Digital Radiographic Uterus Size for Detecting Uterine Disease Diagnosed by Ultrasound in Dogs

Abstract

It has been believed that the normal uterus is not seen on abdominal radiography in intact female dog. Empirically, however, the uterus can be visualized on radiographs even if the dogs do not have with uterine diseases. The objectives of this study were to prove that the normal non-gravid uterus can be seen on abdominal radiographs, to determine a quantitative index for normal uterus diameter and to evaluate its usefulness in predicting uterine disease in practice. A total of 213 intact female dogs with abdominal radiographs and abdominal sonograms including full examination of reproductive system were included. They were classified into normal and abnormal groups (cystic endometrial hyperplasia or dilated uterus such as hydro-, muco-, and pyometra) based on the ultrasonographic findings. For each dog, the height of the body of the fifth lumbar vertebra (L5) and the maximal uterus size (U, if identified) were measured on right lateral radiographs and the maximal uterus diameter to the height of the body of the fifth lumbar vertebra (U/L5) ratio was calculated. Seventy eight dogs were into normal group and one hundred thirty five dogs were into abnormal group. Normal uterus was not infrequently identified on abdominal radiographs (twenty seven dogs, 35% in normal group), so identification of the uterus on radiographs alone was not necessarily meaning that the dog have uterine diseases. It was suggested that U/L5 ratio of 1.18 ± 0.53 (mean± 2 SD) be used as normal radiographic uterus size in intact female dogs and a value of 1.60 was recommended for clinical use as having uterine disease is very likely if the value is greater than this.