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Intracranial Stenosis (intracranial + stenosis)
Selected AbstractsEpidemiology of Intracranial StenosisJOURNAL OF NEUROIMAGING, Issue S1 2009M. Fareed K. Suri MD ABSTRACT Intracranial stenosis is a common etiology for ischemic stroke. Due to limitations of imaging studies, there are limited data on the prevalence of symptomatic and asymptomatic intracranial stenosis. Intracranial stenosis is more prevalent in Asian, Hispanic, and African-American populations. The reported proportion of patients with symptomatic intracranial stenosis among those hospitalized for ischemic cerebral events varies from 1% in non-Hispanic whites to as high as 50% in Asian populations. In population-based studies, the estimated prevalence of symptomatic intracranial disease varies from 1 in 100,000 for whites to 15 in 100,000 in African Americans. A Chinese population-based study reported intracranial stenosis in 7% of the population aged more than 40 years. Autopsy studies have noted intracranial atherosclerotic disease in about 23% of population in the 6th decade and 80% of population in the 9th decade of life. Angiotensin-converting enzyme polymorphisms, plasma endostatin/vascular endothelial growth factor ratio, glutathione S-transferase omega-1 gene polymorphism, and plasma homocysteine levels are non-modifiable risk factors noted to be associated with intracranial stenosis. Hypertension and serum lipid profile are major modifiable risk factors, whereas sickle cell disease is an uncommon risk factor that can be managed to reduce risk. Associations of intracranial atherosclerosis with diabetes mellitus, metabolic syndrome, Alzheimer's disease, aortic plaques, radiotherapy, and meningitis are less well documented. [source] Symptomatic stenosis of the vertebrobasilar arteries: results of extra- and intracranial stent-PTAEUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2009T. Seifert Background and purpose:, About half of all transient ischaemic attacks (TIAs) or strokes in the posterior circulation are caused by the arterial stenosis. The purposes of this study were to determine the safety of stent-assisted percutaneous transluminal angioplasty (stent-PTA) and its efficacy for the prevention of recurrent stroke in patients with symptomatic artery stenosis in the extra- and intracranial posterior circulation. Methods:, Forty-six patients with a previous stroke or TIA who received balloon-mounted coronary stents for vertebral artery origin stenosis (VAOS; 29 patients) or self-expanding nitinol stents for vertebrobasilar intracranial stenosis (VBIS; 17 patients) were followed-up for a mean of 24.1 (VAOS) and 12.7 (VBIS) months. Results:, When all cause morbidity/mortality within 30 days from stent-PTA and stroke or death from stroke in the treated vascular territory during the first 12 months of follow-up are combined, the incidence of periprocedural complications and disease progression for the first year is 10.3% in VAOS patients and 17.6% in the VBIS group. Vessel restenosis ,50% was found in 52.0% of VAOS and in 32.1% of VBIS patients who completed 6 months follow-up. Conclusions:, We observed a higher periprocedural complication rate for patients with VBIS and a higher rate of restenosis in VAOS patients after stent-PTA for symptomatic artery stenosis. [source] EFNS guideline on neuroimaging in acute stroke.EUROPEAN JOURNAL OF NEUROLOGY, Issue 12 2006Report of an EFNS task force Neuroimaging techniques are necessary for the evaluation of stroke, one of the leading causes of death and neurological impairment in developed countries. The multiplicity of techniques available has increased the complexity of decision making for physicians. We performed a comprehensive review of the literature in English for the period 1965,2005 and critically assessed the relevant publications. The members of the panel reviewed and corrected an initial draft, until a consensus was reached on recommendations stratified according to the European Federation of Neurological Societies (EFNS) criteria. Non-contrast computed tomography (CT) scan is the established imaging procedure for the initial evaluation of stroke patients. However, magnetic resonance imaging (MRI) has a higher sensitivity than CT for the demonstration of infarcted or ischemic areas and depicts well acute and chronic intracerebral hemorrhage. Perfusion and diffusion MRI together with MR angiography (MRA) are very helpful for the acute evaluation of patients with ischemic