ABSTRACT
X-ray contrast-enhancing agents are used to opacify the bowel and the arteries and veins and the organs they supply. The former are given orally and/or rectally; the latter are usually given intravenously, but, in some special applications, may be administered via an angiographic catheter into, for example, the superior mesenteric artery, the splenic artery or the hepatic artery (see below). The intravascular agents used in routine clinical practice are always iodinated, water-soluble X-ray contrast agents (ionic or non-ionic). It is assumed that it is almost universal practice to use non-ionic agents, as these are associated with a lower incidence of significant side-effects, such as vomiting, which might interrupt the scan, and because they are safer. No consideration will be given in this book to any specialist agents of other kinds.
