Dutch researchers have developed a virtual robot that meticulously scans the heart muscle using images of the heart. The contours detector reduces the work of specialists and does not affect the patients. The research group from the Dutch STW Technology Foundation and medical information technologists from Leiden University Medical Center presented the results last week at the International Society for Magnetic Resonance in Medicine congress in Honolulu.
To map the condition of a patient's heart, physicians have until now used a series of MRI (magnetic resonance imaging) images. The images provide 10 cross-sections of the heart on 20 phases during a single heartbeat.
Then, on at least 40 of the 200 images, the physician marks the contours of the heart muscle by hand. This very accurately but subjectively reveals where the heart muscle is less thick during the heartbeat. These parts of the heart wall have already died or receive less oxygen upon exertion. If the physician requires more information, he marks all 200 images.
In the newly-developed contours detector, a virtual robot delineates the heart boundaries on the MRI images. The contours indicate where the heart wall lies and therefore the thickness of the heart muscle at any given point.
The robot is objective and self-learning. When the image has too little contrast for a boundary line to be drawn with certainty, the robot "remembers" an example from a previous "training."
Together with the rules dictated by the programmers, the intelligent system then constructs a "surgically precise" contour. This makes the time-consuming drawing of the contours by hand obsolete.
Patients are not even aware of the robot, as the entire process takes place in the computer using stored MRI images.
The robot moves like a car along the heart wall, drawing the contours on the images as it goes. The size, speed and minimum turning circle of the virtual vehicle are adjusted by the researchers to the individual properties of the patient's heart, such as the weight and the amount of blood the heart can pump. Sensors on the front and side of the robot help it to navigate safely so that it does not collide with the heart wall.
In this joint project with the STW Technology Foundation, the researchers from Leiden University Medical Center limited themselves to the automatic outlining of the left ventricle in the heart because this pumps blood to the body.
The research was funded by the Netherlands Organization for Scientific Research (NWO).
Related websites:
Leiden University Medical Center
Technologiestichting STW
[Contact: Dr. Faiza Behloul]
29-May-2002
