Biomedical subjects

R Leuwer

Publications and source records attributed to R Leuwer.

39 records · Page 3Linked to original sources

PubMed1992

[Significance of ultrahigh resolution computed tomography in the preoperative diagnosis of Menière's disease].

By means of ultrahigh resolution computed tomography imaging of very small labyrinthine structures such as the vestibular aqueduct and the rima sacci endolymphatici is possible. Aim of the present study was to demonstrate the significance of ultrahigh resolution CT in the preoperative management of Menière's disease. The study was carried out on 16 patients who underwent endolymphatic mastoidal shunt operation. Postoperative imaging and clinical findings were compared. By means of ultrahigh resolution technique the vestibular aqueduct could be examined in all of our patients. Two CT-findings of atresia of the external aperture were confirmed intraoperatively. Preoperative ultrahigh resolution computed tomography is a reliable method to demonstrate the distinct variability of the oto-surgical landmarks for endolymphatic shunt operation. There is no reliable correlation between the width, shape and bony contrast of the vestibular aqueduct and the postoperative outcome. Thus in our opinion preoperative ultrahigh resolution computed tomography is mandatory for the preoperative management of Menière's disease.

Follow-Up Studies↗

PubMed1992

[Ultrasound diagnosis of isolated vagus neurofibroma in Recklinghausen disease].

We report on an isolated cervical vagus nerve neurofibroma in a patient with neurofibromatosis Recklinghausen. B-scanechography showed a well limited tumor without infiltration of adjacent structures and with cranial and caudal dendrites. The inner structure of the neurofibroma was characterized by a homogenous picture of low ultrasound reflection. Although ultrasound allows an exact description of the tumor's topography, it is impossible to give a histological interpretation by the sonomorphology.

Adult↗

PubMed1987

Tissue pO2 of human brain cortex--method, basic results and effects of pentoxifylline.

A polarographic multiwire surface electrode was used for measurement of local oxygen partial pressure (pO2) on human brain cortex during neurosurgical operations. The two major problems encountered in this application of the electrode involved sterility of the equipment and mounting of the electrode. The described method of sterilization does not alter the electrical properties of the electrode. A special mount was designed to allow free three-dimensional placement of the electrode without exerting pressure on the cortex. Basic results of this technique demonstrated that it is possible to distinguish different pO2 distribution patterns displayed in pO2 histograms for various types of brain tumors and edematous brain tissue. In patients with arteriovenous malformations (AVMs) of the brain, an increase of tissue pO2 in cortical areas adjacent to the AVM was the result of extirpation of the lesion. The effect of intravenously administered pentoxifylline was studied during extraintracranial bypass operations in patients with cerebrovascular disease. In 7 patients a consistent shift of the pO2 histograms to the right, i.e., to higher pO2 values, could be demonstrated. Mean pO2 values increased statistically significantly by 16 +/- 7 mmHg as early as ten minutes after infusion of pentoxifylline. The rapid improvement of tissue oxygenation of human brain cortex is thought to be the result of an improvement of microcirculation, for other parameters influencing tissue pO2 showed no significant alterations if any.

Arteries↗