Double-contrast artifacts.

With the increasing use of double-contrast technique in radiological evaluation of the gastrointestinal tract, certain artifacts peculiar to this mode of examination need to be identified. These artifacts arise because of: (a) the characteristics of the barium suspensions used for double-contrast studies; (b) the see-through effect obtained on double-contrast studies whereby opacities lying in front of or behind the organ being examined may simulate pathologic lesions; (c) infolding of the mucosa which may simulate pathology; (d) extraneous or foreign material which is frequently detected and must be differentiated from intrinsic disease; (e) certain anatomical structures such as the cardia, pylorus, and retrogastric structures which are seen with unusual clarity and detail and which, in some cases, may simulate pathology. In general, these artifacts may simulate diffuse superficial ulceration, discrete ulceration, or polypoid lesions. Familiarity with the double-contrast technique and an understanding of these artifacts will help to avoid diagnostic errors.