stroke. MRI and MRA are the recommended techniques for screening cerebral aneurysms and for the diagnosis of cerebral venous thrombosis and arterial dissection. For the non-invasive study of extracranial vessels, MRA is less portable and more expensive than ultrasonography but it has higher sensitivity and specificity for carotid stenosis. Transcranial Doppler is very useful for monitoring arterial reperfusion after thrombolysis, for the diagnosis of intracranial stenosis and of right-to-left shunts, and for monitoring vasospasm after subarachnoid hemorrhage. Currently, single photon emission computed tomography and positron emission tomography have a more limited role in the evaluation of the acute stroke patient. [source] Secondary prevention of ischemic stroke: Challenging patient scenarios,JOURNAL OF HOSPITAL MEDICINE, Issue S4 2008Kiwon Lee MD Abstract The risk for recurrent stroke following a stroke or transient ischemic attack (TIA) is high. Prevention of a secondary event is a priority, as the associated morbidity and mortality are great. Antiplatelet agents have been shown to reduce this risk, but the choice of treatment modality depends on a number of factors, including the underlying cause of the stroke and the patient's comorbidities. For example, a cardioembolic stroke is best treated with anticoagulants, whereas one of noncardioembolic origin requires antiplatelet therapy. A number of challenging patient scenarios are explored in this article, and appropriate medical management is discussed, with the goal of examining the most recent trial data and information in the context of an actual case. Eight sample cases are presented: stroke prevention in a patient with recent stent placement, low ejection fraction, intracranial stenosis, carotid stenosis, atherosclerosis of the aortic arch, symptomatic coronary artery disease, antiplatelet failure, and stroke prevention in a patient already on warfarin. Journal of Hospital Medicine 2008;3(4 Suppl):S20,S28. © 2008 Society of Hospital Medicine. [source] Epidemiology of Intracranial StenosisJOURNAL OF NEUROIMAGING, Issue S1 2009M. Fareed K. Suri MD ABSTRACT Intracranial stenosis is a common etiology for ischemic stroke. Due to limitations of imaging studies, there are limited data on the prevalence of symptomatic and asymptomatic intracranial stenosis. Intracranial stenosis is more prevalent in Asian, Hispanic, and African-American populations. The reported proportion of patients with symptomatic intracranial stenosis among those hospitalized for ischemic cerebral events varies from 1% in non-Hispanic whites to as high as 50% in Asian populations. In population-based studies, the estimated prevalence of symptomatic intracranial disease varies from 1 in 100,000 for whites to 15 in 100,000 in African Americans. A Chinese population-based study reported intracranial stenosis in 7% of the population aged more than 40 years. Autopsy studies have noted intracranial atherosclerotic disease in about 23% of population in the 6th decade and 80% of population in the 9th decade of life. Angiotensin-converting enzyme polymorphisms, plasma endostatin/vascular endothelial growth factor ratio, glutathione S-transferase omega-1 gene polymorphism, and plasma homocysteine levels are non-modifiable risk factors noted to be associated with intracranial stenosis. Hypertension and serum lipid profile are major modifiable risk factors, whereas sickle cell disease is an uncommon risk factor that can be managed to reduce risk. Associations of intracranial atherosclerosis with diabetes mellitus, metabolic syndrome, Alzheimer's disease, aortic plaques, radiotherapy, and meningitis are less well documented. [source] Natural History of Asymptomatic Intracranial Arterial StenosisJOURNAL OF NEUROIMAGING, Issue S1 2009Robert A. Taylor MD ABSTRACT The prevalence and natural history of asymptomatic intracranial arterial stenosis are not very well characterized. Existing data suggest that incidentally discovered asymptomatic intracranial stenosis presents a fairly low risk of stroke, though substantial uncertainty remains. Patients may be at greater risk if there are tandem stenoses. Methods to stratify the risk of stroke with asymptomatic intracranial atherosclerotic lesions have yet to be established and validated. In general, aggressive intervention for an asymptomatic intracranial stenosis is not currently recommended. [source] Screening for Intracranial Stenosis With Transcranial Doppler: The Accuracy of Mean Flow Velocity