MRI the Movie: Coming to an Office Near You
Christopher Chalk, D.C., M.P.H. • Wed, November 23rd, 2016
Florence, Italy-based Esaote, one of the top 10 medical imaging companies in the world, has made orthopedics and, more specifically, kinematic and weight bearing MRIs a centerpiece of their U.S. marketing.
With more than 2, 400 MRI units in the field, it is time to investigate further how this approach to imaging may be uniquely suited to the orthopedic clinic.
Esaote, by the way, is a private Italian company with consolidated sales of € 280.1 million (that’s $299.9 million) in 2015, up 6.8% over 2014. Dedicated MRI sales, however, increased by 34% and are clearly finding traction among clinics and surgeons.
Motion and MRI – Contradiction in Terms or Ideal for Orthopedics?
“We featured the G-scan Brio weight-bearing MRI (WB-MRI) at the North American Spine Society’s meeting this year, ” Lisa Joos the senior director of marketing for Esaote told OTW. “This revolutionary MRI has a unique tilting system allowing doctors to image patients in the horizontal and vertical positions. The G-scan Brio enables clinicians to conduct weight-bearing MR studies to view anatomy in positions that are more typical of daily activities.”
Revolutionary? Let’s take a closer look at the G-scan Brio and see why at all the fuss is about. First of all, it is a dedicated musculoskeletal, not multi-purpose, MRI and doesn’t require any cooling. “The G-scan is a high-quality open MRI with low running costs, so the break-even figure is significantly lower than traditional MRI units, ” Joos said.
Clinical Implications of WB-MRI
According to Mikael Boesen, M.D., Ph.D., head of Musculoskeletal Research at the Department of Radiology, Bispebjerg & Frederiksberg Hospital and Parker Institute in Copenhagen, Denmark, these are the benefits of WB-MRI.
- Using WB-MRI, physicians were able to identify foraminal stenosis in 52.6% of symptomatic test subjects as compared to a 33.2% rate when using supine MRI (which illustrates a higher diagnostic accuracy rate and a greater ability to identify patients with foraminal stenosis).
- Focal posterior disc herniations enlarge and change their configuration on WB-MRI which helps the physician to separate asymptomatic from symptomatic disc herniations. Also, the rate which the operator can spot disc protrusions rises from 50.1% on supine MRI to 73.3% on WB-MRI.
- WB-MRI increases the sensitivity for detecting spinal stenosis, particularly functional spinal stenosis so the operator can detect a higher percentage of spinal stenosis in patients.
- Compared to supine MRI, WB-MRI has increased sensitivity for detecting hyperintensity zone lesions and facet joint cysts.
- When patients stand, radiologists can see the smallest changes in vertebral movement, which then allows the radiologist to more accurately diagnose instability.
A March 2014 paper published in the journal Radiologia Medica titled “Occult neural foraminal stenosis caused by the association between disc degeneration and facet joint osteoarthritis: A demonstration with a dedicated upright MRI system” tackled the differences between weight bearing and non-weight bearing MRI systems. As the University of L'Aquila researchers wrote in their study, “Imaging of the lumbar spine with the patient in a supine, nonweight-bearing position is likely to misrepresent the degree and potential risk of spinal stenosis.”
From a cohort of 630 symptomatic back pain patients who had a supine lumbar MRI, they evaluated 160 who had both supine and WB-MRIs (using Esaote’s G-scan).
Their findings? The researchers were able to detect 61 stenotic levels using WB-MRI but not even one using supine MRI. They called this condition occult stenosis.
The researchers concluded that the disc pathology and facet arthrosis could cause occult foraminal stenosis, and that imaging the spine under weight-bearing conditions improved the ability to identify stenosis and, ultimately, the pain generator.
But what about image quality? Esaote uses a couple of key software programs (SpeedUp and TR reduction) which both shorten scan times (up to 40%) and according to Esaote, heightens image quality.
Esaote’s G-scan can also be used on patients with metal implants. So…post operatively…even hip or knee implant patients can have an MRI.
Kinematic MRI of the Extremities
The G-scan Brio also has cervical flexion and extension kinematic capabilities. Kinematic MRI captures movement. So, instead of static MRI pictures the physician can actually see a movie of the shoulder or neck, for example, moving backward and forward. “Kinematic MRI is useful in conditions like whiplash injury, ” saud Sheila Hughes, company MRI clinical marketing manager. The usefulness would seem obvious. Radiologists should be able to measure instability from ligamentous tearing and visualize changes in disc pathology as the neck moves from flexion to extension.
A copy of an MRI video is available at this web link: https://videopress.com/v/sm1NiEI7
Being able to image extremity joints in motion on MRI is a new technology and Esaote has been able to do this with their O scan which is a 0.31 Tesla open unit with real-time imaging for extremities.
I know what you’re thinking, 0.31 Tesla? How can a radiologist generate a quality image with such low power?
According to Esaote, power expressed as gradient-factor is the power related to the magnetic field, and it provides a much better idea about the effective power of the gradients as it takes into consideration the gradient-magnet combination.
According to Esaote, an O scan compares favorably to a typical 1.5 Tesla MRI by gradient-factor. In short, the Esaote low powered open MRI has image quality similar to a 1.5 Tesla unit.
High praise comes from Dr. Thomas Lange from Freiburg University in an interview with Esaote. He had compared the O scan with a traditional MRI on patients at the University. “If more details are necessary, we still have the opportunity to clarify this on the high-field MRI. High-field MRI, however, has hardly been necessary, which helps us to avoid duplicate examinations while maintaining maximum quality in Diagnostics.”
“Feedback on kinematic MRI from physicians in the field has been very positive. In a traditional knee MRI for example, it is impossible to move the knee because the coil is not suited for this, there is no space to move. Esaote MRI systems have been designed by our research and development team with motion MRI in mind with an ergonomically shaped knee coil that allows the patient to move and also keep the knee in a fixed place in the iso-center, ” Lisa Joos said.
New O scan software entered the U.S. market in 2015 and provided Dicom format capabilities which allows physicians to see the MRI as a series of moving pictures—a movie, in other words. This technology also allows the physician to stream the movie and share with patients.
The advantages of this MRI movie technology, we think, are pretty clear. According to Sheila Hughes at Esaote it is useful for clinicians in patellar tracking problems of the knee. Visualization by the operator of abnormal tracking can be helpful to physicians in diagnosing patella-femoral joint dysfunction. Joos also said that motion is useful in measuring the degree of soft tissue tearing in musculotendinous conditions.
G-scan Brio and S-scan MRI systems are also indicated for cranial and brain imaging. “Over the years we improved the image quality of our musculoskeletal MRI scanners thanks to a multi-year collaboration with one of the main Universities in Germany. Today the image quality of the Esaote MRI systems is excellent including for the spine, and this enabled us to make the steps into brain imaging, ” said Joos.
The FDA cleared Esaote’s systems for brain imaging in 2016.
Future iterations of the Esaote line, we’re told, will include upgraded image quality and a further lowering of scan times. In closing Joos said, “We are also experimenting with decision support systems that facilitate the postural analysis of the spine, but this is in the early stage of development.”