Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Case Reports
Human brain temperature in vivo: lack of heating during color transcranial Doppler ultrasonography.
This study was undertaken to assess the effect of ultrasound on human brain temperature in vivo. The investigation consisted of direct recording of intracranial temperature during color transcranial Doppler (TCD) sonography in a neurosurgical patient. The temperature was recorded from 3 thermocouples. ⋯ The ipsilateral tympanic temperature increased by only 0.06 degree C, and this value may be regarded as a measure of the overall increase in brain temperature. Passive cooling effect produced by the transducer, which was at ambient temperature, was found to reach the brain surface and to surpass any possible heating caused by the ultrasound. The results indicate that no noticeable increases in human brain temperature occur in response to ultrasound emitted by a color TCD device at high transmitter power settings within the diagnostic range.
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Fabry disease is an X-linked recessive deficiency of lysosomal alpha-galactosidase A associated with an increased risk of early onset cerebrovascular disease. The disorder is reported to affect the posterior circulation predominantly. This hypothesis was investigated directly by the measurement of regional cerebral blood flow with positron emission tomography (PET). ⋯ The affine transformation was constrained by choosing corresponding cerebral landmark "tie points" between the SPM(t) [symbol: see text] MRI template images and the cerebral arterial territory maps. The data demonstrated that the posterior circulation is the predominant arterial territory with a significantly increased rCBF in Fabry disease. No arterial distribution had a decreased rCBF.
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The authors establish accuracy parameters of a broad diagnostic battery for bedside transcranial Doppler (TCD) to detect flow changes due to internal carotid artery (ICA) stenosis or occlusion. ⋯ In symptomatic patients, bedside TCD can accurately detect flow changes consistent with hemodynamically significant ICA obstruction; however, TCD should not be a substitute for direct carotid evaluation. Because TCD is sensitive and specific for a > or = 70% carotid stenosis or occlusion in both extracranial and intracranial carotid segments, it can be used as a complementary test to refine other imaging findings and detect tandem lesions.
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Comparative Study
Transcranial Doppler pulsatility indices as a measure of diffuse small-vessel disease.
Elevation in pulsatility indices (PIs) as measured by transcranial Doppler (TCD) have been postulated to reflect downstream increased vascular resistance caused by small-vessel ischemic disease. ⋯ Elevation in PIs as measured by TCD shows strong correlation with MRI evidence of small-vessel disease. TCD may be a useful physiologic index of the presence and severity of diffuse small-vessel disease.
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Comparative Study
Helical high-resolution volume-rendered 3-dimensional computer tomography angiography in the detection of intracranial aneurysms.
This study was carried out to determine whether high-resolution 3-dimensional prospective-volume-rendered computed tomographic (CT) angiography can replace conventional intra-arterial digital subtractional angiography in the diagnostic evaluation of patients with an acute subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysm. ⋯ CT angiography with 3-dimensional post-processing is a sensitive, noninvasive method that provides a 3-dimensional view of intracranial vessels and the aneurysm. It is also very useful in planning either surgical or endovascular treatment.