Randomized comparison of the quality of realtime fetal ultrasound images transmitted by ISDN and by IP videoconferencing

Telementored ultrasonography: a narrative review

BACKGROUND

Teleradiology consists of electronic transmission of radiological images from one location to another, including between countries, for interpretation and/or consultation. It is one of the most successful applications of telemedicine. Combining this methodology with ultrasound (called telesonography) can accelerate the process of making diagnoses. Despite this rationale, the quality of the evidence about the effectiveness and accuracy of teleradiology remains unknown.

OBJECTIVE

To review the literature on the evidence that exists regarding use of telemedicine for ultrasound in situations of synchronous transmission.

DESIGN AND SETTING

Narrative review conducted within the evidence-based health program at a federal university in São Paulo (SP), Brazil.

METHODS

A search of the literature was carried out in April 2020, in the online databases MEDLINE, EMBASE, Cochrane Library, Tripdatabase, CINAHL and LILACS, for original publications in all languages. The reference lists of the studies included and the main reviews on the subject were also evaluated.

RESULTS

We included ten studies that assessed procedures performed by different healthcare professionals, always with a doctor experienced in ultrasound as a distant mentor. Among these, only one study assessed disease diagnoses in relation to real patients.

CONCLUSIONS

Despite the promising position of telesonography within telemedicine, no studies with reasonable methodological quality have yet been conducted to demonstrate its effectiveness.

Improving the quality of breast ultrasound examination performed by inexperienced ultrasound doctors with synchronous tele-ultrasound: a prospective, parallel controlled trial

PURPOSE

This prospective study explored the value of synchronous tele-ultrasound (US) to aid doctors inexperienced in US with breast US examinations.

METHODS

In total, 99 patients were enrolled. Two trainee doctors who were inexperienced in US (trainee A [TA] and trainee B [TB]) and one doctor who was an expert in US completed the US examinations sequentially. TA completed the US examinations independently, while TB was instructed by the expert using synchronous tele-US. Subsequently, the expert performed on-site US examinations in person. Separately, they selected the most clinically significant nodule as the target nodule. Consistency with the expert and image quality were compared between TA and TB to evaluate tele-US. Furthermore, TB and the patients evaluated tele-US through questionnaires.

RESULTS

TB demonstrated higher consistency with the expert in terms of target nodule selection than TA (93.3% vs. 63.3%, P<0.001). TB achieved good inter-observer agreement (>0.75) with the expert on five US features (5/9, 55.6%), while TA only did so for one (1/9, 11.1%) (P=0.046). TB's image quality was higher than TA's in gray value, time gain compensation, depth, color Doppler adjustment, and the visibility of key information (P=0.018, P<0.001, P<0.001, P=0.033, and P=0.006, respectively). The comprehensive assessment score was higher for TB than for TA (3.96±0.82 vs. 3.09±0.87, P<0.001). Tele-US was helpful in 69.7% of US examinations and had a training effect in 68.0%. Furthermore, 63.6% of patients accepted tele-US and 60.6% were willing to pay.

CONCLUSION

Tele-US can help doctors inexperienced in US to perform breast US examinations.

Remotely supported prehospital ultrasound: A feasibility study of real-time image transmission and expert guidance to aid diagnosis in remote and rural communities

Introduction

Our aim is to expedite prehospital assessment of remote and rural patients using remotely-supported ultrasound and satellite/cellular communications. In this paradigm, paramedics are remotely-supported ultrasound operators, guided by hospital-based specialists, to record images before receiving diagnostic advice. Technology can support users in areas with little access to medical imaging and suboptimal communications coverage by connecting to multiple cellular networks and/or satellites to stream live ultrasound and audio-video.

Methods

An ambulance-based demonstrator system captured standard trauma and novel transcranial ultrasound scans from 10 healthy volunteers at 16 locations across the Scottish Highlands. Volunteers underwent brief scanning training before receiving expert guidance via the communications link. Ultrasound images were streamed with an audio/video feed to reviewers for interpretation. Two sessions were transmitted via satellite and 21 used cellular networks. Reviewers rated image and communication quality, and their utility for diagnosis. Transmission latency and bandwidth were recorded, and effects of scanner and reviewer experience were assessed.

Results

Appropriate views were provided in 94% of the simulated trauma scans. The mean upload rate was 835/150 kbps and mean latency was 114/2072 ms for cellular and satellite networks, respectively. Scanning experience had a significant impact on time to achieve a diagnostic image, and review of offline scans required significantly less time than live-streamed scans.

Discussion

This prehospital ultrasound system could facilitate early diagnosis and streamlining of treatment pathways for remote emergency patients, being particularly applicable in rural areas worldwide with poor communications infrastructure and extensive transport times.

Fetal endoscopic telesurgery using an Internet Protocol connection: Clinical and technical challenges

Until recently, fetoscopic laser surgery to seal the placental anastomoses that cause severe twin-to-twin transfusion syndrome has been available in only a few centres worldwide. The technique typically takes a long time to learn. We have used a dedicated Internet Protocol (IP) connection for tele-education to assist the introduction of fetoscopic laser surgery to Australia. During the implementation of the international telemedicine link, there were multiple clinical and technical problems, which were eventually overcome. The quality of images and of video-sequences was comparable to that supported by an ISDN connection. Pictures of live surgery performed by an expert in Florida, USA, were transmitted and viewed by a novice team in Brisbane, Australia. The Australian team has performed 19 fetoscopic laser operations to date. Preliminary results are comparable to those from centres that have performed over 100 procedures.

