shu-508 and Carotid-Stenosis

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.

Topics: Carotid Stenosis; Cerebrovascular Disorders; Contrast Media; Humans; Image Enhancement; Polysaccharides; Risk Factors; Ultrasonography, Doppler

Ultrasound is widely used in the assessment of neurovascular diseases. In spite of its effectiveness there are considerable limitations such as low flow detection in carotid disease or limited bony windows in transcranial Doppler. One approach to overcome these limitations is the use of ultrasound contrast enhancing agents. The usefulness of ultrasound contrast enhancing agents Levovist, EchoGen and BY 963 in neurovascular applications has been evaluated. Contrast enhanced colourflow Doppler for the diagnosis of carotid disease has been investigated in three small trials and might be effective for improving the diagnostic yield in severe disease. Contrast enhanced transcranial colourflow Doppler has been relatively more widely explored also with promising results. Based on the combined findings out of these preliminary investigational trials, it appears to be reasonable to undertake larger trials for assessment of usefulness of ultrasound contrast agents for a variety of neurovascular applications.

Topics: Brain; Brain Ischemia; Carotid Stenosis; Contrast Media; Fluorocarbons; Humans; Image Enhancement; Phosphatidylcholines; Polysaccharides; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial; Vertebrobasilar Insufficiency

Determination of vasomotor reserve (VMR) with the transcranial Doppler-CO(2) (TCD-CO(2)) test is used to assess the risk of impending cerebral ischemia in patients with high-grade stenosis or occlusion of the internal carotid artery. In patients with a poor temporal window, however, this examination is limited. The aim of this study therefore was to examine whether the use of an ultrasound contrast agent (USCA) influences the results of the TCD-CO(2) test.. In the first part of the study, 6 control subjects and 20 patients were examined with the TCD-CO(2) test. The VMR was determined first without the application of a contrast agent and then with continuous infusion of an USCA (Levovist, 300 mg/mL, 1 mL/min). In the second part of the study, 2 tests without USCA were performed in each of 13 patients and 2 tests with USCA infusion were performed in each of 12 patients. Statistical analysis included differences between the VMR determined with the 2 comparative measurements (VMR), the mean (M(VMR)), and SD.. Based on the mean difference, the TCD-CO(2) test produced the same results with and without USCA (M(VMR) 1.8%), although the differences showed a wide distribution (2 SDs, +/-20.7%). Similar spreads were seen in repeated determinations of VMR in the same patient without USCA (2 SDs, +/-20.0%), whereas the distribution under continuous USCA infusion was considerably smaller (2 SDs, +/-8.2%).. The TCD-CO(2) test can be performed with continuous infusion of an USCA without influencing the results. Even with a good temporal window, the results of the TCD-CO(2) test show better reproducibility and thus better reliability if an USCA is used.

Topics: Administration, Inhalation; Adult; Aged; Blood Flow Velocity; Carbon Dioxide; Carotid Artery, Internal; Carotid Stenosis; Cerebrovascular Circulation; Female; Humans; Infusions, Intravenous; Male; Middle Aged; Middle Cerebral Artery; Polysaccharides; Predictive Value of Tests; Reproducibility of Results; Sensitivity and Specificity; Ultrasonography, Doppler, Transcranial; Vasodilation; Vasomotor System

The aim of the present study was to assess the use of an echo-enhancing agent (Levovist; Schering AG) in equivocal carotid bifurcation ultrasound studies and compare the information obtained with digital subtraction angiography (DSA). Contrast-enhanced carotid ultrasound studies were performed on 30 carotid bifurcations in 28 patients. The standard carotid ultrasound examinations were considered equivocal for two reasons: apparent acute internal carotid artery occlusions (n = 10), and possibly patent but critically stenosed internal carotid arteries with the residual flow lumen being incompletely visualized (n = 20). All patients underwent subsequent carotid digital subtraction angiography. All patients with apparent acute carotid occlusions (n = 10) were correctly characterized on contrast-enhanced ultrasound when compared with DSA. The majority were complete occlusions (n = 8) although in two cases there were critical carotid stenoses requiring surgical endarterectomy. In the 'incompletely visualized lumen' group (n = 20), the majority (n = 16) were correctly characterized on contrast enhanced ultrasound: 13 cases of critically stenotic but patent internal carotid arteries, two cases without a haemodynamically significant stenosis and one case of a carotid occlusion with patent vasa vasorum. One of the critical carotid stenoses was prospectively reported as occluded on the 'gold standard' angiography. In three cases the flow lumen was still incompletely visualized due to calcified plaque despite an echo-enhancing agent; angiography revealed no significant stenosis in all cases. There was one false negative for internal carotid occlusion. This occurred early in the series and could be considered to be a technical error. Importantly, there were no false positives for carotid occlusion. Contrast-enhanced carotid ultrasound significantly improves diagnostic confidence in equivocal carotid ultrasound studies. In appropriate clinical settings this may reduce the need for subsequent carotid angiography.

