Niche

NICHE (syn. Haudek's niche), a symptom observed during X-ray fluoroscopy and radiography of the stomach and duodenum, caused by the presence of an ulcerative process in their walls. In superficial gastric ulcers, the ingested contrast medium is not retained on them; in deep ulcers, however, the contrast medium penetrates into the depth of the wall. In such chronic ulcers, a ridge forms around their edges, the base thins out, and due to pressure inside the stomach, a more or less deep protrusion of the wall is formed. According to some authors (Haudek, Bergmann), this is facilitated by narrowing of the ulcer entrance due to contraction of the longitudinal muscles. In this depression, when the stomach is filled, the contrast medium accumulates, the contours of which protrude beyond the stomach contour in the form of a formation designated as a "niche" [see separate table (Vol. X, pp. 75-76), Figs. 7 and 8]. The classic form of N. was described by Haudek in penetrating gastric ulcers, where adhesions form between the stomach and surrounding organs. Here, N. is extremely demonstrative. It consists of a round cavity connected to the stomach cavity by a narrow neck. The contents of N. consist of three layers: a lower layer of contrast medium, a middle layer of less contrasting food residue, and an upper layer of light air. Such an N. resembles a mushroom on a stalk and is also found in deep callous ulcers. During X-ray fluoroscopy or radiography of the stomach some time after evacuation of the contrast medium, a spot remains at the site of such an N. N. can also have a triangular shape with uniformly contrasting contents. If the stomach is not sufficiently filled with contrast medium, such N. may be overlooked. In such cases, if there are clinical data in favor of an ulcer, X-ray examination should be performed with the patient in a horizontal position. During such an examination, the ulcer sometimes fills better with contrast medium, and N. is clearly visible. Besides this, fairly common form, the most typical are round N. and triangular ones, but polygonal, rhomboid, and others also occur. The deeper the ulcer, the sharper the N. According to some authors, N. can be seen in very small ulcers - up to 3 mm in diameter. For better filling of N. with contrast medium, it should not be too thick: with a narrow ulcer entrance, such a medium cannot penetrate into the depression. But even with liquid contrast medium, it is sometimes possible to introduce it into the ulcer only with the help of deep palpation or with the patient lying on the left side. Most niches are located on the lesser curvature in the pars media; much less frequently - in the pars pylori ca. N. on the greater curvature are extremely rare. N. are almost always single, but double N. have also been described. If an ulcer is not found on the lesser curvature, it is necessary (as with every X-ray examination of the stomach) to rotate the patient in front of the screen to find the ulcer if it is located on the anterior or posterior wall of the stomach. Often, N., especially a shallow one, is easily detected when examining the relief of the stomach: demonstrably, the direction of the mucosal folds in the form of star-shaped rays going to the center - the ulcer. The niche is observed in the same patient for quite a long time. With a favorable course of therapeutic treatment, it may disappear. - N. are quite common in the duodenum as well. The process of their formation is the same as in gastric ulcers. They are very small and are mostly located on the lesser curvature of the bulb in the form of a protrusion of varying size. Since there is often a constriction on the greater curvature of the bulb, this leads to deformation. Some N. of the anterior or posterior wall appear as a dense contrasting spot. In order to detect N., it is necessary to perform the examination in different positions: frontal, sagittal, first and second oblique. The application of all the latest techniques for X-ray examination of ulcers also helps: targeted serial films, dosed compression, and examination of the relief. Here, as with gastric N., the characteristic direction of the mucosal folds is observed (see also Stomach, Duodenum, X-ray diagnosis of diseases).