shu-508 and Cerebrovascular-Disorders

Extracranial and transcranial colour-coded duplex sonography (TCCD) are used routinely in clinical practice to assess physiologic and pathologic arterial blood flow to the brain. Such investigations are straightforward, safe, and cost effective, and can be repeated frequently for patient follow-up. In addition, the portability of extracranial colour-coded duplex sonography and TCCD provides the option of bedside investigations, particularly useful for evaluation of the critically ill patient. However, duplex ultrasound can be hampered by insufficient acoustic penetration, an unfavourable insonation angle, or by conditions of low or no flow. Echocontrast agents capable of surviving pulmonary and capillary transit have been developed, and such agents increase the Doppler signal and, therefore, the success rate of neurosonographic investigations. Approximately 20% of TCCD studies involve poor insonation conditions and, therefore, the use of echocontrast agents is of particular interest for this application. Levovist and SonoVue are the two agents currently approved for use in neurosonography. Such agents have a relatively long-lasting effect (up to 7 min), and can be administered as a single injection or, alternatively, a fractionated injection protocol can be used, depending on the quality of the window.

Topics: Cerebrovascular Circulation; Cerebrovascular Disorders; Contraindications; Contrast Media; Humans; Image Enhancement; Microbubbles; Phospholipids; Polysaccharides; Sulfur Hexafluoride; Ultrasonography

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.

Topics: Cerebrovascular Disorders; Contrast Media; Humans; Image Enhancement; Magnetic Resonance Imaging; Polysaccharides; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

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

Transcranial Doppler (TCD) and transcranial color-coded duplex sonography (TCCD) are ultrasound neuroimaging modalities that can provide useful diagnostic information on the intracranial vasculature with a high degree of safety. However, the skull can serve as an effective bone barrier, reducing reflected ultrasound signal by up to 100% in some patients and thereby challenging both technical quality and clinical interpretation of TCD and TCCD. Levovist is an IV ultrasound echo-enhancement agent that withstands passage through the heart and lung, increasing signal throughout the entire vascular pool. As part of European phase II and III clinical trials, this agent has been studied for utility of enhancement for TCD and TCCD studies in patients with signs and symptoms of cerebrovascular disease. All patients had either highly insufficient or nonexistent native signal on baseline transcranial ultrasound studies before administration of Levovist. The agent was administered at concentrations of 200, 300, or 400 mg/ml, and studies were repeated. In all studies, 300 to 400 mg/ml was sufficient for enhancement, although in several phase II studies 300 mg/ml Levovist was the preferred dosage in terms of superior imaging with a low level of side effects. In a phase III study, Levovist improved diagnostic utility of TCD and TCCD without compromising safety. Reviews of clinical phase II and III studies show that echo enhancement with Levovist facilitates routine clinical investigation of intracranial vascular anatomy in patients with signs and symptoms of intracranial vascular disease. In patients with no native signal, Levovist-enhanced imaging permits visualization of small peripheral vessels, venous circulation, tissue characteristics, and perfusion data, with no significant loss of safety.

Topics: Aged; Animals; Brain Neoplasms; Cerebrovascular Disorders; Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Contrast Media; Female; Humans; Male; Middle Aged; Polysaccharides; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

To confirm the reliability of a refill kinetic method of ultrasonic harmonic perfusion imaging (HPI) capable of quantifying separate parameters of microvascular blood flow velocity and volume in brain tissue, we evaluated acetazolamide (ACZ) cerebrovascular reactivity by transcranial HPI in comparison with Doppler sonography (TCD). Methods. HPI during continuous Levovist infusion with changing pulsing intervals (t) and TCD time-averaged maximum velocity (TAMX) in the middle and posterior cerebral arteries were evaluated before and after ACZ administration in 12 patients, 8 without and 4 with a temporal skull defect. Plateau value (A) and rise rate (beta) of intensity (I) represented by HPI time-intensity curves of I(t) = A(1 - e(-beta*t)) were analyzed on the axial diencephalic plane.. 1) A significantly decreased in proportion to the region of interest location depth only in the intact skull cases. 2) Despite inter- and intra-individual data scattering, in correspondence with TAMX increases after ACZ, significant beta increases were more frequently identified than increases of A.. Cerebral vasoreactivity analysis utilizing refill kinetics of transcranial HPI can potentially provide separate quantification based on microvascular blood velocity and volume (capillary patency) with consideration of depth-dependant ultrasound attenuation. This should be suitable for bedside evaluation of neurointensive care patients.