Topics: Acute Disease; Aged; Aged, 80 and over; Angiography, Digital Subtraction; Carotid Artery, Internal; Carotid Stenosis; Contrast Media; Female; Humans; Injections, Intravenous; Male; Middle Aged; Polysaccharides; Prospective Studies; Ultrasonography, Doppler, Color

Our aim was to assess reproducibility of three different lumen reduction measuring methods--North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and common carotid--using power Doppler and color Doppler sonography before and after Levovist enhancement. We included 20 symptomatic patients with mild or severe carotid disease. North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and common carotid measurements on longitudinal views and European Carotid Surgery Trial measurements on transverse views were performed. Examinations were repeated and the results compared to assess reproducibility of measurements. Correlation with angiography was obtained by calculating Pearson correlation coefficients. Reproducibility was significantly better (P < 0.05) for European Carotid Surgery Trial and common carotid measurements (95% limits of agreement between -10% to 10% and -19% to 17%) as compared to North American Symptomatic Carotid Endarterectomy Trial measurements (95% limits of agreement between -11% to 21% and -21% to 23%). Variability of measurements after enhancement increased slightly (not significant) for both power and color Doppler sonography. Additionally, European Carotid Surgery Trial measurements, using nonenhanced power Doppler or color Doppler sonography, did not correlate significantly with angiography, whereas North American Symptomatic Carotid Endarterectomy Trial and common carotid measurements correlated well with angiography, particularly in power Doppler mode after enhancement (r = 0.88 and r = 0.82, respectively). We conclude that for lumen reduction measurements of the internal carotid artery with power and color Doppler sonography, the common carotid method is the only method that is reproducible and has good correlation with angiography, which slightly improves after Levovist enhancement.

Topics: Aged; Aged, 80 and over; Angiography; Blood Flow Velocity; Carotid Artery, Internal; Carotid Stenosis; Contrast Media; Female; Follow-Up Studies; Humans; Image Enhancement; Injections, Intravenous; Male; Middle Aged; Observer Variation; Polysaccharides; Reproducibility of Results; Ultrasonography, Doppler, Color

Some patients with internal carotid artery (ICA) occlusion or stenosis are at risk of developing a hemodynamic stroke. Transcranial ultrasonography using an echo-contrast bolus technique might be able to assess the extent of hemodynamic compromise. We describe a transcranial Doppler sonographic method that analyzes the differences in echo-contrast bolus arrival between both middle cerebral arteries after intravenous echo-contrast application. Ten patients with 50%-79% ICA stenosis, 10 patients with 80%-99% ICA stenosis and 22 patients with ICA occlusion were studied and compared with 15 age-matched controls. There were significant increases in delayed filling of the middle cerebral artery in both 80%-99% stenoses and occlusions compared with controls. The extent of the observed delays did not correlate with vasomotor reactivity. Echo-contrast bolus arrival time can be used to gain additional information on the intracranial hemodynamic effects of extracranial carotid artery disease that seems to be independent of the established ultrasound indices.

