Optimization of a teleradiology system between two geriatric hospitals and a radiology department of a CHU

The routine use of a 64 kb/sec Numeris network requires that a compromise be reached between image quality and time required for image transfer. Our goal was to present our experience and describe our choices when reporting examinations for two geriatric hospitals located at a short distance from our radiology department. Different digitization parameters were tested (resolution, compression) for 10 plain films corresponding to the usual clinical situations: abdominal X ray, chest X ray, wrist, spine and pelvis X rays. A subjective analysis of the global quality and of the quality of a region of interest enlarged twelve times has been performed. After result analysis, our choices were: digitization using 75 or 150 DPI and systematic use of a reversible compression format. This system proved satisfactory for both clinicians and radiologists; since its implementation, 1,800 files have been reviewed.     

The diagnostic performance of a PC-based teleradiology link.

AIM: Evaluation of the diagnostic performance of a personal computer based teleradiology link. MATERIALS AND METHODS: Two experienced radiologists assessed 100 cases, all based on chest and skeletal films using teleradiology for 50. These assessments were compared with the consensus of a panel of three independent radiologists. RESULTS: Diagnostic performance of teleradiology and conventional film was similar (sensitivity 88 vs. 90%; specificity 96 vs. 90%; accuracy 91 vs. 90%; not significant). However, the quality of teleradiology images was rated poorer, and the confidence in diagnosis was lower with teleradiology. ROC curve analysis, taking into account diagnostic confidence, showed significantly poorer performance for teleradiology at all thresholds when chest X-rays only were considered. There was no significant difference for skeletal images, although the two smooth curves crossed, suggesting teleradiology might be better when the specificity is high. CONCLUSION: These findings suggest that when this type of teleradiology system is used, the value of rapid reporting must be balanced against poorer image quality, particularly for chest X-rays.     

Privacy and security in teleradiology

Teleradiology is probably the most successful eHealth service available today. Its business model is based on the remote transmission of radiological images (e.g. X-ray and CT-images) over electronic networks, and on the interpretation of the transmitted images for diagnostic purpose. Two basic service models are commonly used teleradiology today. The most common approach is based on the message paradigm (off-line model), but more developed teleradiology systems are based on the interactive use of PACS/RIS systems. Modern teleradiology is also more and more cross-organisational or even cross-border service between service providers having different jurisdictions and security policies. This paper defines the requirements needed to make different teleradiology models trusted. Those requirements include a common security policy that covers all partners and entities, common security and privacy protection principles and requirements, controlled contracts between partners, and the use of security controls and tools that supporting the common security policy. The security and privacy protection of any teleradiology system must be planned in advance, and the necessary security and privacy enhancing tools should be selected (e.g. strong authentication, data encryption, non-repudiation services and audit-logs) based on the risk analysis and requirements set by the legislation. In any case the teleradiology system should fulfil ethical and regulatory requirements. Certification of the whole teleradiology service system including security and privacy is also proposed. In the future, teleradiology services will be an integrated part of pervasive eHealth. Security requirements for this environment including dynamic and context aware security services are also discussed in this paper.     

Clinical evaluation of a teleradiology system utilizing personal computers and public telephone line.

Practical usefulness of a teleradiology system using CCD camera, personal computer and telephone line was evaluated in a daily clinical practice. Image quality of this system is diagnostic for the majority of abnormalities on radiological images including plain radiographs. Radiological consultation between hospitals in the same city as well as between distant cities using this moderately priced system was thought to be useful in 90% of cases. Teleradiology using compact systems like ours is expected to be useful in the urban clinical environment as well as in distant areas.     

