Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Case Reports
Vertebral artery dissection in Turner's syndrome: diagnosis by magnetic resonance imaging.
Aortic artery dissection is a rare but well-recognized complication of Turner's syndrome. Isolated carotid or vertebral artery dissection has not previously been reported. The authors report the clinical and magnetic resonance imaging findings in a 30-year-old woman with Turner's syndrome who developed a high cervical spinal cord infarction with a Brown-Sequard syndrome owing to bilateral vertebral artery dissection. The diagnosis and management of the case is reviewed.
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Over the past decade, a number of new kinetic modeling techniques have been developed for PET and SPECT ligands. This article will review commonly used modeling solutions for reversible positron-emission tomography (PET) and single photon emission computed tomography (SPECT) radioligands, with an emphasis on noninvasive methods. ⋯ These parameters will be defined, and their relationship to analogous parameters in pharmacology will be discussed. Then the major approaches are presented under the categories of graphical or mathematical as well as invasive or noninvasive.
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Case Reports
Localization of clinical syndromes using DWI: two examples of the "capsular" warning syndrome.
The capsular warning syndrome (CWS) is a subtype of transient ischemic attack characterized by its recurrent nature, absence of cortical signs, and high probability of early capsular stroke. Currently, standard imaging techniques have identified only internal capsule lesions in this entity. The authors present 2 cases with an otherwise typical CWS in whom a brainstem stroke was detected by diffusion-weighted imaging (DWI). DWI's ability to differentiate between acute and chronic infarcts may assist in more accurate localization of clinical syndromes.
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The intracranial effects of acetazolamide on flow velocities can be monitored noninvasively by transcranial Doppler (TCD) sonography. Extracranial volume flow changes can now reliably be measured with color duplex M-mode systems. The authors tested the volumetric effects of acetazolamide in patients with high-grade unilateral carotid disease to quantify the amount of flow changes. ⋯ Intracranial flow velocities rose from 49 (54) cm/s by 27 (41)%. Volume flow data showed the expected decline in patients with high-grade ICA stenosis and even more pronounced in patients with occlusion of the vessel. Cerebral reserve capacity was less sufficient in patients with a patent OA, despite an additional supply of 30 ml/min, indicating a hemodynamically critical situation.
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Whether acute stroke patients with major early infarct signs on computed tomography (CT) should be treated with intravenous (i.v.) thrombolysis remains controversial. The authors sought to define the outcomes in 5 consecutive patients who were not treated with i.v. thrombolysis, according to established guidelines. ⋯ Given the poor prognosis of patients with hemispheric stroke and early CT changes, alternative treatment modalities such as intra-arterial thrombolysis, early hemicraniectomy, and neuroprotective therapy should be vigorously pursued.