ThresholdsJOURNAL OF NEUROIMAGING, Issue 1 2002Robert A. Felberg MD ABSTRACT Background. Patients with 50% intracranial arterial stenosis may require more intensive therapies for stroke prevention. Transcranial Doppler (TCD) is a convenient noninvasive screen for intracranial stenosis. The accuracy of different mean flow velocity (MFV) thresholds for determining the degree of stenosis remains uncertain. Methods. The authors prospectively compared the accuracy of TCD criteria and MFV thresholds to magnetic resonance, computed tomography, and digital subtraction angiography in patients with symptoms of recent or remote stroke or transient ischemic attack. Stenosis on angiography was measured as 0%, <50%, or ,50% diameter reduction. Results. Of 136 consecutive patients, 33 (24%) had distal internal carotid artery (ICA), middle cerebral artery (MCA), posterior cerebral artery, or basilar artery stenosis on angiography (14 patients [10%] were excluded due to incomplete TCD examinations, mainly from a lack of temporal windows). TCD showed 31 true-positive, 9 false-positive, 2 false-negative, and 94 true-negative studies. For all vessels, TCD had a sensitivity of 93.9% (confidence interval [CI] = 89%-98%), a specificity of 91.2% (CI = 87%-96%), a positive predictive value (PPV) of 77.5%, and a negative predictive value (NPV) of 97.9%. The trade-off in sensitivity and specificity for MCA MFV thresholds was as follows: MFV ,80 cm/s had a sensitivity of 100%, a specificity of 96.9% (CI = 94%-99%), a PPV of 84%, and an NPV of 100%. MFV,100 cm/s had a sensitivity of 100%, a specificity of 97.9% (CI = 96%-99%), a PPV of 88.8%, and an NPV of 94.9%. MFV,120 cm/s had a sensitivity of 68.7% (CI = 61%-78%), a specificity of 100%, a PPV of 100%, and an NPV of 94.9%. Reasons for false-positive findings include collateralization of flow in the presence of proximal ICA stenosis and prestenotic to stenotic MCA velocity ratios of 1:,2. Conclusion. TCD is both sensitive and specific in identifying ,50% intracranial arterial stenosis. A MFV threshold cutoff of 100 cm/s has an optimal sensitivity and specificity trade-off for ,50% MCA stenosis. To help avoid false-positive results, a prestenotic to stenotic MCA velocity ratio of 1:,2 should be used in addition to the MFV threshold. [source] Comparison of Transcranial Color-Coded Sonography and Magnetic Resonance Angiography in Acute Ischemic StrokeJOURNAL OF NEUROIMAGING, Issue 4 2001Li-Ming Lien MD ABSTRACT Background and Purpose. This study was designed to assess the accuracy of transcranial color-coded sonography (TCCS) as compared to magnetic resonance angiography (MRA) for detecting intracranial arterial stenosis in patients with acute cerebral ischemia. Methods. The authors prospectively identified 120 consecutive patients admitted with acute ischemic stroke and performed both TCCS and MRA with a mean interval of 1 day. TCCS data (sampling depth, peak systolic and end diastolic angle-corrected velocity, mean angle-corrected velocity, and pulsatility index) for middle cerebral arteries (MCAs) were compared to MRA data and classified into 4 grades: normal (grade 1): normal caliber and signal; mild stenosis (grade 2): irregular lumen with reduced signal; severe stenosis (grade 3): absent signal in the stenotic segment (flow gap) and reconstituted distal signal; and possible occlusion (grade 4): absent signal. The cutoffs were chosen to maximize diagnostic accuracy. Results. Interobserver agreement for MRA grading resulted in a weighted-kappa value of 0.776. The rate of poor temporal window was 37% (89/240). Doppler signals were obtained in 135 vessels, and the angle-corrected velocities (peak systolic, end diastolic, mean) were significantly different (P= .001, P= .006, P < .001) among the MRA grades: grade 1 (100, 47, 68 cm/s), grade 2 (171, 72, 110 cm/s), grade 3 (226, 79, 134 cm/s), grade 4 (61, 26, 39 cm/s). Additionally, an angle-corrected MCA peak systolic velocity ,120 cm/s correlates with intracranial stenosis on MRA (grade 2 or worse) with high specificity (90.5%; 95% confidence interval = 78.5%,96.8%) and positive predictive value (93.9%) but relatively low sensitivity (66.7%; 95% confidence interval = 61.2%,69.5%) and negative predictive value (55.1%). Conclusion. Elevated MCA velocities on TCCS correlate with intracranial stenosis detected on MRA. An angle-corrected peak systolic velocity ,120 cm/s is highly specific for detecting intracranial stenosis as defined by significant MRA abnormality. [source] | ||||||||||