A team of engineers, radiologists, and physicians from the University of Cambridge have developed an algorithm that builds a 3D model of an individual’s knee joint to map where arthritis is affecting the knee. It then automatically creates ‘change maps,’ which not only tell researchers whether there have been significant changes but allow them to locate exactly where these are. This technique could boost efforts to develop and monitor new therapies for arthritis.
“We don’t have a good way of detecting these tiny changes in the joint over time in order to see if treatments are having any effect,” said James MacKay, MA, MB, BChir, MRCP, FRCR, PhD, from Cambridge’s Department of Radiology. “In addition, if we’re able to detect the early signs of cartilage breakdown in joints, it will help us understand the disease better, which could lead to new treatments for this painful condition.”
The same team previously developed an algorithm to monitor subtle changes in arthritic joints in CT scans. Now, they are using similar techniques for MRI, which provides more complete information about the composition of tissue—not just information about the thickness of cartilage or bone. MRI is already widely used to diagnose joint problems, including arthritis, but manually labelling each image is time-consuming, and may be less accurate than automated or semi-automated techniques when detecting small changes over a period of months or years.
The technique MacKay and his colleagues from Cambridge’s Department of Engineering developed, called 3D cartilage surface mapping (3D-CaSM), was able to pick up changes over 6 months that weren’t detected using standard X-ray or MRI techniques.
The software is freely available to download and can be added to existing systems. MacKay said that the algorithm can easily be added to existing workflows and that the training process for radiologists is short and straightforward. To access the software, visit https://mi.eng.cam.ac.uk/Main/StradView.