Cerebral Haemodynamic Disturbances in Patients with Moderate Carotid Artery Stenosis
ABSTRACT Dynamic MR perfusion imaging can detect cerebral perfusion deficits resulting from severe internal carotid artery (ICA) stenosis. It is unknown, however, whether moderate ICA stenosis (50-69%) also causes haemodynamic disturbance. We investigated whether cerebral perfusion deficits were detectable in patients with moderate ICA stenosis.
Eighteen patients underwent T2* weighted cerebral MR perfusion imaging with a gadolinium based contrast agent. Differences in mean time to peak (mTTP) and relative cerebral blood volume (rCBV) between cerebral hemispheres were calculated for middle cerebral artery territory regions by a reader blinded to the angiographic and clinical findings.
There were significant differences in mTTP between cerebral hemispheres in 15 patients with a mean inter-hemispheric delay in mTTP of 0.49 s (95% confidence intervals, 0.25 and 0.72 s) which was statistically significant ( p <0.001). In 1 patient with bilateral moderate stenosis there was no difference in mTTP.
Moderate ICA stenosis results in significant ipsilateral cerebral perfusion delays detectable by dynamic susceptibility MRI. Follow-up studies might reveal whether these delays improve following carotid endarterectomy.
- SourceAvailable from: Dafna Ben Bashat
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- "In stroke patients, DSC perfusion imaging is important to confirm diagnosis, to monitor the extent and severity of the ischemic lesion during the acute phase, and is considered to be an important outcome predictor (Farr and Wegener, 2010; Seevinck et al., 2010). Perfusion imaging was also used to study patients with carotid stenosis, to differentiate between asymptomatic and symptomatic patients (Soinne et al., 2003), to study patients with moderate stenosis (Trivedi et al., 2005), and for the assessment of cerebrovascular * Correspondence to: D. Ben Bashat, The Functional Brain Center, The Wohl Institute for Advanced Imaging, 6 Weizmann Street, Tel- Aviv 64239, Israel. Tel: +972-3-6973056, mobile: +972-52- 4262515; fax: +972-3-6973080. "
ABSTRACT: Characterization of the brain's vascular system is of major clinical importance in the assessment of patients with cerebrovascular disease. The aim of this study was to characterize brain hemodynamics using multiparametric methods and to obtain reference values from the healthy brain. A multimodal MRI study was performed in twenty healthy subjects, including dynamic susceptibility contrast (DSC) imaging and blood oxygen level dependence (BOLD) during hypercapnia and carbogen challenges. Brain tissues were defined using unsupervised cluster analysis based on these three methods, and several hemodynamic parameters were calculated for gray matter (GM), white matter (WM), blood vessels & dura (BVD); the three main vascular territories within the GM; and arteries and veins defined within the BVD cluster. The carbogen challenge produced a BOLD signal twice as high as the hypercapnia challenge, in all brain tissues. The three brain tissues differed significantly from each other in their hemodynamic characteristics, supporting the graded vascularity of the tissues, with BVD>GM>WM. Within the GM cluster, a significant delay of ∼1.2 sec of the bolus arrival time was detected within the posterior cerebral artery territory relative to the middle and anterior cerebral arteries territories. No differences were detected between right and left middle cerebral arteries territories for all hemodynamic parameters. Within the BVD cluster, a significant delay of ∼1.9 sec of the bolus arrival time was detected within the veins relative to the arteries. This parameter enabled to differentiate between the various blood vessels, including arteries, veins and choroid plexus. This study provides reference values for several hemodynamic parameters, obtained from healthy brains, and may be clinically important in the assessment of patients with various vascular pathologies.Neuroscience 03/2013; 240. DOI:10.1016/j.neuroscience.2013.03.004 · 3.33 Impact Factor
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- ". However, these results may have been confounded as no measure of carotid artery stenosis was made, which affects CBF measurements . "
ABSTRACT: Late-onset epilepsy (LOE) first occurs after 60 years of age and may be due to occult cerebrovascular disease (CVD) which confers an increased risk of stroke. However, patients with late-onset epilepsy are not currently consistently investigated or treated for cerebrovascular risk factors. We discuss how abnormalities of neurovascular unit function, namely, changes in regional cerebral blood flow and blood brain barrier disruption, may be caused by occult cerebrovascular disease but present clinically as late-onset epilepsy. We describe novel magnetic resonance imaging methods to detect abnormal neurovascular unit function in subjects with LOE and controls. We hypothesise that occult CVD may cause LOE as a result of neurovascular unit dysfunction.Cardiovascular Psychiatry and Neurology 03/2011; 2011:130406. DOI:10.1155/2011/130406
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- "Journal of Cerebral Blood Flow & Metabolism (2007) 27, 850–856 & 2007 ISCBFM All rights reserved 0271-678X/07 $30.00 www.jcbfm.com 2005; Trivedi et al, 2005 "
ABSTRACT: Although the Virchow's triad on thrombosis includes reduced blood flow as a factor, there has been relatively little data on the importance of total cerebral blood flow on the risk of subsequent stroke. In the current study, we investigate whether total cerebral blood flow helps predict stroke recurrence. Extracranial arterial blood flow volume estimated by color velocity imaging quantification ultrasound (CVIQ) is an index of cerebral blood flow measurement. We performed a cohort study of 210 consecutive acute stroke patients. Patients were studied with transcranial Doppler and duplex ultrasound for intra- and extracranial large artery disease within 3 days of symptom onset. The association between the risk of recurrent stroke and CVIQ was analyzed with Cox proportional hazards model. Thirty-nine patients (17.7%) developed an ischemic stroke during a mean follow-up of 47.5 months. The mean extracranial blood flow volume was significantly lower for patients who had a recurrent stroke than those without (594.4+/-130.3 versus 683.8+/-176.9 mL/min; P=0.003). In a Cox proportional hazards model adjusting for potential confounding variables, extracranial blood flow volume (hazard ratio (HR) for lowest tertile, 4.1; 95% confidence interval (CI), 1.5 to 11.0) along with male sex (HR, 2.5; 95% CI, 1.3 to 5.1), diabetes (HR, 2.5; 95% CI, 1.2 to 5.0) and large artery stenosis (HR, 2.2; 95% CI, 1.1 to 4.4) were independent predictors for stroke recurrence. Our data indicated that patient with low amount of blood flow to the brain is at risk of recurrent stroke.Journal of Cerebral Blood Flow & Metabolism 05/2007; 27(4):850-6. DOI:10.1038/sj.jcbfm.9600392 · 5.34 Impact Factor