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Biomedical subjects

B Bergh

Publications and source records attributed to B Bergh.

16 recordsLinked to original sources
PubMed2004

[Remote access to a web-based image distribution system].

PURPOSE: To assess different network and security technologies for remote access to a web-based image distribution system of a hospital intranet. MATERIALS AND METHODS: Following preparatory testing, the time-to-display (TTD) was measured for three image types (CR, CT, MR). The evaluation included two remote access technologies consisting of direct ISDN-Dial-Up or VPN connection (Virtual Private Network), with three different connection speeds of 64, 128 (ISDN) and 768 Kbit/s (ADSL-Asymmetric Digital Subscriber Line), as well as with lossless and lossy compression. RESULTS: Depending on the image type, the TTD with lossless compression for 64 Kbit/s varied from 1 : 00 to 2 : 40 minutes, for 128 Kbit/s from 0 : 35 to 1 : 15 minutes and for ADSL from 0 : 15 to 0 : 45 minutes. The ISDN-Dial-Up connection was superior to VPN technology at 64 Kbit/s but did not allow higher connection speeds. Lossy compression reduced the TTD by half for all measurements. CONCLUSIONS: VPN technology is preferable to direct Dial-Up connections since it offers higher connection speeds and advantages in usage and security. For occasional usage, 128 Kbit/s (ISDN) can be considered sufficient, especially in conjunction with lossy compression. ADSL should be chosen when a more frequent usage is anticipated, whereby lossy compression may be omitted. Due to higher bandwidths and improved usability, the web-based approach appears superior to conventional teleradiology systems.

Internet↗
PubMed2003

Upload capacity and time-to-display of an image Web system during simultaneous up- and download processes.

The aim of this study was to assess the up- and download performance of an image Web system (IWS) during simultaneous up- and download procedures. Following preparatory tests, the upload capacity (UC) with and without simultaneous download and the time-to-display (TTD) with and without simultaneous upload were determined for different image, server and compression types, and with up to 16 concurrent clients. The UC varied between 1.7-5.5 Gigabyte per hour (GB/h) and was slightly influenced by a simultaneous download; however, the TTDs were substantially prolonged during an upload and only below 5 s with up to four to six concurrent clients. The choice of image and server type had a strong impact on UC and TTD. Lossy primary compression proved slightly superior. An effective UC of approximately 4.0 GB/h or 96 Gigabyte per day (GB/day) can be achieved, which appears suitable even for large institutions. Because of its substantial influence on UC and TTD during simultaneous up- and download, the server hardware should be equipped with two processors and 1 GB RAM. Lossy primary compression may be used with slight performance benefits when full-resolution images are not required. The upload is a time-demanding process, and it is possible that during peak hours the waiting times are unacceptable for clinicians.

Data Compression↗
PubMed2003

Performance of Web-based image distribution: server-oriented measurements.

The aim of this study was to assess the performance of Web-based image distribution when multiple personal computers (PCs) are downloading images simultaneously for different server hardware configurations. Using specially developed software, the time-to-display (TTD) of different image types was measured with up to 16 concurrent PCs for various combinations of processor, random access memory (RAM), network connection and image compression. The TTD increased linearly with the number of concurrent PCs but remained under 5 s in most of the cases, even with 16 concurrent PCs. Only with a 10-Mbit/s network connection or with lossy compression were TTDs above 5 s obtained. Two processors instead of one led to a slight and constant improvement of the TTD. Reducing the amount of RAM increased the TTD mainly for computed radiography (CR) images. There was no difference between a 200- and 100-Mbit/s network, but 10 Mbit/s proved significantly worse. When increasing the number of clients lossless compression performed substantially better than lossy. A standard off-the-shelf server provides an appropriate download performance even with 16 concurrent clients. Processor speed and RAM amount are of minor importance, but it is highly recommended to use a 100-Mbit/s network connection and to avoid the application of on-demand lossy compression in a local area network.

Internet↗
PubMed2003

Performance of Web-based image distribution: client-oriented measurements.

The aim of this study was to define a clinically suitable personal computer (PC) configuration for Web-based image distribution and to assess the influence of different hard- and software configurations on the performance. Through specially developed software the time-to-display (TTD) for various PC configurations was measured. Different processor speeds, random access memory (RAM), screen resolutions, graphic adapters, network speeds, operating systems and examination types (computed radiography, CT, MRI) were evaluated, providing more than half a million measurements. Processor speed was the most relevant factor for the TTD; doubling the speed halved the TTD. Under processor speeds of 350 MHz, TTD mostly remained above 5 s for 1 CR or 16 CT images. Here Windows NT with lossy compression were superior. Processor speeds of 350 MHz and over delivered TTD <5 s. In this case Windows 2000 and lossless compression were preferable. Screen resolutions above 1280 x 1024 pixels increased the TTD mainly for CR images. The RAM amount, network speed and graphic adapter did not have a significant influence. The minimum threshold for clinical routine is any standard off-the-shelf PC better than Pentium II 350 MHz, 128 MB RAM; hence, high-end PC hardware is not required.

