Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Transcranial duplex real time sonography (TCCS) is a non-invasive imaging modality that allows repetitive examinations of central nervous system vascular and parenchymal anatomy; a broad spectrum of cerebral pathology may be disclosed: vascular changes include ischemic and hemorrhagic stroke, arteriosclerotic vascular degeneration, arteno-venous malformations and aneurysms, as well as neoplastic and degenerative parenchymal disorders. Imaging was performed with a duplex ultrasound system, employing a 2.25 resp. 2.0 MHz phased-array transducer. Imaging was achieved through the acoustic bone window of the temporal bone and through the foramen magnum. For three-dimensional image reconstruction a mechanical position sensor and online video grabbing was applied. To evaluate the potential of a transpulmonary stable ultrasound contrast enhancing agent we used galactose-based SH U 508 A (Levovist, Schering, Berlin) with 1 to 6 i.v. injections per patient in a phase 2/3 clinical protocol. The signal to noise ratio is significantly improved; the Doppler signal intensity is increased by approx. 25 dB. Levovist was well tolerated and no adverse events occurred, approx. 30% of patients had a sensation of heat and slight pain at the injection site during and shortly after the injection. With the increase in signal intensity, the complete circle of Willis, the peripheral arterial branches, the vertebro-basilar system and the basal venous system may be depicted. In addition, tumour parenchyma vascularisation may be detected, as well as improved delineation of arteriovenous malformations and aneurysms. Three dimensional image reconstruction may represent a novel option in contrast enhanced transcranial duplex imaging including additional information about 3D structure and continuity.
 ...
PMID:Transcranial duplex ultrasound: experience with contrast enhancing agents. 954 16

Early diagnosis of stroke and recognition of preceding transient ischemic attacks (TIAs) is important for clinical outcome. Better education of the signs and symptoms of TIA and stroke and improved diagnostic procedures will help to reduce the impact of stroke. Magnetic resonance imaging (MRI), computed tomography (CT) and single photon emission computed tomography (SPECT) are used to diagnose cerebral infarctions. MRI is the most effective diagnostic modality, however, MRI equipment is expensive and not always available. CT is therefore usually used but it has limitations, in detecting small infarctions, particularly in the posterior fossa. Ultrasound is a safe and inexpensive bedside diagnostic procedure. Ultrasound is often used in patients after TIA or stroke, however, it may be inadequate due to poor insonation conditions through the skull, or because the relevant vessel lies deep within the brain. Arteries with slow flowing blood are also difficult to image. The application of ultrasound has expanded with the development of two-dimensional transcranial color-coded sonography (TCCS) which provides both anatomical and functional information about the major cerebral vessels. In addition, the use of echo-enhancing agents now provides better images of vessels within the skull and enables ultrasound examinations to be performed even in patients with a poor transtemporal window. Echo-enhanced ultrasound can also provide images of vessels deep within the brain, which were previously non-evaluable. The echo-enhancing agent Levovist(R) has been extensively studied in patients undergoing ultrasound examination to detect cerebrovascular disease. Levovist improves diagnostic confidence without compromising safety. The improvement in images obtained of the cerebral vessels, including both arteries and veins, using echo-enhanced ultrasound may make this technique the future method of choice for patients with cerebrovascular disease.
 ...
PMID:Echo-enhanced ultrasound for diagnosis and management in stroke patients. 967 29

Carotid artery stenosis is an important risk factor for stroke. The European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) have demonstrated that the risk of stroke is reduced by surgery in patients with high grade stenosis (70-99%). However, because the two trials used different methods to measure stenosis, the results are not comparable and the level of stenosis which is associated with increased risk of stroke cannot be strictly defined. The benefit of surgery in asymptomatic patients is more controversial. Some studies indicate that surgery reduces the risk of stroke only in patients with ?80% stenosis and others have shown benefits for patients with ?60% stenosis. Overall, the benefits of surgery in asymptomatic patients are more difficult to define. Carotid lesion morphology also plays an important role in determining the risk of stroke; plaques which are ulcerated and echolucent are associated with a higher risk of stroke. Arteriography has been long regarded as the gold standard diagnostic tool for carotid stenosis. It is a costly and invasive technique with potentially serious complications. The results of arteriography have not been standardised which makes comparison of results from different laboratories difficult. Duplex ultrasound is inexpensive, non-invasive and can provide functional and anatomical information about vessel stenosis and plaque morphology. The use of echo-enhancing agents helps to reduce operator variability, improves ultrasound images and can help to distinguish between pseudo and true occlusions, to identify patients who will benefit most from surgery. The echo-enhancing agent Levovist(R) is safe, produces consistent results and can enhance images throughout the blood pool. Clinical studies with Levovist(R) have shown it to be safe and highly effective in improving diagnostic confidence in patients with carotid artery stenosis. The number of non-diagnostic scans is reduced markedly when Levovist(R) is used to enhance ultrasound images.
 ...
PMID:Carotid artery stenosis--where do we go from here? 967 30

