Enhancement with water-soluble contrast media in computed tomography of the brain and abdomen. Survey and present state.

Enhancement of brain lesions occurs as a result of disruption of the blood-brain barrier. The contrast medium will therefore accumulate in the pathologic lesion and a prolonged contact between the potentially toxic contrast medium and the nervous tissue occurs. In the parenchymatous organs of the abdomen the contrast media diffuse freely into the extravascular space and are rapidly washed out again. As a consequence the adverse effects of the contrast media must be more seriously considered in brain than in body CT. Therefore, non-ionic contrast media, which are less toxic than the ionic ones, are recommended in brain CT. A review is given of four randomized, double blind, parallel studies of iohexol at CT. In three of these investigations iohexol was compared with metrizoate and ioglicate at cerebral CT and in a fourth with metrizoate at abdominal CT. All investigations showed a better tolerability of iohexol than of the ionic compounds. No difference in the enhancement properties was found.