VI J. R. VON RONNEN PREFACE This atlas is a selection of the roentgenograms of patients who visited the Radiology Department at the University Hospital in Leiden between 1970 and 1974. The heads of this department are Prof. J. R. von Ronnen and Prof. A. E. van Voorthuisen. In this atlas, the most frequently occurring radiological abnormalities of the small intestine are illustrated as clearly as possible - without the shadows caused by flocculation or segmentation of the contrast fluid. The author hopes it will be a positive contribution towards the attainment of the highest possible diagnostic score. It should be remembered that the key to good diagnostics is not only a perfect examination technique, but also the knowledge and character of the physician. If these factors are optimal, then the best possible series of roentgenograms will be obtained, at least as far as technique is concerned. All patients were examined by the enteroclysis technique. With this method of examination of the small intestine, the contrast fluid is administered via an infusion directly into the duodenum instead of orally. The infusion method has added a new dimension to the radiological examination of the small intestine. This method has turned out to be especially suitable for the comparative evaluation of motility, and also for the study of disturbed motility.