Transcranial doppler ultrasonography in acute ischemic stroke predicts stroke subtype and clinical outcome: a study in Omani population

Background  

Transcranial Doppler ultrasonography (TCD) is being increasingly used for its ability to provide cerebral hemodynamic information in stroke. Few studies have explored its association with cerebral arteriographic changes and stroke subtype. This study explored the relation of TCD changes in acute stroke with stroke subtypes, MR cerebral arteriography and clinical outcome in Omani population.     

Stroke Prevention Trial in Sickle Cell Anemia

Stroke occurs in 7–8% of children with Sickle Cell Disease (Hb SS) and is a major cause of morbidity. Rates of recurrence have been reduced from 46–90% to less than 10% through chronic blood transfusions. Prevention of first stroke, however, would be preferable because even one stroke can cause irreversible brain injury. Transcranial Doppler (TCD) ultrasound can detect arterial blood flow rates associated with subsequent stroke risk. By combining TCD screening and a potentially effective treatment, first stroke may be prevented. The Stroke Prevention Trial in Sickle Cell Anemia (STOP) is the first stroke prevention trial in Hb SS and the first randomized, controlled use of transfusion in Hb SS. This multi-center trial is designed to test whether reducing sickle hemoglobin to 30% or less with periodic blood transfusions will reduce first-time stroke by at least 70% compared to standard care. Primary endpoints will be clinically evident symptoms of cerebral infarction with consistent findings on Magnetic Resonance Imaging and Angiography (MRI/MRA) or symptomatic intracranial hemorrhage. Secondary endpoints will be asymptomatic brain lesions detected by MRI in brain areas not involved in primary endpoints. The design calls for a 6-month start-up interval, 18 months of TCD screening and randomization, and observation for stroke from entry through month 54. Key features of the trial are standardized TCD and MRI/MRA protocols interpreted blindly, and blinded adjudication of endpoints. The sample size (60 per treatment group) is based on prospective data relating TCD velocity to risk of stroke. A time-averaged mean velocity of ⩾200 cm/sec is associated with a 46% risk of cerebral infarction over 39 months. The sample size is sufficient to detect 70% reduction in the primary endpoint at 90% power. This trial will determine if transfusion is effective in the primary prevention of stroke. Secondary aims may further the understanding of the effects of transfusion on the brain and guide future research into cerebrovascular disease in Hb SS.     

Transcranial Doppler in stroke.

Transcranial Doppler (TCD) has been extensively used in various clinical situations, and in the last two decades has established its role in the management of patients with cerebrovascular disease and stroke. Based on the Doppler principle, it uses ultrasound waves to insonate the blood vessels supplying the brain to obtain hemodynamic information. Anatomic abnormalities of vascular occlusion, stenosis and spasm can be indirectly derived. Intracranial arterial disease is an important cause of ischemic stroke and TCD can detect these with a fair amount of sensitivity and specificity. In hemodynamically significant extracranial internal carotid artery disease, TCD shows significant abnormalities in flow dynamics of the anterior circulation and abnormalities of cerebral vasomotor reactivity. A distinct advantage of TCD is the ability to monitor blood flow in a blood vessel over prolonged periods of time, which has shown microembolic signals in acute ischemic stroke, carotid artery disease, atrial fibrillation and during angiography. In acute ischemic stroke, TCD can be used to elucidate stroke mechanisms, plan and monitor treatment, and determine prognosis. In an era when stroke is increasingly being recognized as an emergency requiring immediate treatment, TCD may be capable of providing rapid information about the hemodynamic status of the cerebral circulation, within the time frame of the rather small 'therapeutic window'. TCD predicts vasospasm with a high degree of sensitivity and specificity and because of its non-invasive nature repeated assessments can be performed after subarachnoid hemorrhage.     

中青年隐源性DWI阴性急性缺血性脑卒中合并卵圆孔未闭两例

该文报道2例中青年隐源性弥散加权成像(DWI)阴性急性缺血性脑卒中合并卵圆孔未闭男性患者,均为38岁,急性起病,以轻度神经功能缺损症状就诊,既往无脑血管病危险因素,以左侧肢体功能障碍为主要表现,DWI均阴性,经颅多普勒超声发泡检查和经食管心脏彩色多普勒超声检查发现卵圆孔未闭,其后均接受抗血小板、调脂等治疗,好转出院后随访显示2例均接受了卵圆孔未闭封堵治疗,均痊愈。应通过该2例的诊治过程提高对局灶性神经功能缺损合并卵圆孔未闭的认识,当患者出现局灶性神经功能缺损,即使DWI阴性亦不能排除急性缺血性脑卒中,应积极进行危险因素筛查,尤其是在中青年隐源性患者中,应高度重视卵圆孔未闭的检测及治疗,减少卵圆孔未闭所致的脑卒中及卒中复发。     

