Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Conventional transcranial color-coded real-time sonography of the vertebrobasilar system is limited by imaging problems of the distal segment of the basilar artery. Lung-stable contrast-enhancing agents may overcome this problem by enhancing the quality of Doppler signals by as much as 20%. Fourty-two patients underwent sonographic evaluation of the vertebrobasilar system before and after receiving intravenously administered galactose-based contrast-enhancing agent Levovist by transforaminal and transtemporal routes. ⋯ After signal enhancement with Levovist, category 1 covered 0%, category 2 2.4%, category 3 7.14%, category 4 59.5% and category 5 30.9% (p < 0.001). Unenhanced transtemporal approach allowed identification of the basilar tip in 78.6% with an average length of 6.3 +/- 2 mm; contrast enhancement improved this values to 92.9% and 8.3 +/- 3.3 mm respectively (p < 0.05). The application of transpulmonary contrast-enhancing agents improves the reliability of transcranial color-coded duplex sonography of the basilar artery.
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Comparative Study
Imaging of dopamine transporters with technetium-99m TRODAT-1 and single photon emission computed tomography.
The authors wanted to evaluate the usefulness of 99Tcm-TRODAT-1 as an imaging agent for measuring changes in dopamine transporter concentrations in Parkinson disease (PD) and correlate the findings to the severity of the disease as measured by the Hoehn and Yahr scale (H/Y). Twenty-two healthy volunteers and 27 patients with PD of H/Y stage I-IV were evaluated. ⋯ Patients with PD showed a significant decrease in the striatal uptake of 99Tcm-TRODAT-1 compared to healthy volunteers, and the ST/CB ratios were closely related to the stage of PD. The present study demonstrates that it is possible to visualize and quantify changes in dopamine transporter in the striatum of patients with PD using 99Tcm-TRODAT-1 and SPECT with good correlation to H/Y stage and unified Parkinson's disease rating scale (UPDRS) scale.
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Reversible vasospasm in the bilateral middle cerebral artery in a patient with postpartum cerebral angiopathy was evaluated with serial transcranial color-coded sonography (TCCS). The authors propose TCCS as the method of choice for assessing the time course of vascular changes in postpartum cerebral angiopathy because it allows for precise placement of the sample volume and adjustment of the incident angle.
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A 47-year-old male with a 5-year history of palatal myoclonus was found on magnetic resonance imaging (MRI) examination to have an ectatic dominant left vertebral artery that compressed the left inferior olive. Microvascular decompression effectively eliminated his symptoms. This case and a similar case presented here with an ectatic vertebral-basilar system illustrate the value of standard MRI in conjunction with magnetic resonance angiography (MRA) in evaluating palatal myoclonus, and they suggest a potential role for decompressive surgery when persistent, highly symptomatic inferior olivary ischemia or compression occurs.
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Acute effects of smoking on human cerebral blood flow: a transcranial Doppler ultrasonography study.
Middle cerebral artery (MCA) flow velocity was continuously monitored during smoking in an observational study (n = 14) using transcranial Doppler (TCD) ultrasonography. Cerebral autoregulatory vasodilator capacitance under inspired CO2 challenge was also measured before smoking and at peak smoking effect. ⋯ Gender subgroup analysis showed smoking acutely suppressed the CO2 vasodilator capacitance by 56% in men but only by 5% in women (p = 0.05). The magnitude of the acute smoking-induced increases in MCA flow velocities appeared to be independent of the estimated cigarette yields for nicotine, carbon monoxide, and "tar." Smoking in healthy subjects acutely increased MCA mean flow velocity, which may reflect a global increase in cerebral blood flow via complex influences on the cerebral autoregulation.