Topics: Acetazolamide; Brain; Cerebrovascular Circulation; Cerebrovascular Disorders; Contrast Media; Female; Humans; Image Enhancement; Image Interpretation, Computer-Assisted; Kinetics; Male; Polysaccharides; Reproducibility of Results; Sensitivity and Specificity; Ultrasonography, Doppler, Transcranial

Ultrasonography (US) is a well-established method used to assess the brain-supplying arteries in the acute stroke setting. However, several technical and anatomic limitations are known to reduce its diagnostic accuracy and confidence level. Echocontrast agents (ECA) are known to improve the signal-to-noise ratio by enhancing the intensity of the reflecting Doppler signal. We undertook this prospective study to evaluate the diagnostic value of ECA in a consecutive, nonselected cohort of acute stroke patients with insufficient native US investigations.. During a 1-year period, 25 patients were examined within 48 hours of the onset of stroke. The need for ECA was due to an insufficient transtemporal (n=18), transforaminal (n=4), or extracranial (n=3) imaging of arteries potentially involved in the ischemic event. In 12 patients, a diagnostic suspicion could natively be raised, whereas in the other 13 patients, the strongly reduced image quality did not allow for any neurovascular conclusions. Four grams of Levovist was injected at a concentration of 200 mg/mL and 400 mg/mL for the extracranial and transcranial insonations, respectively. The effect of the echocontrast enhancement was assessed with respect to (1) signal enhancement, (2) image quality, (3) final diagnostic confidence, and (4) the need for additional neurovascular imaging methods.. In all but one patient (96%), a strong signal enhancement was noted, leading to a moderate (n=11) or strong improvement (n=10) of the transcranial image quality. Thus in a total of 18 patients (72%), the echoenhancement provided a neurovascular diagnosis of sufficient confidence. This led to the confirmation of the previously suspected findings and disclosed three further occlusions and four stenoses of the intracranial arteries. In contrast, for the three extracranial examinations the image quality was not sufficiently improved because of persistent color artifacts derived from adjacent neck vessels. Besides the seven patients with inconclusive examinations, five patients with conclusive echoenhanced US studies (48% in total) demanded additive neurovascular imaging studies, based on the clinical decision of the attending physicians. This led to confirmation of all high-confident sonographic diagnoses.. In summary, in approximately three fourths of our acute stroke patients with insufficient native US investigations, echocontrast enhancement enabled a reliable neurovascular diagnosis, allowing the cancellation of additive neurovascular imaging procedures in half of our cohort. Our preliminary results suggest that ECA can reasonably support the early cerebrovascular workup in the acute stroke setting.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Cerebral Angiography; Cerebrovascular Disorders; Contrast Media; Diagnostic Imaging; Female; Follow-Up Studies; Humans; Image Enhancement; Image Processing, Computer-Assisted; Magnetic Resonance Angiography; Male; Middle Aged; Pilot Projects; Polysaccharides; Sensitivity and Specificity; Tomography, X-Ray Computed; Ultrasonography, Doppler, Transcranial

We sought to evaluate the diagnostic value of echo-enhanced transcranial color-coded duplex sonography (TCCD) and the clinical relevance of vascular pathology assessed by sonography for early clinical outcome in acute ischemic stroke.. We present 23 consecutive patients with an anterior circulation stroke in whom clinical examination, CT, and ultrasonography were performed within 5 hours after the onset of symptoms. Transcranial Doppler sonography (TCD) and unenhanced and contrast-enhanced TCCD (Levovist, 4 g, 300 mg/mL) were compared for their ability to detect middle cerebral artery (MCA) occlusion and flow velocity reduction suggesting hemodynamic impairment in the MCA distribution pathway. Sonographic examination times were registered. Baseline clinical characteristics and CT findings were assessed. Neurological deficit was quantified according to the National Institutes of Health Stroke Scale score, with an early clinical improvement defined as decrease of the score by 4 or more points or a complete resolution of the deficit on day 4.. Contrast-enhanced TCCD enabled diagnosis of intracranial vascular pathology in 20 affected hemispheres, whereas unenhanced TCCD and TCD were conclusive in 7 and 14 hemispheres, respectively (P=0.0001). Contrast-enhanced TCCD was superior in evaluating distal carotid (carotid-T) occlusion and differentiating major vessel occlusions from patent arteries with flow velocity diminution. Mean examination time for enhanced TCCD ranged from 5 to 7 minutes, depending on the number of investigated vessels (without or with MCA branches). Logistic regression selected a patent MCA without reduced blood flow velocity as the only independent predictor for an early clinical improvement (P<0.01).. Contrast-enhanced TCCD is a promising tool for early prognosis in anterior circulation stroke. It is considered superior to unenhanced TCCD and TCD.

