Potential role of Calogen as an oral contrast medium in the evaluation of the gastric wall at MRI.

Evaluation of gastric wall pathology using cross-sectional imaging has proved difficult, particularly in the imaging of early, localized disease. The properties of Calogen as a negative oral contrast agent for the evaluation of the upper gastro-intestinal tract and retroperitoneum in CT has been well described. We assess the suitability of this agent as an oral contrast medium for use in MRI examination of the gastric wall, finding the mean scores for Calogen and water with regard to gastric distension to be 8.46 and 5.49, respectively (P < 0.01). Concerning obliteration of mucosal detail, the respective scores are 8.48 and 3.84 (P < 0.01). Calogen is also statistically superior to water with regard to prevention of peristalsis and homogeneity (mean scores 8.15 vs. 5.74 and 8.69 vs. 6.30, respectively). Oral Calogen, therefore, is superior to water as an oral contrast agent for MRI examination of the gastric wall. Its ingestion allows identification of the gastric wall with fat intensity material on both sides, further aiding characterisation of subtle mural anomalies.