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Biomedical subjects

H Evers

Publications and source records attributed to H Evers.

At least 19 recordsLinked to original sources
PubMed2004

[Immunophenotyping of haematologic malignancies].

Over the last 10 years, immunophenotyping of haematologic malignancies has become an indispensable diagnostic supplement to the classical morphological approach. Immunophenotyping of haematopoietic cells is performed with the use of a number of monoclonal antibodies (MOABs), which are directed specifically against structures of blood cells that become expressed at the different stages of differentiation and maturation. Cells to which the fluorescently labelled MOABs are directed can be recognised and measured using fluorescence microscopy or fluorescence flow cytometry. Many MOABs, fluorochromes and user-friendly flow cytometers have become available in the last 15 years, as a result of which immunophenotyping is now routinely applied in clinical practice. Immunophenotyping has the potential to classify leukaemias and other malignant lymphomas according to cell type and stage of maturation. This information is important for the establishment of the right diagnosis and prognosis, and for the optimal treatment choice. In a number of cases immunophenotyping provides information which cannot be obtained by simple morphological investigation. The immunophenotyping of blood and bone-marrow cells is also a sensitive method for detecting minimal residual disease after an apparent complete remission has been achieved.

Antibodies, Monoclonal↗
PubMed2000

Interactive realtime Doppler-ultrasound visualization of the heart.

Heart valve insufficiencies can optimally be assessed using transesophageal, triggered, three-dimensional ultrasound imaging. The dynamic ultrasound data contain morphological as well as functional components which are recorded and displayed simultaneously. It allows the visualization of intracardiac motion which is an important parameter to detect abnormal flow caused by defect valves. A realtime reconstruction is desired to get a spatial impression on the one hand and to interactively clip parts of the volume on the other hand. Therefore, we use the OpenGL Volumizer API. Scalability of the visualization was tested with respect to different workstations and graphics resources using a Multipipe Utility library. The combination of both APIs enables a visualization of volumetric and functional data with frame rates up to 10 frames per second. By using the proposed method, it is possible to visualize the jet in the original color-coding which is employed during a conventional two-dimensional examination for displaying the velocity values. The morphological and the functional data are handled as two independent data channels. A good scalability from low cost up to high end graphic workstations is given by the use of the MPU. The quality of the resulting 3D images allows exact differentiation of heart valve insufficiencies to support the diagnostic procedure.

Computer Graphics↗
PubMed2000

Design of a distributed CORBA based image processing server.

This paper presents the design and implementation of a distributed image processing server based on CORBA. Existing image processing tools were encapsulated in a common way with this server. Data exchange and conversion is done automatically inside the server, hiding these tasks from the user. The different image processing tools are visible as one large collection of algorithms and due to the use of CORBA are accessible via intra-/internet.

Computer Systems↗
PubMed1999

Virtual surgery in a (tele-)radiology framework.

This paper presents telemedicine as an extension of a teleradiology framework through tools for virtual surgery. To classify the described methods and applications, the research field of virtual reality (VR) is broadly reviewed. Differences with respect to technical equipment, methodological requirements and areas of application are pointed out. Desktop VR, augmented reality, and virtual reality are differentiated and discussed in some typical contexts of diagnostic support, surgical planning, therapeutic procedures, simulation and training. Visualization techniques are compared as a prerequisite for virtual reality and assigned to distinct levels of immersion. The advantage of a hybrid visualization kernel is emphasized with respect to the desktop VR applications that are subsequently shown. Moreover, software design aspects are considered by outlining functional openness in the architecture of the host system. Here, a teleradiology workstation was extended by dedicated tools for surgical planning through a plug-in mechanism. Examples of recent areas of application are introduced such as liver tumor resection planning, diagnostic support in heart surgery, and craniofacial surgery planning. In the future, surgical planning systems will become more important. They will benefit from improvements in image acquisition and communication, new image processing approaches, and techniques for data presentation. This will facilitate preoperative planning and intraoperative applications.

Surgical Procedures, Operative↗
PubMed1998

[Integration of functional and morphologic MRI data for preoperative 3D visualization of tumors. Example: cervical carcinoma].

