33rd Annual Scientific Meeting proceedings

Introduction
Accurate diagnosis of left dorsal displacement of the large colon (LDDLC) is important for treatment planning. Ultrasonography features of large colon disease are not well described.

Materials and Methods
A retrospective search of horses with LDDLC was performed in a 9-year period, cases of right dorsal displacement (RDDLC) and large colon volvulus (LCV) were searched for comparison in the same period. Signalment, clinical information and ultrasonographic features were recorded. Ultrasonographic features of LDDLC were compared with those of RDDLC and LCV.

Results
Thirty-six horses with LDDLC were included. Left kidney was obscured by a gas-filled large intestine loop in all cases, however this finding was also identified in horses with RDDLC and LCV (21/36 and 14/26, respectively). Presence of large colon mesenteric vasculature at the left dorsal abdomen was only seen in horses with LDDLC (24/36), whereas in RDDLC and LCV was identified either at the right or left sides of the abdomen within the middle or ventral segments. Ventral displacement of the spleen (30/36) and stomach (24/36) were also common features in horses with LDDLC, being extremely uncommon in the other large colon diseases.

Discussion/Conclusions
Ultrasound is a useful diagnostic tool for large colon diseases. Lack of visualisation of the left kidney is an unspecific finding that can be identified in different diseases. Therefore, additional significant ultrasonographic features such as the presence of large colon mesenteric vasculature at the left dorsal abdomen and ventral displacement of the spleen and/or stomach should be evaluated for diagnosis of LDDLC.