The use of dilute Calogen((R)) as a fat density oral contrast medium in upper abdominal computed tomography, compared with the use of water and positive oral contrast media

AIM: Oral contrast media are commonly given prior to computed tomography (C T) examination of the upper abdomen. Although positive oral contrast media are normally used, there is increasing interest in using negative agents su ch as water and less commonly fat density products. The aim of this study w as to compare a positive oral contrast medium, water, and a diluted emulsio n of arachis oil (Calogen (R), a fat density food supplement) for assessmen t of the upper abdomen. MATERIALS AND METHODS: Seventy-one patients referred for upper abdominal CT were randomized to receive either 500 ml water, 2% sodium diatrizoate or a dilute suspension of Calogen (R). The CT images were scored independently by three radiologists. Distension and anatomical identification was assesse d for the stomach, duodenum and jejunum, with anatomical identification rec orded for the pancreas, retroperitoneum, liver, gallbladder and spleen. RESULTS: Dilute Calogen (R) produced a significant improvement (P < 0.01) i n distension and anatomical visualization of the stomach and proximal duode num. Only minimal differences were demonstrated between the three contrast media for visualization of more distal small bowel or identification of the other upper abdominal viscera. Significantly more artifacts were caused by positive contrast media than with the Calogen (R) mixture. CONCLUSION: A dilute suspension of Calogen (R) as an oral contrast medium i s recommended when disease is suspected within the stomach or proximal duod enum. (C) 2001 The Royal College of Radiologists.