Biomedical subjects

D Meyer-Ebrecht

Publications and source records attributed to D Meyer-Ebrecht.

11 recordsLinked to original sources

PubMed1994

Picture archiving and communication systems (PACS) for medical application.

The term 'Picture Archiving and Communication Systems' (PACS) applies to networks of digital image modalities, image workstations and mass image stores connected among each other by image data communication structures and controlled by appropriate image and data management. Predominantly, PACS are intended for application in the medical imaging domain, particularly in hospitals, where, by completely replacing the currently used films, they are supposed to lead to the 'filmless radiology'. The development of PACS is still one of the challenging tasks in the computer engineering field, because the giant amounts of digital image data produced in medical diagnostics require the introduction of novel architectures and technologies. This article describes the key components of PACS. Typical user environments are analysed and the requirements on the performance of the elements of a PACS are defined. The bottlenecks of current technologies are evaluated and examples of advanced approaches to PACS networks, archive modules and image workstations are given.

Computer Communication Networks↗

PubMed1994

Computational principles in Purkinje I and IV reflection pattern evaluation for the assessment of ocular alignment.

PURPOSE: To develop a standardized reasoning for the evaluation of Purkinje I and IV Reflection Pattern data in primary, secondary, and tertiary positions of gaze in the diagnosis of strabismus with a mathematical approach. To demonstrate the applicability of certain mathematical relations and the appropriate graphic representation of computed ocular alignment data. METHODS: Starting from the known Reflection Pattern Evaluation formulae, equations were derived that allowed for the computation of the relative and absolute positions of the optical and visual axes of both eyes from original data in binocular and monocular fixation. These equations were simplified for clinical use. RESULTS: The authors obtained a set of equations that could be applied to the objective, quantitative analysis of eye alignment in screening for microtropia, in concomitant and incomitant diagnoses of strabismus in primary and nonprimary positions. CONCLUSIONS: Purkinje I and IV Reflection Pattern Evaluation can be extended to the diagnosis of strabismus in nonprimary positions with sufficient clinical accuracy. The newly presented principles and equations serve as a basis for a convenient graphic representation of Purkinje I and IV Reflection Pattern data. These principles of evaluation may be applied to any data dealing with ocular alignment, independently of the method.

Afterimage↗

PubMed1994

[Networks for image communication. Current status].

Networks for the transport of digital images are key components of PACS systems. In order to create a platform for the selection of appropriate network technology, first the quantitative requirements for image data communication in a PACS system are analyzed. State-of-the-art local area networks as well as developments in progress are mentioned, and their performance is discussed with respect to the PACS requirements. Furthermore, the linkage of PACS systems and hospital or radiology information systems is discussed. Finally, a scenario is outlined for extra-mural applications of medical image communication.

Computer Communication Networks↗

PubMed1993

Digital image communication.

Networks for digital image communication are an essential prerequisite for picture archiving and communication systems (PACS). The scenario of a 'filmless' radiology is based on the assumption that complete sets of medical images can be transferred throughout the hospital without a noticeable delay even though digital images represent data volumes of a thousand-fold greater size than, for example, office documents. This paper deals with an in-depth analysis of the anticipated image communication requirements in a future PACS environment. It gives a survey of technologies for data communication with emphasis on the basic concepts of established local area networks (LAN) and their limiting factors with respect to the specific PACS demands. Likewise, a description of a network particularly developed to satisfy the users-to-be of PACS systems is included. Furthermore, this paper treats the connection of image data with patients' data, i.e. the interlinking of PACS and RIS/HIS structures. Another topic of interest is the extension of the PACS structure beyond the limits of the individual hospital (extramural PACS operation). Moreover, current standardization attempts are discussed here.

Computer Communication Networks↗

PubMed1992

[Movement correction of digital sequence angiographies of the retina].

