Power transcranial Doppler ultrasound in the detection of intracranial aneurysms

Sonografisches Neuromonitoring auf der Stroke Unit und in der neurologischen Intensivmedizin

Hintergrund Der Artikel gibt einen Überblick über die aktuellen diagnostischen Einsatzmöglichkeiten sonographischer Anwendung in der neurologischen Intensivmedizin.

Methoden Selektive Literaturrecherche mit kritischer Beurteilung ab dem Jahr 1984 sowie nationaler und internationaler Leitlinien sowie Expertenmeinung.

Ergebnisse Neben der raschen validen Abklärung akuter Schlaganfälle bieten verschiedene neurosonografische Monitoring-verfahren gerade in der Intensivmedizin spezifische Vorteile wie die beliebig häufige Wiederholbarkeit am Patientenbett selbst und die Darstellung in Echtzeit. Innovative Entwicklungen machen die Neurosonografie auch wissenschaftlich zu einem interessanten Gebiet.

Schlussfolgerung Die neurosonografische Diagnostik nimmt seit Jahren einen wichtigen Stellenwert in der neurologischen Intensivmedizin ein. Weitere Anstrengungen sind notwendig, um die Verbreitung der Methode zu fördern und durch wissenschaftliche Evidenz zu stärken.

Association Between Flow Acceleration in the Carotid Artery and Intracranial Aneurysms

OBJECTIVES

In physiologic pulsatile flow, velocity acceleration is an independent factor determining wall shear stress experienced by the vascular endothelium. The purpose of this study was to evaluate Doppler indices of systolic velocity acceleration in extracranial cerebral vessels and the occurrence of intracranial aneurysms.

METHODS

We reviewed medical records and 3.0-T brain magnetic resonance imaging with 3-dimensional time-of-flight magnetic resonance angiography of 1323 adults who underwent health checkups from June 2006 to November 2011, in whom 53 intracranial aneurysms were identified in 45 patients. Doppler ultrasound parameters of the carotid and vertebral arteries were analyzed in these 45 patients with aneurysms and compared with another 45 control participants matched for age and sex. We defined the maximum systolic acceleration (ACC_max ) as the maximum slope of the early phase of systolic acceleration on the Doppler waveform and the maximum acceleration index (AI_max ) as the ratio of the ACC_max and peak systolic velocity.

RESULTS

The Doppler analysis showed a significantly increased AI_max and ACC_max in the common carotid artery (CCA), internal carotid artery, and vertebral artery in the aneurysm group. A cutoff 13.89 s^-1 for the AI_max of the CCA had sensitivity of 80% with a negative predictive value of 99% for intracranial aneurysms.

CONCLUSIONS

This study suggests that the AI_max of the CCA with a cutoff of 13.89 s^-1 may be an alternative to 3-dimensional time-of-flight magnetic resonance angiography or computed tomographic angiography as a screening tool for intracranial aneurysms. Further prospective studies are needed to validate the diagnostic performance and cost-effectiveness of these indices for screening.

Intracranial aneurysm in childhood and interrupted aortic arch

BACKGROUND

Intracranial aneurysms are very rare in children. Headache and nausea/vomiting are the most prominent clinical findings. The only effective treatment is obliteration of aneurysm by surgical or endovascular techniques. Interrupted aortic arch is also a rare, congenital cardiovascular malformation characterized by the lack of continuity between the ascending and descending thoracic aorta. Aortic interruption is an uncommon cause of intracranial aneurysm. The course of disease is lethal unless effective collateral flow develops. Long-term survival may be possible with surgical repair.

METHOD

We report on a 17-year-old boy affected with interrupted aortic arch disease and associated multiple intracranial aneurysms. Both aneurysms clipped successfully. After patient had recovered, he referred to cardiovascular surgery for further treatment.

CONCLUSION

Surgical or endovascular obliteration remains the main therapy for intracranial aneurysms. Accompanying systemic diseases such as interrupted aortic arch challenge the management of both diseases.

Iatrogenic intracranial aneurysms in childhood: case-based update

PURPOSE

Iatrogenic aneurysms are very rare in children. Characteristic clinical manifestations are variable and asymptomatic course is possible especially for fusiform dilatation of internal carotid artery. Even though radiological diagnosis is easy, the management of iatrogenic intracranial aneurysm is still a subject for discussion.

METHODS

Fusiform dilatations of internal carotid artery were diagnosed on three pediatric patients during follow-up imaging after primary surgery for suprasellar-parasellar tumor. All patients were asymptomatic. Conservative treatment was proposed because the lesion did not show any progression in subsequent examinations. Patients are stable under conservative treatment.