PURPOSE: The goal of this exemplary study was to integrate morphological and functional MRI to establish computer-based, pre-operative therapy planning for tumors, instancing cervical carcinoma. METHODS: For morphological representation T1-weighted, filtered 3D sequences were investigated within a hierarchical segmentation approach. Using a method for image registration, segmented structures were combined and overlaid with functional information of contrast medium-enhanced, dynamic MRI. After assigning colour attributes to the segmented structures, they were presented using a method for direct volume visualisation. RESULTS: Segmentation of organs and vessels as well as tissue differentiation yielded a morphological visualisation of anatomical structures that were overlaid with pharmacokinetic parameters derived from dynamic MRI, subsequently. Thereby, three-dimensional, arbitrary views on the functional data were displayed. CONCLUSIONS: Image analysis and visualisation of the acquired MR data establishes both a morphologic and functional evaluation of suspect lesions and adjacent organs. By integrating morphologic and functional MRI additional information can be gathered that possibly impinge on preoperative planning.

Data Interpretation, Statistical↗
PubMed1998

Extending a teleradiology system by tools for 3D-visualization and volumetric analysis through a plug-in mechanism.

This paper describes ongoing research concerning interactive volume visualization coupled with tools for volumetric analysis. To establish an easy to use application, the 3D-visualization has been embedded in a state of the art teleradiology system, where additional functionality is often desired beyond basic image transfer and management. Major clinical requirements for deriving spatial measures are covered by the tools, in order to realize extended diagnosis support and therapy planning. Introducing the general plug-in mechanism this work exemplarily describes the useful extension of an approved application. Interactive visualization was achieved by a hybrid approach taking advantage of both the precise volume visualization based on the Heidelberg Raytracing Model and the graphics acceleration of modern workstations. Several tools for volumetric analysis extend the 3D-viewing. They offer 3D-pointing devices to select locations in the data volume, measure anatomical structures or control segmentation processes. A haptic interface provides a realistic perception while navigating within the 3D-reconstruction. The work is closely related to research work in the field of heart, liver and head surgery. In cooperation with our medical partners the development of tools as presented proceed the integration of image analysis into clinical routine.

Humans↗
PubMed1996

[Chylothorax as a complication of sarcoidosis].

This case report features a male patient of 45 years of age presenting with a right sided moderately compressive pleural effusion, that was clearly identified as chylothorax on thoracocentesis. Sarcoidosis with systemic involvement had already been diagnosed in 1995 by a parotid gland biopsy. Thoracoscopy revealed multiple discrete nodules parietally besides a number of more extensive yellowish lesions resembling malignant lymphoma. However visualization of a thoracic duct leakage was not possible. Histologically the biopsies taken represented exclusively non-caseating sarcoidosistype granulomas. Complete and permanent remission of the chylothorax was achieved within only ten days following talcum pleurodesis, alimentary measures and induction of systemic steroid therapy. The etiological classification of this extremely rare complication appears very clear. Pathogenetic and differential therapeutic aspects are discussed against the background of a review of the literature.

Biopsy↗
PubMed1995

The image related services of the HELIOS software engineering environment.

This paper describes the approach of the European HELIOS project to integrate image processing tools into ward information systems. The image processing tools are the result of the basic research in image analysis in the Department Medical and Biological Informatics at the German Cancer Research Center. These tools for the analysis of two-dimensional images and three-dimensional data volumes with 3D reconstruction and visualization ae part of the Image Related Services of HELIOS. The HELIOS software engineering environment allows to use the image processing functionality in integrated applications.

Computer Communication Networks↗
PubMed1995

Integrated image processing in clinical applications: the HELIOS approach.

This paper describes the approach of the European HELIOS project to integrate image processing tools into ward information systems. The image processing tools are the result of the basic research in image analysis in the Department Medical and Biological Informatics at the German Cancer Research Center. Tools for the analysis of 2-dimensional images and 3-dimensional data volumes with 3-dimensional reconstruction and visualization are part of the Image Related Services of HELIOS.

Europe↗
PubMed1994

Local analgesic and vascular effects of intradermal ropivacaine and bupivacaine in various concentrations with and without addition of adrenaline in man.

Ropivacaine, a new long-acting amino-amide local anaesthetic agent, and bupivacaine, in various concentrations with or without addition of adrenaline, were tested in a randomized, double-blind study using intradermal wheals. Ten non-smoking, healthy, young male volunteers participated. In series I plain solutions of ropivacaine (0.25%, 0.5%, 0.75% and 1%) and bupivacaine (0.25%, 0.5% and 0.75%) were injected intradermally and in series II the same concentrations, with the addition of adrenaline 5 ug.ml-1 (1:200,000), were used. The same volunteers took part in both series, with an interval of at least three weeks between the experiments. Saline was included as control in both series. Pin-pricking was used to assess the dermal analgesia. Plain solutions of ropivacaine produced significantly longer durations of dermal analgesia than did plain solutions of bupivacaine, in all tested concentrations. A significant increase in duration was seen for both local anaesthetics when adding adrenaline. Local vascular effects at the injected areas were determined by visual inspection (nil, pink, pale). Local blanching (pale) was significantly more frequent for plain solutions of ropivacaine, in all tested concentrations. Local redness (pink) was significantly more frequent with plain bupivacaine, in a dose-dependent relation. An initial redness was frequently observed for both local anaesthetics containing adrenaline, followed by blanching at most sites.

