Showing papers by "Ulrich Bogdahn published in 2003"

"Motor circuit" gray matter changes in idiopathic cervical dystonia.

Abstract: Background: Idiopathic cervical dystonia (ICD), the most common adult-onset focal dystonia, is clinically characterized by involuntary uni- or bilateral contractions of head and neck musculature. One crucial criterion for the diagnosis of ICD is normal results on MRI of the brain. Objective: To test the hypothesis whether subtle brain structure changes occur in ICD. Methods: Using voxel-based morphometry, the authors compared the brain structure of 10 patients with ICD with that of 10 healthy sex- and age-matched controls using high-resolution MRI. Results: Patients with ICD showed an increase in gray matter density bilaterally in the motor cortex and in the cerebellar flocculus and unilaterally in the right globus pallidus internus. In addition, a decrease in gray matter density was observed in the right caudal supplementary motor area as well as in the right dorsal lateral prefrontal and visual cortex. Conclusions: These results demonstrate for the first time in vivo subtle morphologic alterations in ICD. These data challenge the principal concept that patients with ICD have no brain structure abnormalities and that this movement disorder is solely due to abnormal cerebral function.

Preoperative evaluation of carotid artery stenosis: comparison of contrast-enhanced MR angiography and duplex sonography with digital subtraction angiography.

Abstract: BACKGROUND AND PURPOSE: Contrast-enhanced MR angiography and extracranial color-coded duplex sonography are noninvasive, preoperative imaging modalities for evaluation of carotid artery stenosis. Innovative techniques and improvements in image quality require frequent reassessment of accuracy, reliability, and diagnostic value compared with those of digital subtraction angiography (DSA). We evaluated contrast-enhanced MR angiography and duplex sonography compared with DSA for detection of high-grade carotid artery stenoses. METHODS: Four readers, blinded to clinical symptoms and the outcome of other studies, independently evaluated stenoses on contrast-enhanced MR angiograms in 71 vessels of 39 symptomatic patients. Duplex sonography was also performed in all vessels. The severity of stenosis was defined according to North American Symptomatic Carotid Endarterectomy Trial criteria (0-29%, 30-69%, 70-99%, 100%). Results of both modalities were compared with the corresponding DSA findings. RESULTS: Contrast-enhanced MR angiography had a sensitivity and specificity of 94.9% and 79.1%, respectively, for the identification of carotid artery stenoses of 70% or greater. Sensitivity and specificity of duplex sonography were 92.9% and 81.9%, respectively. Combining data from both tests revealed a sensitivity and specificity of 100% and 81.4%, respectively, for concordant results (80% of vessels). CONCLUSION: Concordant results of contrast-enhanced MR angiography and duplex sonography increase the diagnostic sensitivity to 100%. The reliability of MR angiography is comparable to that of DSA. The combination of contrast-enhanced MR angiography and duplex sonography might be preferable over DSA for preoperative evaluation in most patients, thus reducing the risk of perioperative morbidity and improving the overall outcome.

Brain perfusion imaging of a craniopharyngioma by transcranial duplex sonography.

Abstract: Transcranial duplex sonography in combination with contrast specific imaging methods might be helpful to visualize perfusion defects without loss of morphological information.

Medulloblastome im erwachsenenalter

Abstract: Das Medulloblastom ist der haufigste maligne Hirntumor im Kindes- und Jugendalter. Medulloblastome bei Erwachsenen sind relativ selten und stellen nur einen Anteil von 1% aller Hirntumoren des Erwachsenenalters. Die Inzidenz bei Erwachsenen wird um 0,5/Mio./Jahr angegeben [11, 26], betragt jedoch in der Altersgruppe von 15–19 Jahren um 2,33/Mio./Jahr und nimmt dann mit steigendem Alter kontinuierlich ab [26]. Der Beginn des Erwachsenenalters wird in der Literatur unterschiedlich definiert. Die meisten der klinischen Studien schliesen diesbezuglich Patienten >15 Jahre ein. Die Gruppe der sog. embryonalen Tumoren reprasentieren im Kindesalter mit einem Anteil von 25% unter den Hirntumoren die zweithaufigste Entitat. Sie entstehen wahrscheinlich aus unreifen neuralen Progenitorzellen des ZNS. Am haufigsten ist ein primitiv neuroektodermaler Tumor (PNET), der zu 85% vom Kleinhirn ausgeht und dann Medulloblastom genannt wird [24]. Nach der WHO-Klassifikation fur zentralnervose Tumoren sollte der Begriff PNET ausschlieslich solchen Tumoren vorbehalten sein, die Eigenschaften eines primitiv neuroektodermalen Zelltyps im engeren Sinn auspragen [53].