Carotid Doppler ultrasound findings in patients with left ventricular assist devices

Left ventricular assist devices (LVADs) have been used to treat advanced heart failure refractory to medical management, as bridge therapy to myocardial recovery, as bridge therapy to cardiac transplantation, or as destination therapy for patients with unfavorable transplant candidacy. Neurologic complications are some of the most common and devastating complications in these patients. Preoperative carotid ultrasound is, therefore, a standard evaluation in patients at risk for cerebrovascular disease. Postoperative carotid artery Doppler sonography is performed in those patients with neurologic symptoms. It is likely, therefore, that sonographers, radiologists, and other physicians working in a center where LVADs are implanted will likely encounter a carotid artery Doppler study in this patient group. To our knowledge, the carotid Doppler findings in these patients have never been published. We review the Doppler ultrasound findings in 6 patients after LVAD insertion.     

Editorial

Right-to-left shunt through a patent foramen ovale was searched for in 80 patients with acute ischemic stroke by simultaneously performing transthoracic two-dimensional echocardiography and transcranial Doppler during agitated saline injection. A patent foramen ovale was detected by echocardiography in 14 patients (17.5%). Transcranial Doppler correctly identified all 14 patients, and 7 more patients in whom echocardiographic findings were indeterminate. Prevalence of patent foramen ovale by transcranial Doppler was therefore 26.3% (21 of 80 patients). Concordance between the two tests was 91.3% (73 of 80 patients). The delivery of contrast material to cerebral vessels is therefore demonstrable by transcranial Doppler in all patients diagnosed by contrast echocardiography, suggesting that paradoxical embolization through a patent foramen ovale may be more frequent than previously thought. Transcranial Doppler with contrast injection is a valid alternative in case of poor echocardiographic image quality.     

Effects of Action Observational Training on Cerebral Hemodynamic Changes of Stroke Survivors: A fTCD Study

[Purpose] The purpose of this study was to investigate the effect of Action Observational Training (AOT) on cerebral hemodynamic changes, including cerebral blood flow velocity (CBFV) and cerebral blood flow volume (CBFvol) in healthy subjects and stroke survivors. [Subjects] This study had a cross-sectional design. Seven healthy subjects and six patients with a first-time stroke participated in this study. [Methods] All subjects were educated about AOT, and we measured their systolic peak velocity (Vs), mean flow velocity (Vm), pulsatility index (PI), and resistance index (RI) in the middle cerebral artery (MCA), the anterior cerebral artery (ACA), and the posterior cerebral artery (PCA), before and after performance of AOT, using Functional Transcranial Doppler (fTCD) with a 2-MHz probe. [Results] Both healthy subjects and stroke survivors showed significant improvements of Vs and Vm in MCA, ACA and PCA after AOT. [Conclusion] Our findings indicate that AOT increases CBFV in healthy subjects and stroke survivors, because the brain requires more blood in order to meet the metabolic demand of the brain during AOT.Key words: Action observational training, Cerebral blood flow, Functional transcranial Doppler (fTCD)     

Color and power Doppler sonography of extracranial and intracranial arteries in Moyamoya disease

PURPOSE: To study the hemodynamic characteristics of moyamoya disease with color Doppler (CD) and power Doppler (PD) sonography. METHODS: The hemodynamic parameters of intracranial and extracranial arteries from 17 patients with moyamoya disease confirmed via digital subtraction angiography and 30 healthy controls were studied with conventional and transcranial CD and PD. RESULTS: The moyamoya vessels were detected as scattered color Doppler signal with low velocity and a low resistance index (RI) at the base of the brain in 10 of the 17 patients. The RI of the common carotid arteries and the internal carotid arteries of the patients was significantly higher, whereas the peak velocity was lower than in controls. The posterior carotid arteries were more frequently involved in children (43.8%) than in adults (5.6%). CONCLUSIONS: Transcranial CD and PD can be used to demonstrate the stenosis and occlusion of intracranial arteries and the abnormal vascular network at the base of the brain in most cases. Combined with the hemodynamic characteristics of extracranial arteries and the symptoms of the patients, an accurate diagnosis of moyamoya disease could be made in the majority of cases using PD.     

Grading and hemodynamic follow-up study of arteriovenous malformations with transcranial Doppler ultrasonography.