Topics: Aged; Carotid Stenosis; Computer Simulation; Contrast Media; Female; Humans; Image Interpretation, Computer-Assisted; Infarction, Middle Cerebral Artery; Male; Middle Aged; Models, Cardiovascular; Polysaccharides; Reproducibility of Results; Sensitivity and Specificity; Ultrasonography, Doppler, Transcranial

Occlusion of the internal carotid artery (ICA) and stroke may be the consequence of either local thrombosis due to atherosclerosis or massive embolism. Up to date, there are only few reports of subsequent recanalization.. We report 12/76 cases of acute ICA occlusion leading to ischemic stroke, in which early recanalization was identified. Ultrasound and stroke MRI findings, therapeutic options, and outcome are described.. 10/12 patients showed an- or hypoechogenic morphology of occlusion. While in 7/12 cases complete recanalization was seen, in 5/12 patients partial recanalization with filiform flow (4) or residual high-grade stenosis (1) was detected. 10/12 patients had territorial or subcortical infarction, while two showed small cortical lesions only. In 7/12 cases, a potential cardiac source of embolism was found. Five patients received tPA; four patients underwent early carotid endarterectomy of the partially recanalized ICA within 48 hours. In the 10-day follow-up examination 10/12 patients showed clinical improvement as measured by the NIHSS.. Spontaneous recanalization after occlusion of the ICA may occur and might be more frequent than hitherto assumed. Echogenicity analysis and serial examinations of symptomatic ICA occlusion is useful for identifying a patient subgroup that might benefit from further therapy.

Topics: Acute Disease; Aged; Carotid Artery, Internal; Carotid Stenosis; Contrast Media; Female; Gadolinium DTPA; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Polysaccharides; Remission, Spontaneous; Stroke; Ultrasonography, Doppler, Duplex

The aim of this study is to assess contrast-enhanced transcranial color-coded duplex sonography (CE-TCCS) diagnosis of basilar artery (BA) stenosis.. CE-TCCS and cerebral angiography were performed in 120 consecutive patients. The patients were angiographically divided into five groups: (1) intracranial arteries (ICA) stenosis but no BA stenosis as intracranial stenosis (ICS) group, (2) both ICA and BA stenoses as internal carotid arteay and basilar arteay stenoses (IBS) group, (3) BA stenosis as basilar artery stenosis (BAS) group, (4) BA occlusion as basilar artery occlusion (BAO) group, and (5) no arterial lesions as Control group. We compared the peak systolic flow velocity (PSV) of BA using CE-TCCS.. PSV was highest in the BAS group (n= 9, 206.1 +/- 118.6 cm/sec), followed by the ICS (n= 27, 74.9 +/- 36.1 cm/sec) and Control (n= 70, 58.2 +/- 17.3 cm/sec) groups. IBS group had two patients (PSV: 102 cm/sec and 167 cm/sec). Sensitivity-specificity curve analysis revealed a cutoff PSV of 120 cm/sec to distinguish the BAS group from other groups, and then we calculated sensitivity of 100%, specificity of 95%, positive predictive value of 64%, negative predictive value of 100%, and accuracy of 95%.. Measurement of PSV of the BA using CE-TCCS is useful for the identification of BA stenosis.

Topics: Aged; Angiography, Digital Subtraction; Blood Flow Velocity; Brain Ischemia; Carotid Stenosis; Cerebral Angiography; Cerebral Hemorrhage; Cerebral Infarction; Contrast Media; Female; Humans; Image Enhancement; Ischemic Attack, Transient; Male; Middle Aged; Polysaccharides; Prospective Studies; Sensitivity and Specificity; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial; Vertebrobasilar Insufficiency

Proper assessment of endovascular patency after carotid stent (CS) placement with carotid color-coded duplex sonography (CCCD) can be difficult. We investigated the usefulness of contrast-enhanced (CE) CCCD for post-CS follow-up. CCCD images could not depict the entire bloodstream in overlapped stents and in highly positioned stents. CE-CCCD images, however, did provide anatomic information almost equivalent to that of intra-arterial angiography. CE-CCCD is useful in screening for post-CS restenosis.

Topics: Aged; Angiography, Digital Subtraction; Carotid Arteries; Carotid Stenosis; Contrast Media; Female; Humans; Male; Middle Aged; Polysaccharides; Recurrence; Stents; Ultrasonography, Doppler, Color; Vascular Patency

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.