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. Electronic Publication     

A description of a low field resistive magnetic resonance imaging system and its application in imaging midline central nervous system pathology

A commercial low field magnetic resonance imaging (MRI) system installed in the Royal Infirmary, Edinburgh at the end of 1983 has since been used for the clinical investigation of over 1000 patients. This system uses an interlaced saturation recovery and inversion recovery pulse sequence which yields four types of clinical image. AT1 weighted image has been found to be the most sensitive for the detection of pathology. Several examples of pathology with negative X-ray computed tomography examinations including three examples of a syrinx and two cases of tonsillar herniation have been demonstrated using this system. It is suggested that the system could provide a routine clinical service for imaging the central nervous system.     

The reliability and validity of a field hockey skill test

High test retest reliability is essential in tests used for both scientific research and to monitor athletic performance. Thirty-nine (20 male and 19 female) well-trained university field hockey players volunteered to participate in the study. The reliability of the in house designed test was determined by repeating the test (3 - 14 days later) following full familiarisation. The validity was assessed by comparing coaches ranks of players with ranked performance on the skill test. The mean difference and confidence limits in overall skill test performance was 0.0 +/- 1.0 % and the standard error (confidence limits) was 2.1 % (1.7 to 2.8 %). The mean difference and confidence limits for the "decision making" time was 0.0 +/- 1.0 % and the standard error (confidence limits) was 4.5 % (3.6 to 6.2 %). The validity correlation (Pearson) was r = 0.83 and r = 0.73 for female players and r = 0.61 and r = 0.70 for male players for overall time and "decision making" time respectively. We conclude that the field hockey skill test is a reliable measure of skill performance and that it is valid as a predictor of coach-assessed hockey performance, but the validity is greater for female players.     

The design and test of a new volume coil for high field imaging

A major problem in the development of high field (>100 MHz) large volume (>6000 cm³) MR coils is the interaction of the coil with the subject as well as the radiation loss to the environment. To reduce subject perturbation of the coil resonance modes, a volume coil that uses an array of freely rotating resonant elements radially mounted between two concentric cylinders was designed for operation at 170 MHz. Substantial electromagnetic energy is stored in the resonant elements outside the sample region without compromising the efficiency of the overall coil. This stored energy reduces the effect of the subject on the circuit and maintains a high Q, facilitating the tuning and matching of the coil. The unloaded Q of the coil is 680; when loaded with a head, it was 129. The ratio of 5.3 of the unloaded to loaded Q supports the notion that the efficiency of the coil was maintained in comparison with previous designs. The power requirement and signal-to-noise performance are significantly improved. The coil is tuned by a mechanism that imparts the same degree of rotation on all of the elements simultaneously, varying their degree of mutual coupling and preserving the overall coil symmetry. A thin radiofrequency shield is an integral part of the coil to reduce the radiation effect, which is a significant loss mechanism at high fields. MR images were collected at 4T using this coil design with high sensitivity and B₁, homogeneity.     

交互式远程放射学系统在不同网络通讯条件下的应用及性能测试研究

目的测试采用自行研发的交互式远程放射学系统测试在不同网络通讯条件下的应用性能。方法系统将分别所采集的数字化放射影像通过卫星网、非对称数字用户环线网(ADSL)和上海卫生系统专用宽带广域网进行传输及远程放射学会诊应用实验，记录影像在这3种网络条件下传输时耗并主观评测会诊实时性效果，对所获实验数据进行分析。结果在卫星网络环境下，系统影像传输时间长，实时性交互操作效果可以接受；在宽带网络环境下系统影像传输时间短，交互操作同步无时延。系统在卫星网等窄带中速网络中，可对小矩阵尺寸图像和经压缩的大矩阵尺寸图像的影像集合进行会诊，影像传输以192kbps带宽传输性能优；在宽带网络环境中，未经压缩的CR等大矩阵尺寸影像可快速传送用于会诊。结论系统实时交互性的会诊操作对网络环境的要求不高，不同的网络通讯条件下均能实现对不同的会诊影像集合的交互性会诊操作。     

