Computed tomographic colonography versus double-contrast barium enema for the preoperative evaluation of rectal cancer.

PURPOSE: We investigated whether or not computed tomographic colonography (CTC) is a viable alternative to double-contrast barium enema (BE) for a preoperative rectal cancer evaluation.

METHODS

The size and distance from the anal canal to the lower or upper tumor borders were laterally measured in 147 patients who underwent CTC and BE. Measurements were grouped into early cancer, advanced, and after chemoradiation therapy (CRT).

RESULTS

In the early and advanced cancer groups, all lesions were visualized by BE. In contrast, 3 (7.8%) early and 8 (7.3%) advanced cases, located at the anterior wall near the anal canal, were not visualized by CTC because of liquid level formation. In the CRT group, 16 (23.5%) and 4 (5.8%) cases were not visualized by CTC and BE, respectively. The BE and CTC size measurements were similar among cohorts. However, the distance from the anal canal's superior margin tended to be longer with BE, especially in early cancer. The differences in distance from the anal canal were significantly larger in the early cancer group than in the other two groups (p = 0.0024).

CONCLUSION

CTC may be a viable alternative imaging modality in some cases. However, BE should be employed in anterior wall cases near the anal canal and CRT cases.