In rural, remote or doctor-shortage areas, access to cardiological expertise can be difficult. In such cases, robot-assisted ultrasound for cardiac examinations may offer a solution to this problem. Using a remotely controlled robotic arm, a specialist carries out the examination, thereby sparing the patient long journeys to receive cardiological care. This article presents the results of two studies that evaluated this approach using AdEchoTech’s MELODY system. The first analyses the reliability of tele-operated ultrasound in patients with heart disease. The second evaluates the performance of a mobile tele-ultrasound platform on 4G/LTE wireless networks.
How does robotic ultrasound work for cardiac examinations?
A robot to remotely operate the ultrasound probe
Echocardiography requires precise positioning of the probe in order to identify the various cardiac acoustic windows. As these are narrower than those used in certain abdominal or obstetric applications, the ability to precisely control the probe’s orientation and movement is a key aspect of the examination.
In the first study, conducted by Philippe Arbeille’s team (P. Arbeille et al., 2014), the robotic system under investigation comprised several components:
- a robotic arm controlling the tilt, rotation and orientation of the probe;
- a motorised plate enabling the probe to be moved across the patient’s skin;
- a tiltable mechanical arm operated by a non-specialist ultrasound operator;
- a dummy probe or control interface operated remotely by the expert;
- an internet connection ensuring the transmission of commands and ultrasound images;
- an audio and video system enabling the expert to communicate with the operator situated near the patient.
The MELODY robot enables the key movements performed by an ultrasound technician during a cardiac examination to be transmitted remotely. The on-site operator plays a crucial role in setting up and adjusting the device. They can intervene to adjust the ultrasound scanner’s settings if necessary.
A validation study of remote-controlled ultrasound in 41 patients
The first study (P. Arbeille et al., 2014) aimed at assessing the reliability of robot-assisted ultrasound for cardiac examinations was conducted on 41 patients who were due to undergo a conventional echocardiogram. The assessment took place prior to the reference examination, which was carried out by another sonographer using the same imaging system.
The remote examination was deliberately limited to ten minutes to keep the study duration short. It relied primarily on apical views. The aim was to:
- visualise the four cardiac chambers;
- measure the dimensions of the atria;
- assess the left ventricle during systole and diastole;
- calculate the left ventricular ejection fraction;
- measure certain parameters of the right ventricle;
- assess aortic blood flow velocity;
- screen for mitral, tricuspid or aortic regurgitation;
- detect any aortic stenosis.
The results revealed that the views required for cardiac measurements were obtained in 93 per cent to 100 per cent of cases, depending on the parameter under consideration. The left ventricular ejection fraction was measured in 95 per cent of cases, aortic velocity in 93 per cent of cases, and the right ventricular function parameter in 100 per cent of cases.
The measurements taken remotely were broadly comparable to those obtained during conventional cardiac ultrasound. Statistical analyses did not reveal any significant differences for the majority of the parameters assessed. These results show that tele-echocardiography yielded measurements comparable to those of the reference echocardiography for the majority of the parameters assessed, with no statistically significant differences between the measurements compared.
Detecting cardiac abnormalities remotely
The study also assessed the ability of remote robotic ultrasound to detect certain cardiac abnormalities. Despite a tele-operated protocol deliberately limited to ten minutes and focused primarily on apical views, 61 of the 71 valvular abnormalities or aortic stenoses identified during the reference examination were detected remotely. This equates to a detection rate of 86 per cent, with no false positives reported.
The rates observed varied depending on the abnormality:
| Anomaly being investigated | Detection rate |
|---|---|
| Tricuspid regurgitation | 85% |
| Mitral regurgitation | 84% |
| Aortic regurgitation | 100% |
| Aortic stenosis | 100% |
| Mitral valve regurgitation | 81% |
No false-positive diagnoses were reported in this study. The results should nevertheless be interpreted with caution: the examination was time-limited and did not cover all the views used in routine clinical practice. The authors emphasise that a longer examination, allowing for the assessment of several acoustic windows, would probably have improved image quality and the detection of certain subtle abnormalities.
These results support the value of robot-assisted ultrasound in enabling an expert to remotely acquire and assess several cardiac parameters, particularly when the patient is located far from a centre with the necessary expertise. Its use forms part of a care pathway defined by healthcare professionals.
Cardiac tele-ultrasound: transmitting images in real time
4G for transmitting ultrasound images
A second study focusing on AdEchoTech’s mobile platform examined the possibility of combining robotic tele-manipulation with video transmission over LTE wireless networks (S. Avgousti et al., 2016).
The platform was required to carry several types of data simultaneously:
- robot commands, which require low latency;
- ultrasound images, which require more bandwidth;
- ambient audio and video streams, used for communication between the patient, the local operator and the remote expert.
Tests carried out on 4G/LTE networks in Cyprus achieved a download speed of 10 Mbit/s, an upload speed of 9 Mbit/s, a latency of 29 ms and an average jitter of 8 ms. This performance enabled the robot to be controlled in a responsive manner and allowed for the transmission of ultrasound videos.
Low latency is crucial for remote cardiac examinations. The expert must be able to quickly observe the effect of probe movement on the displayed image. Excessive delay could complicate probe positioning, slow down the examination and impair the clinical experience.
The expert rated the robot’s responsiveness as satisfactory during the tele-ultrasound sessions. Furthermore, the video transmission delay proved to be compatible with probe positioning and the performance of the examination following a short learning phase.
Optimising the transmission of cardiac images
The transmission of a cardiac ultrasound scan depends on a balance between image quality, bit rate and latency. Excessive compression can lead to the loss of details that are important for clinical interpretation, such as the contours of the chambers, valve movements or Doppler signals.
