[Diagnostic imaging in constipation]

Diagnostic imaging modalities play a key role in the definition of the possible causes of constipation. Barium Enema (BE), Defecography (DG), Intestinal Transit Time (ITT), Computed Axial Tomography (CT) and Magnetic Resonance (MR) are necessary diagnostic tools for the identification either of the possible organic causes of the disease or of the functional disorders. The ITT evaluation is the main investigation to look for functional colic constipation; this method is in fact able to distinguish between the hypertonic type (in which the fecal progression is slowed down to such an extent that radiopaque markers accumulate in the most proximal part of the colon) and the atonic one (characterized by a global slowing down with the markers distributed along the whole colon). DG gives very accurate dynamic documentation of the pathologic alteration of the rectum-anal conduit, as well as of the disease of the supporting and anchoring system and of the levator complex; this type of investigation allows the definition (characterisation) of the different types of the functional rectum-anal constipation. Even in this case TAC and RM can greatly contribute to the definition of the whole picture of the constipation.