Beyond the Surface: Imaging Referral Practices

He's been poked and prodded, trotted in straight lines and flexed, hoof-tested and blocked, and yet there's nothing standing out in these examinations or on his X rays that would explain your horse's intermittent lameness. There are no obvious swellings, no apparent sensitivities to said prodding, and you can't recall an injury incident. His shortened steps come and go, and sometimes you can even hear something odd in his footfalls when you trot him down the barn aisle for your veterinarian. Despite your doc's years of experience and his practiced eye, he's stumped, and you're both at wit's end.

This horse is your top show prospect, your favorite home-bred, your best friend--and you'd do anything if just this once he could simply speak up and let you know exactly where it hurts.

Diagnostic Imaging Referral Facilities

Veterinary practices that are 100% devoted to equine diagnostic imaging are emerging. Associates spend their hours working up a horse until they figure out the cause of a lameness, and they are not faced with routine veterinary care, intensive medical care, surgery, or emergencies. After gathering diagnostic information these practitioners can package the material and present it to the referring veterinarian and/or the horse owner, and consult on treatment.

The first of this type of practice--and likely still a leader in its arena--is Virginia Equine Imaging (VEI), which is tucked away in the hills of foxhunting country near Middleburg, Va., Kent Allen, DVM, established the practice in 1996. His vision was to develop a format that focused entirely on lameness, sports medicine, prepurchase exams, and state-of-the-art diagnostic imaging.

Allen has been at the forefront of equine diagnostic ultrasound and nuclear scintigraphy (bone scans), and he was the first to use scintigraphy as a clinical tool in subclinical performance cases. Virginia Equine Imaging was the first practice worldwide to use direct digital radiology. Veterinarians from other clinics around the country and world have visited VEI to see the imaging systems in action before adding the technology to their own clinics.

Anatomy of an Imaging Referral Practice

Virginia Equine Imaging's spacious barn contains offices, stalls, an aisle, an upstairs apartment for veterinary school externs, and several exam rooms. All of the imaging equipment (aside from the nuclear scintigraphy unit) is on carts, so it can be rolled between rooms or out of the way. There are also movable stocks for restraint and handler/veterinarian safety during exams. In addition to radiography, scintigraphy, and ultrasound, VEI also offers magnetic resonance imaging (MRI). It leases out the space through a partnership with the Virginia-Maryland Regional College of Veterinary Medicine in Leesburg, Va., several days per week. There's a riding arena with jumps for under-saddle examinations, and the practice recently built a large covered round pen for longeing.

Connectivity is an important part of making the diagnostic process efficient. Network outlets in every room ensure that all of the imaging equipment is connected to the practice's main imaging server that holds nothing but images (also, a T1 line connects to a server in California that provides off-site backup). These images are tagged onto VEI's practice management software, held on another server, and they can be pulled up at any of several workstations throughout the building, one of which is in the client waiting room. Using these stations the practitioners can assess images by adjusting contrast and zooming in on areas to find pathology.

Four other full-time veterinarians work with Allen, and VEI has one veterinary intern on staff each year. It's a distinct team effort. "We all look at the cases together, and we always try to make sure whoever has the most expertise in a given area is doing it," says Allen. For example, he spends more time on ultrasound and another veterinarian might focus on injecting hocks or sacroiliac joints, while another is practiced at using acupuncture.

"It's a group collaborative effort," he adds. "Anyone can have the brilliant insight on a case."

Besides collaborating on cases daily at VEI, Christiana Ober, DVM (one of Allen's associates), and the intern move to a satellite clinic in Ocala, Fla., for the winter/spring show season. Another associate, Susan Johns, DVM, goes to horse-saturated areas of North and South Carolina several times a year for diagnostic work. Additionally, Allen and his colleagues have participated as official vets for the Rolex Kentucky Three-Day Event for 10 years, and they are a fixture in the eventing world. In fact, Allen recently was chosen to be the veterinary coordinator for the 2010 Alltech World Equestrian Games to be held in Lexington, Ky.


At least 50% of VEI's cases are area referrals for specific advanced imaging or lameness workups. The other 50% consists of prepurchase exams or horses that owners have brought directly to the practice as a part of VEI's sports medicine program.