Topics: Acute Disease; Aged; Aged, 80 and over; Arterial Occlusive Diseases; Cerebral Arteries; Cerebrovascular Disorders; Contrast Media; Diagnostic Imaging; Female; Humans; Image Enhancement; Male; Middle Aged; Polysaccharides; Prognosis; Reproducibility of Results; Sensitivity and Specificity; Time Factors; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

To evaluate the potential and limitations of echocontrast enhancement using Levovist in a non selected consecutive cohort of neurological patients with insufficient native ultrasound investigations.. In 91 patients an indication for echocontrast application was seen after an insufficient extracranial (n = 17), transtemporal (n = 54), and transforaminal (n = 20) Doppler- und color-coded Duplex sonography. Levovist was injected at a concentration of 400 mg/ml and 200-400 mg/ml for the transcranial and extracranial approach, respectively. The effect of the echocontrast enhancement was assessed semiquantitatively with respect to signal enhancement, imaging quality, and diagnostic confidence.. In a total of 83 patients (91%) the signal enhancement led to a moderate to high imaging quality allowing to reach 67 definite neurovascular diagnoses (74%). In subgroup analysis, the amount of sufficiently confident examinations was significantly higher for the transtemporal and transforaminal (both 80%) than for the extracranial approach (47%). The latter was mostly due to artificial signals derived from adjacent neck vessels.. Levovist constitutes a safe and highly effective diagnostic tool especially for the transtemporal and transforaminal neurosonographical imaging. By means of a differentiated application of echocontrast agents, its cost-effectiveness can be increased and the need for other potential invasive and expansive neuroimaging methods can be further reduced.

Topics: Adult; Aged; Aged, 80 and over; Cerebrovascular Disorders; Contrast Media; Female; Humans; Image Enhancement; Male; Middle Aged; Polysaccharides; Ultrasonography, Doppler

Pulsed color Doppler imaging of cerebrovascular structures permits rapid visual identification of the intracranial vessels. In some patients, however, the clinical utility of transcranial ultrasound examinations is limited by poor tissue penetration and inadequate imaging of vessels. This phase-two clinical trial evaluates whether administration of an echocontrast agent in such ultrasound-refractory patients enhances image acquisition enough to yield meaningful diagnostic impressions.. This is a phase-two clinical trial of safety and efficacy of the "galactose/palmitic acid-based microbubble preparation" Levovist injection (Berlex Laboratories). Thirty subjects with clinical indications for cerebrovascular imaging but refractory to transcranial Doppler studies were enrolled in a nonrandomized, single-center study. Echocontrast agent was administered intravenously in a tiered-dose protocol. Safety was determined by clinical and laboratory monitoring for 18 to 24 hours. Efficacy of contrast enhancement was determined by comparisons between each patient's precontrast (control) and postcontrast images.. No significant patient discomfort, side effects, or adverse reactions occurred that were due to the intravenous administration of the echocontrast agent. Optimal image enhancement was obtained using the 300-mg/mL concentration (3 g bolus) of contrast. Visualization of both individual arterial segments and/or the entire circle of Willis was demonstrated. Clinical confidence of diagnostic impressions was achieved in 77% (23/30) of subjects.. The transpulmonary ultrasound contrast agent (Levovist injection) was easily administered and found to be safe in the 30 patients studied and increased the diagnostic utility of transcranial ultrasound in 77% of the patients studied.

