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Biomedical subjects

Wolfgang Reith

Publications and source records attributed to Wolfgang Reith.

26 records · Page 2Linked to original sources
PubMed2003

[Anatomical differences in optic nerve, chiasma and tractus opticus in human albinism as demonstrated by standardised clinical and MRI evaluation].

BACKGROUND: There has been long-standing clinical and electrophysiological evidence that in patients with albinism the visual pathways cross atypically: most fibres from one eye cross to the contralateral visual cortex. PURPOSE OF THE STUDY: to determine whether the size and configuration of the optic chiasm in human albinos is different from normally pigmented controls. PATIENTS AND METHODS: 17 patients (11 female, mean age 35.8 years) with oculocutaneous albinism underwent a standardised graded morphological and functional evaluation. Magnetic resonance images were reformatted to the region of the optic chiasm and analysed using observer-independent morphometry. In addition, fMRI of the visual cortex was performed during VEP analysis (1.5 Tesla Siemens Vision). Morphological and fMRT results were compared to an age-correlated group of n = 16 normally pigmented healthy volunteers with normal visual acuity and stereopsis. RESULTS: 65 % of the patients (n = 10) showed signs of dysplasia of the optic nerve head. Statistical morphometry showed distinct differences in chiasmal morphology between albinos and normally pigmented probands (smaller optic nerves, different angles of optical entry into the chiasm and of the beginning of the Tractus optici leaving the chiasm, overall chiasmal width and height). CONCLUSIONS: Optic nerve head anomalies are frequent in albinism and influence visual outcome. Size and configuration of the optic chiasm in human albinos is distinctly different from normally pigmented control persons and reflects the atypical crossing of optic fibres.

Adult↗
PubMed2003

Configuration of the optic chiasm in humans with albinism as revealed by magnetic resonance imaging.

PURPOSE: To determine whether the size and configuration of the optic chiasm in humans with albinism is different from that in normal control subjects. METHODS: Seventeen patients and 15 control subjects underwent magnetic resonance imaging of the entire head. Images were reformatted to the chiasm region and analyzed with observer-independent morphometry and measurements by a blinded observer. RESULTS: The albino group showed significantly smaller chiasmatic widths, smaller optic nerves and tracts, and wider angles between nerves and tracts. Statistical morphometry showed a different configuration of the optic chiasm. CONCLUSIONS: Size and configuration of the optic chiasm in humans with albinism are distinctly different from those in normal control subjects and reflect the atypical crossing of optic fibers.

Adult↗
PubMed2003

Transient dystonia following magnetic resonance imaging in a patient with deep brain stimulation electrodes for the treatment of Parkinson disease. Case report.

Data from previous studies have shown that magnetic resonance (MR) imaging of the head can be performed safely in patients with deep brain stimulators. The authors report on a 73-year-old patient with bilaterally implanted deep brain electrodes for the treatment of Parkinson disease, who exhibited dystonic and partially ballistic movements of the left leg immediately after an MR imaging session. Such dystonic or ballistic movements had not been previously observed in this patient. In the following months, this focal movement disorder resolved completely. This case demonstrates the possible risks of MR imaging in patients with deep brain stimulators.

Aged↗
PubMed2002

MR cisternography after intrathecal Gd-DTPA application.

The purpose of this study was to establish and to evaluate MR cisternography after intrathecal Gd-DTPA administration to detect rhinobasal cerebrospinal fluid (CSF) fistulae in patients with suspected CSF rhinorrhoea. Ten patients with suspected CSF rhinorrhoea were examined. The MR cisternography included the following investigation steps: acquisition of nonenhanced fat-suppressed T1-weighted spin-echo (SE) scans of the skull base and the paranasal sinuses, lumbar puncture with administration of 1 ml Gd-DTPA solute with 4 ml NaCl and performance of MR cisternography with the same fat-suppressed T1-weighted sequences as used initially. In 10 patients with suspected CSF rhinorrhoea Gd-DTPA enhanced MR cisternography detected 5 CSF fistulae. In 3 of 5 CSF leaks were located in the cribriform plate and in 2 of 5 sphenoidal. Whereas 4 of these depicted leaks were confirmed surgically, in 1 case the CSF fistula closed spontaneously. In another case, CSF leakage after severe head injury was clinically highly suspected but ceased prior to MR cisternography with inability to detect the temporary fistula. In the remaining 4 patients with serous rhinorrhoea MR cisternography did not provide any evidences for CSF fistulae. Intrathecal Gd-DTPA injection was tolerated excellently. Clinical and EEG examinations showed no gross behavioural or neurological disturbances and no seizure activity, respectively. The MR cisternography after intrathecal administration of Gd-DTPA represents a safe, promising and minimally invasive method for detection of CSF fistulae. This MR investigation provides excellent depiction of CSF spaces and pinpoints CSF fistulae.

