10th Mar 2020

Using ultrasound to catch osteoarthritis in early stages

10th Mar 2020

Curated by Dr Maria Pastrama

Osteoarthritis, a currently irreversible condition is a real pain in the leg. And diagnosing it is a bit complicated. Researchers have discovered a method that is potentially faster, cheaper and safe for patients who had to avoid MRI scans and X-rays.

In 10 seconds? Ultrasound could soon be the way to spot osteoarthritis. Currently, we use it to see how organs or tissues deform in real-time. We found a way to track this change in cartilage too, which could help trace the damage that leads to this painful condition. (Read the science)

Osteoarthritis is currently uncurable

Why ultrasound? Before answering the question here is some background: the cartilage in knee osteoarthritis has different structure and properties from healthy tissue. This can be spotted by looking at the mechanical properties of tissue and seeing how it deforms under load. My team has found that we can track these deformations with a method that is more accessible and cheaper than current osteoarthritis diagnosis methods - ultrasound! (Read how we track deformations in heart tissue)

And how does this new method work? In my research, I use knee cartilage from cows. I push the cartilage with a small tip (indenter), then I use ultrasound to look at how the tissue comes back to its initial shape. Using a series of images and a method called ultrasound elastography I can then calculate the deformations inside the tissue over time. Research involving the heart already proved this method useful. (More on how it works in muscle)

Wait, but isn’t ultrasound imaging of soft tissues old news? Well yes, for soft tissues that are easily accessible, such as liver, heart, or fetal (baby) ultrasound. However, to image knee cartilage, the ultrasound waves first have to go through the hard bones, where they kind of get ‘’lost‘’. Luckily, high-frequency ultrasound methods are now available, which help to look at cartilage with higher resolutions, providing more detail, thus allowing us to spot the damage. These methods are non-invasive and low cost, so we want to make use of them in osteoarthritis diagnosis. (More on measuring cartilage thickness with ultrasound)

Ok, and why is this better than the current method? Current Magnetic Resonance Imaging methods have many limitations. Machines are bulky and complex, they need dedicated infrastructure and personnel, which means MRI scans are expensive and have long waiting times. Also, it is unsafe for patients with cardiac pacemakers, metal implants or prostheses to get MRI scans because of the strong magnetic field. Just check out this fun video to see how strong it is!As to researchers working with MRI scanners: they need to check their pockets for keys and phones every time before going into the MRI room! (Find out more about tracking cartilage deformations with MRI)

So, when will ultrasound be available? 
Well, this is ongoing research, so stay tuned! For now, we’ve proved in the lab that the method works on cow knee cartilage. The next step is to apply it to human cartilage and make correlations between deformation patterns and the degree of osteoarthritis. To make it handy for practical applications, we aim to design a hand-held device that both applies slight pressure to the tissue and registers its deformations patterns to establish tissue health. (More on a possible model for the device)

Why is osteoarthritis hard to catch in its early phase?

In my research, I’ve worked with both bone and cartilage. Unlike bone, cartilage is pretty high-maintenance: it’s soft and wobbly, full of water, and it doesn’t always warn you it’s damaged. 

That’s why sometimes osteoarthritis starts from a small cartilage defect that you never knew you had. In the end the cartilage wears away letting the bone ends rub against each other and a knee replacement might be necessary.

We hope, in the future, to use our ultrasound method to find out that tiny defect even before you experience any physical symptoms. This way, patients can get appropriate treatment for their cartilage from the earliest stages of osteoarthritis.

In the meantime there is an ongoing clinical trial testing a new painkilling method, known as radiofrequency ablation. It involves blocking the nerves in the knee from sending pain signals to the brain.

(Psst, Maria distilled 11 research papers to save you 997.5 min)

Curated by

Dr Maria Pastrama

Post-doctoral researcher at the Eindhoven University of Technology, investigating bone and cartilage mechanics using computational and experimental methods to understand mechanical requirements for tissue-replacement biomaterials.

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