Abstract
The purpose of the present study is to evaluate the benefit of microdensitometry by using X-ray radiographs to diagnose metabolic bone diseases in cats. X-ray radiographs of the right femurs of 24 healthy cats were obtained as normal controls. The images were taken by computed radiography (CR). Bone density and cortical bone indexes at 20 percentiles of the femur from the distal end were measured. Mean values and standard deviation of bone density in normal cats were 6.06±1.59mg/mm3. The corresponding values for cortical bone index were 0.33±0.05. The large variations occurring in bone density probably resulted from differences in femoral-muscle thicknesses among individuals. Cortical bone index, on the other hand, was almost constant regardless of age, sex, and body weight. Bone density and cortical bone indexes of three animals with chronic renal failure were measured and compared with those of healthy cats. The lower cortical-bone-index values found in two cases suggest active bone resorption and/or inhibition of mineralization secondary to renal dysfunction. These results indicate that microdensitometry is useful for clinical diagnosis of feline metabolic bone diseases. In addition, it has the merits of being noninvasive and inexpensive and of producing data rapidly.