Johns says, "We try to foster good relationships with all the veterinarians--there are quite a lot of veterinarians in this area that send horses here for advanced ultrasounds, radiographs of the neck and back, and also stifles. If you don't have digital imagery, and you're trying to do these specific areas in the field, it's very difficult to get diagnostic-quality images."

Just like in the example opening this article, VEI veterinarians examine many horses with lameness of an unknown cause, and sometimes they see apparently sound horses that are displaying decreased performance ability (for example, a grand prix jumper that's usually eager about his job, but who has begun refusing or dropping rails on a regular basis). According to the associates, the referring veterinarians often have done an excellent job of working up the horse and pinpointing the pathology to a relatively small area, but X rays are unremarkable and a more specific diagnosis needs to be reached.

Johns says for a lameness workup, "We always do a very thorough examination." In addition to flexion tests, hoof testing, and after longeing the horse, they also watch the horse being ridden, whether in person or on video. Often they use nerve blocks to better localize where an injury might be. "As far as imaging modalities, almost every horse either gets ultrasound or radiographs. We usually exhaust one of those before going into a bone scan."

Laurie Tyrrell, DVM, another associate, adds that it might be necessary to perform all four major diagnostic modalities (i.e., X rays, ultrasound, bone scan, and MRI) to get to the root of the problem. "In more complicated cases, every bit of information that each provided was useful in putting together the pieces of the puzzle," says Tyrrell. "We are fortunate to have all of these imaging modalities available to us. It allows us the ability to acquire the most information in the least amount of time, avoiding piecemeal approaches and long, drawn-out work-ups."

Sometimes a referring veterinarian specifically orders a bone scan without an initial workup. This process affords an opportunity once considered rare: The veterinarians can start the diagnostics with the big picture first, showing the horse's "hot spots" before moving on to other methods. For a bone scan, a short-acting radioactive isotope is injected intravenously, and it circulates to anywhere with bony inflammation. The veterinarians or technicians scan the horse eight minutes after the injection to see what areas of soft tissue might already be "lit up," (which indicates bone inflammation) and again two hours later, after the isotope settles into the hard tissues.

Allen, Johns, and Tyrrell all stress the importance of combining the imaging techniques with a good clinical workup, then communicating the results clearly before deciding on a treatment plan. Says Allen, "A bone scan is interesting, but it's simply a piece of information. Unless you closely couple it with a detailed physical exam and a knowledge of what that horse is going to do and not be able to do, roll that whole thing together, and then approach the problem with the tenacity of a pit bull, you're not going to be very successful. Just going and getting a bone scan, getting kind of a vague interpretation, having a once over with the horse, injecting a couple things (as treatment) ... people go home and are frustrated. You've really got to take it down to the details."

Interpreting the Information

An interesting component of VEI's success is the associates' commitment to client education. The veterinarians thoroughly explain each part of the clinical workup and the diagnostic methods.

For example, during the course of a prepurchase exam, Allen notes the horse is slightly lame on the jog, which automatically means the horse will not pass the prepurchase. He explains to the owner and the potential buyer that he can continue the diagnostic process to establish the cause of the lameness, but the financial responsibility would fall on the seller. The seller elects to pursue diagnostics on the horse, and the potential buyer stays for the learning experience. Through nerve blocks and digital radiography, Allen identifies areas of navicular degeneration. He explains each radiographic image using preserved bones and a model of the horse's distal limb so the seller is able to visualize the inside of the affected hoof capsule on her horse.

"It used to be in the old days with film, you'd go ahead and read through first, and then you'd bring the client in and read through it again," says Allen. "But nowadays with digital, usually the client sits beside me, and one of the docs or a tech scribe for me as I explain it to the client. That way we only interpret it once, and the clients appreciate being in on the beginning of it, and not getting necessarily the 'edited version.' "

The clients receive a binder at discharge that includes a signed letter describing horse's diagnosis in detail, a diagram showing the areas of pathology on the horse (color-coded marks show the diagnostic method used), and printed thumbnails of the images. All of the images are included on a CD that includes viewing software. "You can rapidly get lost in the data," says Allen. This is his attempt to make sure the owner has a clear take-home message about her horse's condition.

Moving forward from a diagnosis, the associates offer a variety of means to treat the horse and get it back into work, or to at least get it comfortable. Shock wave therapy and joint injections are the major courses of treatment pursued at the clinic. Elite athletes do not do well if they're pulled out of work for an extended period of time, so the associates try to design treatment methods that allow the horse to remain in some sort of exercise, even if it's just small-paddock turnout. If medical approaches are exhausted, then the practitioners might recommend surgery, after which they'd help the client focus on rehabilitation.