The aim of the study was to evaluate the diagnostic potential of galactose-based microbubble suspension (Levovist) in patients with acute cerebrovascular disease and inadequate transtemporal acoustic window, when examined by transcranial Doppler (TCD). We studied 10 patients with either transient ischemic attack (no. = 3) or stroke (no. = 7). Inadequate transtemporal acoustic window was unilateral in 3 patients and bilateral in the remaining 7 patients. Signals from middle, anterior, and posterior cerebral arteries (MCA, ACA, PCA) were recorded after injecting Levovist 300 mg/ml. Six patients needed 3 injections of Levovist, 1 patient two, and 3 patients one. Mean +/- SD duration of optimal signal enhancement was 175.2 +/- 53.2 s, range 70-290 s. Doppler waveform analysis was possible in 14 (82.3%) MCA, 11 (65%) ACA, and 9 (53%) PCA. Levovist improved the reliability of TCD in patients with acute cerebrovascular disease and insufficient transtemporal insonation.
 ...
PMID:Contrast-enhanced transcranial Doppler sonography in patients with acute cerebrovascular diseases. 1139 66

Proper assessment of intracranial arteries by transcranial Doppler sonography (TCD) in patients with intracranial stenoses is occasionally made difficult by an insufficient temporal bone window, an unfavourable insonation angle, or low flow velocity or volume. This condition is frequently found in Chinese. In these cases, echocontrast could be helpful. We investigated 48 temporal windows of 24 acute Chinese stroke patients with insufficient native transtemporal insonation conditions before and after the application of the echo enhancer Levovist (galactose/palmitic acid) by an injection pump. We classified the signal quality from four segments of the main intracranial arteries: anterior cerebral artery (A1), main stem of the middle cerebral artery (MCA, M1), intracranial segment of the carotid artery (C1), and posterior cerebral artery (P1). The signal quality was classified as follows: 0 = no signal, 1 = poor, envelope curve does not follow spectrum, 2 = adequate, envelope curve follows spectrum. As compared to the pre-contrast scans, echocontrast allowed for more segments to be evaluated by pulsed Doppler sonography. Before Levovist, only 12% of the segments could be detected, after Levovist 63%. For all arteries, signal quality was better after Levovist, p between 0.0180 and 0.0003. In 3 patients, MCA stenoses with peak systolic Doppler flow velocities above 160 cm/s were found only after Levovist. In patients with poor pre-contrast detection, echocontrast-enhanced TCD allows for more arterial segments to be insonated and for the detection of stenoses unnoted during the non-enhanced investigation.
 ...
PMID:Effects of the ultrasound contrast-enhancing agent Levovist on the detection of intracranial arteries and stenoses in chinese by transcranial Doppler ultrasound. 1218 14

Initial reports indicate that cerebral perfusion deficits in acute ischemic stroke might be detectable by means of transcranial harmonic imaging after an ultrasound contrast agent (UCA) bolus injection. Twenty-four patients with acute middle cerebral artery (MCA) infarction were investigated twice with perfusion harmonic imaging (PHI) after Levovist (Schering, Berlin, Germany) bolus injection no longer than 12 h after symptom onset. The findings were compared with those of cranial computed tomography (CCT). All 24 patients suffered from acute ischemic stroke of the MCA territory (median National Institutes of Health Stroke Scale score: 15 points). Corresponding to the area of infarction in follow-up CCT, a marked contrast deficit was visualized in 19 of 24 patients by initial PHI, which had a sensitivity and specificity of 86.4% and 96.2%, respectively, for predicting the occurrence and localization of a definite infarction in the midthalamic plane. The area of hypoperfusion in the initial PHI investigation correlated with the definite area of infarction in follow-up CCT (r=0.66, p<0.01). When time-intensity curves of both hemispheres were compared, the areas under the curve were significantly less in the symptomatic brain regions (p=0.01). With PHI and UCA bolus injection, it is possible to assess cerebral perfusion deficits that correlate with the definite area of infarction in acute ischemic stroke patients.
 ...
PMID:Perfusion harmonic imaging in acute middle cerebral artery infarction. 1455