This study presents and tests the clinical validity of a hemodynamic grading system that depends on noninvasive transcranial Doppler ultrasonographic parameters. The suggested transcranial Doppler-based grading system was compared with the Spetzler-Martin anatomic grading for prognosticative validity and clinical dependability. We concluded the following: (1) The pulsatility index was shown to be a more dependable transcranial Doppler parameter in the clinical evaluation of an arteriovenous malformation because of two reasons: preoperative pulsatility index findings inversely correlated with arteriovenous malformation volume, and the pulsatility index returned to normal values before the mean blood flow velocity did. Therefore, hemodynamic arteriovenous malformation grading can be based on the pulsatility index. (2) A transcranial Doppler-based hemodynamic arteriovenous malformation grading system correlated highly with the Spetzler-Martin grading in predicting postoperative neurologic deficits and adverse radiologic findings. (3) The presented grading system may contribute to the standardization and quantification of the hemodynamic changes during multidisciplinary management of arteriovenous malformations.     

皮层下动脉硬化性脑病血流动力学与血液流变学变化及其临床意义

摘要 目的：探讨皮层下动脉硬化性脑病(SAE)脑血流动力学与血液流变学变化及其临床意义。方法：对64例SAE患者进行经颅多谱勒(TCD)及血液流变学检查，并与同期60例健康老年人比较、分析。结果：SAE组TCD异常率明显高于对照组，主要表现为脑动脉硬化、脑供血不足、脑血管狭窄，SAE组血流变示血粘滞度增高，与对照组相比有显著差异(p<0.001)。结论： SAE患者存在明显的脑血流动力学与血液流变学异常。关键词 皮层下动脉硬化性脑病 经颅多谱勒 血液流变学     

Diagnosis of an intracranial arteriovenous malformation using extracranial carotid Doppler sonography

Carotid sonography is a well-established technique in the evaluation of patients with neurologic symptoms. We describe the case of a woman in whom duplex Doppler sonography of the extracranial carotid circulation showed high-velocity diastolic flow and a low resistance index without turbulence or morphologic abnormality of the artery. A suspected cause of this finding was low-resistance distal circulation secondary to low-resistance intracranial circulation due to an arteriovenous malformation. This diagnosis was later confirmed by CT. Because of the significant risk of bleeding associated with an asymptomatic intracranial arteriovenous malformation, duplex Doppler sonographic findings suggesting a low-resistance waveform in the presence of a morphologically normal carotid artery should prompt further imaging.     

Color Doppler of the extracranial and intracranial arteries in the acute phase of cerebral ischemia

Vascular imaging greatly improves the possibility of locating the site of vascular occlusion in patients with acute cerebrovascular disease. Different occlusive patterns may underlie the same clinical presentation, with different prognosis and different treatment: for this reason, a diagnostic tool able to identify quickly the status of the extra- and intracranial vessels is needed. Color Doppler ultrasound of the extracranial arteries is a reliable and accurate method able to localize and quantify the carotid artery stenosis. The ultrasound quantification of the degree of stenosis is based on both morphological and velocimetric criteria: B-mode, color or power Doppler and spectral analysis are used for this purpose. Also the analysis of the plaque is an integral part of the ultrasound examination: the B mode plaque characterization (structure and surface) plays an important role in the evaluation of risk of stroke. So color Doppler ultrasound is able to select patients who may require medical therapy, carotid endarterectomy or angioplasty and stenting. Transcranial color Doppler is an inexpensive, reliable, fast, non-invasive, bedside tool: in the acute phase of stroke, it is able to evaluate quickly the intracranial arteries and monitor the possible recanalization of occluded vessel ensuring the follow-up of dynamic lesions, such as the intracranial stenosis and occlusions.     

Role of transcranial Doppler in optimizing treatment of cerebral vasospasm in subarachnoid hemorrhage

This study was undertaken to evaluate the role of transcranial Doppler ultrasonography in arterial blood pressure management during hypervolemia/hypertension/ hemodilution therapy in patients with vasospasm from subarachnoid hemorrhage and correlate this data with neurologic outcome. The study included 18 adult patients, Hunt and Hess grades III-IV. Complete neurologic assessment was performed. Transcranial Doppler indices were calculated by standard formulas. On the basis of our results, resistance area product can be used to estimate the optimal arterial blood pressure in hypervolemia/hypertension/hemodilution therapy. An increase in the cerebral blood flow index was associated with better performance on neurologic examination. Estimated cerebral perfusion pressure from transcranial Doppler data analysis showed poor correlation with cerebral perfusion pressure derived from direct measurement of intracranial pressure in patients with cerebral vasospasm (rho = 0.15; 95% CI, 0.11-0.39; P = .2590).     

