As useful as X-rays are for imaging bones, there’s only so much we can see in a flat greyscale image. But this new scanner adds color and a third dimension, creating high resolution, cutaway 3D models that can diagnose bone fractures and monitor healing. New Zealand-based Mars Bioimaging (MBI) has now conducted a feasibility study of the machine, with a larger international trial set to begin soon.
In a traditional CT scan, X-rays are beamed through the target area of the body, and the radiation is absorbed more readily by denser tissues like bone, while passing more easily through softer tissues. The end result is that high contrast black-and-white image we know so well.
But the new technology collects more nuanced data about how the X-rays are absorbed by different tissues. It’s built around a chip called the Medipix3, which tracks every photon that hits every pixel on the sensor, and processes their interactions with various atoms in the body. By doing so, it can determine the density and composition of those tissues more accurately.
Once the new scanner has collected the data, it runs it through specialized algorithms to turn it into a 3D model. Specific densities are assigned different colors, so that bones appear white, muscle appears red, fat appears yellow, and implants can be blue or green.
The models are not only incredibly striking, but they allow doctors to diagnose bone breaks or fractures, and monitor how they’re healing over time more precisely. The 3D scanner is even sensitive enough to pick up blood vessels, without the patient requiring the usual injections of contrast agents.
The Medipix3 chip at the heart of the technology was originally developed at CERN, to help track particles produced in the Large Hadron Collider. After a decade of development into a medical 3D scanner, MBI produced the first images of the human body with it in 2018.
Now the company has developed the scanner further, into a compact piece of equipment that’s almost hospital-ready. The machine, officially called the Mars Microlab 5X120, stands about 1 m (3.3 ft) tall, 1.4 m (4.5 ft) long and 0.75 m (2.5 ft) wide. It’s designed specifically to scan patients’ hands and wrists, so there’s a hole in the middle big enough to stick an arm into.
For this first feasibility study, the team scanned the wrists of three patients with fractures in their scaphoids, a small bone that’s often broken if someone falls onto an outstretched hand. These patients had the new scan a few months after their injury and diagnosis, to monitor how well it was healing.
In each of the three case studies, the 3D scanner was able to show that the fractured scaphoid hadn’t closed back up, and spotted signs of complications such as sclerosis, displacement, and small bony fragments. These diagnoses can help doctors plan what surgeries or further treatments may be needed.
“We chose to target the important clinical problem of wrist injuries because they are common and diagnosis can be challenging, with frequent misdiagnosis and complications such as bones not healing properly,” says Anthony Butler, Chief Medical Officer of MBI. “Unparalleled clarity means diagnosing complications, such as minute fractures that aren’t healing correctly, is dramatically improved. The MBI scanner’s ability to measure and display bone composition makes it far easier to monitor post-surgical healing. It can also focus on the optimal energy spectrum to reduce image distortion caused by metal implants and better assess bone healing and fusion.”
Further human trials will commence in early 2021, in clinics in New Zealand and Europe. After that, MBI says that the scanners could be available for clinical use within the next year, if regulatory approvals are granted.
MBI has published a white paper detailing the first feasibility study.