Reference level for patient dose in dental skull lateral teleradiography

The present work describes an experiment to obtain a local reference dose value in lateral skull teleradiography for dental applications. The reference value was based on patient measurements in seven dental X-ray units, using thermoluminescent chips, and measurements on a rubber globe filled with water at another 78 installations. Dosemeters were located initially in the head and neck of a human phantom to select the most suitable locations, and on the cephalostat of the X-ray unit at two appropriate locations, which did not interfere with the patient or with the usual imaging routine. The skin projection of the Porion point was considered the best position. 523 patients were monitored in the seven units; then patient doses and dose values from measurements on rubber balloons were compared to normalize and combine the data. The provisional reference value proposed is 400 microGy.

Radiology: "killer app" for next generation networks?

The core principles of digital radiology were well developed by the end of the 1980 s. During the following decade tremendous improvements in computer technology enabled realization of those principles at an affordable cost. In this decade work can focus on highly distributed radiology in the context of the integrated health care enterprise. Over the same period computer networking has evolved from a relatively obscure field used by a small number of researchers across low-speed serial links to a pervasive technology that affects nearly all facets of society. Development directions in network technology will ultimately provide end-to-end data paths with speeds that match or exceed the speeds of data paths within the local network and even within workstations. This article describes key developments in Next Generation Networks, potential obstacles, and scenarios in which digital radiology can become a "killer app" that helps to drive deployment of new network infrastructure.

The current status of digital mammography

Digital imaging has shown rapid advances in recent years. Various different digital mammography systems are now available for clinical use. Digital mammography does have clear advantages over traditional screen film mammography, but this is yet to convincingly translate into improved cancer detection rates. This review aims to describe the different technologies, introduce concepts related to image quality and review the current evidence for the use of digital mammography systems in clinical practice. Advanced applications of digital mammography such as computer-aided detection (CAD) are also discussed.

Benefit for the patient of a teleradiology process certified to meet an international standard

To guarantee the quality of teleradiology services in Austria we have developed an easy-to-use and continuously re-evaluated teleradiology workflow model. This is based on the quality management model (ISO 9001:2000) of the International Standardization Organization (ISO) and guarantees the quality of the process. From January 2002 to January 2003 we examined 544 emergency teleradiology computerized tomography studies transmitted to the Department of Radiology 2 in Innsbruck. The patients were from the rural hospital of Reutte. In 450 cases (83%) the sending of the written legal final report took less than 1 h. The numbers of mistakes (mostly minor workflow errors) were reduced from 23 errors per month in January 2002 to 9 errors per month in January 2003. The continuous cross-checking of the workflow and the training of the employees involved guaranteed a better standard of teleradiology in our department. Since December 2002, the whole Tyrolean teleradiology process has been ISO 9001:2000 certified.

Guidelines for teleradiology practice: results of the Tyrolean teleradiology pilot project

The Tyrolean telemedicine pilot project linked the University Clinic of Innsbruck and the district hospital in Reutte. Five medical specialties were investigated: teleradiology, telepathology, teledermatology, tele-ophthalmology and tele-oncology. A Tyrolean 'four-column model of quality management in telemedicine' was introduced to ensure a global view of the project and to avoid mistakes. In teleradiology, a 12-step workflow was developed, which described the medical responsibilities at each stage. We found that the defined teleradiology workflow and the technical equipment for data security and data exchange worked without problems in over 79% of a total of 424 cases. To ensure continuous quality assurance, the whole teleradiology workflow was ISO 9001:2000 certified.

Telemetry takes off

After a slow start, payers are signing on to the telemedicine trend, as rural hospital and major medical centers come to see the benefits of cooperation.

Entspricht die digitale Signatur des DICOM-Standards dem deutschen Signaturgesetz?

The DICOM standard offers the possibilities to generate electronic signatures, valid according to German laws. This enhances the reliability of the correlation between image and patient data. However, only so called qualified electronic signatures--conveniently issued by an accredited supplier--are permissible and not rejectable as evidence in German jurisdiction and are completely equivalent to the handwritten signatures. These qualified electronic signatures can be executed only by individuals, whereas the former are not applicable to technical apparatus like image generating modalities. In consequence, a modality is able to provide its pictures with a "common or advanced signature" solely. This limits the use of the digital signature of the DICOM standard for further applications, e.g. the verifiability within the teleradiology.

Wireless and satellite transmission of prehospital focused abdominal sonography for trauma

OBJECTIVE

As military operations become smaller and more remote and as humanitarian missions increase, ultrasound technology is emerging as a valuable asset for defining injuries in austere settings. This study evaluated the feasibility of focused abdominal sonography for trauma (FAST) examinations in a field environment with real-time images sent wireless to an antenna and over satellite.