Analysis of a reactive agility field test

The purpose of this research was to evaluate a reactive agility test by determining the relationships between the total time recorded for the test and various components. A tester used side-step movements to provide a stimulus for the athlete to change direction. By using electronic timing and high speed video analysis of the test, three times were recorded. These were the time taken for the tester to display the stimulus to change direction (tester time), the time taken by the participant to respond to the stimulus (decision time), and the time taken by the participant to change direction and sprint to the left or right (response movement time). Thirty-one semi-professional Australian Rules football players were assessed by analysing the mean of eight trials of the reactive agility test. The greatest correlation with total time was r = 0.77 for decision time (p = 0.00), with movement time and tester time producing coefficients of 0.59 (p = 0.00) and 0.37 (p = 0.04), respectively. The coefficient of variation for the mean tester time was 5.1%. It was concluded that perceptual skill as measured by decision time is an important component of the reactive agility test and the tester time should be controlled by using high speed video recordings to isolate its influence.     

远程放射学中影像胶片处理和质量评价的初步研究

目的 研究影像胶片处理以达到远程放射学的要求。方法 运用数字化扫描仪对病３张骨盆Ｘ线平片，７８张骨盆ＭＲＩ激光胶片和１张含有病人体征信息的普通彩色照片进行扫描。以普通的个人计算机５８６／ＭＭＸ１６６型和ＨＰ５１００Ｃ型扫描仪与硬件平台，操作系统使用ＷＩＮ９５，采用Ｐｈｏｔｏｓｈｏｐ５．０作为应用处理软件。采集，处理压缩并存储图像数据，建立文件。     

The new Air Force fitness test: a field trial assessing effectiveness and safety

Two thousand one hundred thirty-nine Air Force members were stratified in risk categories based on a questionnaire about their exercise habits and risk factors which could preclude participation in the new Air Force fitness test. Those at risk were interviewed by a practitioner and placed in a supervised fitness program or exempted from testing. All others were tested by the 1.5-mile field run. Based on these data it is estimated that 40% of the Air Force was exercising regularly and only 50% would pass the old category III standards, with 33% passing the new category IV standard. Thirteen percent of the Air Force would be in the highest risk category, but after a practitioner interview alone, only 7.9% would be exempted from testing altogether, almost all for known or suspected cardiac conditions. This screening and interviewing process is not a significant additional workload on Medical Treatment Facilities and may enhance the safety of the new Air Force fitness program.     

The pivot shift phenomenon: results and description of a modified clinical test for anterior cruciate ligament insufficiency

Clinical evaluation of knee instability is often difficult to reproduce, and several different physical tests have become popular. In an attempt to elucidate reasons for variations in the degree of pivot shift phenomenon seen with the use of the various tests, we have prospectively evaluated a group of 37 patients with surgically documented ACL injuries, noting the effects of hip position and tibial rotation. The patients were examined under anesthesia, and the pivot shift was graded as 0 (absent, or negative), 0.5+ (trace), 1+, 2+, or 3+ (with locking). All knees were tested in hip abduction, neutral, and hip adduction, and with the tibia in external and internal rotation, so that six positions were evaluated. Hip position strongly correlated with the degree of pivot shift regardless of tibial rotation. Overall, abduction produced the greatest degree of pivot shift, followed by neutral and finally adduction. External tibial rotation increased the pivot shift score in abduction and neutral, but not in adduction. A grading system for the subject population showed that abduction/external rotation (ABDER) resulted in the highest pivot shift scores, and that adduction/external rotation (ADDER) and adduction/internal rotation (ADDIR) resulted in the lowest scores. Nine patients out of 20 with a 3+ pivot shift in ABDER were negative in ADDER. The pivot shift score was dampened at least one grade from ABDER to ADDER in 92% of the patients. We conclude that hip position and tibial rotation affect the degree of pivot shift phenomenon, and it is our impression that the iliotibial band plays a significant role in controlling the degree of pivot shift observed.(ABSTRACT TRUNCATED AT 250 WORDS)