04 Mar 2020
Laser Doppler vibrometry could lead to rapid and patient-friendly diagnostic technique.
The InSiDe consortium aims to create a hand-held device capable of identifying different stages of CVD, allowing patients to be assessed without in-patient hospital stay and receive timely medical intervention when appropriate.
The device will employ laser Doppler vibrometry, in which a low-power laser is directed towards the skin overlying an artery. The frequency and amplitude of the skin's vibration under the influence of a heartbeat can then be extracted from the Doppler shift of the reflected beam, revealing information about the blood flow within the artery and any restrictions building up.
A key underlying technology is silicon photonics and the use of suitable photonic integrated circuits (PICs), which allow the implementation of advanced optical functionality in a chip produced in a CMOS fab environment, according to Tyndall.
"Manufacturing high volumes of PICs is very expensive, but what really drives the cost of using them in any photonic device is how they are connected to the real world," commented Pádraic Morrissey of Tyndall National Institute. "In the Photonics Packaging Group at Tyndall, we have the capability to design, integrate, and develop fully working research prototypes from these PICs. Our role in the InSiDe project is to take this one step further, developing wafer level photonic packaging and assembly technologies that can create a manufacturable photonic product."
InSiDe builds on the work of Cardis, a recent European project founded to demonstrate the concept of a mobile, low-cost laser vibrometry platform with integrated silicon photonics, and validate the concept for the screening of arterial stiffness, detection of stenosis and heart failure.
According to project partner Imec, the Cardis prototype device underwent a first clinical feasibility study at the Georges Pompidou European Hospital in Paris and the Academic Hospital of Maastricht, collecting a substantial clinical dataset from healthy subjects and those with cardiovascular conditions. It was found that the device enabled fast and reliable measurement of CVD-related biophysical signals through minimal physical contact with the patient and minimal skills from the operator.
Laser Doppler vibrometry in the clinic and beyond
"The quality of the device readings was found to be very good and adequate biophysical signals could be obtained in all subjects, even if the algorithmic translation to relevant markers for medical pathologies needs further work," commented Roel Baets of Imec. "The very promising results from the Cardis project stimulated the consortium to take the next step and aim at bringing the prototype to a true manufacturable product that is useful for GPs and cardiologists in their daily practice."
InSiDe has been created to bring the Cardis prototype device towards commercialisation, and develop a true handheld clinical, battery-operated investigational device. This will involve the parallel development of algorithms capable of translating the interferometer signals into data that are relevant to monitor and diagnose a number of CVDs, along with demonstrations of the device's clinical feasibility for both GPs and cardiologists. A path towards industrialization and manufacturability of the device should then become apparent.
Laser vibrometry is a potentially valuable technique in other sectors beyond biomedicine, since the optical analysis of both natural and unnatural vibrations through a non-contact technique could provide a route to monitoring a number of mechanical and natural systems.
In 2013, a project used the technique as part of its study into the motion of crickets' forewings, as a means to study a particularly specialized form of animal communication. Also in 2013, a joint project between the University of Leicester and Polytec was created to launch the UK's first commercial 3D non-contact laser vibration scanning measurement and modal-analysis research center, targeted specifically at the automotive, aerospace and space sectors. The ASDEC center operated until July 2018.