Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Functional imaging is beginning to outline the brain's functional architecture and mechanisms of recovery from injury. I will review primarily the motor-function literature from normal populations, learning trials, stroke recovery, and rehabilitation with a neural network approach that may prove fruitful in further advancing our understanding of brain plasticity in response to focal lesions. A key consideration in this review will be how the development of distributed motor networks might constrain recovery as a function of the altered connectivity between damaged and nondamaged areas. It will be argued that this connectivity is central to both recovery from injury and response to treatment.
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The importance of the site of occlusion and the presence or absence of collaterals on initial angiography in patients with acute ischemic stroke has been recognized. Qureshi recently proposed a scheme that categorizes patients with ischemic stroke based on findings observed on initial angiography. ⋯ Qureshi grading scheme can be effectively used to stratify patients with anterior circulation ischemic stroke undergoing intra-arterial thrombolysis using initial angiographic findings.
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Case Reports
Intravascular ultrasound to assess extracranial vertebral artery restenosis: case report.
We present a case report of a patient who developed restenosis 5 months after initial stent placement. computed tomography (CT) angiography revealed a 70% stenosis, while conventional angiography revealed a 40% stenosis. An intravascular ultrasound (IVUS) was used to assess the degree of narrowing along with the mechanism causing the stenosis. IVUS can be utilized to resolve discrepancies between imaging modalities for degree of stenosis and also aid in determining the mechanism of restenosis after stent placement in the extracranial vertebral arteries.
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A 51-year-old man with a diagnosis of myelodysplasia and non-Hodgkin's lymphoma underwent an unmatched allogenic bone marrow transplantation and was treated posttransplant with chronic immunosuppressive medication. Eight months following transplantation, he presented with progressive dysarthria, cognitive and visual decline. Evaluation included brain magnetic resonance (MR) imaging demonstrating multifocal areas of increased T2 and FLAIR (fluid attenuated inversion recovery) signals involving the left frontal, parietal, and occipital lobes. ⋯ Serum serology for HIV was negative as well. A brain biopsy was subsequently performed. The clinical and neuroimaging differential diagnoses as well as neuropathologic correlation are presented.
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Functional neuroimaging and electrophysiological studies suggest that dysplastic neural tissue in malformations of cortical development may participate in task performance, and that functional organization can be altered beyond visible lesion boundaries. The aim of this work was to investigate cortical function in a heterogeneous group of patients with malformations of cortical development. ⋯ In accordance with previous reports, our findings indicate that dysplastic neural tissue can be activated during task performance, and that in some patients, extensive functional reorganization occurs, highlighting the importance of functional magnetic resonance imaging in presurgical planning in those patients for whom epilepsy surgery is considered as an option.