Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Artery-to-artery embolism generally occurs in patients with not only moderate to severe arterial stenosis but also plaque vulnerability. Two unique cases with free-floating thrombi at the distal side of the small plaque in the internal carotid artery without stenosis are presented and its clinical implications are discussed. ⋯ In these two cases, duplex ultrasonography revealed free-floating thrombi developed at the distal region of small plaques. Aggressive treatment should be considered in a patient with thromboembolic stroke who has the small plaque presenting "snake fang" sign even if there is no stenosis or plaque vulnerability.
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Cerebral autoregulation (CA) enables the brain to maintain stable cerebral blood flow (CBF). CA can be assessed noninvasively by determining correlations between CBF velocity (CBFV) and spontaneous changes in blood pressure. Postrecording signal analysis methods have included both frequency- and time-domain methods. However, the test-retest reliability, cross-validation, and determination of normal values have not been adequately established. ⋯ CA parameters obtained by time- and frequency-domain methods correlate well, and show good interhemispheric and test-retest reliability. Group means from healthy controls may provide adequate norms for determining abnormal CA in cerebrovascular patients.
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The detection rate of typical transient global amnesia (TGA) lesions on diffusion-weighted imaging (DWI) can be improved, up to 85% with optimal DWI parameters and imaging time. There is limited evidence that these findings are similar to those observed in large-scale consecutive patients with TGA in clinical practice. ⋯ A modified TGA DWI protocols for detecting TGA lesions are useful in large-scale clinical practice for confirming the diagnosis of TGA patients with clinical findings.
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Comparative Study
Natural history of acute stroke due to occlusion of the middle cerebral artery and intracranial internal carotid artery.
The natural history of acute ischemic stroke (AIS) due to anterior circulation large artery occlusion is not well established. This information is essential for assessment of clinical benefit derived from recanalization therapies. ⋯ Outcome of AIS patients with anterior circulation large artery occlusion not treated with reperfusion therapies is extremely poor in TICA and proximal MCA occlusions with better outcomes noted in distal MCA occlusions. These findings are relevant for estimation of treatment effect of reperfusion therapies according to occlusion location.
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Bilateral paramedian thalamic infarction is a rare subtype of stroke the etiology of which still remains undetermined in many patients. ⋯ Vascular imaging is useful to determine underlying vascular pathologies and may support the diagnosis of small vessel disease in those patients with isolated bilateral paramedian thalamic infarction, hypoplastic/absent P1 segment of the PCA, and lack of vascular pathology.