Ultrasound evaluation of small bowel thickness compared to weight in normal dogs

The use of ultrasound to measure small bowel thickness is an important part of any ultrasound examination of the abdomen. Increased thickness of the intestinal wall is a hallmark for the detection of diseases ranging from inflammatory bowel disease to neoplasia. Our subjective impression has been that dogs with no clinical signs of gastrointestinal disease often have sonographic measurements greater than published norms. The purpose of this study was to prospectively reevaluate these norms. The clinical history on all dogs receiving an abdominal ultrasound examination was evaluated for signs of gastrointestinal disease. Those without clinical signs were entered into this study. The documentation of body weight, breed, jejunal thickness, and duodenal thickness was made in 231 dogs. Dogs were placed into five groups based on their weight. Sixty-nine breeds were represented with weight ranging from 2.1 to 64 kg. A statistically significant (P ≤ 0.05) correlation between body weight and both jejunal and duodenal thickness was observed. We also found that the maximum thickness in both jejunum and duodenum in healthy dogs was larger than previously reported. These data indicate norms for the jejunum of ≤4.1 mm for dogs up to 20 kg, ≤4.4 mm for dogs between 20 and 39.9 kg, and ≤4.7 mm for dogs over 40 kg. The data indicate norms for the duodenum ≤5.1 mm for dogs up to 20 kg, ≤5.3 kg for dogs between 20 and 29.9 kg, and ≤6.0 mm for dogs over 30 kg.