DIAGNOSIS AND STAGING OF COLONIC TUMORS BY CONVENTIONAL ABDOMINAL SONOGRAPHY AS COMPARED WITH HYDROCOLONIC SONOGRAPHY

Background. Ultrasonic examination has become increasingly important in the diagnosis of diseases of the gastrointestinal tract. In neoplastic diseases of the large intestine, however, the diagnostic value of conventional transabdominal sonography is limited. The purpose of this investigation was to determine whether the evaluation and staging of colonic tumors would be improved by the retrograde instillation of water into the colon in a procedure called hydrocolonic sonography. Methods. Three hundred patients were examined in a prospective study in which both conventional transabdominal sonography and transabdominal hydrocolonic sonography were performed before the diagnosis was verified by colonoscopy. The indication for the examinations was abdominal pain, diarrhea, weight loss, or the presence of occult blood in a stool specimen. Results. With the instillation of water into the colon, it was possible to display the colon sonographically from the rectosigmoid transition to the cecum in 97 percent of the patients examined. In addition to permitting the evaluation of the colonic lumen, the procedure allowed the five layers of the colonic wall and the connective tissue surrounding the colon to be examined in detail. Only 9 of 29 carcinomas were diagnosed by conventional abdominal sonography (31 percent), whereas hydrocolonic sonography permitted the diagnosis of 28 (97 percent). No polyps could be detected by conventional abdominal sonography, whereas hydrocolonic sonography permitted the diagnosis of 38 of 42 polyps greater-than-or-equal-to 7 mm (91 percent) and 3 of 12 polyps <7 mm (25 percent). In addition, detailed evaluation of the structure of the bowel wall with hydrocolonic sonography permitted a more precise staging of colonic tumors. Conclusions. Hydrocolonic sonography, a new diagnostic procedure, can facilitate the diagnosis and staging of colonic tumors.