Topics: Adult; Aged; Aged, 80 and over; Carotid Arteries; Cerebrovascular Disorders; Contrast Media; Female; Humans; Injections, Intravenous; Male; Middle Aged; Polysaccharides; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial; United States; Vascular Diseases

The purpose of this first patient study (phase II) was to evaluate the clinical usefulness of a new echo contrast agent at transcranial Doppler ultrasonography (US). Twenty patients were selected from a group of 242 patients undergoing conventional transcranial Doppler US who had low (n = 18) or absent (n = 2) Doppler signals from the middle cerebral artery (MCA). The extent and duration of Doppler signal increase was measured in 30 MCAs and in 14 basilar arteries following the intravenous injection of a transpulmonary galactose microparticle suspension (SH U 508 A) at three concentrations (200, 300, and 400 mg/mL). Doppler waveform analysis became possible in 93% (28 of 30) of the MCAs following injection. The maximal increase in average Doppler signal intensity (11 dB at 200 mg/mL, 15 dB at 300 mg/mL, and 17 dB at 400 mg/mL) and the increase in average duration of the signal enhancement (163 seconds at 200 mg/mL, 219 seconds at 300 mg/mL, and 240 seconds at 400 mg/mL) depended on contrast agent concentration. Doppler waveform analysis became possible in 79% (11 of 14) of the basilar arteries. The intravenous injection of this new echo contrast agent markedly increases Doppler signal intensity in patients with nondiagnostic results at conventional Doppler US.

Topics: Basilar Artery; Blood Flow Velocity; Cerebral Arteries; Cerebrovascular Circulation; Cerebrovascular Disorders; Contrast Media; Dose-Response Relationship, Drug; Echoencephalography; Female; Humans; Male; Middle Aged; Polysaccharides

Intracranial stenoses are associated with a considerable number of strokes each year. The clinical value of a workstation-based three-dimensional (3D) reconstruction system for transcranial color-coded sonography was evaluated in patients with intracranial stenosis or occlusion.. Twenty-six patients (13 men, 13 women; mean age, 57 years +/- 12 [SD]) with 36 intracranial stenoses or occlusions, as detected at two-dimensional (2D) color Doppler imaging (CDI) and digital subtraction angiography (DSA), underwent Levovist-enhanced power Doppler imaging (PDI), with subsequent 3D reconstruction. A workstation connected to a magnetic sensor capable of spatial localization of the probe was used to reconstruct 3D images of the circle of Willis from serial PDI images.. At DSA, seven (19%) stenoses were estimated to less than 50%, 24 (67%) were 50% or more, and five (14%) were occluded. DSA and 3D-PDI estimates of the degree of stenosis agreed in 33 cases (92%), with a weighted kappa value of 0.86. Disagreement occurred with two subtotal basilar artery stenoses and one subtotal middle cerebral artery stenosis, which were evaluated as being complete occlusions at 3D-PDI. Interobserver agreement between two experienced 3D investigators in estimating the percentage of stenosis was high (correlation coefficient,.98).. 3D-PDI enables the investigator to reconstruct virtually any arbitrary viewing angle. Compared with conventional CDI, 3D-PDI offers easier spatial assessment of intracranial stenoses, and its findings are sufficiently correlated with angiographic findings. Because different investigators can postprocess the same 3D data, improving reproducibility and reducing investigator dependency in transcranial color-coded sonography may be possible.

Topics: Aged; Angiography, Digital Subtraction; Cerebrovascular Disorders; Circle of Willis; Constriction, Pathologic; Contrast Media; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Middle Aged; Polysaccharides; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial

Since the introduction of contrast media, transcranial colour-coded sonography (TCCS) has become increasingly important for examination of the intracranial vessels. However, the widely practised bolus injection of these agents leads to initial blooming artefacts and thereafter the level of contrast enhancement decreases rapidly, reducing the effective time of enhancement. It was our aim to investigate the effect of continuous administration of contrast medium at a defined infusion rate. We performed 28 TCCS examinations of the intracranial vessels in 26 patients using a 2.25 MHz phased-array transducer during administration of 4 g Levovist (Schering, Berlin, Germany) 300 mg/ml with a constant infusion rate of 60 ml/h into an antecubital vein. The degree of enhancement was graded over time in a subjective analysis by two independent observers. During continuous administration, a constant level of contrast enhancement was reached after 60.1+/-26.2 s and this lasted 663.4+/-55.8 s as assessed by the first observer (66.6+/-26.2 s and 664.3+/-55.9 s according to the second observer). The limits of inter-observer agreement ranged from -10.1% to 9.9%. No major blooming effect was seen in the initial phase of the examination.

Topics: Artifacts; Brain; Cerebrovascular Disorders; Contrast Media; Female; Humans; Infusions, Intravenous; Male; Middle Aged; Observer Variation; Polysaccharides; Prospective Studies; Time Factors; Ultrasonography, Doppler, Transcranial

A case of a successful systemic thrombolysis of an acute middle carotid artery occlusion is reported. The case underlines the role of contrast-enhanced transcranial color-coded duplex sonography as a noninvasive technique for rapid diagnosis of vessel occlusion in acute stroke. The diagnostic potential of transcranial color-coded duplex sonography for indication and monitoring of intravenous systemic thrombolytic therapy is demonstrated.