CONCLUSIONS

Iatrogenic aneurysm may have an unusual presentation and their therapy still remains unclear. Fusiform dilatation of internal carotid artery rarely causes symptoms and there is no published paper of subarachnoid bleeding. Treatment would be difficult, since the main arterial branches arise from the dilated carotid segment. Conservative treatment is a choice only if aneurysm has no progression or in case of spontaneous healing. Intervention should be performed only in case of progression or if the aneurysm becomes symptomatic.

[Sonographic diagnostics in neurological emergency and intensive care medicine]

BACKGROUND

This article gives an up-to-date overview of neurosonographic emergency and intensive care diagnostics.

METHODS

Selective literature research from 1984 with critical appraisal and including national and international guidelines.

RESULTS

Fast and valid diagnostics in acute stroke is the main field of application of neurosonography. Specific monitoring methods bear great advantages for intensive care patients, especially "as-often-as-wanted" repetitive imaging under real-time conditions. A number of new developments make neurosonography an interesting area of research.

CONCLUSIONS

Neurosonography has played a key role in neurological emergency and intensive care medicine for many years. It remains important to continuously support dissemination of the method.

Suitability of Temporal Bone Acoustic Window: Conventional TCD Versus Transcranial Color-Coded Duplex Sonography

PURPOSE AND BACKGROUND

To determine whether the proportion of patients with suitable temporal bone acoustic windows is different for conventional transcranial Doppler sonography (TCD) and transcranial color-coded duplex sonography (TCCS), based on a head-to-head comparison in the same population of patients.

SUBJECTS AND METHODS

Ninety patients, age 22-88 years (mean 57.1 +/- 11.7 years), 46 women and 44 men, 66 Caucasian, 19 African-American, and five Hispanic, underwent routine conventional TCD and the TCCS examination close in time to each other. Suitability of temporal bone acoustic window was defined by ability to insonate the middle and posterior and/or anterior cerebral arteries, while partial suitability was defined by ability to detect the posterior cerebral artery but not the middle cerebral artery. To compare proportions of suitable temporal bone windows for both sonographic methods, exact sign test by Liddell was used.

RESULTS

Bilateral absence of temporal bone acoustic window was reported in six patients when studied with both conventional TCD and TCCS, whereas at least unilateral absence was reported in 10 patients. Partial, at least unilateral, suitability was reported in 11 patients with conventional TCD, and in 7 with TCCS. All differences in proportions were not significant (two-sided P>0.05).

CONCLUSIONS

This study suggests that success rate of insonating the intracranial vessels through the temporal bone acoustic window is the same for conventional TCD and imaging TCCS.

Current Diagnostic Modalities for Intracranial Aneurysms

Aneurysm diagnosis has evolved considerably over the last years. Technological advances have brought CT angiography and MR angiography to the forefront of ruptured and nonruptured intracranial aneurysm diagnosis. This article highlights current diagnostic modalities for intracranial aneurysms.

Current diagnostic approaches to subarachnoid haemorrhage

Over the past decade, significant advances have been made in the field of subarachnoid haemorrhage (SAH). Prompt diagnosis with high-resolution CT and intensive critical care support remain key aspects of good patient management. Early identification and definitive treatment of underlying ruptured aneurysms is generally advocated to reduce the risk of re-bleeding, a complication with high mortality and morbidity. Although intra-arterial digital subtraction angiography (DSA) is still considered the gold standard for sourcing aneurysms, CT angiography, especially with the evolution of multi-slice technology, is slowly gaining acceptance as a rapid, accessible and minimally invasive method which appears likely to replace DSA as first-line modality in the future. Furthermore, the advent of Guglielmi detachable coils and the ISAT trial have revolutionised the treatment of ruptured aneurysms, with a significant trend towards endovascular coiling away from operative clipping. Improvements in clinical experience, coiling technology and assistive devices now allow interventionalists to potentially treat the majority of aneurysms, including wide-necked or complex lesions. The uncertain long-term results of coiling, however, still fuel strong debate and controversy. This review summarises current diagnostic approaches to SAH from a radiological perspective, with an emphasis on aneurysmal SAH and an evidence-based approach to the role of imaging and interventional radiology in diagnosis, treatment and follow-up.

Intraoperative power Doppler ultrasonography with a contrast-enhancing agent for intracranial tumors

Object. The goal of this study was to evaluate intraoperative power Doppler ultrasonography when used with a contrast-enhancing agent for operations on intracranial tumors.

