Three-dimensional ultrasonographic telepresence

Telesonography in emergency medicine: A systematic review

Ultrasound is an efficacious, versatile and affordable imaging technique in emergencies, but has limited utility without expert interpretation. Telesonography, in which experts may remotely support the use of ultrasound through a telecommunications link, may broaden access to ultrasound and improve patient outcomes, particularly in remote settings. This review assesses the literature regarding telesonography in emergency medicine, focussing on evidence of feasibility, diagnostic accuracy and clinical utility. A systematic search was performed for articles published from 1946 to February 2017 using the Cochrane, Medline, EMBASE, and CINAHL databases. Further searches utilising Scopus, Google Scholar, and citation lists were conducted. 4388 titles were identified and screened against inclusion criteria which resulted in the inclusion of 28 papers. These included feasibility, diagnostic accuracy and clinical pilot studies. Study design, methodology and quality were heterogeneous. There was good evidence of feasibility from multiple studies. Where sufficient bandwidth and high quality components were used, diagnostic accuracy was slightly reduced by image transmission. There was evidence of clinical utility in remote hospitals and low-resource settings, although reliability was infrequently reported. Further exploratory research is required to determine minimum requirements for image quality, bandwidth, frame rate and to assess diagnostic accuracy. Clinical trials in remote settings are justifiable. Telecommunication options will depend on local requirements; no one system conveys universal advantages. The methodological quality of research in this field must improve: studies should be designed to minimise bias, and must include details of their methods to allow replication. Analysis of cost effectiveness and sustainability should be provided.

Recent Developments in Tele-Ultrasonography

A long-standing trend that will continue to grow in healthcare is providing high quality services for all the patient, no matter the distance and no matter the place. One approach currently being used to increase population access to healthcare services is telemedicine. This narrative review presents one branch of e-health, in particular the use of teleultrasonography (TUS) in clinical practice, the challenges and barriers encountered. Current advances in ultrasound technology, including the growth of portable and small ultrasound devices have increased the range of applications of TUS, from traumatic patients in emergency medicine, maternal ultrasound and even for monitoring and screening for chronic illnesses. Even though some barriers are still looking for a solution, like standardized training and protocols, errors in data acquisition, the lack of trained professionals to operate in remote areas, TUS has the potential to redesign future health care systems.

Remote just-in-time telementored trauma ultrasound: a double-factorial randomized controlled trial examining fluid detection and remote knobology control through an ultrasound graphic user interface display

BACKGROUND

Remote-telementored ultrasound involves novice examiners being remotely guided by experts using informatic-technologies. However, requiring a novice to perform ultrasound is a cognitively demanding task exacerbated by unfamiliarity with ultrasound-machine controls. We incorporated a randomized evaluation of using remote control of the ultrasound functionality (knobology) within a study in which the images generated by distant naive examiners were viewed on an ultrasound graphic user interface (GUI) display viewed on laptop computers by mentors in different cities.

METHODS

Fire-fighters in Edmonton (101) were remotely mentored from Calgary (n = 65), Nanaimo (n = 19), and Memphis (n = 17) to examine an ultrasound phantom randomized to contain free fluid or not. Remote mentors (2 surgeons, 1 internist, and 1 ED physician) were randomly assigned to use GUI knobology control during mentoring (GUIK+/GUIK-).

RESULTS

Remote-telementored ultrasound was feasible in all cases. Overall accuracy for fluid detection was 97% (confidence interval = 91 to 99%) with 3 false negatives (FNs). Positive/negative likelihood ratios were infinity/0.0625. One FN occurred with the GUIK+ and 2 without (GUIK-). There were no statistical test performance differences in either group (GUIK+ and GUIK-).

CONCLUSIONS

Ultrasound-naive 1st responders can be remotely mentored with high accuracy, although providing basic remote control of the knobology did not affect outcomes.

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.

Simple, almost anywhere, with almost anyone: remote low-cost telementored resuscitative lung ultrasound

BACKGROUND

Apnea (APN) and pneumothorax (PTX) are common immediately life-threatening conditions. Ultrasound is a portable tool that captures anatomy and physiology as digital information allowing it to be readily transferred by electronic means. Both APN and PTX are simply ruled out by visualizing respiratory motion at the visceral-parietal pleural interface known as lung sliding (LS), corroborated by either the M-mode or color-power Doppler depiction of LS. We thus assessed how economically and practically this information could be obtained remotely over a cellular network.

METHODS

Ultrasound images were obtained on handheld ultrasound machines streamed to a standard free internet service (Skype) using an iPhone. Remote expert sonographers directed remote providers (with variable to no ultrasound experience) to obtain images by viewing the transmitted ultrasound signal and by viewing the remote examiner over a head-mounted webcam. Examinations were conducted between a series of remote sites and a base station. Remote sites included two remote on-mountain sites, a small airplane in flight, and a Calgary household, with base sites located in Pisa, Rome, Philadelphia, and Calgary.