Topics: Acute Disease; Brain Ischemia; Carotid Artery Diseases; Cerebral Arteries; Cerebrovascular Circulation; Cerebrovascular Disorders; Contrast Media; Fibrinolytic Agents; Follow-Up Studies; Humans; Image Enhancement; Male; Middle Aged; Polysaccharides; Thrombolytic Therapy; Thrombosis; Tissue Plasminogen Activator; Ultrasonography, Doppler, Duplex; Ultrasonography, Doppler, Transcranial

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-coded sonography (TCCS) has been used to investigate major brain-supplying arteries, draining veins and brain parenchyma. Here, we describe a contrast-enhanced TCCS analysis of cerebral arteriovenous transit time (cTT) as a measure of cerebral microcirculation. We evaluate its reproducibility and its correlation with clinical impairment of brain function and neuropsychological tests. A total of 27 patients with cerebral microangiopathy and 30 healthy controls were examined. CTT is defined by the time an ultrasound contrast agent requires to pass from the P2-segment of the posterior cerebral artery to the vein of Galen. This was measured by comparison of power Doppler intensity in two off-line defined regions of interest. Serial intraindividual cTT measurements within several min showed a good reproducibility of this parameter. cTT was significantly longer in patients with cerebral microangiopathy than in controls (Mann-Whitney U test,p < 0.001) and related to cognitive impairment measured by the Mini-Mental-State examination. We conclude that it is a quick and reliable parameter related to increased vascular resistance of the microcirculation or a rarefaction of microvessels. Further studies are needed to show the sensitivity and specificity of cTT in the diagnosis of small vessel disease and the interference of important circulation factors, such as heart failure or blood viscosity.

Topics: Aged; Aged, 80 and over; Cerebral Arteries; Cerebral Veins; Cerebrovascular Circulation; Cerebrovascular Disorders; Contrast Media; Female; Humans; Male; Microcirculation; Middle Aged; Polysaccharides; Time Factors; Ultrasonography, Doppler, Transcranial

The purpose of this study was to evaluate the potential of contrast-enhanced three-dimensional (3-D) power Doppler (CE3DPD) in the assessment of intracranial vascular structures, and to compare the results with unenhanced 3-D power Doppler (3DPD) and magnetic resonance angiography (MRA) findings. We insonated 25 patients without cerebrovascular diseases through the temporal bone window using 3DPD and CE3DPD; for comparison, 13 patients underwent MRA. Identification rates of vascular segments and of small branches of intracranial vessels were evaluated by two independent investigators blinded to MRA results. In 21 patients with adequate insonation conditions, CE3DPD significantly improved identification rates compared to 3DPD for the complete visualization of the P1 segment (80.9 vs. 19.0%, p < 0.005, P2 segment (80.9 vs. 42.8%, p < 0.05 and A1 segment (85.7 vs. 38.1%, p < 0.005). Furthermore, CE3DPD depicted, in significantly more examinations, branches of the middle (MCA) and posterior cerebral artery (PCA). Interobserver agreement was higher than 95% for the main intracranial segments and branches of the MCA, but relatively low (80.1-85.7%) for branches of the PCA. In comparison to CE3DPD, MRA identified only parieto-occipital branches of the PCA, temporal branches of the MCA, frontal branches of the anterior cerebral artery and the MCA bifurcation more frequently and accurately. In 4 patients with inadequate acoustic temporal bone windows, the application of a galactose-based microbubble suspension allowed clear 3-D visualization of almost all major intracranial vascular segments and some branches of the large arteries. In conclusion, CE3DPD is a more sensitive ultrasonic tool compared to unenhanced 3-D reconstructions. It makes 3-D ultrasound imaging of the basal cerebral circulation easier to perform and interpret, by providing an improved spatially oriented display of image position. As such, this method may increase operator diagnostic confidence level under pathologic conditions.

Topics: Adult; Aged; Brain; Cerebral Arteries; Cerebrovascular Disorders; Contrast Media; Female; Humans; Injections, Intravenous; Magnetic Resonance Angiography; Male; Middle Aged; Observer Variation; Polysaccharides; Reproducibility of Results; Ultrasonography, Doppler, Transcranial