Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Transcranial Doppler (TCD) ultrasound with the intravenous injection of agitated saline as contrast (cTCD) is an effective method for detecting right-to-left intracardiac and extracardiac shunt (RLS); however, the sensitivity of cTCD in the diagnosis of RLS remains slightly less than that of transesophageal echocardiography, even in patients with adequate transtemporal ultrasonic bone windows. The authors present a case with cTCD underestimating RLS because of jugular valve incompetence in a 42-year-old man presenting with an episode of transient aphasia. Three weeks after transcatheter closure of a patent foramen ovale associated with an atrial septal aneurysm, he experienced 2 episodes of amaurosis fugax. ⋯ A single microbubble (MB) was detected in the left MCA in only 1 of 5 studies; the remaining runs all failed to detect an RLS. Significant MB reflux was noted in the left internal jugular vein because of jugular valve incompetence. The authors conclude that incompetence of the jugular vein valve can result in a false negative cTCD study for RLS detection.
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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.