METHODS

Using a 6-lb SonoSite portable ultrasound device with battery pack, FAST examinations were performed on a healthy volunteer, transferred wireless at distances of 1,000 and 1,500 feet from the receiving antenna using a vest-mounted microwave transmitter, and then redirected over satellite (INMARSAT) to a remote hospital for review by emergency physicians, and a radiologist.

RESULTS

Real-time wireless transmissions at 1,500 feet reliably yielded images without quality or interpretability drop compared with those recorded digitally at the examination site. A 32% reduction in image quality and interpretability was seen with still images and a 42% reduction was noted with cine loops using INMARSAT. The authors did not find the upper distance limit of the wireless transmitter used.

CONCLUSION

This study suggests 1) that remote FAST examinations are plausible for prehospital care and triage using new-generation portable ultrasound units, 2) that line-of-sight transmission of FAST examinations when compared with on-site images results in no degradation in image quality or interpretability at distances used, 3) that ranges greater than 1,500 feet are feasible for interpretable examinations and therefore line-of-site mass casualty or field triage sites, and 4) that real-time INMARSAT transmission of FAST examinations at 64 kbps may serve a limited role for remote clinical interpretation.

Telemedicine and neurosurgery: experience of a regional unit based in South Africa

We carried out a retrospective analysis of all emergency referrals to the neurosurgery department of the Wentworth Hospital from 1996 to 1999. The hospital provided a service to seven peripheral hospitals with computerized tomography (CT) scanners and 46 hospitals without, in the province of KwaZulu Natal. By the end of the study, six of the hospitals with CT scanners had facilities for teleradiology and the mean patient return rate had fallen to 17%. In comparison, almost half the patients seen from the hospitals with no CT scanners were returned to hospital after assessment at the Wentworth Hospital. We also carried out a prospective analysis of 100 consecutive teleradiology-assisted consultations from January to March 2000. Of the 57 patients (79%) who remained at their referral hospitals, 45 had a good outcome, while the other 12 (21%) patients had a poor outcome. The implementation of teleradiology-assisted consultation decreased the number of inappropriate inter-hospital transfers while maintaining appropriate patient care and improving outcome.

Evaluation of emergency CT scans of the head: is there a community standard?

OBJECTIVE

This study was designed to assess the accuracy of general radiologists in the interpretation via teleradiology of emergency CT scans of the head.

MATERIALS AND METHODS

We studied the interpretations of 716 consecutive emergency CT scans of the head by a group of 15 board-certified general radiologists practicing in the community (as opposed to an academic setting). The scans were sent via teleradiology, and the preliminary interpretations were made. Three of the general radiologists were functioning as nighthawks, and the remaining 12 were acting as on-call radiologists in addition to their normal daytime duties. Each CT examination was interpreted by one of five neuroradiologists the day after the initial interpretation had been performed. The findings of the final interpretation and the preliminary interpretation were categorized as showing agreement, insignificant disagreement, or significant disagreement. The reports in the two categories indicating disagreement were reviewed and reclassified by a consensus of three university-based neuroradiologists.

RESULTS

Agreement between the initial interpretation by the general radiologist and the final interpretation by the neuroradiologist was found in 95% of the CT scans. The interpretations were judged to show insignificant disagreement in 3% (23/716) of the scans and to show significant disagreement in 2% (16/716). Of the 16 significant errors, five were false-positive findings and 11 were false-negative findings. Forty-seven CT scans depicted significant or active disease, and in 11 (23%) of these scans, the final report differed significantly from the preliminary interpretation. Three patients had pituitary masses, none of which had been described on the preliminary interpretation.

CONCLUSION

The rate of significant discordance between board-certified on-call general radiologists and neuroradiologists in the interpretation of emergency CT scans was 2%, which was comparable to previously published reports of residents' performance. The pituitary gland may be a blind spot, and additional attention should be focused on this area.

The quality of medical records in teleconsultation

We collected and examined the medical records from telemedicine cases dealt with by the telemedicine centre of Shanghai Hospital No. 85. This centre handles the second largest number of teleconsultations in the entire network. There were 658 telemedicine cases in total. The medical records included the patient record in 599 cases (91%), transmitted images in 392 cases (60%), the consultant's opinion in 595 cases (90%) and a video-recording of the teleconsultation in 203 cases (31%). The quality of patient records was reviewed and found to be acceptable in 58% of cases. In total, 1794 radiology images (85% of all images) were transmitted via the telemedicine network. The consultant considered 352 of them (20%) to be unreadable on the screen (i.e. 80% of radiology images were considered to be acceptable). For optimum performance of telemedicine, the patient record and associated images should be delivered in advance and the relevant parts of the patient record should be available during a teleconsultation. Three aspects of the management of the medical records for teleconsultations are particularly important: multimedia collection, standardization of patient/record identification and classification, and information management.

