In vivo demonstration of small intestinal villi in dogs and monkeys using radiographic magnification.

Direct radiographic magnification (3.6 x) and a microfocal spot radiographic tube (0.13 mm) were used in double contrast studies of intestinal villi in adult dogs and monkeys. The villi appeared as lucent lines surrounded by barium in profile, and as lucent dots en face; this was verified by specimen radiographic and histological analysis. The use of fast screen-film combination, motility depressant, microfocal spot tube, and air-gap technique produced a radiograph of greater detail than that obtained with conventional focal spot, source-image distance, and film-screen combination. The advantages and limitations of microfocal direct magnification radiography of the small intestine are discussed.