The authors reviewed findings of enhanced abdominal computed tomographic (CT) scans to the difference between a higher dose of conventional ionic contrast media(iothalamate meglumine) and a lower dose of a new, nonionic contrast material (ioversol). One hundred adult patients were divided into two groups. Each group consisted of 50 patients. Iothalamate meglumine and ioversol were intravenously administered in each group. The ratio of the male to female in the former was 28.22, and the latter 29:21. We examine the degree of renal streak artifact and measure the Hounsfield number of urine in renal collecting system. There were significant differences of the degree of the streak artifact depending upon the osmolality of contrast media used and that was related with urine CT number (P value<0.005). We authors conclude that nonionic low osmolar contrast media is prone to cause streak artifacts and distortions of renal image than conventional ionic high osmolar contrast media.