[Colorectal diseases: diagnosis].

Colonoscopy is now the accepted diagnostic procedure for most colorectal diseases, although studies comparing sensitivity and specificity of double-contrast barium enema with total colonoscopy or combined procedures such as sigmoidoscopy and same-day double-contrast barium enema versus colonoscopy are still being performed. For diagnosis of diverticulitis and fistulas, however, barium enema is still the diagnostic procedure of first choice. Several studies have demonstrated a high sensitivity and specificity for ultrasonography in diagnosis of appendicitis. It seems that the number of unnecessary laparotomies in suspected appendicitis can be reduced by ultrasonography. In rectal carcinoma the therapeutic procedures are determined by the grade of local tumor infiltration and by tumor invasion of local lymph nodes. To predict the tumor stage, rectal endosonography has become the most reliable method. New genetical tests have been developed to diagnose presymptomatic stages in persons at risk of family adenomatous polyposis.