Topics: Aged; Aged, 80 and over; Asian People; Blood Flow Velocity; Carotid Stenosis; Contrast Media; Female; Humans; Image Enhancement; Infarction, Middle Cerebral Artery; Injections, Intravenous; Intracranial Arteriosclerosis; Male; Middle Aged; Polysaccharides; Signal Processing, Computer-Assisted; Ultrasonography, Doppler, Transcranial

We prospectively evaluated 30 consecutive patients with echo-enhanced transcranial color-coded duplexsonography (TCCD) and correlative transfemoral digital subtraction angiography to assess the diagnostic efficacy of echo-enhanced TCCD for evaluation of collateral pathways through the circle of Willis in patients with limited acoustic bone windows and critical symptomatic carotid disease. Echo-enhanced TCCD detected collateral blood flow through the anterior communicating artery in 16 of 18 patients (sensitivity 89%, 95% CI 65-99%) and was false positive in one out of 12 patients without collateral flow (specificity 92%, 95% CI 59-100%). For the posterior communicating artery, sensitivity was 11/14 (79%, 95% CI 49-95%) and specificity was 15/16 (94%, 95% CI 70-100%). Echo-enhanced TCCD enables to study collateral blood flow through the communicating arteries of the circle of Willis with high sensitivity and specificity in patients with obstructions of the internal carotid artery and limited acoustic bone windows.

Topics: Aged; Angiography, Digital Subtraction; Carotid Stenosis; Cerebrovascular Circulation; Circle of Willis; Collateral Circulation; Contrast Media; Female; Humans; Male; Middle Aged; Polysaccharides; Prospective Studies; Sensitivity and Specificity; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

The use of low frequency probes allows to overcome the resistance of the skull and evaluate Willis's circle by B-mode and Trans-Cranial Color-Doppler (TCCD) to obtain morphological and functional information related to brain circulation during pathologic conditions. With the new software available today modern technology allow us to measure the transient scattering produced by the rupture of the contrast medium microbubbles and estimate the presence of the contrast medium both in macro- and microcircle. In this way it is possible to appraise parenchymal perfusion. This study aims to assess the intracranial micro- and macrocircle using TCCD with contrast medium (Levovist) and to compare the results with the patients' clinical signs.. We studied 21 subjects aged 45-73 years (mean 68 years) with atheromatous uncomplicated plaques in the internal carotid artery producing varying degrees of stenosis and 10 healthy controls. The examinations were performed using an ATL HDI 3000 ultrasound machine with a Phased Array 3.25 MHz probe. The mechanic index was calibrated to high values to obtain rupture of the microbubbles under insonation. Intensity/time curves of transient scattering were extrapolated for both the cerebral macrocircle and the parenchymal microcircle in the region of interest.. The curves were compared with the clinical presentation of the different classes of patients and the results obtained were consistent in showing a clinical pattern of perfusional deficit in subjects with symptoms of chronic brain ischemia. In particular, it was possible to compare the morphologic data relative to the contrast medium decay curves with the patient's clinical condition, confirming the suspicion of cerebral microcircle pathology.. Thanks to improvements in the software and to the definition of effective algorithms, contrast-enhanced TCCD will be able to provide information on brain perfusion in a simple, inexpensive and relatively non-invasive manner.

Topics: Adult; Aged; Algorithms; Brain Ischemia; Carotid Artery Diseases; Carotid Artery, Internal; Carotid Stenosis; Cerebrovascular Circulation; Chronic Disease; Contrast Media; Humans; Intracranial Arteriosclerosis; Middle Aged; Polysaccharides; Software; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

The purpose of this study was to evaluate the use of an echo-enhancing agent in patients with carotid artery occlusion to improve the sensitivity and specificity of carotid color flow ultrasonography.. Between January 1997 and December 1998, a prospective study involving 85 cases of carotid artery occlusion in 84 patients was carried out. After a baseline duplex ultrasonography (DU) diagnosis, a second (DU) along with an echo-enhancement agent (SHU-508-A [Levovist]) study was carried out (echo enhancement ultrasonography diagnosis [DUEE]). In 82 cases, a contrast angiography was performed to confirm the diagnosis, whereas in the other three cases the diagnoses were confirmed with surgery.. From the 85 internal carotid artery occlusions diagnosed at the initial DU examination, seven came out to be false occlusions in the DUEE examination (8,2%). There was a 100% correlation of the cases between the DUEE examination and the contrast angiography in the 82 cases in which this had been done. In three of the cases, the diagnosis was confirmed surgically because these displayed severe stenoses according to the DUEE studies in symptomatic patients, and so they required urgent treatment.. The DUEE study is a potent diagnosis tool that allows the differentiation between true carotid artery occlusions and pseudo-occlusions.

