Fraunhofer has developed an innovative ultrasound transducer that would soon provide a rapid and reliable method for diagnosing middle-ear infections.
The Fraunhofer Institute for Photonic Microsystems IPMS and a U.S. company are teaming up to develop and apply this novel technology. Incorporated into an otoscope, the ultrasound transducer helps doctors to resolve whether a course of antibiotics is actually required.
Middle-ear infections are more common in young children and infants. In such cases, antibiotics are usually the preferred treatment. However, the device used for diagnosing this condition has remained stagnant for many years. Consequently, physicians can only make a diagnosis that is both unreliable and subjective. For such a condition, diagnostic precision is often as low as 50%, not least when it comes to differentiating between a viral and bacterial infection.
This implies that antibiotics are unnecessarily being prescribed to many numbers of children. Consecutively, this is driving an increasing resistance to antibiotics across the world.
To address this, the Fraunhofer Institute for Photonic Microsystems IPMS has developed a new kind of ultrasound transducer that can resolve this problem. The device uses air-coupled ultrasound to allow an accurate diagnosis of the middle-ear infection—a condition also referred to as otitis media.
OtoNexus Medical Technologies, a U.S.-based company, has developed an otoscope in which this technology is integrated. This device is currently going through clinical trials. It can be used by doctors, including pediatricians, to assess the external auditory canal and, more specifically, the region behind the eardrum. This will allow them to quickly identify whether fluid or air is present in the middle ear and to subsequently characterize this fluid.
This will also allow the doctors to differentiate between different phases of the illness and thus decide on a suitable treatment.
Echo Signal Reveals the Degree of Infection
The classic otoscope is an optical system and hasn’t changed in decades. But when fitted with our ultrasound transducer, which is both a transmitter and receiver, it develops new functions.
Dr Sandro Koch, Physicist, Fraunhofer IPMS
The device produces ultrasonic pulses and then captures the echo that gets reflected back from the eardrum. Based on this data, the transducer produces a reading that informs the physician about the extent of infection.
The new ultrasound transducer is developed to work through the medium of air. It includes a capacitor created by a pair of electrodes isolated by a tiny air-filled gap.
“One of these electrodes is flexible,” Koch explained. “We use the vibrations of this electrode to transmit ultrasonic pulses. When the echo from this signal strikes a flexible membrane, the resultant vibration is converted into a detectable electrical signal.”
Industry partner OtoNexus developed the proprietary software, which examines the echo signal. Preliminary clinical studies have validated the precision of the analysis, which means the reading gives doctors a dependable indication of middle-ear infection.
Miniaturized and Suitable for Mass Production
The new device is a so-called capacitive micro-machined ultrasonic transducer (CMUT). It is created on a silicon wafer using unique microelectromechanical systems, or MEMS, technology designed at Fraunhofer IPMS. The ultrasound transducer consumes minimum power and can be produced cost-effectively at a large scale.
And, unlike traditional ceramic piezoelectric ultrasound transducers, our MEMS transducer can be miniaturized. That’s a major advantage here, because it means the CMUT can be incorporated much more easily in an otoscope.
Dr Sandro Koch, Physicist, Fraunhofer IPMS
Featuring a Fraunhofer CMUT, the novel otoscope is presently at the prototype stage and is likely to be introduced into the market within a few years.
The MEMS transducer can also be used in other areas, in addition to medical applications. For example, ultrasound transducers can be installed in vehicles to regulate onboard infotainment systems or integrated into tablets and smartphones to allow gesture control. In addition, the device can deliver numerous functions in robotics, including distance measurement.