Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Case Reports
Cortical reorganization in linear nevus sebaceous syndrome: a multimodality neuroimaging study.
The authors report the findings of multimodal structural, functional, and metabolic imaging in a patient with linear nevus sebaceous syndrome, intractable seizures, and right megalencephaly. Despite nearly continuous paroxysmal electrical activity from the megalencephalic region, imaging studies suggested nonfunctional tissue in this region with reorganization of cortical function to the unaffected ipsilateral hemisphere. Hemispherectomy has been successfully performed in previous patients; however, it could have led to marked left hemiparesis with significant functional morbidity in this patient because of ipsilateral reorganization of the primary motor cortex.
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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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Previous functional neuroimaging studies performed during transient global amnesia (TGA) have not answered the central question regarding the etiology of TGA, namely: whether the observed hypoperfusion in the mesial temporal lobe structures reflects a primarily ischemic process or whether it represents a secondary phenomenon resulting from locally decreased metabolism. The authors performed Tc 99-m-bicisate brain single photon-emission computed tomography (SPECT) scanning in a 66-year-old man during an episode of TGA, 24 hours after the episode and 3 months after the episode. To the authors' knowledge, this is the only reported study in which a follow-up SPECT scan was performed within 24 hours. ⋯ Resolution of the SPECT scan abnormalities correlated well with resolution of the memory loss. These findings agree with previously reported SPECT, positron-emission tomography (PET), and diffusion magnetic resonance imaging (MRI) studies that indicate the mesial temporal lobe structures as the major site of pathology in TGA. The authors suggest that a process causing decreased local metabolism, such as cortical spreading depression, constitutes the primary pathophysiologic mechanism in this case.
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Bell's palsy (idiopathic facial paralysis) is the most common cause of unilateral peripheral facial neuropathy. Bilateral involvement occurs in less than 10% of cases. The authors describe a 20-year-old man with bilateral idiopathic facial weakness. ⋯ There was no facial nerve swelling. Three months later he had improving residual bifacial weakness. To the authors' knowledge, this is the first report of abnormal MRI findings in bilateral Bell's palsy.
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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.