'Nontoxic' contrast agents for computed tomography

The potential usefulness of several nontoxic contrast agents for computed tomography (CT) is discussed. Normal saline and washed, packed red blood cells are possible agents for CT angiography. Xenon produces positive enhancement by increasing the X-ray absorption values of tissues in immediate contact, particularly those containing lipid; this method of contact enhancement may be useful in the central nervous system and in double-contrast CT examination of the colon. Air-contrast CT of the colon is a promising new technique which we believe can revolutionize the detection of colon polyps; it therefore has great potential for reducing the morbidity and mortality of colon cancer. (Auth.)