盆腔内器官周围因有脂肪间隙的存在 ,CT检查能清晰分辨 ,但因直肠是肌性管道 ,自然充盈不良 ,不能形成良好的对比。因此难以对直肠癌的存在或侵犯范围予以确定 ,尤其是对直肠壁的轻度局限性增厚更难以与正常肠壁区分 ,这样就给直肠癌的早期发现和诊断带来困难。为了解决直肠自 Because of the presence of fat space around the pelvic organs, CT examination can be clearly distinguished, but because the rectum is a muscular duct, natural filling poor, can not form a good contrast. Therefore, it is difficult to determine the extent of the presence or extent of rectal cancer. In particular, the mild localized thickening of the rectal wall is more difficult to differentiate from the normal intestinal wall, thus posing difficulties in the early detection and diagnosis of rectal cancer. In order to solve rectum self