Only radiographs taken of a dog that is identified with an ID number can be subject to grading. A dog’s ID number must always be verified when images are taken. Radiographs must be marked in a way that cannot be altered afterwards (radiographic lead). Mandatory information that must be included in radiographs: date, registration number of the dog (or ID number), and side marker (internationally recognizable, for instance sin, dex, R, L).
A certificate can be issued for a dog younger than 12 months if signs of osteochondrosis are found in the joint (OC Affected). The grading OC Unaffected or Open to interpretation cannot be obtained before the age of 12 months. The dog must be under sedation for imaging. Both shoulder joints are radiographed on the same occasion.
Instructions for taking shoulder joint radiographs:
Radiographs taken for screening of osteochondrosis are mediolateral images of the shoulder joint. The image is taken as follows:
The cassette is placed under the shoulder joint that is radiographed. The limb subject to imaging is pulled as far down and forward as possible, and the limb on top of it as far back as possible. The head is pulled diagonally upwards so that the trachea does not summate with the shoulder joint. The image is focused on the shoulder joint and cropped sufficiently. Side marker and radiographic lead (identification) are placed on the table into the image so that these do not summate with the subject of imaging.
For grading of osteochondrosis, optimal positioning is very important. The positioning must be correct, especially for assessment of very small or shallow changes.
Images must be taken in a neutral position, i.e., there cannot be any supination/pronation and the shoulder joint must be stretched out as forward as possible. In addition, there cannot be any summation with the caudal humeral head (for instance by the shoulder blade, tracheal cartilage rings, pectoral muscles, or the sternum). Images must not be grainy.