Retinal hemodynamics can be quantified from videoangiographic image sequences by digital image processing. Intensity changes of dye dilution curves provide dynamics parameters of the local retinal blood flow. The measuring points of dye dilution curves have to be fixed on identical image contents in each image of a complete image sequence. To obtain measurements for every pixel on the retinal surface a motion-compensated image sequence is required. A new method adapted to the compensation of eye motion and movement artifacts in Scanning Laser Ophthalmoscopy in long image sequences (300-500 images) is presented in this paper. To inhibit error propagation of time sequential motion estimation, the eye movement is divided into two dynamic movements components. The method presented permits compensation for eye motion in retinal fluorescein angiographic sequences. Owing to the short calculation times, this algorithm can be used in clinical routine.

Artifacts↗

PubMed1990

[Quantifying retinal capillary circulation using the scanning laser ophthalmoscope].

The quantitative picture analysis of video fluorescein angiograms allows one to evaluate retinal hemodynamics. However, this method does not permit us to quantify the retinal capillary perfusion. Now, for the first time, we are able to quantify capillary bloodflow directly and objectively by means of scanning laser ophthalmoscopy. Even the measurement of the bloodflow velocity in all capillaries is now possible. Using digital frame-to-frame picture analysis of digital recordings, bloodflow velocities can be measured on the basis of the movement of dye boluses.

Blood Flow Velocity↗

PubMed1989

[CAS (computer assisted surgery). A new procedure in head and neck surgery].

Computer assisted surgery (CAS) is a new imaging technique designed to assist the head and neck surgeon during surgery. This method is based upon a three-dimensional volume model of the patient's skull generated by computer tomographic imaging procedures such as CT and MR. Body points can be marked in the 3-D model by intra-operative correlation of model and patient using a volume digitizer. Real-time positioning of surgical instruments without visual control can be achieved. The use of the system in surgery of the skull base, orbit and the paranasal sinuses is demonstrated.

Computer Simulation↗

PubMed1988

[PACS (picture archiving and communication systems) or the future workplace of the radiologist].

PACS (picture archiving and communication systems) is a synonym for the replacement of the traditional photographic film by means of technologies that will communicate and store images exclusively in digital form. Digital mass storage will replace the film archives and will be linked to all image sources by means of a data communication network. More significantly, PACS will also introduce a novel type of image-evaluation modality, the diagnostic image work station. Images will be displayed on TV monitors. In addition, a variety of support functions will become available for image handling and processing. The replacement of the light box by a digital work station will definitely cause dramatic changes in the radiologist's work.

Germany, West↗

PubMedDate not supplied

Diagnostic image workstations for PACS.

Image workstations will be the 'window' to the complex infrastructure of a PACS with its intertwined image modalities (image sources, image data bases and image processing devices) and data processing modalities (patient data bases, departmental and hospital information systems). They will serve for user-to-system dialogues, image display and local processing of data as well as images. Their hardware and software structures have to be optimized towards an efficient throughput and processing of image data.

Hospital Information Systems↗

PubMedDate not supplied

ImNet: a fibre optic LAN for digital image communication.

Data communication requirements in computer networks for medical diagnostics cannot be satisfied by existing LANs if digital images are involved because of the volumes of image data and the heterogeneity of data communication tasks. A user-oriented network behaviour requires a data transport rate which is beyond the physical bit rate of currently used LAN data channels. The key to an increased data transport efficiency is the separation of management data communication and image data communication. For the latter ImNet, a novel type of fibre optic network has been developed. Its hyperstar topology, its asynchronous data transport mechanism and its distributed network control make it particularly suited for PACS applications.

Computer Systems↗

PubMedDate not supplied

Images for medical diagnoses.

Dr. Dietrich Meyer-Ebrecht provides a broad and helpful overview of the many techniques and latest trends in diagnostic imaging. Latest sensing technology is reviewed including: X-ray systems, ultrasound, thermography, radionuclide imaging, endoscopy, and optical methods. Approximate system cost ranges are indicated. This paper examines the technological trends in: sensors, imagers, hardcopy production, computer enhancement, storage, and communication of images. Dr. Meyer-Ebrecht describes three generations of computed tomographic scanners and alternative approaches to three-dimensional imaging. Image storage is presented as a major limitation of present technology. A view of future systems approaches envisions "picture bases" that will complement present data bases of hospital information systems. Integration of latest technology into diagnostic picture information systems will lead to advanced systems.

Computers↗