The way Danny W. Dutton, DVM, sees it, “If precision is the placement of several darts on a dart board, and accuracy is the placement of those darts in the bull’s-eye, ultrasound is the nexus of accuracy and precision in diagnosis and treatment for a large number of equine veterinary problems.”
Dr. Dutton, chief of staff for Frontera Division – Equine Sports Medicine & Surgery in Sunland Park, N.M., says ultrasound has allowed him to detect arthritis and osteochondromas missed on radiographs. He’s also able to follow up with increasing precision the recovery of horses from a variety of musculoskeletal injuries.
“With improved detail and technique, we are now putting our finger right on the problem instead of addressing a ‘general area,’ ” Dutton says. “Having the ability to look under the skin greatly enhances success, perception of ability and accuracy of prognosis.”
Carol Gillis, DVM, of Vacaville, Calif., says she was one of the first equine practitioner to use musculoskeletal ultrasound. Before 1984, Dr. Gillis says, ultrasound was used only in reproductive modalities. Today, practitioners use CT and MRI scans, but she still likes to use ultrasound for lame horses.
“Ultrasound can evaluate damage from inflammation and swelling as well as torn ligaments,” she says. “It is an inexpensive, non-invasive way to see if you are on the correct path.
“Ultrasound technique is all in the hands of the operator,” she says. “There can be a long learning curve for using ultrasound. It takes a long time to put it together in your head, to learn to take and interpret ultrasound. But once you have the experience, you can monitor even subtle changes.”
Betsy Vaughan, DVM, assistant clinical professor of ultrasound at the University of California, Davis, says, “Ultrasound guidance is very useful for successful injection of tendon and ligament injuries, especially as treatments such as stem cells, bone marrow aspirate concentrate and platelet-rich plasma become more commonly utilized.
“As healing progresses, the tendon may stabilize or get smaller in size and the area of injury will begin to fill in with a more normal fiber pattern. Some tendons and ligaments are slower to show signs of healing than others. Nonetheless, it is important to monitor these regions to watch for early signs of re-injury during the rehabilitation process.”
Another technological advancement the veterinarians appreciate: Digital imaging can be stored, e-mailed or burned to a DVD.
“Ultrasound provides an incredible way to look at joints,” Gillis says. “In early ultrasounds we were only looking at the metatarsal area. As we got more proficient and equipment was more capable, we were able to look for a pathology associated with joint problems rather than just injuries to the joint.”
With new developments in computer technology, the equipment gets better every year, all the veterinarians agree. The equipment is smaller and easier to transport and has more storage capability. Digital imagery is refined.
While the smaller ultrasound units are becoming more affordable, elaborate units featuring better image quality and higher technology are naturally more expensive. “I had a veterinarian tell me he just paid more for a new ultrasound machine than he did for his first house,” Gillis says.
Gillis became interested in ultrasound early in her career. She was a large animal/equine surgical resident at UC Davis and had started her doctorate work on tendon and ligament pathology. She followed procedures to the letter and learned to know what injured body parts should look like. Ultrasound also uncovered soft tissue damage.
“We discovered we could look at the whole horse and look for other problems that would confirm the diagnosis,” Gillis says.
“Ultrasound goes hand-in-hand with thorough exams,” she says. “We can not only fine-tune treatment to enhance the healing process, we can provide overall good maintenance and provide the fastest and best outcome for the animal, going forward with the best treatment.”
Dutton says tissue harmonics and multiple array probes have significantly improved the visible range of tissue acoustics.
Rather than the grainy, low-contrast images ultrasounds have provided for years, newer digital ultrasounds seem to “have mastered the process of tissue harmonics, gleaning crisper, highly detailed images,” he says.
“A lot of emphasis lately has been placed on the tremendous value of magnetic resonance imaging, especially in the equine field,” Dutton says. “I don’t doubt that value at all. We will continue to learn by leaps and bounds using MRI on distal limbs and skulls of adult horses and even entire foals.
“But the truth is, most veterinary practitioners don’t have MR, and most of us can’t afford to get one. And while it is true that ultrasound does not reveal the exciting detail and depth of MR, of those structures that we can assess with ultrasound, I believe that there is a high positive predictive value in ultrasound examination.
“Digital ultrasound machines afford the practitioner the benefit of ‘scanning’ the horse and doing the measurements later, storing the results, and even providing means for reporting with images provided in an easy-to-read and easy-to-create style,” Dutton says.
“Horsemen want answers,” he notes. “They want a clear path to recovery. They want to know ‘how bad it is,’ and they want to know what to do to get through it. Sometimes, they just want to know if the career of the horse has ended.”
Dee Gregg, DVM, one of the owners of Oklahoma City Equine in Oklahoma City, uses ultrasound daily during breeding season to synchronize breeding and for diagnosing pregnancy.
“We use it 50 to 100 times a day to check ovaries and uteruses, and to monitor pregnancies,” Dr. Gregg says. “In early pregnancies we use the rectal probe, but for later ones we use it transabdominally to monitor the fetus’s heart rate or monitor the placenta.
“Some mares have problems such as an infection in the placenta. Ultrasound lets us monitor her daily to make sure we still have a viable fetus. We can determine at what stage she is in trouble and induce or perform some other type of intervention.
“We also use ultrasound to determine if we have viable embryos,” Gregg says. “We transfer embryos on Day 7 and can take our first ultrasound four days later on Day 11. They are single vesicle, about 3 to 7 millimeters in length, and look like a black hole on the ultrasound. We can pick up a viable heartbeat on ultrasound at 24 days.”
Kelly Fredrickson, DVM, of Beverly Hills, Fla., says ultrasound allows for better timing of insemination, following of the mare’s cycle, assessing and managing twin pregnancies, determining fetal sex, determining probable fetal viability, and earlier detection of early embryonic death, as well as “allowing us to better evaluate problem pregnancies and placental issues.”
Veterinarians can “better pinpoint areas that may be the instigating cause of decreased fertility,” Dr. Fredrickson says. “Ultrasounds assist us in a more accurate assessment of the mare, fetus and occasionally the stallion. I think we should always strive for better quality images.” <HOME>
The way Danny W. Dutton, DVM, sees it, “If precision is the placement of several darts on a dart board, and accuracy is the placement of those darts in the bull’s-eye, ultrasound is the nexus of accuracy and precision in diagnosis and treatment for a large number of equine veterinary problems.”The way Danny W. Dutton, DVM, sees it, “If precision is the placement of several darts on a dart board, and accuracy is the placement of those darts in the bull’s-eye, ultrasound is the nexus of accuracy and precision in diagnosis and treatment for a large number of equine veterinary problems.”