Computers↗
PubMed2002

Evaluation of a "no-cost" Internet technology-based system for teleradiology and co-operative work.

The aim of this study was to assess the suitability of a no-cost system based on standard Internet technology components for teleradiology. The system was composed of free software (communication, DICOM viewer, compression) and standard off-the-shelf hardware components. For different image (CR, CT, MR) and network types (LAN and ISDN) the File Transfer, Audio and Video Conference, and Co-operative Work properties were examined and compared with the literature referring to standard complete packages and dedicated teleradiology systems. The main advantages of the no-cost system are: price; ease of use; independence from specific hardware; and potential connection to any possible partner. The performance of the File Transfer and the Audio and Video Conference was comparable to the other system groups with slight disadvantages in the usability. For Co-operative Work the employed "application sharing" technology does not meet the clinical requirements, which applies identically to the standard complete packages. Here the specialized systems prove superior, although they are proprietary. With minimal restraints the evaluated no-cost solution can be used for File Transfer and Conference scenarios. The usage for Co-operative Work with ISDN is not recommended, unless for the purpose of gaining experience or when dealing with small amounts of cases or images.

Computer Systems↗
PubMed2002

[Feather--data acquisition in gynaecology and obstetrics].

Nowadays many types of medical documentation are based on computer facilities. Unfortunately, this involves the considerable disadvantage that almost every single department and specialty has its own software programs, with the physician having to learn a whole range of different programs. In addition, data sometimes have to be entered twice - since although open interfaces are often available, the elaborate programming required to transfer data from outside programs makes the financial costs too high. Since 1995 the University's of Frankfurt am Main Department of Gynecology and Obstetrics has therefore developed a consistent program of its own under Windows NT for in-patient facilities, as well as for some outpatient services. The program does not aim to achieve everything that is technically possible, but focuses primarily on user requirements. In addition to the general requirements for medical documentation in gynecology and obstetrics, the program can also handle perinatal inquiries and gynecological quality control (QSmed [Qualitätssicherung in der Medizin] of the BQS [Bundesgeschäftsstelle Qualitätssicherung]).

Computers↗
PubMed2001

[Neoplasms of the temporomandibular joint (TMJ). Diagnosis, differential diagnosis and intervention].

PURPOSE: To evaluate the effectiveness of diagnostic and interventional radiological techniques for neoplastic lesions of the temporomandibular joint (TMJ). MATERIAL AND METHODS: Modern diagnosis of the TMJ is based on the clinical use of conventional X-ray techniques, computed tomography (CT), magnetic resonance imaging (MRI) and interventional techniques like biopsies, vascular occlusion and ablation. RESULTS: Conventional X-ray still forms the basic diagnostic procedure applied in open and closed mouth position. CT improves the diagnostic information and serves as the standard diagnostical instrument for cartaliganeous or osseous neoplastic lesions. MRI evaluates soft tissue infiltration in multiplanar techniques and high spatial resolution. Interventional vascular and ablative techniques improve the treatment of neoplastic disorders. CONCLUSION: Radiological diagnostic procedures are essentials for the diagnosis and intervention of neoplastic lesions of the temporomandibular joint.

Biopsy↗
PubMed2000

[Internet technology for clinical applications in a digital radiography department].

PROBLEM: To provide an overview and to assess the clinical feasibility of Internet technology-based systems for hospital-wide image and report distribution as well as for video conferencing. METHODS: The paper describes the theoretical concept behind, the various technical approaches and the experience gained from different systems. RESULTS: Image and report distribution: Advantages include the universal availability of images and reports inside and outside hospitals; ease of use; security features; image and report integration; cost savings by reducing support and training efforts and by optimising available hardware. The main critical issues are performance and workflow integration with RIS and PACS. Video conferencing: main advantages are the standardised, software-based approach and the low investments for hard- and software. Depending on the desired usage the communication performance can be seen as inappropriate. CONCLUSION: Today, Internet technology-based systems appear to satisfy the main clinical needs in radiology. The mentioned drawbacks could be eliminated by means of modified software implementation and focused standardisation efforts. Considering the numerous advantages of these systems a further distribution can be expected for the future.

Communication↗
PubMed1999

WWW-based access to radiological patient data: two years of experience.

