean difference between the brain CT scan and TCCS in measuring the midline shift was 0.30 ± 2.1 mm (intraclass correlation coefficient: 0.93; p < 0.01). An excellent correlation was also observed between the methods in assessing the third ventricle width (intraclass correlation coefficient: 0.88; p < 0.01). Bland–Altman plots did not show any systematic bias in either agreement analysis. TCCS showed good accuracy in predicting non-compressed peri-mesencephalic cisterns (AUC: 0.83, 95% CI 0.46–1.0) and the presence of the Sylvian fissure (AUC: 0.91, 95% CI 0.73–1.0) on CT scan.

Conclusion

TCCS is a promising tool and may be an alternative to CT scans for evaluating TBI patients.

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.

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.

[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.

Transcranial color coded duplex sonography in the intensive care unit

Case report

A case of a 43-year-old male with severe pancreatitis complicated with neurological deterioration is presented.

Methods and result

Different neurosonological examinations using transcranial color coded duplex sonography (TCCS) were combined to obtain a certain diagnosis.

Conclusion

This case illustrates some of the applications of TCCS at bedside in ICU patients. These sonographic explorations are useful in the monitoring of ICU patients, and may avoid hazardous transfers to the radiology department for the patient.

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.

Transcranial shear-mode ultrasound: assessment of imaging performance and excitation techniques

Transcranial ultrasound imaging is limited by poor acoustic windows and skull induced distortions to the beam. Shear waves in the skull have a better impedance match with longitudinal waves in water and thereby produce a more coherent focus inside the skull. This study presents work on an imaging technique that utilizes shear-wave propagation through the skull. The pulse-echo lateral distortion introduced by the skull was analyzed by imaging a point scatterer behind ex vivo human craniums at 1 MHz. Brightness images of the target obtained with either shear-mode or conventional longitudinal-mode transmission in the bone were assessed to quantify lateral resolution. As compared to longitudinal-mode transmission, it was found that the use of shear-mode resulted in improved localization along the propagation (depth) axis at the expense of degraded lateral resolution. The signal-to-noise ratio (SNR) limitations introduced by severe attenuation of shear-waves in the skull were overcome with frequency modulated (FM) coded excitations. This gain in SNR was exchanged with resolution and used for compensation of frequency-dependent attenuation in the skull, resulting in a greater than 20% improvement in lateral resolution for both modes of transcranial transmission. The results are an important step towards enhancing the quality of transcranial sonography.

Sonographic evaluation of hemorrhagic transformation and arterial recanalization in acute hemispheric ischemic stroke

BACKGROUND AND PURPOSE

We conducted this prospective study to evaluate the time course of hemorrhagic transformation (HT) and arterial recanalization in the early phase of ischemic stroke using transcranial sonography (TCS).

METHODS

Fifty-five patients with acute ischemic hemispheric stroke <32 hours after symptom onset were studied. A 2-MHz sector probe was used to evaluate brain tissue by TCS and basal cerebral arteries by transcranial color-coded sonography. Follow-up investigations were performed up to 6 days. Lesion size and localization were determined by cranial computed tomography.

RESULTS

Of 20 patients with HT, 18 displayed by computed tomography could be identified by TCS. In 1 patient, TCS provided a wrong positive result, and in another 2 patients with small cortical HT, a wrong negative result was provided (sensitivity 90.0%, specificity 97.4%). HT was detected in the first 60 hours after symptom onset in 62.5% of patients treated with tissue plasminogen activator in comparison to 33.3% without thrombolysis. Recanalization of middle cerebral artery occurred earlier in tissue plasminogen activator-treated patients compared to those without tissue plasminogen activator treatment (in the first 60 hours after symptom onset: 78.5% vs 50.0%, respectively; P=0.34). There was a significant time difference between middle cerebral artery recanalization and HT occurrence (n=13, median time interval: 20 vs 60 hours; P=0.035).

CONCLUSIONS

Transcranial ultrasound is a useful bedside method to depict and closely monitor HT in patients with acute hemispheric stroke. The strong influence of tissue plasminogen activator treatment on HT could be demonstrated. HT development is dependent on the time of artery recanalization.

Sonographic monitoring of mass effect in stroke patients treated with hypothermia. Correlation with intracranial pressure and matrix metalloproteinase 2 and 9 expression

Severe stroke leads to subsequent cerebral oedema. Patients with severe stroke develop midline shift (MLS) which can be measured by transcranial duplex sonography (TCD). We measured MLS with TCD in 30 patients with large infarction in the territory of the middle cerebral artery (MCA). All of the examined patients had intracranial pressure (ICP) measure devices and the ICP at the time of the TCD was recorded. MLS was also determined on CT scan on day 4. Ten of the 30 patients were treated with hypothermia. We also determined matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) in serum by zymography. MLS measured by TCD correlated significantly with MLS on CT. In addition there was a strong correlation between the ICP measured at the time of TCD and MLS. In patients treated with hypothermia MLS was less pronounced. MMP9 and MMP2 showed a characteristic time course and had strong associations with MLS. We confirm earlier reports that TCD is a reliable noninvasive method for serially monitoring patients with intracranial lesions. Hypothermia reduces MMP9 activity as well as MLS. TCD may reduce the need for repetitive CT scans in neurological critically ill 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.

