Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Comparative Study
Screening for intracranial stenosis with transcranial Doppler: the accuracy of mean flow velocity thresholds.
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. ⋯ TCD is both sensitive and specific in identifying > or = 50% intracranial arterial stenosis. A MFV threshold cutoff of 100 cm/s has an optimal sensitivity and specificity trade-off for > or = 50% MCA stenosis. To help avoid false-positive results, a prestenotic to stenotic MCA velocity ratio of 1: > or = 2 should be used in addition to the MFV threshold.
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Headaches are a universal experience and one of the most common causes for physician consultation. The physician must determine whether a neuroimaging study is warranted to aid in the diagnosis of primary or secondary headaches. ⋯ Neuroimaging has been crucial in the investigation of the pathogenesis of migraine and cluster headaches. Secondary headaches, which may be diagnosed by neuroimaging studies, include subarachnoid hemorrhage, cerebral venous thrombosis, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, aqueductal stenosis, and arterial dissection.
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Multicenter Study Clinical Trial Controlled Clinical Trial
Transcranial duplex imaging with a sulfurhexafluoride echocontrast agent: enhancement and diagnostic quality.
The authors investigate characteristics of ultrasound enhancement and diagnostic quality of a sulfurhexafluorides (SF6)-containing echocontrast agent (SonoVue) in cerebrovascular patients with insufficient temporal bone window by transcranial color-coded duplex (TCCD) sonography. ⋯ Administration of SonoVue led to a quality improvement in 21 patients. In TCCD, it optimizes visualization of the cerebral arteries in patients with inadequate bone window. A dose of at least 1.2 mL provides the best enhanced images.
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Subcortical laminar heterotopia (SLH) is a subtype of malformation of cortical development characterized by laminar gray matter between the cortex and ventricles, which can vary in thickness and may be continuous or discontinuous. The objective of this study is to describe a normal finding of high-resolution magnetic resonance imaging that may simulate an SLH. SLH is isointense to cortex on both T1- and T2-weighted/FLAIR images, usually both anteriorly and posteriorly in location. Conversely, pseudo-SLH is a normal variant present only at the posterior aspect of the brain, and with dark signal on both T1- and T2-weighted/FLAIR images.
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The authors report on a 32-year-old man with common variable immunodeficiency and high signal intensity in basal ganglia on T1-weighted images. No signal alteration on T2-weighted and postcontrast images was observed. The patient had elevated levels of manganese in the serum. The authors conclude that the unusual hyperintensity in the basal ganglia area on T1-weighted images resulted from manganese deposition due to liver dysfunction.