Topics: Aged; Angiography; Arterial Occlusive Diseases; Carotid Artery Diseases; Carotid Artery, Internal; Carotid Stenosis; Confidence Intervals; Contrast Media; Evaluation Studies as Topic; False Positive Reactions; Female; Humans; Image Enhancement; Male; Polysaccharides; Predictive Value of Tests; Prospective Studies; Radiographic Image Enhancement; Reproducibility of Results; Sensitivity and Specificity; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Duplex

Echocontrast agents (ECA) are known to improve transcranial color-coded duplex (TCCD) imaging, but its diagnostic benefit in the routine clinical setting has not clearly been defined. The authors investigated the diagnostic benefit of ECA application in 54 patients with insufficient transtemporal bone window, consecutively referred to their ultrasound laboratory. According to the precontrast imaging quality, patients were assigned to three categories: A, no intracranial structures or vessel segments visible on B-mode imaging and TCCD (n = 5); and intracranial structures visible on B-mode imaging and vessel segments less than 5 mm in length (B, n = 21), or larger than 5 mm in length (C, n = 28) visible on TCCD. The effect of the echocontrast enhancement was assessed with respect to signal enhancement, imaging quality, and diagnostic confidence. In 49 out of 54 patients (91%), a significant improvement of the imaging quality was noted, enabling 43 (80%) neurovascular diagnoses of sufficient diagnostic confidence. The diagnostic ECA effect was strongly dependent on the precontrast imaging quality: upon echoenhancement, a satisfactory image quality was obtained in none of the patients of category A, as opposed to 16 (76%) and 27 (96%) patients of categories B and C, respectively. In summary, in 80% of our consecutive patient series with insufficient transtemporal bone window, application of ECA allowed for a conclusive TCCD study. Properties of the transtemporal precontrast scans are strongly predictive of the diagnostic benefit and should be taken into the decisive consideration.

Topics: Adult; Aged; Aged, 80 and over; Brain; Brain Ischemia; Carotid Stenosis; Cerebrovascular Disorders; Cohort Studies; Contrast Media; Female; Forecasting; Humans; Image Enhancement; Male; Middle Aged; Polysaccharides; Prospective Studies; Temporal Bone; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Duplex; Ultrasonography, Doppler, Transcranial

Transcranial color Doppler sonography permits the accurate assessment of intracranial arteries. The latest Doppler units, using the color and power techniques, can show even very small flow volumes (1 x 1 mm). Low frequency (2-2.5 MHz) and very focused transducers are used in transcranial color Doppler. The skull is a very strong barrier for ultrasounds, which requires the use of some acoustic windows like some thin portions of the skull bone or some natural skull foramina. The use of echocontrast agents in color Doppler seems to increase the applications of transcranial studies.. (1) To report on transcranial color Doppler technique and findings. (2) To assess the role of contrast agents in the visualization of intracranial vessels. (3) To define the main indications of this technique.. The temporal, the orbital and the suboccipital are the main acoustic windows used for transcranial color Doppler studies. We use phased-array transducers (2-2.5 MHz) and, preferrably, the echocontrast agent. We examined 15 patients with severe internal carotid artery stenoses after the infusion of Levovist (Schering AG, Berlin, Germany) suspension (8 ml at 300 mg Galactose/ml, infused at 0.5 ml/s).. Levovist infusion permitted to depict the main intracranial vessels in all cases. The middle and the anterior cerebral arteries are shown through the temporal window. The former is the main cerebral artery, it is the easiest to identify and presents the highest peak systolic velocity. The orbital window can be used to visualize the ophthalmic artery and the internal carotid artery siphon, while the vertebral and the basilar arteries are demonstrated through the suboccipital window.. We report the most important findings and discuss the main indications of transcranial color Doppler studies. In addition to flow presence and direction, the main indices of arterial flow can be measured thanks to contrast agent administration, namely the peak systolic velocity, the end diastolic velocity, the resistance index and the pulsatility index. A morphological assessment of the Willis circle can also be carried out with color and power Doppler. Functional studies can be performed to assess the residual autoregulatory function of the cerebral circle in the patients with internal carotid artery stenosis or occlusion. The development of intracranial collateral circles can also be studied in these patients. Moreover, the M1 segment of the middle cerebral artery and the internal carotid artery siphon can be demonstrated directly. Transcranial color Doppler is also a useful tool to detect vasospasm after subarachnoid hemorrhage and to monitor blood flow velocity in the middle cerebral artery during carotid endarterectomy. The assessment of blood supply to arteriovenous malformations and to intracranial neoplasms is another application.. With reference to internal carotid stenoses, the main applications of transcranial color Doppler are the study of intracranial vessels, of intracranial arterial stenosis, of arteriovenous malformations and of Willis circle aneurysms, as well as the monitoring of blood flow velocity during carotid endarterectomy. Echocontrast agents play an important role in the visualization of intracranial vessels.

