title: High-field magnetic resonance imaging investigation of distal border fragments of the navicular bone in horses with foot pain.
abstract: BACKGROUND
  Distal border fragments of the navicular bone can be seen in lame and nonlame horses and their clinical significance remains open to debate.
  
  
  OBJECTIVE
  To describe the magnetic resonance imaging (MRI) appearance of distal border fragments and the adjacent navicular bone. To investigate the relationship between fragments and other abnormalities of the navicular bone and the distal sesamoidean impar ligament (DSIL).
  
  
  METHODS
  Horses were included if pain causing forelimb lameness was localised to the foot and high-field MR images were acquired. The size and location of distal border fragments were recorded. Abnormalities in the adjacent navicular bone were graded to obtain a fragment grade. A total navicular bone grade was assigned. The DSIL was also graded. A Chi-squared test was used to test for associations between the presence of a fragment and specific lesions involving the distal border of the navicular bone, the total grade of the navicular bone, and the grade of the DSIL.
  
  
  RESULTS
  427 horses were included and 111 fragments observed. There was a significant association between the presence of a fragment and the total navicular bone grade, osseous cyst-like lesions, increased number and size of the synovial invaginations of the distal border, increased signal intensity on fat suppressed images and size of distal border entheseophytes.
  
  
  CONCLUSIONS
  There is an association between distal border fragments and other pathological MRI abnormalities of the navicular bone.
  
  
  CONCLUSIONS
  Distal border fragments are part of navicular disease, but their contribution to pain and lameness remains to be clarified.
authors.affiliation: Universita' degli Studi di Milano, Dipartimento di Scienze Cliniche Veterinarie - Reparto di Radiologia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Biggi
authors.forename: S
authors.initials: S
authors.lastname: Dyson
mesh_terms: D000818:Animals; D005260:Female; D005534:Foot Diseases / Q000473:pathology / Q000662:veterinary*; D005552:Forelimb; D050723:Fractures, Bone / Q000473:pathology / Q000662:veterinary*; D006734:Horse Diseases / Q000000981:diagnostic imaging*; D006736:Horses; D008279:Magnetic Resonance Imaging / Q000662:veterinary*; D008297:Male; D010146:Pain / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000662:veterinary*; D011859:Radiography