RESULTS

In all lung fields (20/20) on all occasions, LS could easily and quickly be seen. LS was easily corroborated and documented through capture of color-power Doppler and M-mode images. Other ultrasound applications such as the Focused Assessment with Sonography for Trauma examination, vascular anatomy, and a fetal wellness assessment were also demonstrated.

CONCLUSION

The emergent exclusion of APN-PTX can be immediately accomplished by a remote expert economically linked to almost any responder over cellular networks. Further work should explore the range of other physiologic functions and anatomy that could be so remotely assessed.

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.

A comparison of telesonography with standard ultrasound care in a rural Dominican clinic

We compared telesonography to usual patient care in a rural clinic in the Dominican Republic. A total of 108 low-income Dominican and Haitian patients volunteered to participate. The patients were randomly assigned to either telesonography or control groups. Patients in the telesonography group were scanned and sonographic images and Request for Interpretation (RFI) forms were sent by email to six volunteer radiologists in the USA. Completed RFI forms were transmitted back to the clinic at the radiologists' earliest convenience. Patients in the control group received an ordinary ultrasound referral, which required travel to a tertiary medical centre where their scans were completed by a local sonographer. Sonographic reports from the control group were hand delivered to the referring physician at patient follow-up. The telesonography system provided a four-fold increase in the proportion of patient follow-ups and a six-fold increase in the proportion of returned radiological reports. In the telemedicine group, the median total elapsed time from referral to report return was 17.8 h (interquartile range, IQR 12.2-27.1) and the median time to patient follow-up was 67.1 h (IQR 45.9-113.7). The latter was similar in the control group, where the median total elapsed time was 76.7 h (IQR 65.8-144.7). The pilot study demonstrated that store-and-forward telesonography reduced time to diagnosis and increased the continuity of care compared to the usual ultrasound referral system in the region of the Dominican Republic which was studied.

Clinician performed resuscitative ultrasonography for the initial evaluation and resuscitation of trauma

BACKGROUND

Traumatic injury is a leading cause of morbidity and mortality in developed countries worldwide. Recent studies suggest that many deaths are preventable if injuries are recognized and treated in an expeditious manner - the so called 'golden hour' of trauma. Ultrasound revolutionized the care of the trauma patient with the introduction of the FAST (Focused Assessment with Sonography for Trauma) examination; a rapid assessment of the hemodynamically unstable patient to identify the presence of peritoneal and/or pericardial fluid. Since that time the use of ultrasound has expanded to include a rapid assessment of almost every facet of the trauma patient. As a result, ultrasound is not only viewed as a diagnostic test, but actually as an extension of the physical exam.

METHODS

A review of the medical literature was performed and articles pertaining to ultrasound-assisted assessment of the trauma patient were obtained. The literature selected was based on the preference and clinical expertise of authors.

DISCUSSION

In this review we explore the benefits and pitfalls of applying resuscitative ultrasound to every aspect of the initial assessment of the critically injured trauma patient.

The clinical and technical evaluation of a remote telementored telesonography system during the acute resuscitation and transfer of the injured patient

BACKGROUND

Ultrasound (US) has an ever increasing scope in the evaluation of trauma, but relies greatly on operator experience. NASA has refined telesongraphy (TS) protocols for traumatic injury, especially in reference to mentoring inexperienced users. We hypothesized that such TS might benefit remote terrestrial caregivers. We thus explored using real-time US and video communication between a remote (Banff) and central (Calgary) site during acute trauma resuscitations.

METHODS

A existing internet link, allowing bidirectional videoconferencing and unidirectional US transmission was used between the Banff and Calgary ERs. Protocols to direct or observe an extended focused assessment with sonography for trauma (EFAST) were adapted from NASA algorithms. A call rota was established. Technical feasibility was ascertained through review of completed checklists. Involved personnel were interviewed with a semistructured interview.

RESULTS

In addition to three normal volunteers, 20 acute clinical examinations were completed. Technical challenges requiring solution included initiating US; audio and video communications; image freezing; and US transmission delays. FAST exams were completed in all cases and EFASTs in 14. The critical anatomic features of a diagnostic examination were identified in 98% of all FAST exams and a 100% of all EFASTs that were attempted. Enhancement of clinical care included confirmation of five cases of hemoperitoneum and two pneumothoraces (PTXs), as well as educational benefits. Remote personnel were appreciative of the remote direction particularly when instructions were given sequentially in simple, nontechnical language.

CONCLUSIONS

The remote real-time guidance or observation of an EFAST using TS appears feasible. Most technical problems were quickly overcome. Further evaluation of this approach and technology is warranted in more remote settings with less experienced personnel.

Tele-virtual sonography

OBJECTIVES

3D-Ultrasound reconstruction, routinely available since 1994, has brought new technical capabilities such as virtual sonography that can be tele-consulted. Our experience is summarized in the present paper.

