New MRI technique illuminates the wrist in motion

January 2, 2014, UC Davis

If a picture is worth 1,000 words then a movie is worth far more, especially when it comes to diagnosing wrist problems.

UC Davis radiologists, medical physicists and orthopaedic surgeons have found a way to create "movies" of the in motion using a series of brief scans. Called "Active MRI," the technique could be useful in diagnosing subtle changes in physiology that indicate the onset of conditions such as wrist instability.

The outcome of the team's first test of the new technique is published online today in the journal PLoS ONE.

"These fast images are like a live-action movie," said Robert Boutin, professor of radiology at UC Davis and lead author of the study. "The movie can be slowed, stopped or even reversed as needed. Now patients can reproduce the motion that's bothering them while they're inside the scanner, and physicians can assess how the wrist is actually working. After all, some patients only have pain or other symptoms with movement."

Wrist instability, explained senior author Abhijit Chaudhari, occurs when carpal bones become misaligned and affect joint function, often as a result of trauma that injures the ligaments between wrist bones. It causes abnormal mobility and chronic pain that can lead to osteoarthritis, a major socio-economic burden to patients and health-care systems. Good outcomes in managing the condition are more likely with early diagnosis, when less-invasive treatments are possible.

Methods such as dynamic computed tomography and fluoroscopy can image the moving wrist, but these approaches involve radiation and do not show soft tissue such as ligaments—a major part of the wrist's intricate architecture—as well as MRI scans.

"MRI scans provide detailed anatomical information of wrist structures without using ionizing radiation, but they cannot help diagnose problems with bone or tendon position that are best seen when the wrist is moving," said Chaudhari, assistant professor of radiology at UC Davis. "Active-MRI provides a detailed and 'real time' view of the kinesiology of the wrist in action using a widely available and safe technology."

The researchers overcame a number of hurdles in adapting MRI capabilities to providing moving images. A complete MRI exam usually takes 30 to 45 minutes, with each image set requiring at least three minutes—not nearly fast enough to make a video. The team developed a new MRI protocol that takes one image every 0.5 seconds, delivering a series of images in a half minute.

Another barrier was the presence of imaging errors called banding artifacts. Movement of the bones in the wrist area can interfere with the scanner's magnetic field, creating signal drop-offs. The resulting dark bands can obscure the moving wrist. The team overcame this problem with dielectric pads, which stabilize the magnetic field and shift artifacts away from the area of interest and to the side, allowing doctors to clearly see the wrist bones.

For the current study, Active-MRI was tested on 15 wrists of 10 subjects with no symptoms of wrist problems. The participants' wrists were imaged as they performed motions such as clenching the fist, rotating the wrist and waving the hand side-to-side. Each exam lasted ten minutes.

"It's quite phenomenal that we can look inside the body while it's in action using MRI," said Boutin. "Routine MRI provides exquisite details, but only if the body is completely motionless in one particular position. But bodies are made to move. We think Active MRI will be a valuable tool in augmenting traditional, static MRI tests."

"Our next step is to validate the technology by using it on patients with symptoms of wrist instability," added Chaudhari. "We also want to use Active-MRI to study sex distinctions in musculoskeletal conditions, including why women tend to be more susceptible to hand osteoarthritis and carpal tunnel syndrome."

Explore further: For some women facing angioplasty, wrist entry may be better, study finds

More information: PLoS ONE Published: December 31, 2013 DOI: 10.1371/journal.pone.0084004

Related Stories

For some women facing angioplasty, wrist entry may be better, study finds

November 1, 2013
(HealthDay)—For women at high risk for bleeding during angioplasty, the wrist may be a better entry site than the groin, a new study indicates.

Recommended for you

Best of Last Year—The top Medical Xpress articles of 2017

December 20, 2017
It was a good year for medical research as a team at the German center for Neurodegenerative Diseases, Magdeburg, found that dancing can reverse the signs of aging in the brain. Any exercise helps, the team found, but dancing ...

Pickled in 'cognac', Chopin's heart gives up its secrets

November 26, 2017
The heart of Frederic Chopin, among the world's most cherished musical virtuosos, may finally have given up the cause of his untimely death.

Sugar industry withheld evidence of sucrose's health effects nearly 50 years ago

November 21, 2017
A U.S. sugar industry trade group appears to have pulled the plug on a study that was producing animal evidence linking sucrose to disease nearly 50 years ago, researchers argue in a paper publishing on November 21 in the ...

Female researchers pay more attention to sex and gender in medicine

November 7, 2017
When women participate in a medical research paper, that research is more likely to take into account the differences between the way men and women react to diseases and treatments, according to a new study by Stanford researchers.

Drug therapy from lethal bacteria could reduce kidney transplant rejection

August 3, 2017
An experimental treatment derived from a potentially deadly microorganism may provide lifesaving help for kidney transplant patients, according to an international study led by investigators at Cedars-Sinai.

Exploring the potential of human echolocation

June 25, 2017
People who are visually impaired will often use a cane to feel out their surroundings. With training and practice, people can learn to use the pitch, loudness and timbre of echoes from the cane or other sounds to navigate ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.