Because of Allen's involvement with cutting-edge diagnostics and treatments, sometimes he and his staff can offer unique treatment options. In addition to using conventional joint injections, VEI veterinarians currently are participating in a double-blinded, controlled study on the use of Tildren (tildronate) for treating navicular disease. This drug, which has been used successfully for a variety of joint pathologies in Europe, cannot be used in the United States except under a special research license. Horse owners will be able to receive treatment at a discounted rate since they are participating in the development/approval of a product.

Future Directions

Allen and his colleagues agree the basis of sports medicine diagnostic imaging remains the clinical exam, and veterinarians should continue to sharpen these examination skills. In the meantime, they expect horse owners of all disciplines and levels will begin demanding this in-depth diagnostic imaging information to help solve their horses' lameness issues.

Imaging referral practices are changing the face of lameness diagnosis and treatment. Allen says, "I remember when I was a kid riding around with my dad (also an equine veterinarian), his comment would be, 'The horse doesn't look very lame, you're going to have to go back and work it to make it lame for us to come out here and proceed further.' And Dad would always get back in the truck and apologize for making that comment. He said that's not where veterinary medicine is going.

"He foresaw what I'm doing today," adds Allen. "If we've done nothing else in the last 10 years, we've elevated the status of sports medicine and diagnostic imaging to the point where you don't have to make that comment anymore. If the client is willing to let you dig deep enough, 98% probability we're going to get to the bottom of it."


A group of sport horse veterinarians, including Kent Allen, DVM, owner of Virginia Equine Imaging, has developed the International Society of Equine Locomotor Pathology (ISELP,, a program designed to teach practitioners how to better diagnose and manage equine lameness.

Completing the ISELP program takes two years; candidates attend four two-day seminars per year held at four different equine clinics across the country.

The seminar topics rotate through eight modules focusing on lameness evaluation in specific anatomic regions. Once the candidates finish the eight modules, they will be eligible to undergo competency examination for society certification. Those passing will carry the designation of "Dipl. ISELP." --Stephanie L. Church


Suppose your veterinarian is on one side of the Atlantic Ocean, and you’re considering purchasing a horse on the other side. This conundrum used to involve days of waiting for express package delivery of X ray films and possibly even flight purchases to get the veterinarian where the horse was. Kent Allen, DVM, of Virginia Equine Imaging, and Eklin Medical Systems have been working together for several years to develop the Prepurchase Exam network. This network will promote and allow connectivity between veterinarians to consult on a horse that isn’t geographically convenient to both individuals.

Participating veterinarians with the appropriate equipment, T1 line, and high-speed Internet fill out a standardized form in the program that collects detailed, standardized information about the horse’s prepurchase exam. Everything from a general description of the horse ("3-year-old bay Quarter Horse gelding") to the details ("the horn quality of his front feet is excellent") are included. The veterinarian can upload digital images, specifically of the Digital Imaging and Communications in Medicine (DICOM) standard. Images in this DICOM format can be manipulated during viewing so the veterinarian can better see any pathology, but the original file cannot be altered. (Allen explains that human DICOM images are the medical legal standard in court cases.) Additionally, the veterinarians can upload and attach videos to the exam.

Ultimately, the veterinarian on the receiving end (the client’s regular veterinarian) can view the images in real time and request more X ray angles, for example. He’s able to see the exact same images and video the sending veterinarian saw, he can consider the sending veterinarian’s analysis, and then he can interpret this information and make a recommendation to his client. "When clinics sign up to do this, the idea is to be inclusive, not exclusive," says Allen. "If they have the technology, then we can go ahead and have anybody do it."

The program was in beta testing at press time. Look for more information about this network and its release on --Stephanie L. Church

About the Author

Stephanie L. Church, Editor-in-Chief

Stephanie L. Church, Editor-in-Chief, received a B.A. in Journalism and Equestrian Studies from Averett College in Danville, Virginia. A Pony Club and 4-H graduate, her background is in eventing, and she is schooling her recently retired Thoroughbred racehorse, Happy, toward a career in that discipline. She also enjoys traveling, photography, cycling, and cooking in her free time.

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