Barium enema: colorectal polyps and carcinoma

Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy: prospective comparison

BACKGROUND

The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests.

METHODS

Patients with faecal occult blood, haematochezia, iron-deficiency anaemia, or a family history of colon cancer underwent three separate colon-imaging studies--ACBE, followed 7-14 days later by CTC and colonoscopy on the same day. The primary outcome was detection of colonic polyps and cancers. Outcomes were assessed by building an aggregate view of the colon, taking into account results of all three tests.

FINDINGS

614 patients completed all three imaging tests. When analysed on a per-patient basis, for lesions 10 mm or larger in size (n=63), the sensitivity of ACBE was 48% (95% CI 35-61), CTC 59% (46-71, p=0.1083 for CTC vs ACBE), and colonoscopy 98% (91-100, p<0.0001 for colonoscopy vs CTC). For lesions 6-9 mm in size (n=116), sensitivity was 35% for ACBE (27-45), 51% for CTC (41-60, p=0.0080 for CTC vs ACBE), and 99% for colonoscopy (95-100, p<0.0001 for colonoscopy vs CTC). For lesions of 10 mm or larger in size, the specificity was greater for colonoscopy (0.996) than for either ACBE (0.90) or CTC (0.96) and declined for ACBE and CTC when smaller lesions were considered.

INTERPRETATION

Colonoscopy was more sensitive than other tests, as currently undertaken, for detection of colonic polyps and cancers. These data have important implications for diagnostic use of colon imaging tests.

Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study

BACKGROUND

The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients. Thus, this study compared the sensitivity and the specificity of air-contrast barium enema and colonoscopy for detection of colonic lesions in patients with fecal occult blood.

METHODS

Over a 30-month period, patients with fecal occult blood were recruited. Patients underwent standard air-contrast barium enema, followed by colonoscopy 7 to 14 days later. Colonoscopists were blinded to the results of air-contrast barium enema until the colonoscopy was completed, after which the results were disclosed. If the findings were discrepant, colonoscopy was repeated.

RESULTS

A total of 100 patients were evaluated. Nine air-contrast barium enemas were reported to be inadequate, and the cecum was not intubated at colonoscopy in two patients. In the remaining patients, 5 cancers were identified (1 each cecum, transverse colon, descending colon, sigmoid colon, and rectum) by both studies. Sixty-six polypoid lesions were identified in 30 patients. Diverticula were identified in 42 patients by air-contrast barium enema and in 18 patients by colonoscopy. Air-contrast barium enema detected 3 of 36 polypoid lesions 5 mm or less in diameter, 5 of 15 adenomas 6 to 9 mm in size, and 4 of 15 adenomas 10 mm or greater in diameter (sensitivity 8%, 33%, and 27%, respectively). After excluding patients with diverticula, air-contrast barium enema detected 3 of 7 adenomas 10 mm or greater in size. Overall, 12 polypoid lesions or filling defects were identified by air-contrast barium enema that could not be verified by colonoscopy. The specificity of air-contrast barium enema for lesions 1.0 cm or greater in size was 100%; for those 6 mm or greater, it was 97%.

CONCLUSIONS

Air-contrast barium enema accurately detects colon cancer and diverticula. Its sensitivity for detection of polypoid lesions or adenomas is poor and was confounded by the presence of diverticula.

Colorectal carcinoma: radiological diagnosis and staging

Colorectal carcinomas are the most common gastrointestinal tract tumors. 50-60% of the colorectal carcinomas originate in rectum and sigmoid colon. The new developments in imaging modalities have brought improvements in therapeutic aspects. The survival rates in these patients depend on the tumor penetration and the presence of regional lymph node or distant metastasis. The recurrence rates have decreased with the new operation techniques and preoperative radiotherapy, thus increasing the importance of accurate tumor staging. Double contrast barium enema studies enable the diagnosis while staging and follow-up is best done by topographic imaging techniques.

A retrospective 5-year study on the accuracy of the barium enema examination performed by radiographers

Barium enema examinations have been undertaken by radiographers at the Frenchay Hospital for more than 10 years. We have performed a retrospective study to assess the accuracy of this radiographer service by reviewing those patients who have been examined by both Barium enema and colonoscopy/flexible sigmoidoscopy to determine agreement, and reasons for disagreement. This paper does not attempt to compare the two techniques. In the 5 years between 1992 and 1996, 595 patients had both barium enema and colonoscopy or flexible sigmoidoscopy. In 488 (82%) of these patients the barium enema examination was performed by a radiographer. Comparisons with endoscopy indicate that 96% of polyps >1 cm, and 97% of carcinomas were detected radiologically. We conclude that radiographer performed barium enemas with double reporting produces a very high standard of examination with detection rates for significant lesions comparable with published data.

The future of barium radiology

Barium radiology of the gastrointestinal tract has had a long history but its survival into the next century will be a challenge. The numbers of barium studies performed has declined in recent decades due to several factors; also, health care reforms in the United States will further impact on the use of barium examinations. The future status of these radiological procedures will change depending on these factors and the organ system being examined; an increased emphasis on functional evaluation of the gastrointestinal tract will also have an effect on the evolving role of barium radiology. We provide a brief historical review of the evolution of barium radiology in the twentieth century, discuss the present and changing status of the various gastrointestinal examinations, and offer our thoughts concerning the potential future of this specialty.