A study conducted on 4G/LTE networks (S. Avgousti et al., 2016) compared several video transmission technologies. The most recent solutions proved to be more effective. They deliver higher-quality images whilst using less data.
This efficiency is important in tele-ultrasound, as it enables the transmission of detailed images, even with a low- or medium-speed connection. Consequently, the clinician can observe cardiac structures and guide the movements of the robotic probe with greater precision.
The clinical evaluation confirmed these results. Objective and clinical assessments showed that the video compression technologies evaluated could provide image quality deemed by the authors to be free from diagnostic loss. This performance was achieved at data rates compatible with the capabilities of the LTE networks tested.
These results show that a wireless connection can support remote robotic ultrasound, provided it offers sufficient bandwidth and low latency. Performance may, however, vary depending on network quality, the equipment used and transmission conditions.
What are the benefits of remote cardiac ultrasound?
The use of a remotely operated robot for cardiac examinations offers several potential advantages.
Facilitating access to cardiological expertise
A specialist centre can support several healthcare facilities located in areas lacking cardiologists or specialist sonographers. This means that patients can receive an initial assessment without having to be transferred immediately to a regional hospital.
Reducing patient travel
Tele-echocardiography can minimise the need to transport frail, elderly or dependent patients. It can also help speed up the referral of patients who genuinely require hospital care.
Carrying out cardiac examinations in remote areas
The mobile platform can be used in small medical centres, rural facilities, medical missions or certain emergency situations where access to a wired network is limited.
Facilitating remote patient monitoring
Patients with a known heart condition could benefit from follow-up examinations carried out locally, under the supervision of a remote specialist. This method could prove particularly useful when regular examinations are required.
Assessing patients in emergency situations
In crisis situations, a portable robot connected to a telemedicine platform could help to carry out a remote cardiac assessment, provided that the necessary safety, set-up and connectivity requirements are met.
👉 AdEchoTech develops robotic tele-ultrasound solutions designed to enable remote ultrasound examinations. Its MELODY system combines a robotic probe-handling device with a communication platform, allowing a remote expert to guide the image acquisition process. Discover the MELODY robotic tele-ultrasound solution.
What are the requirements and key considerations for remote cardiac ultrasound?
Studies also show that there are several technical and clinical challenges to be overcome.
The initial positioning of the robot remains a crucial step. The operator present with the patient must place the device near the apical window, whilst the remote expert then adjusts the position of the probe. This step requires coordination between the operator at the patient’s side and the remote expert in order to optimise the initial positioning of the device.
As with any echocardiography, image quality depends on the positioning and orientation of the probe, as well as on obtaining the appropriate acoustic windows. In the teleoperated system, the remote expert controls the movements of the probe to optimise image acquisition.
In this study, the teleoperated examination was deliberately limited to ten minutes and relied primarily on apical echocardiographic views. This methodological constraint must be taken into account when interpreting the results. Additional views might have improved the detection of certain problems, but this would also have prolonged the duration of the examination.
Finally, the quality of the connection is crucial. As with any real-time telemedicine application, the quality and stability of the connection are key factors. The trials carried out in the study using a 4G/LTE network demonstrated performance levels compatible with the remote operation of the robot and the transmission of ultrasound images. Consequently, clinical implementation requires a secure infrastructure, technical monitoring and procedures specific to telemedicine.
The available results demonstrate the potential of robot-assisted ultrasound to facilitate access to specialised cardiac examinations. Indeed, in most cases, the method yielded measurements comparable to those of standard echocardiography. Furthermore, tests on an LTE network have demonstrated that remote control of the robot and real-time video transmission can be supported by a wireless connection. This work illustrates the value of robotic tele-ultrasound in the development of telemedicine solutions enabling the specialist to participate directly in image acquisition from a distance. Robotic ultrasound for cardiac examinations offers new possibilities in remote areas, local healthcare facilities and settings where immediate access to a specialist is limited.
👉 Find out about other applications of this technology by reading our article on robotic ultrasound in antenatal care.
FAQ
What is a robotic cardiac ultrasound scan?
It is an ultrasound examination during which a remote expert controls the movements of an ultrasound probe attached to a robot. A non-specialist operator remains with the patient to set up the device and intervene if necessary.
What is the role of the MELODY system?
MELODY is a robotic tele-echocardiography system developed and marketed by AdEchoTech. It enables an echocardiographer to remotely control the orientation and movement of an ultrasound probe.
Can robotic ultrasound detect heart disease?
The studies presented have shown that the system can be used to perform several cardiac measurements and detect certain valvular abnormalities. However, performance depends on image quality, the time available, the views obtained and medical expertise.
Is a 4G connection sufficient?
In the study focusing on the mobile platform, the LTE networks tested enabled the transmission of robot commands and ultrasound videos in real time. Actual performance depends on the coverage, data rate, latency and stability of the network used.
Does telemedicine ultrasound replace a conventional examination?
No. It provides a means of accessing expertise remotely and can be used for assessment, referral or follow-up, depending on the clinical context. Its use must be integrated into an appropriate care pathway and in accordance with protocols approved by the relevant professionals.
Sources :
Avgousti, Sotiris et al. “Cardiac ultrasonography over 4G wireless networks using a tele-operated robot.” Healthcare technology letters vol. 3,3 212-217. 28 Sep. 2016, doi:10.1049/htl.2016.0043
Arbeille, Philippe et al. “Teles-operated echocardiography using a robotic arm and an internet connection.” Ultrasound in medicine & biology vol. 40,10 (2014): 2521-9. doi:10.1016/j.ultrasmedbio.2014.05.015