UNLABELLED: This paper describes the theoretical concept behind, the technical implementation of, and the experiences created with a self-developed system to access radiological patient data by WWW-technology. MATERIALS AND METHODS: The WWW-system interfaces the RIS via HL7 and the PACS via DICOM. Core components are a secure Web-Server and an underlying database system (DB). The DB contains all relevant information from the RIS and thumbnails of corresponding images archived in the PACS. After authorization, the user receives this information in the form of dynamically generated Web pages. By mouse-clicking a thumbnail, the original DICOM-image is sent. It is displayed with a helper application (DICOM-Viewer), allowing all kinds of image manipulation and post-processing. RESULTS: Determined advantages of the system were: platform independence, security features, a fixed link of image and report, universal availability, and simple usage. The only critical issue was performance. Cost savings could be seen in: a reduction of DICOM workstations, employment of all available hardware, and reduced training and teaching efforts. CONCLUSIONS: The author believes that a WWW-based concept is the only feasible approach which is in the same way technically possible, clinically acceptable, and financially affordable in order to grant a variety of users access to radiological data--although improvements in performance have to made by, e.g., closer implementation of those systems to the RIS and PACS architecture, and by employing high-grade image compression.

Equipment Design↗
PubMed1998

[Comparative findings of digital thoracic images and digital images of statistical phantoms as film copy, a radiological work station and a PC].

INTRODUCTION: An ROC analysis was carried out in order to determine the reliability of digital luminescence radiography review at a PC and this was compared with a radiological work station and with X-ray film on a viewing box. MATERIAL AND METHOD: 54 chest images obtained by digital luminescence radiography were selected, 31 of these contained small pulmonary nodules. In order to evaluate critical detail, five images of a phantom showing round foci were used. Five radiologists examined these, using a Siemens Magic View work station, a PC with proprietary software (ViewMed) and X-ray films on a viewing box. Image processing of the work station used the standard clinical application. ViewMed performs linear scaling of grey levels to 8 Bit. The results were examined statistically by means of a t-test. RESULTS: As far as the chest images were concerned there was no significant difference in the diagnostic value of these methods. There was, however, a highly significant loss of diagnostic information with respect to the round focus phantom when using the PC compared with the other methods. CONCLUSION: In the configuration in which it was used, the PC should not be relied on as a primary means of examination since critical details cannot always be seen. In routine use these play a subordinate role and there was no significant diagnostic loss where the chest images were concerned. We expect that by improvements in the frequency and contrast processing the PC accuracy will be considerably increased.

Humans↗
PubMed1996

[Teleradiology: use of multimedia PC for access to electronic patient records and teleconsultation].

A PC-platform is presented using internet technology on Ethernet (local) or ISDN (external) for access to digital hospital infrastructures comprising electronic multimedia patient records integrating information systems of all clinical departments. In addition, a videoconferencing system is implemented for teleconsulting, and a document camera allows transmission of analogue data. In combination with the multimedia-PC. Ethernet as well as ISDN offer satisfying performance for transmission of medical data including images. In 20 cases, visualisation of the electronic patient record, an average CT with report and 58 GIFF Images', or transfer of an ACR-NEMA file from CT, took seconds (Ethernet) or up to 3.5 minutes (ISDN - 58 CT images and report).

Computer Communication Networks↗
PubMed1994

[The digital reprocessing of underexposed x-rays. Studies with a fluorescent light scanner].

Incorrect exposure of conventional radiographs frequently leads to repetition of the examination and thereby to increased radiation exposure for the patient. Underexposed films of an Alderson-Rando phantom, an ankle joint and a patella were digitised by means of an inexpensive fluorescent light scanner, and subsequent image manipulation improved quality so as to make the image diagnostically adequate. For the demonstration of markedly underexposed structures digitalisation with subsequent contrast enhancement was used. Well exposed structures are best evaluated in contrast enhanced transmitted light. Our results suggest it should be possible to reduce the number of repeat exposures and thereby to limit radiation exposure.

Ankle Joint↗
PubMed1992

[Catheter-induced vascular lesions: a comparison of the diagnostic value of Doppler color sonography versus angiography].

One hundred and thirty-two patients with suspected lesions of the femoral arteries following diagnostic and/or therapeutic cardiac catheterisation were studied by colour Doppler sonography (CDS) and digital subtraction angiography (DSA) and the results were compared. CDS was unable to demonstrate 5 out of 23 av fistulae. Intra-arterial DSA showed all av fistulae found at operation. CDS showed lower reliability (95%) than DSA (100%) for the demonstration of pseudoaneurysms. CDS can indicate hematoma and thrombi in pseudo-aneurysms and their exact extent is better shown by sonography. Arterial dissections (2 cases) and intra-luminal thromboses or occlusions of the femoral artery (4 cases) are shown equally well by the two procedures.

Adult↗
PubMed1989

[Medical Latin].

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History, Ancient↗