Double contrast study of colon: routine lateral recumbent view.

Abstract

The difficulties and pitfalls involved in identifying small polypoid lesions of the colon by means of double-contrast enema are well recognized. The medical literature contains a considerable number of articles concerning various technics of preparation, examination, and positioning, including such innovations as dilute barium (1) and high-voltage radiography (2). It is the purpose of this article to re-emphasize the diagnostic usefulness of routine left and right lateral decubitus views as part of the survey procedure. The use of the horizontal beam is as old as air-contrast study itself. Fischer (3), in 1925, was the first to describe a satisfactory method, and as part of that initial technic he examined his patients in the upright and lateral decubitus positions, preferring to use a horizontal beam. Weber (4) and Gershon-Cohen (5), the early exponents of the double-contrast study in this country, used primarily the vertical beam for their survey films, with certain other modifications of Fischer's method. The need for multiple views was recognized early because of poor visualization due to overlapping coils of bowel, and the desirability of reproducing questionable changes in more than one projection. The commonly described views include anteroposterior and postero-anterior, which are often taken stereoscopically, the obliques, and Trendelenburg. For all these projections a vertical beam is used. It is our belief that not enough emphasis has been placed on use of the horizontal beam. Polgar (6), one of the more recent advocates of the horizontal beam, recommends performance of both the, regular barium enema and air study in the recumbent position. He describes the convenience of this method in terms of ease of technical procedure and the use of local air filling in segmental evaluation, but he does not sufficiently stress the diagnostic superiority of total colon survey films in this position over those obtained with the more commonly employed vertical beam. Our procedure of double-contrast examination is as follows: The patient is scheduled at least two days in advance, so that he may be placed on a low-residue diet for forty-eight hours prior to study. He is given a mimeographed diet sheet and instructions and is advised of the importance of carefully following them. Institution of the low-residue diet has resulted in noticeable improvement in the degree of cleanliness of the bowel, and has proved particularly useful in evaluation of the right colon. One ounce of castor oil is taken at four o'clock the afternoon prior to examination; 2 ounces are given if the patient is in the habit of taking laxatives. Use of the low-residue diet allows the patient to continue his meals, there being no elimination of either the evening meal or breakfast prior to examination. In the mid-morning, tap-water enemas are taken until the return is clear. The enema tip is lubricated with soap rather than vaseline.