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Transcranial Doppler Ultrasonography (transcranial + doppler_ultrasonography)
Selected AbstractsImportance of Jugular Valve Incompetence in Contrast Transcranial Doppler Ultrasonography for the Diagnosis of Patent Foramen OvaleJOURNAL OF NEUROIMAGING, Issue 3 2003M. Akif Topçuoglu MD ABSTRACT Transcranial Doppler (TCD) ultrasound with the intravenous injection of agitated saline as contrast (cTCD) is an effective method for detecting right-to-left intracardiac and extracardiac shunt (RLS); however, the sensitivity of cTCD in the diagnosis of RLS remains slightly less than that of transesophageal echocardiography, even in patients with adequate transtemporal ultrasonic bone windows. The authors present a case with cTCD underestimating RLS because of jugular valve incompetence in a 42-year-old man presenting with an episode of transient aphasia. Three weeks after transcatheter closure of a patent foramen ovale associated with an atrial septal aneurysm, he experienced 2 episodes of amaurosis fugax. Following a negative 45-minute embolus detection study with power M-mode TCD, the patient underwent a cTCD study with monitoring of the left middle cerebral artery (MCA), the anterior cerebral artery, and the submandibular extracranial internal carotid artery. A single microbubble (MB) was detected in the left MCA in only 1 of 5 studies; the remaining runs all failed to detect an RLS. Significant MB reflux was noted in the left internal jugular vein because of jugular valve incompetence. The authors conclude that incompetence of the jugular vein valve can result in a false negative cTCD study for RLS detection. [source] Transcranial Doppler Blood Flow Assessment in Patients With Mild Heart Failure: Correlates With Neuroimaging and Cognitive PerformanceCONGESTIVE HEART FAILURE, Issue 2 2008Raymond L. C. Vogels MD Cardiac output and cerebral perfusion are reduced in patients with advanced stages of heart failure. Our aim was to determine whether cerebral blood flow velocity measured by transcranial Doppler ultrasonography was reduced in outpatients with mild heart failure in comparison to controls and, if so, whether this reduction was related to cognitive performance and abnormalities of the brain diagnosed by magnetic resonance imaging. [source] Patent Foramen Ovale: Comparison among Diagnostic Strategies in Cryptogenic Stroke and MigraineECHOCARDIOGRAPHY, Issue 5 2009Concetta Zito M.D. Objective: The aim of this study was to compare transthoracic echocardiography (TTE) and transcranial Doppler ultrasonography (TCD) with transesophageal echocardiography (TEE) in order to define the best clinical approach to patent foramen ovale (PFO) detection. Methods: In total, 72 consecutive patients (33 men) with a mean age of 49 ± 13 years were prospectively enrolled. The TEE indication was cryptogenic stroke (36 patients) or migraine (36 patients, 22 with aura). All patients underwent standard TTE, TCD, and TEE examination. For any study, a contrast test was carried on using an agitated saline solution mixed with urea-linked gelatine (Haemaccel), injected as a rapid bolus via a right antecubital vein. A prolonged Valsalva maneuver was performed to improve test sensitivity. Results: TEE identified a PFO in 65% of the whole population: 56.5% in the migraine cohort and 43.5% in the cryptogenic stroke cohort. TTE was able to detect a PFO in 55% of patients positive at TEE (54% negative predictive value, 100% positive predictive value, 55% sensitivity, and 100% specificity). TCD was able to identify a PFO in 97% of patients positive at TEE (89% negative predictive value, 98% positive predictive value, 94% sensitivity, and 96% specificity). Conclusions: In patients with cryptogenic stroke and migraine, there is a fair concordance (k = 0.89) between TCD and TEE in PFO recognition. Accordingly, TCD should be recommended as a simple, noninvasive, and reliable technique, whereas TEE indication should be restricted to selected patients. TTE is a very specific technique, whose major advantage is the ability to detect a large right-to-left shunt, particularly if associated with an atrial septal aneurysm. [source] Dynamic cerebral autoregulation in healthy adolescentsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2002M. S. Vavilala Background: There is little information on the limits of cerebral autoregulation and the autoregulatory capacity in children. The aim of this study was to compare dynamic cerebral autoregulation between healthy adolescents and adults. Methods: Seventeen healthy volunteers 12,17 years (n = 8) and 25,45 years (n = 9) were enrolled in this study. Bilateral mean middle cerebral artery flow velocities (Vmca; (cm/s)) were measured using transcranial Doppler ultrasonography (TCD). Mean arterial blood pressure (MAP) and end-tidal carbon dioxide were measured continuously during dynamic cerebral autoregulation studies. Blood pressure cuffs