Том 9, брой 2 - 2013/ Vol. 9, No. 2 - 2013

D. Russell
Oslo University Hospital, Department of Neurology – Oslo, Norway

Several non-invasive imaging modalities have shown their potential to identify unstable carotid artery plaques. Echolucent plaques are thought to be more unstable than echo-rich plaques. Images can be evaluated either visually or by computer-assisted gray-scale median (GSM) measurements. Visual evaluation of plaque echogenicity has only fair reproducibility, whereas objective characterization is more reliable and less observer dependent. Plaque irregularity on ultrasound has also been reported to be a risk factor for stroke in general but not for ipsilateral stroke alone.

Symptomatic patients with microembolic signals (MES), assessed by TCD, have been shown to be at high risk for developing ipsilateral stroke. Whether MES positive asymptomatic patients also are at increased risk has not been clarified. The use of ultrasound contrast agents may be helpful in determining plaque surface and plaque neovascularization.

C. Vetta 1, S. Horner 1, H. Deutschmann 2, T. Gattringer 1, K. Niederkorn 1
1 Department of Neurology,
2 Department of Radiology, Medical University – Graz, Austria

Objective: Stenoses of intracranial arteries (IAS)are responsible for 10% - 15% of all ischemic strokes.The purpose of the present study was to retrospectively identify the outcome of endovascular treatments of IAS with Stent-PTA performed at the University Hospital Graz during the period of 2003 to 2012.

Material and Methods: Data from all patients who underwent interventional procedures during the period 2003–2012, caused by a symptomatic (transient ischemic attack or stroke) stenosis of a major intracranial artery, were extracted from a stent data base. Technical success, clinical outcome, the rate of instent restenosis (ISR) and recurrent stroke as well as prognosis were defined as primary objectives. Examinations were at 24 hours and 6 months after the procedure, as well as the last consultation of the stroke outpatient clinic.

R. Aaslid
Hemodynamics AG – Bern, Swaziland

Objective: Earlier attempts at non-invasive determination of ICP used ABP and TCD waveforms to estimate critical closing pressure (CCP). However, the CCP was found to be strongly influenced by vascular tone and a poor indicator of absolute ICP levels.

Material and Methods: An important effect of raised ICP is a decrease in intracranial compliance. This, in turn, causes the pulsations in the ICP waveform to increase. These pulsations are primarily caused by the changes in cerebral blood volume (CBV) throughout the heart cycle. We investigated a relatively simple model of the cerebral circulation where the relative changes in CBV were determined by integrating the difference between the arterial flow velocity (FV) waveform as recorded by TCD, and the venous outflow which we assumed to be non-pulsatile.

C. Levi
Department of Neurology, John Hunter Hospital – New Lambton, Australia

M. Tanter
Institut Langevin, ESPCI, INSERM, CNRS – Paris, France

In the last fifteen years, the concept of plane wave transmissions rather than line by line scanning beams broke the conventional limits of ultrasound imaging. By using such large field of view transmissions, the frame rate reaches the theoretical limit of physics dictated by the ultrasound speed and an ultrasonic map can be provided typically in tens of micro-seconds (>1000 frames per second). Interestingly, this leap in frame rate is not only a technological breakthrough offering completely new ultrasound imaging modes and open new application, but at such frame rates, it becomes possible to track in real time transient vibrations – known as shear waves – propagating through organs and provides quantitative maps of tissue stiffness whose added value for diagnosis has been recently demonstrated in many fields of radiology.

W. Mess
University Hospital – Maastricht, Netherlands

It has been shown for different patient categories that the detection of microembolic signals (MES) in the middle cerebral artery helps to estimate the risk of future cerebrovascular events. The strength of the evidence for this relationship differs for the different clinical situations. So, the question whether automated MES detection should be applied in the daily clinical context depends not only on the adequacy of the detection system. However, a properly functional system is a prerequisite for its succesful clinical application. This comprises not only the correct identification of MES in the transcranial Doppler signal but also the ease of use. Only if both criteria are fulfilled automated MES detection is likely to be used in clinical practice. Several automated MES detection systems are currently commercially available.