Topics: Arterial Occlusive Diseases; Blood Flow Velocity; Brain; Carotid Stenosis; Contrast Media; Humans; Polysaccharides; Reference Values; Sensitivity and Specificity; Subarachnoid Hemorrhage; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

Although ultrasound is a highly useful tool for clinical diagnosis, it has certain limitations in accurately quantifying internal carotid stenosis or diagnosing internal carotid occlusion. However, these limitations can be overcome by increasing the echogenicity of flowing arterial blood by use of echo-enhancement agents. Two phase III studies assessed the usefulness of the IV transpulmonary echo enhancer Levovist (SH U 508A) in improving characterization and quantification of severe internal carotid stenosis on ultrasound scans. In addition, Levovist-induced enhancement characteristics of the Doppler frequency spectrum have been analyzed. To be included in the study reviewed here, patients had to have a high-grade (> or = 70%) stenosis or occlusion of an internal carotid artery (ICA), as judged by conventional angiography or by standard cervical Doppler ultrasound. Patients were excluded from consideration if they were pregnant or nursing, had a history of galactosemia, or had received an ionic contrast medium within 24 hours before or after the intended administration of Levovist. Written informed consent was obtained from all patients before entry into the study. Of 32 patients (14 women, 18 men, median age 64 yr) who were included in this study, high-grade stenosis was verified in 30 ICA vessels and occlusion was verified in two vessels. After admission into the study, the carotid bifurcation was insonated in all patients using a 7.5-MHz linear array transducer for color Doppler-assisted duplex imaging and a 4-MHz pulsed-wave Doppler for velocity spectrum measurements before and after injection of the echo enhancement agent Levovist. Levovist-induced increases in carotid blood echogenicity began 11 +/- 2 seconds (mean +/- SD) after the start of injection, peaked at 21 +/- 2 dB, and had a half-life of 75 seconds. A fast Fourier transform of the original Doppler velocity spectrum demonstrated Levovist-induced enhancement throughout the entire velocity spectrum, with an increase in ICA blood flow velocity paralleling an increase in reflected ultrasound energy. Quantitative vascular measurements (cross-sectional luminal area reduction and plaque length) obtained before and during echo enhancement were highly correlated (r > 0.90). However, visualization of the entire length of the intrastenotic residual flow lumen, was significantly improved by Levovist enhancement (52% versus 83%; p = 0.01). Levovist considerably increased interpretable data by improving

Topics: Blood Flow Velocity; Carotid Artery, Internal; Carotid Stenosis; Cerebrovascular Circulation; Contrast Media; Female; Fourier Analysis; Humans; Male; Middle Aged; Polysaccharides; Signal Processing, Computer-Assisted; Ultrasonography, Doppler, Color

