Objectives: To establish whether the intestinal wall thickness, as measured ultrasonographically, is significantly increased in dogs with inflammatory bowel disease (IBD). The results would provide the information necessary to decide whether measurement of ultrasonographic wall thickness can predict IBD in dogs.

Methods: The intestinal wall thickness of 75 dogs with idiopathic IBD, as measured by ultrasonography, was compared with recently published normal values. IBD was either confirmed histologically (n=54) or suspected (n=21). In all cases there was a positive response to immunosuppressive treatment.

Results: A positive association between intestinal wall thickness in dogs and either the histological diagnosis or the response to treatment was not found. Ultrasonographic intestinal wall measurements do not appear to be able to establish a diagnosis of intestinal inflammation and may result in a false negative diagnosis in cases of IBD.

Clinical Significance: The same ‘grey zone’ of between 4 and 6 mm used in humans can be used in the canine duodenum to distinguish the normal range, reserving the term ‘abnormal’ for an intestinal measurement greater than 6 mm in the duodenum and greater than 4·7 mm in the jejunum.