Adult↗
PubMed1994

The HELIOS Image Related Services.

The HELIOS Software Engineering Environment is a tool for the construction of medical ward information systems. This paper describes the image processing tools which are a part of this system. The Image Related Services can be used both as ready-to-use end-user tools and as software modules for the construction of integrated multimedia applications. The tasks and architecture of the end-user tools and their integration into the HELIOS architecture are described. It is shown how the available image processing functionality can be used to build up new applications.

Computer Communication Networks↗
PubMed1992

Screening of pulmonary hypertension in chronic obstructive pulmonary disease and silicosis by discriminant functions.

The aim of our prospective multicentric study was to develop a screening method for pulmonary hypertension in patients with chronic lung diseases. We investigated 710 patients in 10 hospitals: 315 males and 109 females with chronic obstructive pulmonary disease, and 286 males with silicosis. Manifest pulmonary hypertension was defined as pulmonary artery pressure greater than 20 mmHg (2.7 kPa) at rest. The multivariate statistical method used was a stepwise discriminant analysis. In males with chronic obstructive pulmonary disease, the diameter of the right descending pulmonary artery, forced expiratory volume in one second (FEV1) arterial oxygen tension (PaO2) at rest, and age turned out to be relevant for discrimination of groups with and without manifest pulmonary hypertension. For females the FEV1/FVC (forced vital capacity) ratio replaced the absolute value of FEV1 in the calculated discriminant function. In females, sensitivity and specificity were below 80%. In males, both were distinctly above 80%. In silicosis, the diameter of the right descending pulmonary artery was much less important, since it could frequently not be measured precisely. In these cases, precision of the prediction of about 80% could only be obtained by combined evaluation of spirometry, PaO2 during exercise, and body plethysmography. The calculated discriminant functions are appropriate for screening patients with risk of pulmonary hypertension. For different chronic lung diseases, and for both sexes, different combinations of parameters are relevant. The method is recommended to select patients who should undergo an invasive examination of pulmonary haemodynamics.

Discriminant Analysis↗
PubMed1991

Effect of intradermal injection of saline or a local anaesthetic agent on skin blood flow--a methodological study in man.

The influence of intradermal needle insertion and fluid injection on skin blood flow was investigated using laser Doppler flowmetry. Seventeen healthy, young male volunteers participated. Four test sites on each forearm (volar surface) were used in a randomized, double-blind study. Recordings were made at 20, 40, 60 and in Group III also at 90 min after needle insertion or intradermal injection. In Group I (n = 6) different volumes of saline (0.05, 0.1, 0.2, 0.3 and 0.5 ml) were injected, producing an increase in flow, there being no differences between the various volumes. In Group II (n = 4) needle insertions were made using different needle sizes (20 G, 23 G and 30 G), the larger ones being impractical to use. Increases in flow were seen, and were somewhat higher for the larger needles. Group III (n = 12) was studied regarding the effects of three local anaesthetic agents on skin blood flow (0.1 ml, 30 G needle). Injection of bupivacaine 0.75% produced a marked increase in flow, similar to lidocaine 1% but apparently longer lasting. Bupivacaine 0.25% caused less increase in flow, similar to the flow seen with saline. Injections of ropivacaine 0.75% and 0.25%, i.e. in clinical concentrations, caused a decrease in blood flow, this being most marked after 0.25%, indicating a unique flow-decreasing effect of this new local anaesthetic drug.

Adult↗
PubMed1991

[Reference values for spirometry exemplified by FVC and FEV1 parameters--comparison of normal values of the Pathophysiology of Respiration Section and the European Society for Coal and Steel].

Reference values published by the Section Pathophysiology of Breathing in the Society for Pulmology and Tuberculosis of the GDR and reference values of European Community for Coal and Steel (EGKS) were compared on example of FVC and FEV1. It was found a relative well accordance of reference values of FVC and FEV1 in younger and middle-aged men of a height from 160-200 cm (between -5 to +15%). In women with a body height of 150 to 200 cm a well correlation for FVC and FEV1 is also given (-10 to +10%). Reference values are showing a more important difference with increasing age and independent of sex. There are problems concerning the reference values in male and female lower than 155 cm body height.

Adult↗