Teleultrasound: historical perspective and clinical application

The health care of patients in rural or isolated areas is challenged by the scarcity of local resources, limited patient access to doctors and hospitals, and the lack of specialized professionals. This has led to a new concept in telemedicine: teleultrasonography (or teleultrasound), which permits ultrasonographic diagnoses to be performed remotely. Telemedicine and teleultrasonography are effective in providing diagnostic imaging services to these populations and reduce health care costs by decreasing the number and duration of hospitalizations and reducing unnecessary surgical procedures. This is a narrative review to present the potential clinical applications of teleultrasonography in clinical practice. The results indicate that although barriers persist for implementing teleultrasonography in a more universal and routine way, advances in telecommunications, Internet bandwidth, and the high resolution currently available for portable ultrasonography suggest teleultrasonography applications will continue to expand. Teleultrasound appears to be a valuable addition to remote medical care for isolated populations with limited access to tertiary healthcare facilities and also a useful tool for education and training.

Potential Use of Remote Telesonography as a Transformational Technology in Underresourced and/or Remote Settings

Mortality and morbidity from traumatic injury are twofold higher in rural compared to urban areas. Furthermore, the greater the distance a patient resides from an organized trauma system, the greater the likelihood of an adverse outcome. Delay in timely diagnosis and treatment contributes to this penalty, regardless of whether the inherent barriers are geographic, cultural, or socioeconomic. Since ultrasound is noninvasive, cost-effective, and portable, it is becoming increasingly useful for remote/underresourced (R/UR) settings to avoid lengthy patient travel to relatively inaccessible medical centers. Ultrasonography is a user-dependent, technical skill, and many, if not most, front-line care providers will not have this advanced training. This is particularly true if care is being provided by out-of-hospital, “nontraditional” providers. The human exploration of space has forced the utilization of information technology (IT) to allow remote experts to guide distant untrained care providers in point-of-care ultrasound to diagnose and manage both acute and chronic illness or injuries. This paradigm potentially brings advanced diagnostic imaging to any medical interaction in a setting with internet connectivity. This paper summarizes the current literature surrounding the development of teleultrasound as a transformational technology and its application to underresourced settings.

A fetal telecardiology service: patient preference and socio-economic factors

OBJECTIVE

The aims of this study were to evaluate patients' opinions on a fetal cardiology telemedicine service compared with usual outpatient care, the effect of the telemedicine consultation on maternal anxiety and its impact on travel times and time absent from work.

METHODS

Prospective study over 20 months. Eligible patients attended for routine anomaly scan followed by fetal echocardiogram transmitted to the regional centre with live guidance by a fetal cardiologist, followed by parental counselling. All patients were offered a fetal cardiology appointment at the regional centre. Structured questionnaires assessing maternal satisfaction, travel times/days off and anxiety scores completed at time of both fetal echocardiograms.

RESULTS

Sixty-seven patients were recruited and 66 completed the study. Participants expressed very high satisfaction rates with fetal telecardiology, equivalent to face-to-face consultation. The telecardiology appointments were associated with significantly reduced travel times and days off work (p < 0.01). Expectant mothers expressed a clear inclination for a fetal cardiology appointment at the local hospital facilitated by telemedicine (p < 0.01).

CONCLUSIONS

Fetal telecardiology is highly acceptable to patients and is even preferred compared with travelling to a regional centre. There are additional socio-economic benefits that should encourage the development of remote fetal cardiology services.

Near real-time echocardiography teleconsultation using low bandwidth and MPEG-4 compression: feasibility, image adequacy and clinical implications

We assessed the feasibility, image adequacy and clinical utility of a tele-echocardiography service which combined video compression with low-bandwidth store-and-forward transmission. Echocardiograms were acquired by a hospital geriatrician, compressed and transmitted using both near real-time (urgent) and delayed (pre-programmed) protocols via an Internet connection to the notebook PC of a remote cardiologist. Clinical utility was evaluated as a change in therapeutic management. During a one-year period, 101 tele-echocardiography consultations were successfully performed (feasibility = 100%) on 95 patients (age 22-95 years), admitted with cardiovascular or neurological diagnoses (24% of the consultations were urgent). In total, 4617 files (1.4 GByte of data) were transmitted, 2669 of which were short video clips. On average, 46 files (13.8 MByte) were transmitted (mean duration 10 min) at each examination. Consultations (both urgent and pre-programmed) were clinically useful in 83% of examinations. Logistic regression analysis showed that both a low left ventricular systolic function and the examination indication were determinants of clinical utility. The transmitted images were considered adequate for diagnosis in 100% of the pre-programmed teleconsultations. Tele-echocardiography using MPEG-4 video compression is a feasible, adequate and clinically useful tool for telemedicine.

