Peripheral Artery Diseases: A medical robot helps you diagnose

Medicine is making great strides, especially in the techniques used to diagnose increasingly common diseases . This is the case, for example, with diseases affecting the peripheral arteries. In these cases, tests such as computed tomographic angiography, or magnetic resonance angiography, are more used, obtaining 2D ultrasound images of the tissues examined. Researchers from the Technical University of Munich, in collaboration with Zhejiang University and Johns Hopkins University, have developed an innovative diagnostic system . It is a robot capable of diagnosing peripheral arterial diseases much more accurately, obtaining 3D ultrasound images.

Diseases of the peripheral arteries, an increasingly common problem

Diseases of the peripheral arteries are much more common than one might imagine. They affect about 20% of those over 55: a figure like 27 million people between Europe and North America . One of the most common consequences of this type of disease is the narrowing or even obstruction of the arteries found in the limbs. This obviously involves a series of blood circulation problems that can compromise the normal use of the limbs. Pinpointing the tissues involved in the disease with extreme precision can certainly help improve medical diagnosis. The robot developed by the researchers is able to more accurately diagnose diseases of the peripheral arteries by identifying the trajectories that the arteries should follow in normal conditions, thanks to the ultrasound technique of 3D images .

A robot to improve diagnosis

The robotic system developed by the three research groups uses, in fact, an ultrasonic 3D vision system . One of the most common problems of traditional vision systems used so far is the limitation of movements. Very often, in fact, the trajectories described by the arteries under examination are complex and extend for several centimeters. One of the incredible features of the robot is the ability to adjust its position and orientation during the exam , diagnosing more precisely the presence of any peripheral artery disease. In this way, it is able to reconstruct a detailed 3D model even of complex anatomies.

The flow-chart of the algorithm used by the robot to diagnose diseases of the peripheral arteries. Credit: Jiang et al.
The flow-chart of the algorithm used by the robot to diagnose diseases of the peripheral arteries. Credit: Jiang et al.

The computer vision system for diagnosing peripheral artery diseases at the heart of the robot's operation

The heart of the robot is vision software consisting of three main parts. A vision system , an ultrasound system for 3D image reconstruction and a motion adjustment system to adjust the trajectory. The vision is entrusted to an RGB-D camera to extract the image, while passive markers are used to improve the position. Obviously, a doctor supports the screening activity by indicating to the robot which trajectory to follow. The trajectory is drawn with a red line on the patient's skin. Red is used to highlight the contrast with the lighter skin color. Finally, the markers are used to automatically guide the robot along the red line, allowing it to carry out the examination and diagnose any diseases of the peripheral arteries.

This is how the robot manages to diagnose the presence of diseases in the peripheral arteries. The image on the left shows the optimization of the robot movement with respect to the trajectory traced by the doctor. The difference between 3D reconstruction of the artery without motion compensation (a) and with motion compensation (b) is shown on the right. Credit: Jiang et al.
The image on the left shows the optimization of the robot movement with respect to the trajectory traced by the doctor. The difference between 3D reconstruction of the artery without motion compensation (a) and with motion compensation (b) is shown on the right. Credit: Jiang et al.

Autonomy in diagnosis

The most surprising aspect of the robot is its autonomy in diagnosis. The markers, in fact, are spheres applied along the trajectory drawn on the patient. They are covered with a self-reflecting material that enhances their brightness from the rest. By setting a color threshold, the robot is able to distinguish the position of the markers and thus derive the trajectory of the artery . Furthermore, based on a 3D reconstruction, it is able to identify any narrowing of the peripheral arteries, thus diagnosing the presence of any diseases.

Results of tests performed on the robot that can diagnose diseases of the peripheral arteries. Credit: Jiang et al.
The solid lines are the trajectories obtained by the robot, while the dashed ones represent the calculated position error. Credit: Jiang et al.

The first tests of the robot demonstrate great reliability in the diagnosis of peripheral arterial diseases

The system was tested on a mock test tissue on which doctors drew a probable trajectory of an artery. The average error in defining the trajectory was less than 5 millimeters .

“Preliminary validation on the test tissue demonstrates that the proposed approach can provide promising 3D geometry, even when the scanned object is moved. Furthermore, although the proposed method has been tested on a vascular application, it can also be used for other applications, such as ultrasound bone visualization ”.

The researchers who conducted the study.

The surprising results pave the way for a new era in peripheral arterial disease diagnostics, based on the use of motion-sensitive robots. With some small improvements this system could easily be made available on the market as it is based exclusively on the doctor's know-how. Another piece has been wedged into the great puzzle of medical robotics which, day after day, is making incredible leaps and bounds.

The article Peripheral Artery Diseases: A Medical Robot Helps You Diagnose comes from Tech CuE | Close-up Engineering .