Constantly changing posture is central to the human musculoskeletal system. And yet patients have to stand or lie still for X-ray, computer tomography (CT) and magnetic resonance imaging (MRI) scans. "The ’please don’t move’ rule in medical imaging makes it difficult to diagnose many diseases of the musculoskeletal system, for example musculoskeletal pain in the shoulder, back or osteoarthritis of the knee," explains Johannes Heverhagen from Inselspital, Bern University Hospital. "If we could take the images while the patient is moving, we could better diagnose diseases that are currently very difficult to detect."
Innovative technology
This is why Heverhagen, together with his colleagues Klaus Siebenrock and Keivan Daneshvar from Inselspital, Bern University Hospital, in close collaboration with Empa researcher Ameet Aiyangar and sitem-insel, established the Dynamic Imaging Center (DIC), which was opened on 10 November as a laboratory unit that is unique in Europe thanks to the ideal conditions at sitem-insel.Test subjects move either on a treadmill equipped with force sensors or on force plates. Their movements are recorded by 16 infrared (IR) motion capture cameras, X-rays and a muscle electrogram (EMG). At the heart of the new lab is a unique, dynamic X-ray-based high-speed imaging system called Dynamic Biplane Radiographic Imaging (DBRI). "The DBRI can take up to 1’000 X-ray images per second in two different planes, and at very low radiation doses," explains Empa researcher Aiyangar. "This allows us to measure movements with submillimeter accuracy and detect even the finest rolling and sliding movements in the joint."
The moving X-ray images are not intended to replace three-dimensional images from MRI and CT devices, but to supplement them. All the images together provide a comprehensive picture of the situation in the bone or joint, not only at rest but also in motion. Such images are extremely valuable, especially for joint diseases such as osteoarthritis and joint instability. But they can also help diagnose back pain, which afflicts two out of three Swiss people several times a year, and enable better treatment.
Defective joints
A joint consists of two or more bone ends that are movably connected. They are covered by cartilage which, together with the synovial fluid in the joint space, reduces the friction between the bones. In osteoarthritis, the joint cartilage is damaged by inflammation, underload or overload and breaks down over time. As a result, the affected joints can only be moved with pain. Osteoarthritis can be a cause of back pain, as there is also cartilage and joints between the vertebrae in the spine. However, for many sufferers, the cause of this back pain is not clear, which is why the pain is often only treated symptomatically. In the late stages, there are often only two options: to replace the joint with an implant or to stiffen it surgically. However, a more precise diagnosis of the individual causes of joint pain could enable better treatment.Musculoskeletal disorders are among the most common diseases in Switzerland. They cause high healthcare costs and severely impair the quality of life of those affected. "The opening of the sitem-insel DIC as one of the first laboratories of its kind in a hospital environment in Europe demonstrates how innovation in imaging enables new research approaches. The DIC is another example of how we enable the implementation of ideas from everyday clinical practice so that they can be used successfully on the market," says Simon Rothen, CEO of sitem-insel.