Tele-obstetric ultrasound: analysis of first-trimester ultrasound images transmitted in realtime

We evaluated the diagnostic quality of first-trimester ultrasound images transmitted in realtime using low-cost telecommunications. A prospective sample of fetal ultrasound images from 11 weeks to 13 weeks and six days of pregnancy was obtained from pregnant women over 18 years old. The examinations were transmitted in realtime to three independent examiners who carried out a qualitative assessment based on parameters established by the Fetal Medicine Foundation. All fetal structures could be viewed and the quality of images received by the examiners was considered normal. There were significant differences for crown-rump length and nuchal translucency in the transmitted images but the loss in definition was acceptable. Thus the quality of images transmitted via the Internet through the use of low-cost software appeared suitable for screening for chromosomal abnormalities in the first trimester of pregnancy.

Telesonography: foundations and future directions

The practice of telesonography has yielded promising results in several domestic and international projects aimed at providing basic sonography services. Common themes that recur within telesonography-based research include the quality of transmitted images, clinical applications, and technical and nontechnical barriers to implementation. The research base continues to grow in concert with expanding telecommunications capabilities and refinement of small portable sonographic devices. Persistent barriers to the deployment of telesonography systems include a lack of telecommunications access, a lack of standard training and operational protocols, and a paucity of research regarding the long-term health impact of telesonography within target communities. Telesonography may be used directly to improve the standard of care within a given community; however, limited resources and interest may prevent sustained operations. Future projects may use telesonography to supplement the training of health care providers in remote locations in an effort to establish permanent sonography services for their respective communities.

High-grade video compression of echocardiographic studies: a multicenter validation study of selected motion pictures expert groups (MPEG)-4 algorithms

BACKGROUND

Large files produced by standard compression algorithms slow down spread of digital and tele-echocardiography. We validated echocardiographic video high-grade compression with the new Motion Pictures Expert Groups (MPEG)-4 algorithms with a multicenter study.

METHODS

Seven expert cardiologists blindly scored (5-point scale) 165 uncompressed and compressed 2-dimensional and color Doppler video clips, based on combined diagnostic content and image quality (uncompressed files as references). One digital video and 3 MPEG-4 algorithms (WM9, MV2, and DivX) were used, the latter at 3 compression levels (0%, 35%, and 60%).

RESULTS

Compressed file sizes decreased from 12 to 83 MB to 0.03 to 2.3 MB (1:1051-1:26 reduction ratios). Mean SD of differences was 0.81 for intraobserver variability (uncompressed and digital video files). Compared with uncompressed files, only the DivX mean score at 35% (P = .04) and 60% (P = .001) compression was significantly reduced. At subcategory analysis, these differences were still significant for gray-scale and fundamental imaging but not for color or second harmonic tissue imaging. Original image quality, session sequence, compression grade, and bitrate were all independent determinants of mean score.

CONCLUSIONS

Our study supports use of MPEG-4 algorithms to greatly reduce echocardiographic file sizes, thus facilitating archiving and transmission. Quality evaluation studies should account for the many independent variables that affect image quality grading.

How useful is 3D and 4D ultrasound in perinatal medicine?

AIM

The purpose of this paper is to review and analyze the published literature on the use of three-dimensional (3DUS) and four-dimensional (4DUS) ultrasound in perinatal medicine.

METHODS

We systematically searched Medline through PubMED (January 2000-January 2006), including EMBASE/Excerpta Medica database as well as the Cochrane Database of Systematic Reviews. The search terms used to identify clinical application of 3DUS and 4DUS studies in perinatal medicine were technical development, special features, and recommendation for fetal imaging, research on 3DUS or 4DUS, and the usage of invasive 3DUS or 4DUS procedures. The reference bibliographies of relevant books were also manually searched for supplementary citations. Inclusion criteria were as follows: (1) studies related to the use of 3DUS or 4DUS in perinatal medicine; (2) full text were available in English; (3) publication format of original scientific articles, case reports, editorials or literature reviews and chapters in the books.

RESULTS

Five hundred and seventy-five articles were identified, and among those, 438 were relevant to this review.

CONCLUSIONS

3DUS and 4DUS provided additional information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical utility of 3DUS and 4DUS for the diagnosis of congenital heart disease, central nervous system (CNS) anomalies and detection of fetal neurodevelopmental impairment assessed by abnormal behavior in high-risk fetuses.

The effects of wireless channel errors on the quality of real time ultrasound video transmission

In this paper the effect of the conditions of wireless channels on real time ultrasound video transmission is studied. In order to simulate the transmission through a wireless channel, the model of Gilbert-Elliot is used, and the influence of its parameters in transmitted video quality is evaluated. In addition, the efficiency of using both UDP and UDP-Lite as transport protocols has been studied. The effect of using different video compression rates for XviD codec is also analyzed. Based on the obtained results it is observed as the election of the video compression rate depends on the bit error rate (BER) of the channel, since the election of a high compression bit rate for video transmission through a channel with a high BER can degrade the video quality more than using a lower compression rate. On the other hand, it is observed that using UDP as transport protocol better results in all the studied cases are obtained.