title: Forelimb skeletal scintigraphy responses in previously untrained Thoroughbreds undergoing initial treadmill training.
abstract: Scintigraphy has been used in numerous clinical settings to examine horses to determine the origin of lameness problems, but it has not been used previously to monitor prospectively the skeletal responses of a group of similarly-trained racehorses. Our hypothesis was that in naïve Thoroughbred (TB) racehorses, initial treadmill training induces increased radiopharmaceutical uptake in high-motion joints and in the dorsal third metacarpal bone (MC3). Eight previously-untrained TB racehorses underwent sequential skeletal scintigraphic examinations as they exercised daily for 9 weeks on an inclined treadmill. At the end of Weeks 0 (pre-training), 3 (trotting at 4.2 m/s and initial galloping), 6 (galloping at 7.5 m/s), and 9 (sprinting 600 m at 12.5 m/s), horses received 140 mCi 99m Technetium-methylene diphosphonate i.v. followed by a standard skeletal scintigraphic forelimb examination 2 h later. Views were graded for increased radiopharmaceutical uptake by 3 co-investigators who were blinded to horse identification, breed, sex, date, and clinical findings. Results were compared before and after training for each skeletal location using the Mann-Whitney Rank Sum Test with the level of significance set at P<0.05. Initial treadmill training resulted in increased radiopharmaceutical uptake in the carpus (P = 0.031), metacarpophalangeal joint (P = 0.021), proximal phalanx (P = 0.035), and distal phalanx (P = 0.003). Training did not affect dorsal MC3 radiopharmaceutical uptake (P>0.05).
authors.affiliation: Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61802, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Foreman
authors.forename: S K
authors.initials: SK
authors.lastname: Kneller
authors.forename: A R
authors.initials: AR
authors.lastname: Twardock
authors.forename: M D
authors.initials: MD
authors.lastname: Chambers
authors.forename: O J
authors.initials: OJ
authors.lastname: Inoue
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002350:Carpus, Animal / Q000000981:diagnostic imaging; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D005552:Forelimb / Q000000981:diagnostic imaging*; D006734:Horse Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology*; D006736:Horses / Q000033:anatomy & histology / Q000502:physiology*; D007596:Joints / Q000000981:diagnostic imaging; D007794:Lameness, Animal / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011446:Prospective Studies; D011877:Radionuclide Imaging