Double contrast enema and colonoscopy in polyp detection

Predictive value of a diagnosis of colonic polyp on the double-contrast barium enema

The positive predictive value of a diagnosis of colonic polyp on the double-contrast barium enema was determined by analyzing 160 polypoid lesions reported in 105 patients. Of the 160 polyps, 139 were confirmed by endoscopy, surgery, or repeat barium enema for a positive predictive value of 87%. Twenty-one lesions were not confirmed despite repeat endoscopy, repeat barium enema, review of the original study, or surgery, giving a false positive rate of 13%. The individual false positive error rates of 5 radiologists ranged from 8% to 26%. False positive errors were due to stool, diverticula, air bubbles, misinterpretation of the ileocecal valve, and haustration. Many of the false positive errors appeared to have been avoidable if the original examination had been more meticulously interpreted.

Screening for colorectal cancer in a factory-based population with Fecatest

This report concerns a screening programme for colorectal cancer using Fecatest, a relatively sensitive test for faecal occult blood, in a factor-based population. A total of 2420 workers between 40 and 65 years of age returned kits for testing following suitable dietary restriction. In Factory A, in which screening was offered as part of an annual medical examination, 989 men agreed to participate, a compliance rate of 45%. In Factory B, in which screening was offered in their weekly pay packets, 1431 men participated, a compliance rate of 22%. An overall positivity rate of 5.8% was found, 4.6% in Factory A and 6.6% in Factory B. Five cancers were found, two of the rectum, one at the recto-sigmoid junction, one in the sigmoid colon and one in the transverse colon. Two of these lesions were at Dukes Stage A, one at Stage B and two at Stage C. In addition, 25 adenomatous polyps were found in 17 men. In 13 these were characterized as tubular adenomata and in 4 as tubulovillous adenomata. The mean age at diagnosis in the polyp cases was 52.6 years and in the cancer cases 58.8 years. Increased specificity is obtained by excluding participants below 46 years of age. The detection rate in the 46-65 year range is approximately 1 in 100 for adenomatous polyps and 1 in 300 for cancer in the population screened. This detection rate is higher than most comparable studies using a less sensitive Guaiac test on older populations.

Reliability of routine double-contrast examination (DCE) of the large bowel in polyp detection: a prospective clinical study

A total of 2,118 consecutive patients, examined with double-contrast examination of the large bowel (DCE), were evaluated radiographically, clinically, and endoscopically for up to 48 months. A total of 402 polyps were diagnosed during the follow-up period. Of these, 307 were revealed at the first DCE and 95 at subsequent endoscopy or autopsy. The accuracy of the DCE for demonstrating or excluding patients with polypoid lesions of the colon was 97%, whereas the predictive value of a positive DCE report was 96% and a negative one, 97%. However, the ability to demonstrate every known polyp at DCE was only 63%, although the probability of a polypoid lesion demonstrated at DCE being a true polyp was 92%.

Reliability of routine double contrast examination of the large bowel: a prospective study of 2590 patients

A total of 2590 consecutive patients referred for double contrast examination (DCE) of the large bowel were followed up radiographically, clinically, endoscopically, and histopathologically during a four year period. The patients were put into two groups on the basis of the presence or absence of radiographic evidence of colonic disease at the first--that is, index examination. By comparing the findings obtained at the index double contrast examination with those obtained during follow up, the sensitivity, specificity, and accuracy of the index double contrast examination were all calculated at 0.84. The predictive value of a positive report was 0.93 and that of a negative report 0.70. If, however, patients with normal double contrast examinations at the start of this series and not examined further during the follow up period were accepted as free from significant colonic disease, the predictive value of a negative report increased to 0.93. Double contrast examination is thus a reliable method for showing the presence of colonic lesions and therefore considerably helps the management of a given case.

Double versus single contrast gastrointestinal radiology

With experience, air contrast examination of the esophagus, stomach, and duodenum can be performed routinely as quickly and easily as the standard UGI. The air contrast examination is superior for detection of small gastric polyps and the Japanese have found it superior for detection of early carcinoma. The postoperative stomach and the fundus and cardia are most easily examined by air contrast. Clear superiority in the diagnosis of peptic ulcers and peptic esophagitis has not been proved. The most accurate routine examination may be a multiphasic or combined approach utilizing air contrast views as well as filled compression views and careful fluoroscopy. With respect to the colon, we do not suggest that air contrast BE must be done exclusively. However, it is superior for the detection of polyps and small carcinomas. The technique should be available in all radiology departments and should be an integral part of the evaluation of patients at increased risk of developing carcinoma. This includes patients over 40 years of age, with chronic ulcerative colitis, familial multiple polyposis or Gardner's syndrome, family history of inherited cancer, and medical history of adenomatous polyps, colorectal cancer, or female genital cancer. In addition, air contrast enema should be utilized for the sensitive and accurate evaluation of early inflammatory bowel disease. Finally, with respect to the colon examination one fact must be stressed. Irregardless of full column or air contrast method, most missed lesions are due to poor bowel preparation, poor technique, or perceptive error by the radiologist. There can be no substitute for a clean colon, meticulous attention to technical details, and careful review of the radiographs.

Importance of total colonoscopy in the diagnosis of colonic disorders

The need for colonoscopic examination of the whole colon was determined by evaluating the accuracy of a barium enema X-ray report with particular reference to the right colon. Long colonoscopies were performed on 108 patients. The reports of the barium enema X-ray examination in these patients were compared with the colonoscopy reports. Over all, the barium enema X-ray report was accurate in 47% of cases. The rate of false negative reports was 10% and that of false positive reports 43%. For lesions of the right colon, the barium enema X-ray report was accurate in only 32% of cases, with 68% false positive and 15% false negative reports. False positive reports of carcinoma or polyps result mainly from imperfect preparation. Of the eight right colonic lesions missed in the barium enema X-ray examination, five were polyps and one was carcinoma. Long colonoscopy, rather than short colonoscopy, or flexible sigmoidoscopy and barium enema X-ray examination, would be accompanied by the greatest diagnostic accuracy. Air-contrast barium enema X-ray examination and long colonoscopy together offer the best methods of diagnosis of occult lesions in the right colon.