b'A Guide to Equine Diagnostic Imagingand cons of each type of MRI based on their individual situations. Its help-ful to have a conversation with your veterinarian to determine whats best, says Puchalski. Your choice may also COURTESY UC DAVIS SCHOOL OF VETERINARY MEDICINEdepend on where you live, because some regions have many options and others are limited. Computed Tomography (CT) Computed tomography is an imaging procedure that uses special X ray equip-ment to create detailed pictures of areas inside the body. It was previously termed computerized axial tomography (CAT) scan. This is essentially cross-sectional radiographs and very useful, providingNewly developed PET scanners might be useful screening tools for soundness and safety in racehorses.excellent, high-detailed images for bone and fair to good images for soft tissues. Inare now a number of large-bore scan- cone-beam CT scanners that move general, it is not as good as MRI for view- ners in equine practice. We can get thearound the standing horse. Several ing soft tissues, says Puchalski.horses entire head and neck into theseplaces have one of these, including New Depending on the clinic, veterinariansmachines. Bolton Center, but there are not many can perform CT scans with the horseVeterinarians often use CT to diagnoseyet in private practices, says Reilly. It standing and sedated or under generaldental or sinus disease, using it to look atis relatively inexpensive for the client anesthesia. unusual head swellings or sinus swellingsbecause its quick; the horse just stands Historically, one of the challenges withor fractures, says Reilly. With X raysthere sedated and the machine goes over CT scanners is they have a round openingsometimes its hard to tell, with all theboth sides of the horse and moves around that can almost always fit the limbs butfluid and disturbance that occurred in theto get a lot of images.might not physically accommodate largerskull, whereas the CT defines it nicely. The technology is still young, however, parts of the horses body, such as the neckDepending on where you live, you mayand image quality is not as good as con-or upper limbs, says Puchalski. Withinhave access to the large-bore scannerventional scanners, adds Puchalski. the past five years, the medical imagingtechnology. Puchalski says there are two companies have made large machinesavailable in California, for instance. Nuclear Scintigraphy (Bone Scan)designed for bariatric medicine, and thereSome equine clinics also have r oboticVeterinarians can perform bone scans in standing sedated horses at the clinic. A radioactive substance is injected through a catheter placed in the jugular vein, says Reilly. This radioisotope has a very short half-life of six hours (i.e., half scott@vetxray.com | 1-866-820-1694 of the radioactivity will be gone in six QUALITY | INTEGRITY | VALUEsince 1983 hours). Within a few hours of the injec-Ultra 9030Hf Ask about our Price Match Guarantee tion, the horse is moved to a room where 90KvP/30mA a large gamma camera is moved around 15 pounds The Time For Digital Is Now! the horse, and it records where the body has increased amounts of uptake of the substance. These areas are commonly known as hot spotsareas of increased bone activity (or soft tissue inflamma-tion or cell turnover). Abnormal areas can then be further imaged with another modality (e.g., X rays, ultrasound, MRI) to determine the extent of the injury.Thus, this technology is very useful for finding the general location of a problem. The radioisotope uptake, says Pu-chalski, might be because of a fracture or bone inflammation, osteoarthritis, or a number of other things that cause 26 February 2020The Horse|TheHorse.comDiagnosticImaging.indd 26 1/3/20 10:16 AM'