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Double-Contrast Examination of the Colon with Special Emphasis on Studies of the Siqmoid

1953; Radiological Society of North America; Volume: 60; Issue: 4 Linguagem: Inglês

10.1148/60.4.510

1527-1315

Robert D. Moreton,

Diverticular Disease and Complications

In length as well as in position and arrangement, the sigmoid varies within wide limits as compared with other portions of the colon. Its average length is about 45 cm. and it commonly takes a spiral or figure-of-eight course. Sometimes, however, it is short and straight, making a direct connection between the rectum and the descending colon. Occasionally it is longer and may be present as a long, straight loop ascending from the pelvis to the level of the first or second lumbar vertebra or higher. On the other hand, it may appear as multiple loops, referred to by Weber as a “tangled festoon.” Regardless of the type, a complicated arrangement of the sigmoid coils is the rule and their adequate roentgen exposure is often difficult. In addition to this coil arrangement, the sigmoid is usually confined within the boundaries of the bony pelvis, making it inaccessible to manipulation, and direct visualization of each portion by roentgenoscopy is frequently difficult and at times may be impossible. This small portion of bowel is most important pathologically. Buie et al. emphasized this in their distribution studies of polyps and frank carcinoma in various divisions of the large intestine: 70.5 per cent of the carcinomas and 71.2 per cent of the polyps were found in the rectum and sigmoid. It has further been established that 60 per cent of the malignant and potentially malignant lesions of the large intestine occur in the rectum and in that portion of the sigmoid colon which is within reach of the 25-cm. proctosigmoidoscope. It is generally said, moreover, that 50 per cent of the malignant neoplasms occurring in the rectum are discoverable on digital examination. The roentgenoscopic examination of the sigmoid and rectum is no substitute for proctosigmoidoscopy. As has been stated in earlier papers, the radiologist should not be responsible for any lesion at this level. Ideally every patient having a roentgen examination of the colon should also have a proctosigmoidoscopic examination, though it is appreciated that in many instances this is not feasible in large clinics and to a lesser degree in private practice. Also, a great majority of the smaller rectal lesions will undoubtedly escape detection on digital examination (Fig. 1). This we have been taught should be a routine, but we nevertheless see patients in whom it has not been done referred for study of the colon. Even in those patients who have had the ideal examination there are frequently so called “dark areas” in the sigmoid, just above the limit of sigmoidoscopic visualization but below the clear area of roentgenoscopic demonstration, making it impossible to examine the area by either method. For these reasons, I believe we should try to examine these areas as adequately as possible. Occasionally we may find suspicious shadows, in which event we can request proctosigmoidoscopic examination for confirmation of a suspected lesion.