Contrast-enhanced computed tomography of the gastrointestinal tract in clinically normal alpacas and llamas

Abstract

To assess the feasibility and usefulness of CT enterography to evaluate the gastrointestinal tract in clinically normal llamas and alpacas. Prospective observational study. 7 clinically normal alpacas and 8 clinically normal llamas. The imaging protocol included orogastric administration of iodinated contrast material mixed with water. Three hours later, helical CT scanning was performed of the entire abdomen with transverse and multiplanar sagittal and dorsal projections before and after IV iodinated contrast agent injection. Both oral and IV contrast agents were well tolerated, and no adverse reactions were observed. Transverse images depicted the gastrointestinal tract and pancreas in the short axis; however, dorsal and sagittal projections aided in localizing and differentiating the various gastrointestinal segments, including the pancreas. In all camelids, the wall of the gastrointestinal tract was well differentiated. In all but 2 camelids, all gastrointestinal segments were well visualized and differentiated. In those 2 animals, the cecum was difficult to identify. Good distention of the small intestine was achieved by use of the oral contrast agent. The dorsal projections were useful to identify the pancreas in its entire length. The present study supplied new information about gastrointestinal wall thickness, intestinal diameter, and location of the pancreas and ileocecocolic junction in alpacas and llamas. Multiplanar contrast-enhanced CT was useful to reveal the various segments of the gastrointestinal tract, pancreas, and abdominal lymph nodes. The shorter time delay before imaging, compared with the delay with conventional barium studies, makes this technique complementary or superior to conventional radiographic or ultrasonographic studies for evaluation of the gastrointestinal tract.