Strictures of the sigmoid colon: barium enema evaluation

To assess the accuracy of radiologic interpretation, in the absence of clinical information, in the differentiation of benign and malignant sigmoid strictures at barium enema examination.

On two occasions, four independent observers retrospectively assessed examination findings in 78 patients with documented sigmoid strictures (43 benign, 35 malignant). Each stricture was graded by using a five-point scale (definitely malignant to definitely benign).

No significant difference existed between the areas under the receiver operating characteristic curves for the two assessments with any observer. Consensus findings indicated agreement among at least three of the four observers in 68 (87%) and 66 (85%) cases at the first and second assessments, respectively. One benign stricture was called malignant at both assessments. When consensus existed, the positive predictive value for malignant strictures was 96% at both assessments (sensitivity, 63% and 66%). Nine malignant strictures were called benign, three at both assessments. When consensus existed, the positive predictive value for benign strictures was 84% and 88% at the first and second assessments, respectively (sensitivity, 88% and 86%, respectively).

The differentiation between a benign and a malignant sigmoid stricture can be made in most cases at barium enema examination. When a stricture appears malignant, the diagnosis is usually correct, but caution is advised when a stricture appears benign.