Journal of neuroimaging : official journal of the American Society of Neuroimaging
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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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Case Reports
Isolated pontine progressive multifocal leukoencephalopathy: unusual magnetic resonance imaging features.
Progressive multifocal leukoencephalopathy (PML) is an uncommon opportunistic infection that causes focal or multifocal demyelination predominantly in the subcortical white matter. The authors describe the clinical and radiographic features in 2 unusual cases of PML that were initially isolated to the pons. One patient presented clinically with only an isolated sixth cranial nerve palsy.
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Septum pellucidum agenesis is frequently associated with other cerebral malformations. Its isolated agenesis is quite rare. In the literature, all reported cases were diagnosed in early childhood. The authors present an unusual case of isolated septum pellucidum agenesis detected in adulthood with computed tomography and magnetic resonance imaging.
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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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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.