METHODS

During one year, 73 3D-US volumetric images coming from 34 patients were acquired and 68 were consulted at distance. Acquisitions were carried out through an existing 2D device adding a magnetic tracking system on the US-probe. Probe positioning and video output was introduced into a PC running software that allows the generation of 2D-orthogonal and 3D volume images, as well as tele-consultation. Several image analysis techniques for 3D-reconstruction were evaluated.

RESULTS

Final volumes were small (1.5 Mb) and required about 4+/-2 min to be transmitted over one ISDN channel (64 Kbs). Good correlation (k = 0.7) was found between local and distant diagnoses. In 30%, images were considered of low quality and in 29% of good quality; diagnosis could be done with confidence in all except 7 cases. Virtual sonography, by means of oblique cuts in all space directions, improved distant diagnostic confidence. Limitations were linked to incomplete sampling due to the short acquisition time periods (26 s) and difficulties on hand-free probe movement. 3D reconstructions were time consuming (20 min to 4 h) and of limited indication.

CONCLUSIONS

3D reconstruction could reduce multiple explorations due to image constrains such as suboptimal fetal positioning, among others. Virtual sonography was important to reach confidence on distant diagnosis; it was also considered a tool for off-line local review of non-trained sonographer acquisitions.

Review of technology: planning for the development of telesonography

Teleradiology allows contemporaneous interpretation of imaging exams performed at some distance from the interpreting radiologist. The transmitted images are usually static. However, there is benefit to real-time review of full-motion ultrasound (US) exams as they are performed. Telesonography is transmission of full-motion sonographic data to a remote site. We hypothesize that US exams, read after having been compressed utilizing Motion Picture Experts Group version 4 (MPEG-4) compression scheme, transmitted over the Internet as streaming multimedia, decompressed, and displayed, are equivalent in diagnostic accuracy to reading the examinations locally. MPEG-4 uses variable compression on each image frame to achieve a constant output bit rate. With less compression, the bit rate rises, and the only way the encoder can contain bit rate within the set bandwidth is by lowering frame rate or reducing image quality. We review the relevant technologies and industry standard components that will enable low-cost telesonography.

Digital video capture and synchronous consultation in open surgery

OBJECTIVE

To achieve real-time or simultaneous surgical consultation and education to students in distant locations, we report the successful integration of robotics, video-teleconferencing, and intranet transmission using currently available hardware and Internet capabilities.

SUMMARY BACKGROUND DATA

Accurate visualization of the surgical field with high-resolution video imaging cameras such as the closed-coupled device (CCD) of the laparoscope can serve to insure clear visual observation of surgery and share the surgical procedure with trainees and, or consultants in a distant location. Prior work has successfully applied optics and technical advances to achieve precise visualization in laparoscopy.

METHODS

Twenty-five thyroidectomy explorations in 15 patients were monitored and transmitted bidirectionally with audio and video data in real-time. Remotely located surgical trainees (n = 4) and medical students (n = 3) confirmed 7 different anatomic landmarks during each surgical procedure. The study used the Socrates System (Computer Motion, Inc. [CMI], Goleta, CA), an interactive telementoring system inclusive of a telestration whiteboard, in conjunction with the AESOP robotic arm and Hermes voice command system (CMI). A 10-mm flat laparoscopic telescope was used to capture the optical surgical field. As voice, telestrator, or marker confirmed each anatomic landmark the image parameters of resolution, chroma (light position and intensity), and luminance were assessed with survey responses.

RESULTS

Confirmation of greater than 90% was achieved for the majority of relevant anatomic landmarks, which were viewed by the remote audience.

CONCLUSION

The data presented in this study support the feasibility for mentoring and consultation to a remote audience with visual transmission of the surgical field, which is otherwise very difficult to share. Additionally, validation of technical protocols as teaching tools for robotic instrumentation and computer imaging of surgical fields was documented.

Virtual sonography through the Internet: volume compression issues

BACKGROUND

Three-dimensional ultrasound images allow virtual sonography even at a distance. However, the size of final 3-D files limits their transmission through slow networks such as the Internet.

OBJECTIVE

To analyze compression techniques that transform ultrasound images into small 3-D volumes that can be transmitted through the Internet without loss of relevant medical information.

METHODS

Samples were selected from ultrasound examinations performed during, 1999-2000, in the Obstetrics and Gynecology Department at the University Hospital in La Laguna, Canary Islands, Spain. The conventional ultrasound video output was recorded at 25 fps (frames per second) on a PC, producing 100- to 120-MB files (for from 500 to 550 frames). Processing to obtain 3-D images progressively reduced file size.

RESULTS

The original frames passed through different compression stages: selecting the region of interest, rendering techniques, and compression for storage. Final 3-D volumes reached 1:25 compression rates (1.5- to 2-MB files). Those volumes need 7 to 8 minutes to be transmitted through the Internet at a mean data throughput of 6.6 Kbytes per second. At the receiving site, virtual sonography is possible using orthogonal projections or oblique cuts.

CONCLUSIONS

Modern volume-rendering techniques allowed distant virtual sonography through the Internet. This is the result of their efficient data compression that maintains its attractiveness as a main criterion for distant diagnosis.