MRI allows for better diagnosis of bone and soft tissue injuries in horses
February 1, 2007
A Magnetic Resonance Imaging (MRI) system at Virginia Tech's Marion duPont Scott Equine Medical Center offers hope in the form of proper diagnosis to owners of horses suffering from both bone and soft tissue injuries.
The center, which was the first equine hospital in the eastern United States to offer MRI, houses a Hallmarq open 0 .3 Tesla magnet that became operational in April 2004.
“We’re seeing horses here that need that next step in diagnosis including high performance horses with subtle injuries that need further evaluation,” said Dr. Nat White, Jean Ellen Shehan Professor and Director of the Marion duPont Scott Equine Medical Center.
MRI is a non-invasive imaging technique that has been used for human diagnosis since the 1980’s but is a relatively new diagnostic tool in treating horses. It provides incredibly sharp and detailed pictures of soft tissues inside of the body by using a magnetic field and pulses of radio wave energy.
“When the foot is placed in a magnetic field the atoms making up the tissues align with that field. Radiowaves are intermittently pulsed into the magnetic field to alter the atom alignment. When energy gained from the radiowaves is released from the tissue, it is detected as a signal and transmitted to a computer. The less dense tissues emit a signal that appears in white on the final image of the foot,” said White. “So with MRI, we’re really looking at the chemical components of the foot rather than its structure.”
In the resulting images, the dark areas represent the dense bone or tendon and the white areas represent the tissue which contains more water and fat. “When we see an increased signal (increased areas with more white than black) in a dense tendon or bone, it is abnormal and indicates an area of inflammation,” said White.
MRI is especially useful in imaging problems in the foot and lower leg that do not appear in other modalities such as radiographs and ultrasound. It can detect injuries to subchondral bone, joints, ligaments and tendons, as well as attachments of ligaments to bone, infection, hoof damage and foreign bodies.
“For example, if we have a nail puncture into the horse’s foot and pull the nail out, you can’t always find directly where the nail went even with surgery, but with the MRI, we can see it,” said White. “That’s the kind of situation in which there is a huge advantage to using the MRI.”
The standing MRI system does not require general anesthesia which lowers risk and allows for outpatient scheduling. Once the MRI scan is complete, a process that typically takes from one to two hours, a complex digital library system allows the center’s staff to store images for easy access and to share those images with referring veterinarians. Typically 200-250 images are made from a complete series of MRI sequences on a foot.
The addition of the MRI in 2004 strengthened the Marion duPont Scott Equine Medical Center’s extensive lineup of diagnostic capabilities that now includes digital radiology, computed radiography, ultrasonography, video endoscopy, nuclear scintigraphy and high speed video for gait analysis.
“Our MRI unit is yet another means by which we can provide access to state-of-the-art diagnostic care for horse owners,” said White. “I am pleased that this technology has had such a significant impact on the health and well-being of our patients.”
According to Dr. Ken Sullins, professor of equine surgery at the center, the combination of a surgery facility with MR and other imaging capabilities in one location provides significant advantages in caring for horses.
“We can diagnose and treat at one facility,” said Sullins. “That is good for both the horse and its owner.”
Information regarding the Marion duPont Scott Equine Medical Center’s clinicians and services is available online. MRI appointments may be scheduled by calling 703-771-6800.
The Marion duPont Scott Equine Medical Center is a Leesburg, Va., based full-service equine hospital that is owned by Virginia Tech and operated as one of three campuses that comprise the Virginia-Maryland Regional College of Veterinary Medicine.