Minimum technical requirements and evaluating effectiveness of teleradiology

Teleradiology, the electronic transmission of radiological images for the purposes of interpretation and consultation, has successfully entered routine health services. It is, therefore, currently one of the single largest applications of telemedicine. This technology is predicted to play a significant role in improving service access to rural and remote areas. However, teleradiology services are currently characterized by a compromise between expense and quality of digital images. This paper reviews minimum equipment requirements and the technical issues and limits that are experienced when utilizing current teleradiological technology. Categories of service evaluation, including measures of user satisfaction, clinical outcome and financial benefit, are discussed in relation to facilitating a radiology service of the highest quality possible.

ATMTN: a telemammography network architecture

One of the goals of the National Cancer Institute (NCI) to reach more than 80% of eligible women in mammography screening by the year 2000 yet remains as a challenge. In fact, a recent medical report reveals that while other types of cancer are experiencing negative growth, breast cancer has been the only one with a positive growth rate over the last few years. This is primarily due to the fact that 1) examination process is a complex and lengthy one and 2) it is not available to the majority of women who live in remote sites. Currently for mammography screening, women have to go to doctors or cancer centers/hospitals annually while high-risk patients may have to visit more often. One way to resolve these problems is by the use of advanced networking technologies and signal processing algorithms. On one hand, software modules can help detect, with high precision, true negatives (TN), while marking true positives (TP) for further investigation. Unavoidably, in this process some false negatives (FN) will be generated that are potentially life threatening; however, inclusion of the detection software improves the TP detection and, hence, reduces FNs drastically. Since TNs are the majority of examinations on a randomly selected population, this first step reduces the load on radiologists by a tremendous amount. On the other hand, high-speed networking equipment can accelerate the required clinic-lab connection and make detection, segmentation, and image enhancement algorithms readily available to the radiologists. This will bring the breast cancer care, caregiver, and the facilities to the patients and expand diagnostics and treatment to the remote sites. This research describes asynchronous transfer mode telemammography network (ATMTN) architecture for real-time, online screening, detection and diagnosis of breast cancer. ATMTN is a unique high-speed network integrated with automatic robust computer-assisted diagnosis-detection/digital signal processing (CAD/DSP) methods for mass detection, region of interest (ROI) compression algorithms using Digital Imaging and Communications in Medicine (DICOM) 3.0 medical image standard. While ATMTN has the advantage of higher penetration for cancer screening, it provides the diagnosis with higher efficiency, better accuracy and potentially lower cost. This paper presents the development of the infrastructure and algorithm design for ATMTN-based telemammography. The research goals involved: 1) networking stations for telemammography to demonstrate, evaluate, and validate technologies and methods for delivering mammography screening services via high-speed (155 MB/s) links, performing real-time network-transmitted, high-resolution mammograms for immediate diagnosis as a "second opinion" strategy; 2) development of object-oriented compression methods for storage, retrieval and transmission of mammograms; 3) inclusion and optimization of detection algorithms for identification of normal images in different resolutions to increase the speed and effectiveness of telemammography as a "second opinion" strategy; 4) resolving the compatibility issues between images from different equipment (DICOM standards); and 5) optimization of an integrated ATMTN with adaptive CAD/DSP methods that are robust for large image databases and input sources.

Comparison of asynchronous and realtime teleconsulting for orthopaedic second opinions

We studied a teleconsulting service for second opinions in orthopaedics. Three units of the national insurance organization for accidents at work were connected to a large orthopaedic hospital in Bologna. During a 20-month study, 65 consultations were provided: 51 (78%) by asynchronous (store-and-forward) consulting and 14 (22%) by realtime videoconferencing. All the consultations made use of radiology images (radiographs, computerized tomography scans, magnetic resonance imaging scans and ultrasound scans). Video-messages and still images were commonly used to support the asynchronous consultations. More data were transmitted on average for an asynchronous teleconsultation (8 MByte) than in a videoconference (5 MByte). The average time spent by orthopaedic specialists was slightly longer in videoconferences (21 min, SD 8) than in asynchronous teleconsultations (19 min, SD 8). The clinicians confidence in their diagnosis was generally good but was lower in asynchronous consultations. The main problem affecting the telemedicine service was the lack or the low quality of the information received from the referring sites. The clinical complexity of the case and the organizational requirements were declared to be the main factors affecting the choice of consulting procedure. The study showed that the asynchronous method was preferred in the majority of cases and could be easily integrated into clinical practice, although there were some concerns about the diagnostic quality of the information transmitted.