V. Zetola
Federal University of Parana – Curitiba, Brazil

Stroke is an important complication of sickle cell disease. Approximately twenty-four percent of patients have a stroke by the age of 45 years. Blood transfusions decrease stroke risk in patients deemed high risk by transcranial Doppler (TCD) by evidence of elevated intracranial internal carotid or middle cerebral artery velocity. A follow-up of neurologically symptomatic and asymptomatic sickle cell patients increased other factors were significant in the identification of patients at risk that could include: velocity in the ophthalmic artery > that of the ipsilateral MCA, maximum velocity in the posterior cerebral (PCA), vertebral, or basilar arteries > maximum velocity in the MCA, turbulence, PCA visualized without the MCA.

V. Demarin
Aviva Medical Centre – Zagreb, Croatia

Cerebrovascular diseases (CVD) represent conditions which occur as a result of changes in blood vessels of the brain, as well as the vessels supplying the brain. The most common types of CVDs are ischemic stroke, transient ischemic attack, hemorrhagic stroke and vascular dementia. CVDs affect millions of people worldwide, regardless of age, and represent a group of very important medical and social problems. Therefore, their prevention is becoming an imperative. Risk factors, such as age, gender, genetic factors, hypertension, diabetes mellitus, hypercholsterolemia, atrial fibrillation, orlifestyle,are causing changes of vessel walls which lead to CVD. Early changes of the blood vessel wall can be detected by early ultrasound screening methods which allow us to detect changes before the disease becomes clinically evident.

Y. Kim 1, J-H. Lee 2, W-G. Seo 3, S-U. Kwon 4
1 Ewha Womans University Mokdong Hospital – Seoul, Korea,
2 NHIS Ilsan Hospital – Ilsan, Korea,
3 Korea University Guro Hospital – Seoul, Korea,
4 Ulsan University Asan Medical Center – Seoul, Korea

Objective: It is reported that the occurrence of cerebral hemorrhage tends to increase in cases of accompanying lacunar infarction which occurs more frequently in Asians than in Westerners, or periventricular ischemic change which increasingly occurs with ageing. Accordingly, the point is that the occurrence of cerebral hemorrhage should be primarily considered in the treatment of cerebral infarction, along with the phenomenon of an ageing population both in Asian countries including Korea. Nevertheless, so far there has been no clinical research regarding secondary prevention of stroke, particularly considering the risk of occurrence of hemorrhage in cerebral infarction cases. However, according to a recent study, when phosphodiesterase inhibitors including cilostazol are used independently, or in combination with aspirin, secondary prevention can be improved without increasing the occurrence of hemorrhagic side effects.

N. Bornstein
Neurology, Tel Aviv Sourasky Medical Center – Tel Aviv, Israel

Approximately 13 million deaths per year are caused by vascular diseases, ischemic heart disease and stroke account for 22.3% of the total yearly deaths in the world, 12.2% and 9.7% are due to ischemic heart disease and stroke respectively. Myocardial infarction is the leading cause of long-term mortality in stroke surviving patients, although stroke is the leading cause of disability in the world. Atherosclerotic carotid artery disease is the cause of ischemic ischemic stroke in about 20% of cases.

I. M. Pignat 1, V. Mendes Pereira 2, F. Perren 1
1 HUG, University Hospital and Medical Faculty of Geneva, Department of Neurology, Neurosonology Unit – Geneva,
2 HUG, University Hospital and Medical Faculty of Geneva, Department of Radiology, Interventional Neuroradiology Unit – Geneva, Switzerland

Objective: Stent retrievers are new devices that can be also used to perform mechanical intracranial thrombectomy. They have revolutionized endovascular treatment of acute ischemic stroke with good recanalization and acceptable safety. However, previous animal studies have shown that mechanical thrombectomy may cause endothelial injury of the arterial wall leading to myointimal hyperplasia.

Material and Methods: Acute ischemic stroke patients suffering from acute intracranial single large artery occlusion in which mechanical thrombectomy using stent retrievers was performed were studied. Only those with complete vessel recanalization as assessed by post-procedural DSA and in whom MRA and transcranial duplex sonography (TDS) were performed were retained. Complete revascularization was defined as modified TICI 2b or 3. Patients treated with intra-arterial thrombolysis or stenting of these arteries were excluded.

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