Journal of neuroimaging : official journal of the American Society of Neuroimaging
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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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Case Reports
Flumazenil responsive ornithine transcarbamylase deficiency encephalopathy: clinical and radiographic features.
A 22-year-old woman with a negative urine drug screen and somnolence rapidly reversed by intravenous flumazenil was found to have elevated ammonia levels and punctate calcifications of the subcortical frontal white matter. Abnormally high levels of orotic acid were found in serum and urine, confirming the diagnosis of ornithine transcarbamylase deficiency. Although computed tomography findings are non-specific, young patients with unexplained hyperammonemic states of somnolence reversed by flumazenil should be screened for this X-linked recessive metabolic disorder.
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NC100100 (Sonazoid) is a new perfluorocarbon-based ultrasound contrast agent (UCA) that has not been introduced to transcranial harmonic imaging. ⋯ The new UCA Sonazoid is suitable for displaying brain perfusion. As already observed for other UCAs, gray-scale harmonic imaging with Sonazoid leads to a more homogeneous contrast increase in cerebral parenchyma compared to harmonic power Doppler imaging. Sonazoid produces a moderate shadowing effect, with signal attenuation in the underlying deeper regions of interest.
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Collateral flow patterns are important risk factors for brain ischemia in the presence of internal carotid artery (ICA) stenosis or occlusion. Ophthalmic artery (OA) flow reversal, routinely studied by transcranial Doppler sonography, is an important marker for high-grade ICA stenosis or occlusion. The authors sought to define the value of assessing OA flow direction with color flow duplex ultrasonography (CDUS) in the setting of significant ICA disease. ⋯ OA flow direction is easily studied with CDUS. Reversed OA flow direction is highly specific (100%) for severe ipsilateral ICA stenosis or occlusion, with excellent positive predictive value, moderate negative predictive value, and limited sensitivity. OA flow reversal is not only quite specific for severe ICA disease, which may be helpful if the carotid CDUS is difficult or inadequate, but may also provide additional hemodynamic insights (i.e., the inadequacy of other collateral channels such as the anterior communicating artery). OA evaluation can provide important hemodynamic information and should be included as part of carotid CDUS if there is any evidence of ICA stenosis or occlusion.
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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.