Colonic Polyps: Discrete tissue masses that protrude into the lumen of the COLON. These POLYPS are connected to the wall of the colon either by a stalk, pedunculus, or by a broad base.Polyps: Discrete abnormal tissue masses that protrude into the lumen of the DIGESTIVE TRACT or the RESPIRATORY TRACT. Polyps can be spheroidal, hemispheroidal, or irregular mound-shaped structures attached to the MUCOUS MEMBRANE of the lumen wall either by a stalk, pedunculus, or by a broad base.Intestinal Polyps: Discrete abnormal tissue masses that protrude into the lumen of the INTESTINE. A polyp is attached to the intestinal wall either by a stalk, pedunculus, or by a broad base.Colonography, Computed Tomographic: A non-invasive imaging method that uses computed tomographic data combined with specialized imaging software to examine the colon.Adenomatous Polyps: Benign neoplasms derived from glandular epithelium. (From Stedman, 25th ed)Colonoscopy: Endoscopic examination, therapy or surgery of the luminal surface of the colon.Colonic Neoplasms: Tumors or cancer of the COLON.Adenomatous Polyposis Coli: A polyposis syndrome due to an autosomal dominant mutation of the APC genes (GENES, APC) on CHROMOSOME 5. The syndrome is characterized by the development of hundreds of ADENOMATOUS POLYPS in the COLON and RECTUM of affected individuals by early adulthood.Colon: The segment of LARGE INTESTINE between the CECUM and the RECTUM. It includes the ASCENDING COLON; the TRANSVERSE COLON; the DESCENDING COLON; and the SIGMOID COLON.Diverticulosis, Colonic: A pathological condition characterized by the presence of a number of COLONIC DIVERTICULA in the COLON. Its pathogenesis is multifactorial, including colon aging, motor dysfunction, increases in intraluminal pressure, and lack of dietary fibers.Adenoma: A benign epithelial tumor with a glandular organization.Nasal Polyps: Focal accumulations of EDEMA fluid in the NASAL MUCOSA accompanied by HYPERPLASIA of the associated submucosal connective tissue. Polyps may be NEOPLASMS, foci of INFLAMMATION, degenerative lesions, or malformations.Rectal Diseases: Pathological developments in the RECTUM region of the large intestine (INTESTINE, LARGE).Sigmoid Diseases: Pathological processes in the SIGMOID COLON region of the large intestine (INTESTINE, LARGE).Genes, APC: Tumor suppressor genes located in the 5q21 region on the long arm of human chromosome 5. The mutation of these genes is associated with familial adenomatous polyposis (ADENOMATOUS POLYPOSIS COLI) and GARDNER SYNDROME, as well as some sporadic colorectal cancers.Radiographic Image Interpretation, Computer-Assisted: Computer systems or networks designed to provide radiographic interpretive information.Intestinal Mucosa: Lining of the INTESTINES, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. In the SMALL INTESTINE, the mucosa is characterized by a series of folds and abundance of absorptive cells (ENTEROCYTES) with MICROVILLI.Colonic Diseases: Pathological processes in the COLON region of the large intestine (INTESTINE, LARGE).Colorectal Neoplasms: Tumors or cancer of the COLON or the RECTUM or both. Risk factors for colorectal cancer include chronic ULCERATIVE COLITIS; FAMILIAL POLYPOSIS COLI; exposure to ASBESTOS; and irradiation of the CERVIX UTERI.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.