Mini MRI finds & # 39; magic corner & # 39; for knee scans


A prototype mini MRI scanner developed at Imperial College in London can help provide relief to people suffering from knee injuries.

magic corner
Prototype & # 39; mini & # 39; MRI scanner can be used to diagnose knee injuries (Credit: Imperial College London / Journal of Magnetic Resonance in Medicine)

The team said the device – which uses a so-called & # 39; magic angle & # 39; effect – could potentially diagnose knee injuries faster and more accurately.

In a proof-of-concept study with animal knees, the results suggest that the technology can be used to show all structures of the knee.

The scientists say that the device can help diagnose diseases such as anterior cruciate ligament injuries and that the small size means that it can ultimately be used in local clinics and general practices.

Dr. Karyn Chappell, a researcher and radiographer from Imperial & # 39; s MSK Lab, said: "Knee injuries affect millions of people – and MRI scans are crucial for diagnosing the problem, leading to rapid and effective treatment. However, we currently have two problems: connective tissue in the knee is unclear on MRI scans and people wait a long time for a scan.

"This can cause certain problems for women because they are at greater risk of injury to the anterior cruciate ligaments. The reasons for this are unclear, but it can be linked to hormones such as making more elastic estrogens, leading to more joint injuries."

Knee injuries often affect one of three areas: the tendons, the meniscus or the ligaments. After a knee injury, a doctor can refer a patient for an MRI scan to determine which part of the joint is injured. MRI scans use a combination of radio waves and strong magnets to rotate water molecules in the body & # 39 ;. The water molecules send out a signal, creating an image.

However, tendons, ligaments and meniscus are usually not visible with MRI, due to the way water molecules are arranged in these structures, said Dr. Chappell.

To overcome this problem, Dr. Chappell used the power of a phenomenon that the & # 39; magic angle & # 39; is called. "The brightness of these tissues, such as tendons and ligaments in MRI images, strongly depends on the angle between the collagen fibers and the magnetic field of the scanner. If this angle is 55 degrees, the image may be very clear, but for others corners it is usually very dark. "

The team said the magic angle is achieved in their scanner because they are able to easily change the orientation of the magnetic field. While the patient is sitting in a chair, the specially designed magnet can move in different directions around the leg and the magnetic field. This is not possible with the current hospital MRI scanners, which are also much more expensive than the prototype scanner.

"In the past, the phenomenon of the magic angle was seen as a problem because it could mean that medical personnel mistakenly think that the knee is injured. However, I realized that if we took a number of scans around the knee, we would signal it could use the effect of the magic angle to get a clear picture of the knee structures, "said Dr. Chappell.

In a new study, published in Magnetic resonance in medicine, the multidisciplinary team scanned the knee joints of six goats and ten dogs in a conventional MRI scanner.

Dogs suffer from knee injuries and arthritis similar to humans, making them a good subject for the study. The results showed that the use of the magic angle can accurately detect ligament and tendon damage.

The team says they now know that magic angle scanning can visualize the knee, by combining this with the new mini-scanner of the prototype, knees can be accurately scanned with this technology – and they hope to move on to human testing of the & # 39; mini & # 39; scanner in one year.

The research was funded by the National Institute for Health Research.