Can radar replace stethoscopes?

Researchers at FAU’s Institute of Electronics Engineering have developed a radar system which enables touch-free monitoring of heart sounds. The red beams show where the measurement is being made. Image: Kilin Shi

Along with a white coat, a stethoscope is the hallmark of doctors everywhere. Stethoscopes are used to diagnose the noises produced by the heart and lungs. Used in the conventional way, vibrations from the surface of the body are transmitted to a membrane in the chest-piece and then to the user’s eardrum where they are perceived as sounds.

Acoustic stethoscopes are comparatively inexpensive and have been used reliably for several decades, but they have one drawback. The diagnosis of heart murmurs, such as the assessment of heart valve function, is carried out subjectively and is directly dependent on the experience of the doctor conducting the examination.

Radar can measure heart sounds

In a joint project funded by the Federal Ministry of Education and Research, FAU researchers at the Institute of Electronics Engineering (LTE) have now developed a procedure that could eventually replace conventional phonocardiology.

Using a six-port continuous wave radar system, they measured the vibrations on the skin caused by the heartbeat. ‘In principle, we’re using a similar method to detecting speed in road traffic,’ explains Christoph Will, a doctoral candidate at LTE. ‘During this process, a radar wave is aimed at the surface of an object and reflected. If the object moves, the phase of the reflecting wave changes. This is used to calculate the strength and frequency of the movement – of the chest in our case.’

In contrast to radar systems for traffic monitoring, the biomedical radar system can detect changes in movement that measure a few micrometres, which is an important prerequisite to diagnosing even the smallest anomalies such as insufficiency, stenoses or heart valves that do not close properly.

As reliable as established measuring methods

Initial tests were very successful. The test patients were examined in various states of activity such as while resting and after sports and their heart sounds were detected. A direct comparison between the radar system and conventional standard instruments with a digital stethoscope and an electrocardiograph (ECG) showed a very high correlation.

‘While diagnosing S1, which is the first heart sound, for example, we achieved a correlation of 92 percent with the ECG,’ says Kilin Shi, who is also a doctoral candidate at LTE. ‘The correlation was 83 percent in a direct comparison of the signal shapes with the digital stethoscope. That’s absolutely reliable.’

The researchers say that the slight deviations are caused by the fact that measurements using the radar system and the reference systems cannot be carried out simultaneously on exactly the same place on the body. In addition, the radar system measures a surface area and not a single spot like the stethoscope, which is also a reason for the varying measurement values.

Touch-free and objective

The FAU researchers are optimistic that mobile radar systems could replace conventional stethoscopes in diagnosing heart function in the near future. A significant advantage offered by radar is the fact that the values are recorded digitally and are thus not subjective allowing human error to be increasingly ruled out during the diagnosis of anomalies or diseases. Using biomedical radar systems for automated prophylactic examinations for example in doctors’ waiting rooms, at work, or at home, is also feasible.

The researchers are already working on another project for monitoring the vital functions of patients who are seriously ill using stationary radar systems around the clock and without disruptive cables. ‘Touch-free and therefore stress-free measurement of vital parameters such as heart sounds has the potential to revolutionise clinical care and research, for example, in palliative medicine,’ explains Prof. Dr. Christoph Ostgathe, Head of Palliative Medicine at Universitätsklinikum Erlangen at FAU and co-author of the study.

‘For example, we could inform relatives of terminally ill patients more quickly at the beginning of the dying phase, as the radar system immediately detects any changes in patients’ health. It would also be possible to detect any painful symptoms in patients who cannot communicate’.

Technical details:
Kilin Shi
+49 9131 8567733
kilin.shi@fau.de

Medical information:
Prof. Dr. Christoph Ostgathe
+49 9131 8534063
christoph.ostgathe@uk-erlangen.de

‘Scientific Reports’: ‘Radar-Based Heart Sound Detection’, https://doi.org/10.1038/s41598-018-29984-5

Media Contact

Dr. Susanne Langer idw - Informationsdienst Wissenschaft

Further information:

http://www.fau.de/

All news from this category: Medical Engineering

The development of medical equipment, products and technical procedures is characterized by high research and development costs in a variety of fields related to the study of human medicine.

innovations-report provides informative and stimulating reports and articles on topics ranging from imaging processes, cell and tissue techniques, optical techniques, implants, orthopedic aids, clinical and medical office equipment, dialysis systems and x-ray/radiation monitoring devices to endoscopy, ultrasound, surgical techniques, and dental materials.

Back to the Homepage

Comments (0)

Write comment

Latest posts

Seawater as an electrical cable !?

Wireless power transfers in the ocean For drones that can be stationed underwater for the adoption of ICT in mariculture. Associate professor Masaya Tamura, Kousuke Murai (who has completed the…

Rare quadruple-helix DNA found in living human cells with glowing probes

New probes allow scientists to see four-stranded DNA interacting with molecules inside living human cells, unravelling its role in cellular processes. DNA usually forms the classic double helix shape of…

A rift in the retina may help repair the optic nerve

In experiments in mouse tissues and human cells, Johns Hopkins Medicine researchers say they have found that removing a membrane that lines the back of the eye may improve the…

Partners & Sponsors

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close