Computed tomographic air-contrast enema imaging for presurgical examination of colon tumors: assessment with colon phantoms and in patients.

PURPOSE: We investigated the mechanism of colon wall deformities in phantoms and assessed the relation between pathological T staging and wall deformity in patients using computed tomography (CT) enema imaging.

MATERIALS AND

METHODS

We performed multidetector-row CT in mass-containing phantoms with no structural deformities and in 36 patients with colon tumors. In the phantoms, we compared images on double-contrast barium (DCB) and CT enema studies, and we compared wall deformities on CT enema studies and the actual phantom structure. In patients, we compared wall deformities on CT enema studies and T staging.

RESULTS

Images from CT enema and DCB studies were identical in the phantom, and all profile images showed geometrical basal indentations. In patients, the grade of deformity increased with invasion depth; and the diagnostic accuracy of T staging was 82.5%. Geometrical basal indentation and poor colon expansion were the primary reasons for overestimating T staging on CT enema imaging.

CONCLUSION

Although CT enema imaging allows reasonable diagnostic accuracy of T staging, wall deformity is thought to be consistent with tumor infiltration and other factors. We recommend evaluating T staging using not only CT enema imaging but also other techniques, such as virtual endoscopy, axial imaging, and multiplanar reformation imaging.