Neurological impairment during long-term intrathecal infusion of bupivacaine in cancer patients: a sign of spinal cord compression

Adequate pain relief in patients with far advanced cancer sometimes requires intrathecal (IT) administration of a combination of opioids and local anesthetics. Tumor progression as well as the IT administration of local anesthetics can lead to neurologic dysfunction during treatment. Five patients showed symptoms of compression of the cauda equina or spinal cord shortly after the start of combined IT administration of morphine and bupivacaine in a dosage usually not associated with neurologic symptoms. Unexpectedly, neurologic evaluation suggested compression of the cauda equina and spinal cord, which was confirmed radiographically. Manifestation of new neurologic symptoms during low dose bupivacaine infusion intrathecally might therefore be an early indicator of space-occupying processes within the spinal canal in cancer patients.     

Evaluation of wall motion abnormality by comparing values of cardiac output obtained by M-mode and Doppler echocardiography: Parameter revealing wall motion abnormality in stress echocardiography

Dobutamine and dipyridamole stress echocardiographies are both well able to detect myocardial ischemia resulting from coronary diseases by recognizing the regional wall motion abnormality (WMA). Here we report a method for describing WMA in detail. In pharmacological stress echocardiography, because of difficulties in recognizing the two-dimensional pattern, accuracy sometimes depends upon the skill of the operator. Two stroke volumes obtained using the M-mode and Doppler methods were examined to detect abnormal regional cardiac function by the dipyridamole stress test. Stroke volume obtained by the M-modereflects regional cardiac function and that estimated from the outflow using the Doppler methodreflects total cardiac function. These two stroke volumes were compared in normal subjects and patients with coronary-diseases. The results indicated consistent discrepancies between these two stroke volume in the ischemic hearts as a results of coronary stenosis, whereas changes in stroke volumes in the normal subjects showed the same tendency. This method of combining information about the regional and total functions is thus useful in examining the WMA and regional cardiac function, although it can not be applied to subjects whose stroke volume does not increase under stress.     

Cerebral Vasomotor Changes in the Transient Syndrome of Headache With Neurologic Deficits and CSF Lymphocytosis (HaNDL)

We report two patients with the recently described transient syndrome of headache with neurologic deficits and CSF lymphocytosis (HaNDL). Transcranial Doppler sonography performed during and after attacks of HaNDL showed asymmetrical decreases or increases in blood flow velocity of the middle cerebral artery, accompanied by increases or decreases in pulsatility suggesting fluctuations of arteriolar tone. The findings demonstrate focal vasomotor disturbances that link the transient headaches and deficits of HaNDL with attacks of migraine.     

Transient Ischemic Attacks (TIA): Current Issues in Diagnosis and Management

Transient ischemic attacks (TIAs) affect more than 500,000 Americans each year. Stroke risk approximates 4% to 8% within 1 month and increases to 12% to 13% at one year. This has led to stroke being one of the leading causes of death and disability. TIAs are focal neurologic events that are temporary in nature and warn of potential stroke. Most TIAs resolve within 24 hours. Hypertension, smoking, heart disease, and diabetes are the major risk factors for stroke. A comprehensive history of symptoms can help identify carotid vs. vertebrobasilar disease. Timely evaluation of TIAs should be performed according to recent guidelines set forth by the American Heart Association. Aspirin continues to be the gold standard for stroke prevention, conferring a 48% risk reduction in stroke or death. The use of ticlopidine has been recommended as a second-line agent in patients with aspirin intolerance. Surgical intervention (carotid endarterectomy) is indicated in symptomatic patients with high grade stenosis of 70% or greater. For patients with less significant stenosis, inconclusive data exists regarding the benefit of medical vs. surgical treatment. Patient education should address identification of symptoms, the need for prompt medical attention, and risk factor modification. A collaborative plan between clinician and client will facilitate early intervention ultimately leading to preservation of function and prevention of the catastrophic sequelae of stroke.     

Transcranial doppler monitoring during language tasks in stroke patients with aphasia

Purpose. To investigate the pattern of hemispheric activation, according to cerebral blood flow changes, as measured by Transcranial Doppler Ultrasonography (TCD) during language tasks in stroke patients with aphasia.

Method. Prospective study investigating results of TCD monitoring during language naming and recognition tasks in ischemic stroke patients (n = 32) with and without aphasia and 5 control subjects.

Results. Delta mean flow velocity (MFV) in the left Middle Cerebral Artery (MCA) was found to be much lower in aphasia patients as compared to healthy subjects. Negative statistical correlation was found between the improvement of language ability and the blood flow velocity parameters in the left hemisphere. Aphasia patients with good language ability showed much higher MFV in the right MCA during the first test. Left hemispheric blood flow velocity shift was found to be higher during speech tasks in the patients with poor language ability.

Conclusions. Our study suggests that the performance of language tasks in aphasia patients during early recovery after stroke is associated with relatively high right hemisphere activation. High blood flow velocity in the right MCA of aphasia patients was found to be a good prognostic sign for better language ability. Arterial blood flow that shifted towards the left hemisphere during speech tasks was associated with poor language ability.