Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Artery-to-artery embolism generally occurs in patients with not only moderate to severe arterial stenosis but also plaque vulnerability. Two unique cases with free-floating thrombi at the distal side of the small plaque in the internal carotid artery without stenosis are presented and its clinical implications are discussed. ⋯ In these two cases, duplex ultrasonography revealed free-floating thrombi developed at the distal region of small plaques. Aggressive treatment should be considered in a patient with thromboembolic stroke who has the small plaque presenting "snake fang" sign even if there is no stenosis or plaque vulnerability.
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Real-time fMRI is especially vulnerable to task-correlated movement artifacts because statistical methods normally available in conventional analyses to remove such signals cannot be used in the context of real-time fMRI. Multi-voxel classifier-based methods, although advantageous in many respects, are particularly sensitive. Here we systematically studied various movements of the head and face to determine to what extent these can "masquerade" as signal in multi-voxel classifiers. ⋯ Movement tasks of many types (including movements of the eyes, face, and body) can lead to false positives in classifier-based real-time fMRI paradigms.
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To determine whether voxel-based morphometry of the cerebrospinal fluid (CSF) space can accurately differentiate iNPH from other related neurological disorders. ⋯ The VBM-based CSF space analysis can detect disproportionate changes in CSF space and differentiate iNPH patients from those with AD or PD and healthy elderlies accurately.
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Cerebral autoregulation (CA) enables the brain to maintain stable cerebral blood flow (CBF). CA can be assessed noninvasively by determining correlations between CBF velocity (CBFV) and spontaneous changes in blood pressure. Postrecording signal analysis methods have included both frequency- and time-domain methods. However, the test-retest reliability, cross-validation, and determination of normal values have not been adequately established. ⋯ CA parameters obtained by time- and frequency-domain methods correlate well, and show good interhemispheric and test-retest reliability. Group means from healthy controls may provide adequate norms for determining abnormal CA in cerebrovascular patients.
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Residual giant-cystic craniopharyngiomas are amenable to intracavitary bleomycin treatment. Radiologic identification of potential cyst leaks is of paramount for treatment decisions. ⋯ In one case, whose previous water-soluble iodinated contrast-enhanced CT cystography was negative for leaks, intracystic Gd-enhanced MR showed intraventricular Gd enhancement. We conclude that MR imaging after intracystic administration of Gd-based contrast paramagnetic agents is useful in the detection of potential leaks in cases of giant residual craniopharyngiomas.