Methods. Forty intracranial tumors were examined using power Doppler ultrasonography with a galactose micro-particle—based ultrasonographic contrast-enhancing agent during operations on the brain. The tumors included 37 intracranial neoplasms (14 gliomas, six meningiomas, three hemangioblastomas, two malignant lymphomas, three other primary neoplasms, nine metastatic tumors, and three nonneoplastic lesions). All patients also underwent computerized tomography and magnetic resonance imaging, and all but three of the patients underwent digital subtraction (DS) angiography. Before injection of the ultrasonographic contrast agent, intra- and peritumoral power Doppler flow signals were detected in 32 of the intracranial tumors. After the injection, the signals were enhanced in blood vessels around the tumors and in the tumor parenchyma in 36 tumors. The duration of contrast enhancement continued for 70 to 365 seconds (mean 251.8 ± 69 seconds) after the injection. Among the tumors, hemangioblastomas displayed particularly strong contrast enhancement. In these intracranial tumors, the echo signals obtained using contrast-enhanced power Doppler ultrasonography correlated with DS angiographic staining. Power Doppler ultrasonograms with the appropriate contrast agent provided better data on the precise real-time position of the tumors and their relationship to adjacent vessels than ultrasonograms obtained before the injection of the contrast agent.

Conclusions. Intraoperative power Doppler ultrasonography performed using a contrast-enhancing agent can facilitate intraoperative real-time navigation and assessment of the intratumoral vasculature and peritumoral vessels, particularly for tumors having abundant vessels such as hemangioblastomas.

A rapid noninvasive method to visualize ruptured aneurysms in the emergency room: three-dimensional power Doppler imaging

OBJECT

Three-dimensional (3D) power Doppler ultrasonography imaging provides a rapid, noninvasive visualization of ruptured intracranial aneurysms, including their relationship to other vascular structures.

METHODS

The authors used transcranial 3D power Doppler imaging in the emergency room to examine patients with acute subarachnoid hemorrhage. In all patients, the ruptured aneurysm was rapidly located with 3D power Doppler imaging. Conventional x-ray angiography confirmed both the ultrasonography-based diagnosis and the location of aneurysmal bleeding.

CONCLUSIONS

These preliminary results indicate that 3D power Doppler imaging is a rapid, noninvasive screening method for the visualization of ruptured aneurysms.

Assessment of Transcranial Color-coded Duplex Sonography for the Surveillance of Intracranial Aneurysms Treated with Guglielmi Detachable Coils

OBJECTIVE

We sought to evaluate the sensitivity and specificity of transcranial color-coded duplex sonography (TCCS) and the effect of an ultrasonographic contrast agent in the long-term surveillance of intracranial aneurysms treated with Guglielmi detachable coils.

METHODS

Forty-six studies were obtained in patients with intracranial aneurysms treated with coils. All studies were obtained within 2 months of surveillance digital subtraction angiograms, which was adopted as the standard for observing aneurysm refilling. For 34 of the studies, imaging was performed both before and after infusing an ultrasonographic contrast agent (Levovist). The remaining 12 studies were unenhanced. Aneurysms were described either as being fully occluded or as having residual flow. The degree of residual flow was quantified as minor, moderate, or extensive. The operator was blinded to the results of digital subtraction angiography during TCCS assessment.

RESULTS

TCCS correctly identified 19 of 20 aneurysms with complete occlusion (sensitivity, 95%; specificity, 84%). TCCS also identified all 16 of the clinically relevant aneurysms with either moderate or extensive residual flow visualized on digital subtraction angiograms and 5 aneurysms only after contrast enhancement (sensitivity, 100%; specificity, 97%). The overall accuracy of TCCS in identifying clinically relevant aneurysms was 85% without contrast enhancement and 96% with contrast enhancement.

CONCLUSION

Contrast-enhanced TCCS shows promise as a noninvasive imaging method for the surveillance of coiled intracranial aneurysms.

Intracerebral aneurysms: a review with special attention to geriatric aspects

Rupture of an intracranial aneurysm (ICA) remains a devastating complication associated with a high degree of morbidity and mortality. In the past 2 decades, older people were often excluded from active treatment on the unique basis of their chronological age. Recent developments of less-invasive techniques for the diagnosis and treatment of ruptured and unruptured ICAs suggest that this fatalistic attitude toward older patients should be reconsidered. Furthermore, taking into account the heterogeneity of the elderly population, the use of a comprehensive geriatric assessment approach, based on a multidisciplinary evaluation, appears particularly helpful in proposing the optimal treatment strategy for each older patient. This article reviews the geriatric features of epidemiological, physiopathological, as well as clinical and therapeutic aspects of ruptured and unruptured ICAs.