shu-508 and Brain-Ischemia

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

Color-coded perfusion maps can be calculated from ultrasound harmonic gray-scale imaging data after ultrasound contrast agent bolus injection to analyze brain tissue perfusion. First reports indicate that this method can display cerebral perfusion deficits in acute ischemic stroke. We performed a prospective patient study to evaluate this approach.. Thirty consecutive patients suffering from acute middle cerebral artery infarction who presented to our department within 12 hours after symptom onset were investigated with ultrasound perfusion harmonic imaging (PHI) after Levovist bolus injection. Color-coded perfusion maps were calculated from the ultrasound data. In addition, the original gray-scale images were analyzed in cine mode. Findings were compared with those of cranial CT.. All 30 patients suffered from acute ischemic stroke of the middle cerebral artery territory (median National Institutes of Health Stroke Scale score, 16 points). Twenty-three of the 30 patients (76.7%) had sufficient PHI insonation conditions. In 19 of these 23 patients (82.6%), a marked deficit in contrast enhancement could be visualized by initial PHI with the color-coded parameter images and cine-mode images. In 17 of the 23 (73.9%), the perfusion deficit was found on the parameter images. The area of hypoperfusion in the initial PHI investigation corresponded to the definite area of infarction in follow-up cranial CT. In 3 of 23 patients (13.0%), a perfusion deficit could be demonstrated in PHI, although the supplying artery was found patent by transcranial color-coded duplex sonography.. With PHI, it is possible to display cerebral perfusion deficits in acute ischemic stroke. PHI yields additional information on the perfusion state of the human brain compared with extracranial and transcranial color-coded duplex sonography.

Topics: Acute Disease; Adult; Aged; Brain; Brain Ischemia; Contrast Media; Echoencephalography; Female; Humans; Image Processing, Computer-Assisted; Infarction, Middle Cerebral Artery; Male; Middle Aged; Polysaccharides; Predictive Value of Tests; Prospective Studies; Sensitivity and Specificity; Severity of Illness Index; Stroke; Tomography, X-Ray Computed

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

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.

Topics: Aged; Atrial Appendage; Atrial Fibrillation; Blood Flow Velocity; Brain Ischemia; Contrast Media; Echocardiography, Doppler, Pulsed; Echocardiography, Transesophageal; Female; Follow-Up Studies; Humans; Incidence; Injections, Intravenous; Male; Microbubbles; Polysaccharides; Prognosis; Proportional Hazards Models; Recurrence; Reproducibility of Results; Retrospective Studies; Time Factors

We evaluated the usefulness of an agent for contrast-enhanced ultrasonography (galactose parmitine acid: Levovist) in visualizing brain perfusion in rabbits.. Six rabbits were involved in this study. A hole in the skull bone was made under anesthesia and used as an acoustic window. An ischemic model (3 of 6 rabbits) was made by surgically occluding the M1 portion of the middle cerebral artery. Power Doppler images (PDI) and B-mode Harmonic images (HI) before and after intravenous injections of the contrast medium (150 mg/body) were obtained using the HDI5000 (ATL) equipped with a linear-type 5-12 Mhz probe.. Smaller arteries were clearly visualized by contrast-enhanced PDI. However, enhancement of brain parenchyma was not clear on PDI. Enhancement of brain parenchyma was observed clearly on contrast-enhanced HI. Enhancement was strong during the first pass and then diminished quickly. In ischemic models, hypoperfusion in the right cerebral hemisphere (the occluded side) were clearly observed on contrast-enhanced HI.. Brain perfusion in rabbits can be observed on contrast-enhanced Harmonic ultrasonographic imaging. It is suggested to be useful for human clinical cases, including hypoxic ischemic brain injury in infants.

Topics: Animals; Brain; Brain Ischemia; Cerebrovascular Circulation; Contrast Media; Echoencephalography; Female; Image Enhancement; Injections, Intravenous; Male; Perfusion; Polysaccharides; Rabbits; Ultrasonography, Doppler

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

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 real-time sonography (TCCS) is an emerging diagnostic technique that allows noninvasive imaging of intracranial vessels within parenchymal structures. However, in some patients, transcranial ultrasound is particularly hindered by insufficient ultrasound penetration through the temporal bone. The present study evaluates whether or not application of an echo-contrast agent in ultrasound-refractory patients with middle cerebral artery (MCA) trunk occlusion enhances image acquisition enough to yield accurate diagnoses. Contrast-enhanced (CE) TCCS examinations, computed tomography scans and angiographic studies were performed in 20 patients with clinical symptoms suggestive of MCA occlusion within 12 h of the onset of symptoms. For comparison, 20 control persons without history or clinical signs for cerebrovascular diseases were examined using CE-TCCS. In none of the patients or control subjects did unenhanced TCCS investigations depict any color-coded vascular signal of an intracranial vessel. After application of 9 mL of 400 mg/mL galactose-based microbubbles, CE-TCCS was performed. In subjects with MCA occlusion, CE-TCCS examinations were repeated within 24 h, 48 h and 5 days after stroke. In stroke patients (n = 20), CE-TCCS showed an occluded MCA main stem in 11 patients, and this vessel was clearly demonstrable on the unaffected side. On the affected side, the posterior cerebral artery (PCA) and anterior cerebral artery (ACA) could be visualized in 8 of 11 subjects; in 3 patients, at least 1 of these vessels was detectable. Angiographic studies confirmed the diagnosis of MCA trunk occlusion in all 11 individuals. In follow-up investigations, 3 stroke patients had angiographic and CE-TCCS examinations consistent with vessel reperfusion. Nine stroke patients had a patent MCA shown in angiographic and CE-TCCS examinations. In the control group, the MCA trunk could be visualized in all subjects by CE-TCCS. CE-TCCS is a sensitive and specific ultrasound method for the diagnosis of MCA trunk occlusion that overcomes the anatomical hindrance of inadequate acoustic bone window. This technique may help to identify patients suitable for thrombolytic therapies and monitor their response.

Topics: Aged; Aged, 80 and over; Angiography, Digital Subtraction; Arterial Occlusive Diseases; Brain Ischemia; Cerebral Arterial Diseases; Contrast Media; Female; Follow-Up Studies; Humans; Image Enhancement; Infusions, Intravenous; Magnetic Resonance Angiography; Male; Middle Aged; Polysaccharides; Temporal Bone; Tomography, X-Ray Computed; Ultrasonography, Doppler, Transcranial