Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Case Reports
Paradoxical brain embolism from thrombus associated with vena caval filter in a patient with cancer.
A 71-year-old man experienced sudden onset of hemiparesis and aphasia. He had a 4-month history of gallbladder cholangiocarcinoma, complicated with a postoperative deep-vein thrombosis (DVT) that necessitated a vena caval filter placement. Diffusion-weighted magnetic resonance imaging of the brain showed multiple hyperintense foci. ⋯ Abdominal computed tomography showed a thrombus in the inferior vena cava extending through the filters. A transcranial Doppler bubble study revealed the presence of a right-to-left shunt. Paradoxical cerebral embolism must be considered in patients with DVT who have new onset neurologic deficits even in the presence of a caval filter.
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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.
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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.