Monitoring midline shift by transcranial color-coded sonography in traumatic brain injury. A comparison with cranial computerized tomography

OBJECTIVE

Transcranial color-coded duplex sonography (TCCDS) is a non invasive bedside technique that allows the determination of midline shift (MLS). The purpose of our study was to compare MLS measurements using TCCDS with those obtained with cranial computerized tomography (CT) in patients with traumatic brain injury (TBI).

DESIGN

Prospective study.

SETTINGS

Intensive care unit in a university hospital.

PATIENTS

Forty-one traumatic brain-injured patients (35 men and 6 women).

INTERVENTIONS

A total of 60 studies were conducted with a time interval between the cranial CT and the TCCDS studies of 322+/-216 min.

RESULTS

The coefficient of correlation between MLS measured by CT and TCCDS was 0.88, the bias was 0.12 mm, the precision was 1.08 mm and the limits of agreement were +2.33 to -2.07 mm. There were no statistically significant differences in MLS measured by the two techniques in terms of: sex, age or type of lesion according to the Traumatic Coma Data Bank classification.

CONCLUSION

The TCCDS is a non-invasive bedside technique that is valid for determining MLS in patients with traumatic brain injury. Due to the risks involved in the transportation of traumatic brain-injured patients to the radiology department, this bedside technique is specially interesting in 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.

Contrast-enhanced transcranial color-coded sonography in acute hemispheric brain infarction

PURPOSE

The aim of the present study was to investigate the diagnostic potential of contrast-enhanced transcranial color-coded real-time sonography (CE-TCCS) in otherwise ultrasound-refractory acute stroke patients with an ischemia in the territory of the middle cerebral artery (MCA). Furthermore, correlations of CE-TCCS findings with clinical, angiographic, and CT results were investigated.

METHODS

In 90 acute stroke patients with inadequate insonation conditions in unenhanced transcranial color-coded real-time sonography (TCCS) examinations, CE-TCCS, clinical, angiographic, and CT examinations were performed within 12 hours, 36 hours (CE-TCCS only), and 1 week after onset of clinical symptoms. A CT angiography (CTA) as reference method was available in 39 individuals. After application of a galactose-based echo-enhancing agent, the portion of conclusive ultrasound examinations of the MCA, as manifested by an MCA occlusion, decreased or increased flow velocity (FV), and symmetrical MCA FV, was evaluated. CE-TCCS findings on admission and during follow-up were correlated with infarction size as demonstrated on follow-up CT, and clinical findings were assessed by use of the European Stroke Scale.

RESULTS

Adequate diagnosis was achieved in 74 of 90 patients (82%) by the use of echo contrast agents. MCA occlusion or reduction of MCA FV was found in 20 and 27 patients, respectively. MCA occlusion was confirmed by CTA in 17 cases. In one individual, false-positive diagnosis of MCA occlusion was made according to ultrasound criteria. In 5 patients with MCA occlusion, vessel recanalization was observed during follow-up; 15 of 27 patients with decreased flow velocities showed normalization after the third examination that was associated with a significantly better clinical outcome (P<0.0001). Furthermore, MCA occlusion or decreased FV in the first 12 hours were associated with significantly larger infarctions in the MCA territory compared with normal CE-TCCS findings (P<0.0001).

CONCLUSIONS

CE-TCCS enables adequate diagnosis in approximately 80% of acute hemispheric stroke patients with insufficient unenhanced TCCS examinations. It is a reliable diagnostic tool regarding MCA mainstem and branch occlusions. Because this method conveys useful information concerning cerebral tissue and clinical prognosis, it may be useful to identify those patients who benefit most from local or intra-arterial thrombolytic therapy.

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

BACKGROUND AND PURPOSE

The differential diagnosis of intracerebral hemorrhage versus ischemic stroke has critical implications for stroke management. Transcranial color-coded duplex sonography (TCCS) has been shown to identify intracerebral hemorrhages and intracerebral vessel occlusions. We conducted this study to evaluate the sensitivity and specificity of TCCS in this differential diagnosis and in the detection of stroke complications.

METHODS

One hundred fifty-one patients (58 women, 93 men; mean age, 65.6 years [range, 32 to 89 years] ) with acute hemiparesis were enrolled in this prospective study. On admission all patients had a complete neurological examination. A cranial CT scan and a sonographic examination of the brain parenchyma and all extracranial and intracranial cerebral arteries were conducted. The sonographer was blinded for the radiological findings.

RESULTS

According to CT criteria, 60 patients had an intracerebral hemorrhage and 67 patients had an ischemic stroke, and in 24 patients CT findings were inconclusive, showing neither bleeding nor an ischemic stroke. On sonographic examination, 18 patients (12%) had no sufficient acoustic bone window. Of the remaining 133 patients, 126 (95%) were diagnosed correctly by sonography in agreement with CT. Sonography missed 3 atypical bleedings (2 with upper parietal location). In 4 patients without bleeding, an intracerebral hemorrhage was suspected by TCCS because of increased white matter echo density due to microangiopathy. Stroke complications depicted by CT (disturbance of cerebrospinal fluid circulation, hemorrhagic transformation, midline shift, ventricular bleeding) (n=54) were correctly shown by TCCS in 45 patients (83%). No complication was missed that would have required further treatment.

CONCLUSIONS

In comparison to the "gold standard" of CT, TCCS identified stroke complications and differentiated between intracerebral hemorrhage and ischemic stroke with reasonable sensitivity. Thus, if CT is not readily available, TCCS may complement clinical examination in patients with acute stroke. In addition, it may also be useful in detecting stroke complications in the follow-up of stroke patients.