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Biomedical subjects

J Reul

Publications and source records attributed to J Reul.

44 records · Page 3Linked to original sources
PubMed1993

Large thoracocervical intraspinal neuroma: unusual clinical and neuroradiological findings.

The clinical and radiological findings of a giant cystic intraspinal cervical tumour are presented. Symptoms and signs suggesting a polyneuropathy were misleading. On myelography the tumour appeared as a solid mass, but its size was distinctly underestimated. MRI demonstrated the true extent (from C4 to T4) and the cystic structure of the tumour. The histo-pathological diagnosis was fibrillary neuroma (WHO grade I).

Aged↗
PubMed1993

Bilateral chronic subdural haematomas following traumatic cerebrospinal fluid leakage into the thoracic epidural space.

This report describes a patient who developed bilateral chronic subdural haematomas after a stab injury to the thoracic meninges causing prolonged cerebrospinal fluid leakage into the epidural space. Diagnostic findings and therapeutic management are presented and possible pathogenic mechanisms are discussed. This case suggests that patients who have symptoms or signs of increased intracranial pressure after a penetrating spinal injury should be studied for subdural haematoma.

Adult↗
PubMed1993

[Prevention of vascular complications in endonasal paranasal sinus surgery. Part II: Pre- and intraoperative imaging].

Computer-assisted surgery (CAS) is a new intraoperative localization system that is based on digital image generation devices. The system has been used in 189 cases of paranasal sinus procedures, employing computed tomography (CT) image data. Highly accurate imaging and localization of bony structures can be achieved in this way, although definition of vascular structures is limited by representation attributes of vessels in CT. Algorithms have now been developed for the use of magnetic resonance angiography (MRA) data with the system. CAS was used in six cases of endonasal surgery. Imaging helped substantially in all cases, but its application was limited by incomplete reflection of small vessels. In one case, intraoperative findings showed MRA-inherent inaccuracies. These might be avoided using correction programs and phantom selection (shimming) procedures in the future. Additionally, matching of different imaging modalities should improve intraoperative applications of CAS.

Algorithms↗
PubMed1989

Is there a generalized right hemisphere dominance for mediating cerebral activation? Evidence from a choice reaction experiment with lateralized simple warning stimuli.

The influence of simple lateralized visual warning stimuli on decision and movement time (jump reaction) for a centrally presented choice reaction stimulus was examined in 20 normal healthy subjects. Without warning the right hand (left hemisphere) showed faster decision times for the choice reaction stimuli. After presentation of the lateralized warning stimulus this difference was no longer present while for both hands there was improvement after warning. This indicates that the left hand (right hemisphere) showed a more pronounced improvement of decision time following the warning stimulus than the right hand. In contrast, the number of errors (false positives) increased after LVF stimulation. Experimental conditions had no influence on movement time at all. It was concluded that the complexity of the lateralized warning stimulus and not of the centrally presented reaction stimulus determines hemispheric activation dominance.

Adult↗
PubMed1988

Left hemispheric interference with nonverbal performance in aphasics: comparison with data from split-brain studies.

Two nonverbal tasks (Nebes' Figural Unification Test and Arc-Circle Matching Task) were given to 10 aphasic patients and 10 normal controls. Observations in split-brain patients have shown that the right hemisphere performs almost normally on these tasks while the left hemisphere fails completely. Left and right hand performances of aphasics and controls were compared with those of split-brain patients as reported in the literature. In the Figural Unification Test the aphasics' left hand performance was significantly poorer than that of split-brain patients. This is interpreted as an effect of left hemispheric interference with right hemispheric nonverbal performance. The lack of a similar impairment of left hand performance in the Arc-Circle Matching Task suggests that this interference is only provoked by tasks which, due to the possible verbalization of stimulus material, tend to stimulate left hemispheric activity.

Aged↗
PubMedDate not supplied

[Cerebral vein and sinus thrombosis--an important cause of benign intracranial pressure increase in childhood].

The syndrome of raised intracranial pressure without any space-occupying lesion (pseudotumor cerebri) is still of unknown etiology. To some degree, secondary causes can be found. With respect to the therapeutical possibilities, a clinically important cause is the thrombosis of a major cerebral sinus. In children it is sometimes associated with otitis media. However, clinical signs of mastoiditis can be missed because of previous antibiotic treatment. We observed 11 children with pseudotumor cerebri. Four children suffered from an occlusion of a lateral major sinus after otitis media. The treatment with heparin in the acute stage and later on with acetylsalicylic-acid led to complete recovery. Our results suggest that the thrombosis of a major cerebral sinus induced by an otitis media is a frequent cause of pseudotumor cerebri in children and should be excluded by MRI or angiography in any doubtful case. In contrast to the treatment of adults, long term anticoagulation is not necessary.

Adolescent↗
PubMedDate not supplied

MR blood oxygenation level-dependent signal differences in parenchymal and large draining vessels: implications for functional MR imaging.

BACKGROUND AND PURPOSE: One major limitation of current functional MR (fMR) imaging is its inability to clarify the relationship between sites of cortical neuronal activation, small parenchymal venules that are in close proximity to these sites, and large draining veins distant from the active parenchyma. We propose to use gradient-echo blood oxygenation level-dependent (BOLD) fMR time courses to differentiate large draining veins from parenchymal microvasculature. METHODS: In eight research subjects, five of whom presented with space-occupying lesions near the central sulcus, gradient-echo fMR imaging was performed during alternating periods of rest and motor activation. MR signal time courses from parenchymal regions and draining veins of different diameters, which were identified using contrast-enhanced T1-weighted scans, were evaluated. Percent signal changes (deltaS) and the time to the onset of MR signal rise (T0) were calculated. RESULTS: Mean delta(S) for all subjects was 2.3% (SD+/-0.7%) for parenchymal activation, 4.3% (SD +1.0%) for sulcal macrovasculature, and 7.3 (SD+/-1.1%) for large superficial bridging veins. The mean time to onset of MR signal increase was 4.4 seconds for parenchymal task-related hemodynamic changes and 6.6 seconds for venous hemodynamic changes, regardless of vessel size. Both the differences in delta(S) and T0 were statistically significant between venous and parenchymal activation (P < .0001). CONCLUSION: Gradient-echo fMR imaging reveals hemodynamic task-related changes regardless of vessel size and therefore might show macrovascular changes distal to the site of neuronal activity. MR-signal time-course characteristics (delta(S) and T0) can be used to differentiate between small parenchymal and larger pial draining vessels, which is especially important in presurgical planning of neurosurgical procedures involving functionally important brain regions. The knowledge about the differences in (delta)S and T0 between micro- and macrovasculature might lead to a more accurate description of the spatial distribution of underlying neuronal activity.

Adult↗