Bone mineral measurements and Tc-99m IDP retention in the dog

The reproducibility of various procedures for the noninvasive assessment of the skeleton in dogs has been measured. In one animal, dual photon measurements of bone mineral mass were made in the whole body, the lumbar spine, and the proximal femur on 10 occasions during a 15-week period. In two other dogs, repeat measurements of Tc-99m imidodiphosphate (IDP) retention were made. For the total body and the proximal femur, the reproducibilities were 2 and 2.5%, respectively. The reproducibility of the lumbar spine was approximately 10% and was influenced by the variable fraction of the posterior spinous processes included in the measurement. The reproducibility of IDP retention measurements was not established. It was about 8% when all 10 measurements were considered but fell to 1.5% when three consecutive measurements were excluded. Dual photon measurements of the whole body and the proximal femur can be used to assess bone mass changes in the canine skeleton.