were placed around both thighs and inflated to 30 mmHg above the systolic blood pressure for 3 min and then rapidly deflated, resulting in transient systemic hypotension. The change of Vmca to change in MAP constitutes the autoregulatory response, and the speed of this response was quantified using computer model parameter estimation. The dynamic autoregulatory index (ARI) was averaged between the two sides. Results: Adolescents had significantly lower ARI (3.9 ± 2.1 vs. 5.3 ± 0.8; P=0.05), and higher Vmca (75.2 ± 15.2 vs. 57.6 ± 15.0; P<0.001) than adults. Conclusion: The autoregulatory index is physiologically lower in normal adolescents 12,17 years of age than in adults. [source] Haemoglobin oxygen saturation is a determinant of cerebral artery blood flow velocity in children with sickle cell anaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2009Charles T. Quinn Summary Steady-state haemoglobin (Hb) desaturation is a common finding in sickle cell anaemia (Hb SS) that could predispose to stroke by limiting oxygen delivery to the brain. To determine its association with the risk of overt stroke, we examined the relationship between daytime Hb saturation measured by pulse oximetry (SpO2) and cerebral artery blood flow velocity measured by transcranial Doppler ultrasonography (TCD), an established risk factor for overt stroke in Hb SS. We studied 181 children using multivariate models to control for known determinants of TCD velocity, including age, haematocrit, and a measure of stenosis. We found that SpO2 correlated significantly and inversely with TCD velocity in both the right and left middle cerebral arteries. Hb desaturation was associated with increased cerebral artery blood flow velocities and increased odds of abnormal TCD velocities, hence increased risk of stroke. About 5% of the variation in TCD velocity could be ascribed to Hb saturation while controlling for other determinants of TCD velocity. In conclusion, Hb saturation is a determinant of TCD velocity and a risk factor for stroke in children with Hb SS. [source] Transcranial Doppler ultrasonography-directed intravenous glycoprotein IIb/IIIa receptor antagonist therapy to control transient cerebral microemboli before and after carotid endarterectomy,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 6 2008D. van Dellen Background: Patients with a transient focal neurological deficit, critical carotid stenosis and/or microemboli detected by transcranial Doppler ultrasonography (TCD) have a significant risk of stroke. The effect of tirofiban, a selective glycoprotein IIb/IIIa inhibitor, was assessed in patients with microembolic signals on TCD after transient ischaemic attacks or carotid endarterectomy (CEA). Methods: Thirty-three patients with microemboli on TCD (13 symptomatic preoperative, 19 postoperative, one both) were treated with tirofiban between 2002 and 2007. All patients had carotid stenosis greater than 70 per cent. TCD monitoring was used during and after tirofiban therapy. Results: The median (range) rate of microemboli decreased from 22 (4,260) per h before surgery and 81 (44,216) per h after surgery to 0 (0,9) per h in both groups (P < 0·001, Mann,Whitney U test). This occurred rapidly (preoperative median 30 min; postoperative median 45 min) and was well tolerated in all patients, with no serious adverse effects. Conclusion: Cerebral microemboli were controlled by tirofiban both before and after CEA. Further study is required to compare the relative efficacy of tirofiban and dextran. Copyright © 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Effect of carotid endarterectomy on cognitive function: long-term follow-upBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 4 2000A. J. Lloyd Background: Long-term effects of carotid endarterectomy (CEA) on cognitive function are not known. Evidence suggests that perioperative embolization may disrupt cognitive function in the short term. Methods: A controlled study was conducted to examine the cognitive function of 109 patients undergoing CEA before and at 6 months after operation (n = 100). The objective validated psychometric tests assessed attention, memory, language and visuospatial skills. Perioperative embolization was determined using transcranial Doppler ultrasonography. Results: Patients who were spontaneously embolizing before operation had significant preoperative cognitive impairment (P = 0·03). The controlled cognitive function tests showed no evidence of a cognitive deficit 6 months after CEA. The total number of emboli detected for each patient ranged from 0 to 700 (mean 32). There was no evidence of a significant correlation between the number of emboli detected during CEA and change in cognitive function (r = 0·07). Conclusion: CEA is not associated with worsening cognitive impairment. Asymptomatic perioperative microembolization has no long-term effect on cognitive function. © 2000 British Journal of Surgery Society Ltd [source] |