Relationship between pathological findings of colorectal cancer and CT attenuation value on MPR

Thirty-one colorectal cancers were examined by CT colonography (CTC) before resection. The CT attenuation value (the maximum CT density of the whole tumor (Max) and mean CT density within the tumor (Mean)) of each lesion was measured on Multi Planar Reformat (MPR) of enhanced and non-enhanced images. Pathological findings were examined for pathological type, depth, lymphatic invasion and venous invasion. We statistically compared each parameter (Max, Mean and Max-Mean on enhanced and non-enhanced images) with the pathological findings. Relationships that showed a significant difference (P<0.05) were tumor depth and Max, Max-Mean on non-enhanced images, lymphatic invasion and Max, Max-Mean on enhanced images, Max on non-enhanced images, and venous invasion and Max on enhanced and non-enhanced images. The most sensitive parameter by discriminant function analysis was Max-Mean on non-enhanced images for pathological type (well or not well: average 71% accuracy) and venous invasion (v0, v1 or more than V2: average 77% accuracy); and Max on enhanced images for depth (m, sm1 or more than sm2 average: 77% accuracy) and lymphatic invasion (ly0, ly1 or more than ly2 average 74% accuracy). CT attenuation value on MPR of CTC is related to pathological findings of colorectal cancer. (author)