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Biomedical subjects

H Evers

Publications and source records attributed to H Evers.

82 records · Page 5Linked to original sources
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Extending a teleradiology system by tools for 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 three-dimensional-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 a 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 ray-tracing model and the graphics acceleration capabilities of modern workstations. Several tools for volumetric analysis extend the three-dimensional-viewing. They are controlled by adequate input devices to select locations in the data volume, measure anatomical structures or initiate a segmentation process. Moreover, a haptic interface can be connected to provide a more realistic feedback while navigating within the three-dimensional-reconstruction. The work is closely related to research in the field of heart, liver and head surgery. In cooperation with our medical partners the development of tools as presented facilitates the integration of image analysis into the clinical routine.

Humans↗
PubMedDate not supplied

Borderless teleradiology with CHILI.

Teleradiology is one of the most evolved areas of telemedicine, but one of the basic problems which remains unsolved concerns system compatibility. The DICOM (Digital Imaging and Communications in Medicine) standard is a prerequisite, but it is not sufficient in all aspects. Examples of other currently open issues are security and cooperative work in synchronous teleconferences. Users without a DICOM radiological workstation would benefit from the ability to join a teleradiology network without any special tools. Drawbacks of many teleradiology systems are that they are monolithic in their software design and cannot be adapted to the actual user's environment. Existing radiological systems currently cannot be extended with additional software components. Consequently, every new application usually needs a new workstation with a different look and feel, which must be connected and integrated into the existing infrastructure. This paper introduces the second generation teleradiology system CHILI. The system has been designed to match both the teleradiology requirements of the American College of Radiology (ACR), and the functionality and usability needs of the users. The experiences of software developers and teleradiology users who participated in the first years of the clinical use of CHILI's predecessor MEDICUS have been integrated into a new design. The system has been designed as a component-based architecture. The most powerful communication protocol for data exchange and teleconferencing is the CHILI protocol, which includes a strong data security concept. The system offers, in addition to its own secure protocol, several different communication Methods: DICOM, classic e-mail, Remote Copy functions (RCP), File Transfer Protocol (FTP), the internet protocols HTTP (HyperText Transfer Protocol) and HTTPS (HyperText Transfer Protocol Secure),and CD-ROMs for off-line communication. These transfer METHODS allow the user to send images to nearly anyone with a computer and a network. The drawbacks of the non-CHILI protocols are that teleconferences are not possible, and that the user must take reasonable precautions for data privacy and security. The CHILI PlugIn mechanism enables the users or third parties to extend the system capabilities by adding powerful image postprocessing functions or interfaces to other information systems. Suitable PlugIns can be either existing programs, or dedicated applications programmed with interfaces to the CHILI components. The developer may freely choose programming languages and interface toolkits. The CHILI architecture is a powerful and flexible environment for Picture Archiving and Communications Systems (PACS)and teleradiology. More than 40 systems are currently running in clinical routine in Germany. More than 300,000 images have been distributed among the communication partners in the last two years. Feedback and suggestions from the users influenced the system architecture by a great extent. The proposed and implemented system has been optimized to be as platform independent, open, and secure as possible.

Radiology Information Systems↗
PubMedDate not supplied

Skin blood flow after intradermal injection of ropivacaine in various concentrations with and without epinephrine evaluated by laser Doppler flowmetry.

BACKGROUND AND OBJECTIVES: Skin blood flow changes after intradermal injection of ropivacaine in various concentrations with or without epinephrine were investigated using laser Doppler flowmetry. METHODS: Twenty-three non-smoking, healthy, young male volunteers participated. Four test sites were used on each forearm (volar surface) in a randomized, double-blind study. Recordings were made at 20, 40, 60, and 90 minutes after intradermal injection (0.1 ml, 30-gauge needle). Injections of saline and 1% lidocaine and an untreated area served as controls. In Series 1, various concentrations of ropivacaine (1%, 0.5%, 0.375%, 0.125%, and 0.063%) were injected. RESULTS: The data from this series showed a dose-response relationship: 1% ropivacaine provoked an increase in skin blood flow similar to saline; 0.5% and weaker concentrations of ropivacaine showed a reduction in flow compared to saline, this being more pronounced with the weakest solutions (0.125% and 0.063%). In Series 2, injection of 1:200,000 (5 micrograms/ml) epinephrine alone and injections of ropivacaine in various concentrations (1%, 0.5%, and 0.25%) with addition of epinephrine were carried out. Injection of epinephrine alone showed a flow almost as low as at the untreated control sites. Ropivacaine epinephrine injections were followed by a lower skin blood flow compared to saline, but the flow was significantly larger compared to the effect of epinephrine itself at the 20-minute recording. CONCLUSION: The combination of ropivacaine and adrenaline did not accentuate but instead diminished the vasoconstrictive effect of epinephrine.

Adult↗
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Finding the limits.

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Activities of Daily Living↗
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Old, needy--and black.

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Black or African American↗
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Long-acting local anesthetics in oral surgery: an experimental evaluation of bupivacaine and etidocaine for oral infiltration anesthesia.

The effect of bupivacaine 7.5 mg/ml with epinephrine 5μg/ml, etidocaine 15 mg/ml with epinephrine 5 μg/ml, and lidocaine 20 mg/ml with epinephrine 12.5 μg/ml was studied when used for oral infiltration anesthesia. Twenty healthy volunteers took part in the experimental and double-blind study. One ml of the respective anesthetic solution was deposited supraperiosteally in the apical area of the maxillary right lateral incisor. Onset time, frequency of analgesia, gingival spread, and duration of tooth analgesia were studied and duration of soft-tissue numbness registered. The present investigation showed that lidocaine had a shorter onset time compared with bupivacaine. No difference with regard to frequency was found. Bupivacaine and etidocaine had a longer period of soft-tissue numbness, but a significantly shorter duration of tooth analgesia than lidocaine.

Acetanilides↗