Adult↗
PubMed2002

Non-traumatic neurological emergencies: imaging of cerebral ischemia.

Cardiovascular disease is the leading cause of death worldwide with almost one-third of all cardiovascular deaths ascribed to stroke. Imaging modalities, such as CT, MRI, positron emission tomography (PET), and single photon emission CT (SPECT) provide tremendous insight into the pathophysiology of acute stroke. Computed tomography is considered the most important initial diagnostic study in patients with acute stroke, because underlying structural lesions, such as tumor, vascular malformation, or subdural hematoma, can mimic stroke clinically. Diffusion-weighted imaging (DWI) has the ability to visualize changes in diffusion within minutes after the onset of ischemia and has become a powerful tool in the evaluation of patients with stroke syndrome. Territories with diffusion and perfusion mismatch may define tissues at risk, but with potential recovery. An alternative strategy with CT technology uses rapid CT for dynamic perfusion imaging, with similar goals in mind. Angiography can be performed in the hyperacute stage if thrombolytic therapy is being considered. Indications for diagnostic angiography include transient ischemic attacks in a carotid distribution, amaurosis fugax, prior stroke in a carotid distribution, a high-grade stenotic lesion in a carotid artery, acquiring an angiographic correlation of magnetic resonance angiography (MRA) or computed tomographic angiography (CTA) concerning stenotic findings. In 50% of all angiograms performed in the hyperacute stage, occlusion of a vessel is observed; however, the need for angiography has been made less necessary due to the improvements of MRA, duplex ultrasound, and CTA. Numerous etiologies can lead to infarction. In children, pediatric stroke is very uncommon. The most common cause is an embolus from congenital heart disease with right-to-left shunts. Also a dissection of large extracranial vessels may result in cerebral infarction, and although the brain is equipped with numerous venous drainage routes, the occlusion of a large sinus or a widespread vein obstruction will eventually lead to venous infarction. Thus, optimal stroke care requires not only early and exact identification of ischemia, but also a close collaboration between the clinician and radiologist.

Brain↗
PubMed2002

Recovery of semantic word processing in transcortical sensory aphasia: a functional magnetic resonance imaging study.

In a previous functional magnetic resonance imaging (fMRI) study with normal subjects, we demonstrated regions related to conceptual-semantic word processing around the first frontal sulcus (BA 9) and the posterior parietal lobe (BA 7/40) in agreement with several previous reports. We had the possibility, using the same fMRI paradigm, to study two consecutive cases with left middle cerebral artery (MCA) infarction (RC and HP) and lesions affecting either solely the pre-frontal (HP) or both the pre-frontal and posterior parietal part of the network activated in normal subjects (RC). Both patients showed transcortical sensory aphasia (TSA) on acute assessment. This contradicts classical disconnection accounts of the syndrome stating intact conceptual representations in TSA. Their recovery of language comprehension was associated with activation of a left hemispheric network. Mainly activations of left perilesional pre-frontal regions (RC), left Wernicke's area (RC and HP) or the left posterior middle and inferior temporal cortex (HP) were demonstrated in the TSA patients. The latter findings suggest that in our cases of TSA functional take-over has occurred in regions with related functions ('redundancy recovery') rather than in previously unrelated areas ('vicarious functioning'). Our data support distributed models of conceptual-semantic word processing and multiple left hemispheric representations of closely related functions.

Adult↗
PubMed2002

Comparison of tc-99m depreotide and in-111 octreotide in recurrent meningioma.

PURPOSE: For more than a decade, In-111 octreotide has been known to accumulate in meningiomas as a result of the expression of subtype 2 somatostatin receptors. Improved imaging characteristics can be expected with the recently developed radiotracer Tc-99m depreotide, which also binds to subtype 2 somatostatin receptors. MATERIALS AND METHODS: The authors examined a patient with intraorbital and extracranial recurrent meningioma using SPECT with Tc-99m depreotide and In-111 octreotide. The tumor-to-background ratios in the lesions were compared and the findings were correlated with histopathologic findings. RESULTS: Although the tumor-to-background ratios were higher for the In-111-labeled tracer in the largest tumor lesion (5.7 versus 3.3), SPECT with the Tc-99m-labeled compound showed a proved second site of recurrence as a result of the better resolution that can be achieved with that isotope. CONCLUSIONS SPECT: with Tc-99m depreotide appears to be clinically useful for detecting recurrent meningiomas with higher resolution and may outperform In-111 octreotide imaging in patients with meningiomas.

Eye Neoplasms↗