Effect of teleradiology on the diagnosis, treatment and prognosis of patients in a primary care centre

A prospective study was carried out to evaluate the effect of teleradiology on the diagnosis, treatment and prognosis of patients in primary care. A university hospital was sent 685 plain film examinations via an ISDN connection from a primary care centre, for a radiological report. The study was conducted in two phases: during phase 1 (446 cases) general practitioners (GPs) selected the examinations, and during phase 2 (239 cases) all consecutive examinations were transmitted. In phase 1, 40% of the examinations were of the chest and 24% were of the spine; the remaining 36% were mainly bone and sinus examinations. In phase 2, 28% of the examinations were of the chest and 19% were of the spine. The sensitivity and specificity of the GPs' interpretations (compared with the radiologists') were 0.85 and 0.62 respectively in the first phase, and 0.90 and 0.86 in the second. In at least one-third of all cases, teleradiology helped with the diagnosis, although completely new diagnoses were less common. An effect on treatment was noted in 15% of cases and on prognosis in 5%. However, an appropriate consultation level is required for these positive effects. Adequate accuracy and patient safety cannot be achieved if the examinations sent for radiological reporting are preselected by a GP.

Introduction to the DICOM standard

Digital Imaging and Communication in Medicine (DICOM) has become one of the most popular standards in medicine. In the beginning, DICOM was used for communication of image data between different systems. Actual developments of the standardisation enables increasingly more DICOM-based services for the integration of modalities and information systems (e.g. RIS, PACS). In this article a review of the historical background, the technological concept, the organizational structure and current developments is given.

Telemedicine in South Africa: success or failure?

A national telemedicine system for South Africa was planned in 1998. In the first phase, starting in 1999, 28 pilot sites were established in six provinces. The initial applications were teleradiology, tele-ultrasound for antenatal services, telepathology and tele-ophthalmology. Telemedicine equipment was connected by ISDN at 256 kbit/s. From January to September 2000, 2663 radiographic studies were performed at the three Northwest Province teleradiology transmission sites, of which 264 studies (10%) were selected for specialist radiologist reporting by teleradiology. From June to August 2000, nine antenatal care tele-ultrasound consultations were performed in the Northern Cape Province and four transfers were avoided through the use of telemedicine. One area of concern is the relatively low usage of the telemedicine system, which raises questions about its cost-effectiveness. The experience of telemedicine in South Africa confirmed, as others have found, that common problems relate to the technical and organizational challenges of introducing telemedicine.

The effect of resolution, compression, colour depth and display modality on the accuracy of accident and emergency telemedicine

There are no current recommendations regarding the minimum technical specification for realtime telemedicine consultation in accident and emergency (A and E) practice. We assessed the effect of image resolution, compression, colour depth and display modality on perceived image quality and telediagnosis. Test sets of digitized radiographs and clinical images were subjected to a series of standardized manipulations and the resulting output files were evaluated by an expert panel using image scoring and receiver operating characteristic (ROC) analysis. For telemedicine in A and E work, the minimum technical specification should be regarded as images containing at least 250,000 pixels, compressed at up to JPEG 50 (or GIF for colour images) and displayed on a high-resolution computer monitor. These specifications resulted in average file sizes of 17 kByte for digital images and 9 kByte for radiographs.

[Preliminary experience of wireless teleradiology system using Personal Handyphone System]

We investigated the potential of the wireless teleradiology system, using a Personal Handyphone System(PHS) and hand-held personal computer. To provide and interpret CT images, an internet web system was used. It took 5.5 seconds to transmit a single CT image of 28 KB. Therefore, about 2 minutes was required to brawse a series of brain examinations(20 CT images). Although transmission speed needs to be increased, our system makes it possible to perform imaging diagnosis anywhere and is especially useful in emergency situations.

Clinical efficacy of telemedicine in emergency radiotherapy for malignant spinal cord compression

The authors developed a Telecommunication-HElped Radiotherapy Planning and Information SysTem (THERAPIST), then estimated its clinical benefit in radiotherapy in district hospitals where consultation with the university hospital was required. The system consists of a personal computer with an image scanner and a digital camera, set up in district hospitals and directly connected via ISDN to an image server, and a treatment planning device set up in a university hospital. Image data and consultative reports are sent to the server. Radiation oncologists at the university hospital determine a treatment schedule and verify actual treatment fields. From 1998 to 1999, 12 patients with malignant spinal cord compression (MSCC) were treated by emergency radiotherapy with the help of this system. Image quality, transmission time, and cost benefit also were satisfactory for clinical use. The mean time between the onset of symptoms and the start of radiotherapy was reduced significantly from 7.1 days to 0.8 days (P < .05) by the introduction of the system. Five of 6 nonambulant patients became ambulant after the introduction of THERAPIST compared with 2 of 8 before the introduction of THERAPIST. The treatment outcome was significantly better after the introduction of the system (P < .05), and suggested to be beyond the international standard. The telecommunication-helped radiotherapy and information system was useful in emergency radiotherapy in district hospitals for patients with MSCC for whom consultation with experienced radiation oncologists at a university hospital was required.