b'A Guide to Equine Diagnostic Imagingthe bone to be remodeling. Wherever bone cells are turning over (destruction/ The Veterinarians Roleresorbing of the mineral matrix and new material being laid down) the radioactiveWhen discussing all the cool, high-tech machines that can view inside horses bodies, we tracer will accumulate. cant forget about the human element.These cameras are fairly largeup toThe most important part of any diagnostic workup is good veterinary oversighta person 14 by 17 inchesand map as much of thewho knows the horse and what is expected of it, along with intimate knowledge of the clini-skeleton that will fit on the detector, shecal problem, says Sarah Puchalski, DVM, Dipl. ACVR, owner of Puchalski Equine Diagnostic adds. It shows the areas with high activ- Imaging, in Petaluma, California. All of these diagnostic imaging technologies are useful, ity and is most useful for screening whenbut if you dont have an appropriate workup and someone who can take that information a horse has a nonspecific musculoskeletaland apply it back to the horse for proper treatment, it wont do that much good.problem that we havent been able toSometimes people view diagnostic imaging like a vending machine, where you stick the pinpoint. There may not be a detectablehorse in and then the answer comes out, but its not that simple, she continues. Its usually specific lameness, but the horse has poorjust one component of a complicated workup.performance.A common misconception among horse owners is that they can have their veterinarians Veterinarians can also use scintigraphyperform an MRI, for example, and it will give them all the information they need. Thats not to look at large, difficult-to-radiographthe whole picture (it still needs to be interpreted and applied to the horse), and sometimes areas such as the pelvis, neck, and back.its only a small component of the cost involved when dealing with the horses problem, We also use this technology when asays Puchalski. In many circumstances, the cost of an MRI may be the least of the total horse has multiple-limb lameness, suchcost to diagnose and treat the horse and, in fact, spending money on expensive diagnostics as a hind limb and a front limb, saysearly in the process can actually save the horse owner money in the long run, by ensuring that the treatment is correct for the horses condition.Heather Smith ThomasPuchalski. We can look at the whole skeleton at the same time.Before sending a horse home from the clinic post-scan, the veterinarian shouldspecifically designed for equine limbs, soIt enables the veterinarian to view the measure the horses radioactivity to makeveterinarians have another way to lookblood vessels inside the hoof capsule and, sure it has returned to a safe level. Thefor pre-existing injuries. therefore, the status of the foots blood downside of using CT or nuclear scintig- supply, which does not show on normal raphy is that it involves radiation, saysEndoscopy radiographs. If there is swelling within Reilly. There are obviously some humanVeterinarians can pass a 1-meter fiber- the hoof capsule or the coffin bone is health hazards with the radiation. With aoptic endoscope through the nostril anddisplaced (rotated or sinking) due to lami-bone scan, the horse must have a gammainto the airway to view the upper respira- nitis, she explains, the blood vessels can count (performed on blood) before it goestory tract. It lets them visualize the throatbecome occluded or damaged, diminish-back to the owner, to make sure it is not(pharynx, larynx, guttural pouches, epi- ing or curbing blood flow. urinating radioactivematerial. glottis, and soft palate) and see into theVenograms allow veterinarians to trachea. Longer scopes can reach as fardetermine what is wrong and where, and Positron Emission Tomography (PET) as the horses stomach to look for ulcers. come up with an effective treatment plan.This new equine imaging technology inThe former allows us to see abnormal development at the University of Califor- function of the airway, as well as anyTake-Home Messagenia, Davis (UC Davis), uses a radioactiveexudate (pus), blood, or foreign bodiesDiagnostic imaging technology has im-tracer to show how tissues and organs arewithin the upper respiratory tract, saysproved tremendously in the past decades, functioning.Reilly. The endoscope has a biopsy chan- with several effective options to choose The PET scan can be thought of asnel, which allows a variety of diagnosticfrom. Portable on-the-farm diagnos-cross-sectional nuclear scintigraphy,tools (cytology brushes, probes, biopsytics primarily include radiographs and where slices of tissue are evaluated. Thisforceps) to be passed to get a sample ofultrasound, while more highly special-is sometimes done in concert with CTany exudate, remove a foreign body, orized and expensive diagnostics, such as scanning, says Puchalski. The radio- potentially perform airway surgery. scintigraphy, MRI, or CT, must be done in active material can show areas whereHe adds that most horses tolerate en- a hospital setting. high cell metabolism is taking place indoscopic procedures well, with simply aThere are a few new, developing bones, using a slightly different biologicaltwitch or a lip shank and sometimes lighttechnologies that may one day become mechanism to create the image. sedation.stallside but currently are not, says While this technology is still very newPuchalski. in horses, and veterinarians dont haveVenogram What you and your veterinarian select much experience with it yet, she says itA venogram is a radiograph taken afterdepends on your horses injury or health might be useful as a screening tool, suchinjecting contrast material (dye) into acondition and the imaging technology as for soundness and safety in racehorses.vein to show how blood flows through it.available in your region. Costs also vary, In fact, UC Davis has partnered withThis is useful for (working up cases of)depending on the practice or hospital and Santa Anita Park to install a PET scannerlaminitis, says Puchalski.its geographic location.hTheHorse.com|The HorseFebruary 202027DiagnosticImaging.indd 27 1/3/20 10:16 AM'