Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Transcranial Direct Current Stimulation and Cerebral Vasomotor Reserve: A Study in Healthy Subjects.
Cerebral vasomotor reserve (VMR) is the capability of cerebral arterioles to change their diameter in response to various stimuli, such hypercapnia. Changes of VMR due to transcranial direct current stimulation (tDCS) have been poorly studied. ⋯ Our study confirms that tDCS induces a modification of bilateral VMR with a polarity-specific effect; based on this bilateral MFV and BHI modifications, we can speculate an involvement of the SNS in the VMR regulation.
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To determine interobserver spatial variability in language area localization using three commonly employed language tasks. ⋯ While there were no differences between interobserver spatial variability in language area localization between the three tasks, language task choice impacts the accuracy of fMRI language area identification because tasks vary in their rates of interobserver laterality disagreements and failed localizations. A combination of tasks including one with low laterality disagreements (eg, SD) and one with few failed localizations (eg, SC) may offer the best combination.
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Decision-making systems trained on structural magnetic resonance imaging data of subjects affected by the Alzheimer's disease (AD) and healthy controls (CTRL) are becoming widespread prognostic tools for subjects with mild cognitive impairment (MCI). This study compares the performances of three classification methods based on support vector machines (SVMs), using as initial sets of brain voxels (ie, features): (1) the segmented grey matter (GM); (2) regions of interest (ROIs) by voxel-wise t-test filtering; (3) parceled ROIs, according to prior knowledge. ⋯ The classification performance, evaluated as the area under the receiver operating characteristic curve (AUC), reaches AUC = (88.9 ± .5)% in 20-fold cross-validation on the AD/CTRL dataset, when the GM is classified as a whole. The highest discrimination accuracy between MCI converters and nonconverters is achieved when the SVM-RFE is applied to the whole GM: with AUC reaching (70.7 ± .9)%, it outperforms both ROI-based approaches in predicting the AD conversion.
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Case Reports
Symptomatic Spinal Migration of Subarachnoid Hemorrhage due to Ruptured Intradural Vertebral Artery Aneurysm.
A 55-year-old patient was admitted to the hospital with severe acute back pain. Thoracolumbar magnetic resonance (MR) imaging showed hemorrhage in subarachnoidal-subdural space. On cranial MR imaging and MR angiography, an aneurysm was suspected in the V4 segment of the right vertebral artery. ⋯ The final diagnosis was ruptured V4 segment aneurysm with subsequent symptomatic migration of hemorrhage into the spinal subarachnoidal-subdural space. The patient was treated endovascularly by coil occlusion of both the aneurysm and vertebral artery. This rare cause and possible mechanisms for spinal migration of intracranial hemorrhage after aneurysmal rupture is discussed.
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Acute aortic dissection is the most common acute aortic condition requiring urgent surgical therapy. Due to lack of typical symptoms, it is sometimes difficult to identify acute aortic dissection causing ischemic stroke. ⋯ After urgent aortic replacement surgery, the patient recovered with no neurological deficit. This case underscores the crucial role of carotid ultrasonography for the investigation of possible underlying acute aortic dissection when considering the use of intravenous recombinant tissue plasminogen activator therapy for hyperacute stroke.