This study evaluated intracranial cerebral arteries using a new data acquisition system for transcranial three-dimensional (3D) ultrasonography with and without an echo contrast agent, with confirmation by cerebral angiography. Ten patients, studied with diagnostic cerebral angiography, were examined without knowledge of the angiographic results. Data acquisition through the transtemporal acoustic window was performed using a magnetic sensor system to track the spatial orientation of the ultrasound probe while scanning the volume of interest. A color transcranial duplex system with a power Doppler mode was used, and 3D data sets were acquired before and after the injection of transpulmonary-stable ultrasound contrast medium. Ipsilateral to the transducer, the anterior cerebral artery (ACA) in 90%, middle cerebral artery (MCA) in 60%, all three or more branches of the MCA in 60%, posterior cerebral artery (PCA) in 60%, and posterior communicating artery (PCoA) in 60% were successfully imaged without the echo contrast agent. With the contrast agent, the ACA, MCA, three or more branches of the MCA, PCA, and PCoA were visible in 100%. The anterior communicating artery was visualized in 40% without contrast enhancement and in 90% with contrast enhancement. Contralateral to the transducer, the ACA (60%), MCA (30%), all three or more branches of the MCA (10%), PCA (20%), and PCoA (20%) were successfully imaged without contrast. Contrast enhancement improved the imaging success rate for the ACA (90%), MCA (80%), three or more branches of the MCA (80%), PCA (100%), and PCoA (100%). A transpulmonary-stable ultrasound contrast agent used in combination with 3D transcranial duplex ultrasonography can significantly improve the success rate for transcranial color duplex imaging of intracranial arteries.

Topics: Adult; Carotid Stenosis; Cerebral Angiography; Cerebral Arterial Diseases; Contrast Media; Female; Humans; Image Processing, Computer-Assisted; Male; Polysaccharides; Ultrasonography, Doppler, Transcranial

The usefulness of SH-U-508A (Laevovist) in the quantification of high-grade internal carotid stenosis (ICA) is assessed in this study. 32 patients with high-grade ICA stenosis (> = 70%) or occlusion are examined using colour Doppler-assisted duplex imaging (CDDI) before and after injection of SH-U-508A.. The SH-U-508A-induced increase in blood echogenicity started at 9.8 s (mean; SD: 2.2) after bolus injection and peaked at 21 dB (mean; SD: 1.9; n = 12) after 14.8 s (mean; SD: 2.9). In addition, SH-U-508A led to a significant increase in systolic peak velocity determined in the common carotid artery, by 26% (mean; SD: 9; p < 0.05). Significant differences between non-enhanced and enhanced CDDI were found for the visualisation of the entire length of the intrastenotic residual lumen (43% vs 83%; p < 0.01). Correlations between non-enhanced and enhanced CDDI were high (r > 0.9) for the determination of cross-sectional area reduction and plaque length.. SH-U-508A may be useful in quantifying high-grade ICA stenoses with insufficient delineation at non-enhanced CDDI.

Topics: Aged; Blood Flow Velocity; Carotid Artery, Internal; Carotid Stenosis; Contrast Media; Female; Humans; Male; Middle Aged; Polysaccharides; Ultrasonography, Doppler, Color

The remaining limitations of ultrasonographic imaging in accurately quantifying internal carotid stenosis or diagnosing internal carotid occlusion may be overcome by enhancing the echogenicity of flowing arterial blood with contrast agents. This study assessed the usefulness of the intravenous (transpulmonary) contrast medium SH U 508 A in improving the characterization and quantification of severe internal carotid stenosis.. We examined 32 patients (30 had vessels with a stenosis of greater than 70% luminal narrowing and 2 had vessel occlusions) using a 7.5-MHz linear-array transducer for color Doppler-assisted duplex imaging before and after injection of the contrast medium.. The SH U 508 A-induced increase in carotid blood echogenicity began 11 +/- 2 (mean +/- SD) seconds after the start of the bolus injection, peaked at 21 +/- 2 dB, and showed a half-life of 75 seconds. Quantitative vascular measurements (cross-sectional luminal area reduction and plaque length, respectively) obtained before and after contrast application were highly correlated (r > .90). Visualization of the entire length of the intrastenotic residual flow lumen, however, was significantly improved by contrast enhancement (52% versus 83%, P = .01).. This pilot study on patients with extracranial carotid artery disease suggested that ultrasonic contrast media may be most useful in improving the ultrasonography-based diagnosis of internal carotid occlusion.

Topics: Aged; Carotid Artery, Internal; Carotid Stenosis; Contrast Media; Echoencephalography; Female; Fourier Analysis; Humans; Infusions, Intravenous; Male; Middle Aged; Polysaccharides; Probability