title: Vascular distribution of contrast medium during intraosseous regional perfusion of the distal portion of the equine forelimb.
abstract: OBJECTIVE
  To describe the vascular distribution pattern of contrast medium during intraosseous regional perfusion (IORP) of the distal portion of the equine forelimb.
  
  
  METHODS
  13 cadaveric forelimbs from 12 horses without forelimb diseases.
  
  
  METHODS
  Serial lateromedial radiographic views were taken of the distal portion of 10 heparinized cadaveric forelimbs at 0, 1, 2, 6, 15, and 30 minutes during IORP of the third metacarpal bone (MCIII) by use of iodinated contrast medium and a tourniquet placed over the proximal portion of MCIII. Vascular regions of interest (ROI) were created for each radiograph. Reviewers identified the presence or absence of contrast medium-induced opacified vessels in all ROI on radiographs. This information was summarized to identify vessel-filling patterns over time. Vessel identification was verified by use of computed tomography angiography and latex perfusion studies on the distal portion of separate cadaveric forelimbs.
  
  
  RESULTS
  During IORP, contrast medium filled the medullary cavity of the MCIII; exited via transcortical vessels; and diffused distally to the remaining arteries and veins of the forelimb, distal to the tourniquet. Maximum vessel and soft tissue opacification occurred in most specimens at 6 and 30 minutes, respectively. Serial radiography vessel patterns matched those of computed tomography images and dissected specimens.
  
  
  CONCLUSIONS
  IORP provides a repeatable pattern of vascular distribution in the distal portion of the equine forelimb. To our knowledge, our study provides the first documentation of arterial perfusion by use of IORP; results of previous reports indicate that IORP delivers medications to only the venous vessels of the perfused forelimb.
authors.affiliation: Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, 24061-0442, USA.
authors.forename: Graham J
authors.initials: GJ
authors.lastname: Keys
authors.forename: Douglass B
authors.initials: DB
authors.lastname: Berry
authors.forename: R Scott
authors.initials: RS
authors.lastname: Pleasant
authors.forename: Jeryl C
authors.initials: JC
authors.lastname: Jones
authors.forename: Larry E
authors.initials: LE
authors.lastname: Freeman
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000098:blood supply*; D003287:Contrast Media; D005260:Female; D005552:Forelimb / Q000098:blood supply*; D006736:Horses / Q000033:anatomy & histology*; D008297:Male
chemical_list: D003287:Contrast Media