Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Periventricular white matter hyperintensities on postmortem magnetic resonance imaging (MRI) and myelin-stained frontal and parietal histologic sections were evaluated independently in 12 cases. There was a strong relationship between the extent of white matter hyperintensities on MRI and the extent of gross and microscopic changes seen in the white matter of myelin-stained sections, particularly in the frontal lobe. In this material, the extent of myelin rarefaction correlated with a 0- to 8-point white matter hyperintensity scale rating on MRI in the same brains.
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Image registration brings images into a form in which each voxel corresponds to a predetermined anatomic entity and is necessary for comparisons of data across scans. Intrasubject registration is a matter of translating and rotating one image volume into correspondence with another. Intersubject registration is more difficult because it requires the removal of individual anatomy dependence from the data. This article describes, with the help of clinical examples, automated methods for intrasubject registration of scans within and between modalities, and intersubject registration used for registering a three-dimensional brain atlas with a patient's brain scan.
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This study examined possible caffeine-mediated changes in blood flow velocity in the middle cerebral artery (VMCA) induced by tests of cerebrovascular responsiveness. Transcranial Doppler (TCD) sonography provided simultaneous bilateral VMCA measures while healthy college students hypoventilated, hyperventilated, and performed cognitive activities (short-term remembering, generating an autobiographical image, solving problems), each in 31-second tests. ⋯ Time-course analyses showed that VMCA (1) followed a triphasic pattern to increase over baselines during hypoventilation regardless of caffeine condition, (2) slowed below baselines during hyperventilation (with the degree of slowing attenuated under caffeine), and (3) increased over baselines during all cognitive activities (ranges 3.8-6.9%). It is concluded that a large amount of caffeine can suppress VMCA, and this possibility should be anticipated when TCD is used to assess cerebral hemovelocity.
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Hyperacute thrombosis of the basilar artery accompanied urgent treatment of basilar thrombosis with local thrombolytics and arterial reconstruction by balloon angioplasty. Successful placement of an endoprosthesis into the basilar artery permitted sustained restoration of blood flow. To the authors' knowledge, this is the first successful report of intracranial endoprosthesis deployment.
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Case Reports
Hyperkinetic movement disorders caused by corpus striatum infarcts: brain MRI/CT findings in three cases.
Three patients with hemichorea/hemiballismus/hemidystonia caused by discrete contralateral infarction of the corpus striatum are presented. The infarcts were all small on CT or MRI brain scan and were lacunar in type. ⋯ Involvement of contiguous areas, seen with larger infarcts, can suppress such movements. The infrequency of such hyperkinetic movement disorders, and the subtle infarct appearance on brain scan, can lead to a delay in the diagnosis.