Announced at Den Haag 1991
EUREKA PROJECT EU 662
ARTMA (Advanced Real Time Motion Analysis)
In several areas of medicine, such as orthopaedics and rehabilitation, but
also maxillofacial and plastic surgery, it is often important for the physician
to acquire exact information on the location and movements of bones and
other parts of the human body. For example, in the case of a knee injury
it is important for the physician to find out whether it consists of a lesion
of the cross ligaments. Because of muscular compensation, such a lesion
can go unnoticed. But by recording knee movements over a long time, the
physician can determine the nature of the lesion - and treat it properly.
ADVANCED SENSORS FOR ADVANCED DIAGNOSIS
Most systems for the study of motion now available to the physician rely
on mechanical recording devices or on post processing of stereophotometric
data of various imaging systems. To get a complete picture, the physician
has to analyze separately images from different imaging devices, including
video recordings, x-ray images, computed tomography (CT) and magnetic-resonance
imaging (MRI). None of the current systems are capable of displaying motion
in real time, and require computer processing after completion of the recording
EUREKA Project EU 662, ARTMA, developed by Artma Medizintechnik GmbH in
Vienna, is taking motion analysis a step further. By integrating various
imaging systems with information from sensors attached to the body, the
project will equip hospitals around Europe with better diagnostic abilities.
Exact coordinates in three dimensions
"Our approach is completely different to current methods," explains
Dr. Michael Truppe from Artma Medizintechnik. "We do use video images
- but only for visualization, not for data acquisition. We get 3-dimensional
data from a network of sensors attached to the body parts we are interested
in, and then combine this with other types of images and video recordings
using specially developed software. Because no post processing is required,
we have the first and only real-time display of motion."
The sensors are either used to pinpoint certain points on the body to record
their location, or can be attached to a part of the body to study motion
in detail. Usually four sensors are connected to the computer, and work
by recording changes in magnetic reference fields caused by motion. However
several other methods for creating 3D data are available. One of them, a
sonic digitizer, uses three or more microphones to locate the position of
tiny "sparkers" that emit sound. As the body moves, the sensors
supply data on their position to a three-dimensional digitizer, which converts
the signals into data usable by the computer program. This software calculates,
in real time, the coordinates of the sensors in relationship to a reference
point, which can be attached to the body.
This data is then integrated with images obtained by photography, x-ray
radiography and, in some cases, CT scans. The images are scanned and stored
in the computer, or are retrieved from the computerised data-storage systems
used in the hospital. By combining 3D data with existing video recordings
or scanned images, the physician can avoid subjecting the patient to prolonged
x-rays and tests.
The location of the sensors are then superimposed on a video recording.
Alternatively, the computer can display a stick figure in which the position
of the actual bone structure is displayed rather than the position of the
sensors. By updating the coordinates sixty times per second, ARTMA allows
the study of motion in real time. For example, by attaching sensors to the
shoulder, elbow, wrist and palm of a patient with an arm injury, and recording
the motions of the arm, such as wrist flexions and rotations, at regular
intervals, a physician can monitor progress in such a patient undergoing
Better Diagnosis Through Synergy
Because of the high level of accuracy of the coordinates supplied by the
3D digitizer, the system allows a more precise study of motion and diagnosis.
"In itself this is a new type of information available to the physician,
with new diagnostic value," says Dr. Truppe. An important aspect of
the system is that it operates on a second level by enhancing existing information.
One type of information gives us a certain amount of diagnostic help. When
there are several different types of information available, then their combination
can supply new diagnostic information, not available from any of the information
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© Copyright 1996 Artma. All rights reserved. Last
modified May 6, 1996.