It is of crucial importance to predict the presence of stenosis in cerebral artery before occurrence of a stroke. To determine stenosis in the middle cerebral artery (MCA), we examined the effect of contrast agent (Levovist) infusion on transcranial color-coded duplex sonography (TCCD). TCCD was performed in 24 patients with MCA stenosis determined by angiography and/or magnetic resonance angiography, and 42 patients without MCA stenosis were also examined as the control group. All patients participated to assess whether an intravenous infusion of contrast agent has some influence on the peak systolic velocity (PSV) measured along the MCA. Videotaping was initiated at the administration of contrast material and continued until contrast was no longer visible in the vessels. PSV values in normal and stenotic vessels were compared. We found that PSVs were significantly higher in the stenosis group than in the control group. Difference between precontrast and postcontrast infusion was significantly greater in the stenosis group than in the control group (p < 0.05). We conclude that PSV tends to be underestimate in poor visualization of vessels. To improve accuracy of PSV measurement, contrast enhancement material should be used.
J Stroke Cerebrovasc Dis
PMID:Effect of contrast material (Levovist) infusion on peak systolic velocity in middle cerebral artery using transcranial color-coded duplex sonography. 1790 86

Administration of microbubbles (MB) may augment the effect of ultrasound-enhanced systemic thrombolysis in acute stroke. Bubble structural characteristics may influence the effect of MB on sonothrombolysis. We aimed to compare the effects of galactose-based air-filled MB (Levovist) and sulphur hexafluoride-filled MB (Sonovue) on recanalization and clinical outcome. One hundred thirty-eight i.v. recombinant tissue plasminogen activator-(tPA-) treated patients with middle cerebral artery (MCA) occlusion were studied. Presence and location of arterial occlusion and recanalization (RE) were assessed using the thrombolysis in brain ischemia (TIBI) flow grading system. Patients underwent 2 h of continuous transcranial Doppler (TCD) monitoring and received three bolus of MB after 2, 20 and 40 min of tPA bolus. Ninety-one patients received Levovist (LV) and 47 received Sonovue (SV). NIHSS scores were obtained at baseline and after 24 h. Modified Rankin Scale (mRS) score was used to assess outcome at 3 mo. Median admission NIHSS was 17. On TCD, 96 (69.6%) patients had a proximal and 42 (30.4%) a distal MCA occlusion. Age, baseline NIHSS, clot location, stroke subtypes and time to treatment were similar between LV and SV groups. Recanalization rates after 1 h (32.2%/35.6%), 2 h (50.0%/46.7%) and 6 h (63.8%/54.5%) were similar in LV/SV groups (p > 0.3). Clinical improvement (NIHSS decrease >or= 4 points) at 24 h was similar in both groups (54.9%/51.1%, p = 0.400), as well as symptomatic intracranial haemorrhage rate (3.3%/2.1%, p = 0.580) and in-hospital mortality (8.1%/9.3%, p = 0.531). Similarly, the type of MB administered did not affect long-term outcome after sonothrombolysis. Forty-four percent of patients in the LV group and 48.5% in the SV group achieved functional independence (mRS <or= 2) at 3 mo (p = 0.440). MB administration during sonothrombolysis is associated with a high RE rate. However, RE rates, clinical course and long-term outcome are comparable when administering galactose-based air-filled MB (Levovist) or sulphur hexafluoride-filled MB (Sonovue).
 ...
PMID:Do bubble characteristics affect recanalization in stroke patients treated with microbubble-enhanced sonothrombolysis? 1845 Mar 60

The left atrial appendage (LAA) is 1 of the common thromboembolic sources in patients with atrial fibrillation (AF) with stroke. The aim of this study was to examine the usefulness of LAA opacification seen on contrast echocardiography for predicting stroke recurrence in patients with AF. In 192 patients with stroke with AF who underwent transesophageal echocardiography within 7 days after the onset, intracardiac intensity variation at the orifice of the LAA just after intravenous infusion of Levovist (1,500 mg) was measured. During a mean follow-up of 450 days, the association between LAA intensity variation and recurrence of cerebrovascular events was assessed. LAA intensity variation was markedly lower in 19 patients with stroke recurrence than 173 patients without stroke recurrence (8.1 +/- 4.7 vs 12.1 +/- 5.1 dB; p <0.001). LAA thrombus-negative patients with low LAA intensity variation (< or =9.2 dB; n = 45) had higher cerebrovascular recurrent event rates than those with high LAA intensity variation (>9.2 dB; n = 109; 20.0% vs 3.7%; p <0.001) and thrombus-positive patients (15.8%). Cox multivariate hazard analysis showed that of routine echocardiographic parameters, decreased LAA intensity variation was the only independent predictor of stroke recurrence (hazard ratio 5.244, p <0.01). In conclusion, LAA intensity variation on contrast transesophageal echocardiography is a new sensitive index for LAA flow stagnation and recurrent cerebrovascular events in patients with AF with stroke.
 ...
PMID:Usefulness of intensity variation in the left atrial appendage with contrast echocardiography to predict ischemic stroke recurrence in patients with atrial fibrillation. 1848 42