Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Comparative Study
Symmetry of cerebral hemodynamic indices derived from bilateral transcranial Doppler.
The authors evaluated with bilateral transcranial Doppler (TCD) ultrasonography the norm of interhemispheric difference for several cerebrovascular hemodynamic parameters. ⋯ This study gives the reference values for the assessment of left-right symmetry of cerebral hemodynamics using various TCD-derived indices. These reference values should be useful for clinical studies assessing the left-right asymmetry of cerebral hemodynamics on a daily basis.
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To test the sensitivity of whole-brain T1 relaxometry to the evolution of pathological changes in multiple sclerosis (MS). ⋯ Brain T1 maps can be generated quickly and are sensitive to pathological changes over time. T1 values in both the gray and the white matter at the baseline visit were related to disease duration, suggesting that the T1 changes are clinically relevant. Although the absolute values will be different, it is likely that similar changes will be able to be detected at 1.5 T. The role of T1 measurement as a magnetic resonance imaging outcome measure in clinical trials now should be explored.
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Usually, microembolic signal (MES) monitoring is performed for MESs arising from downstream sources. The aim of this study is to describe the special characteristics of MESs originating from nearby sources in the middle cerebral artery (MCA). ⋯ MESs recorded from MCA stenoses may have special characteristics of multiple frequencies on both post-FFT spectra and pre-FFT time domain signals. Our findings may represent rotating or vibrating emboli as they are just dislodged from the thrombus and are moving from the vessel wall to the center. Further clinical and laboratory studies are needed to confirm this hypothesis.
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Comparative Study
Cerebral and systemic hemodynamics changes during upright tilt in chronic fatigue syndrome.
During head-up tilt (HUT), patients with chronic fatigue syndrome (CFS) have higher rates of neurally mediated hypotension (NMH) and postural tachycardia syndrome (POTS) than healthy controls. The authors studied whether patients with CFS were also more likely to have abnormal cerebral blood flow velocity (CBFV) compared with controls in response to orthostatic stress. ⋯ The results of this study are not consistent with the hypothesis that patients with CFS have a distinctive pattern of MCA CBFV changes in response to orthostatic stress.