title: The value of Welin's modification of the double contrast examination in early colorectal cancer.
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging*; D003287:Contrast Media; D006801:Humans; D007417:Intestinal Polyps / Q000000981:diagnostic imaging; D008722:Methods; D011859:Radiography; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media