THE PERSISTENT COMPUTED-TOMOGRAPHY NEPHROGRAM - ITS SIGNIFICANCE IN THE DIAGNOSIS OF CONTRAST-ASSOCIATED NEPHROTOXICITY

A study was undertaken to find out if there is a quantitative relation ship between the development of contrast-associated nephrotoxicity (CA N) and the mean renal cortical attenuation (RCA) as seen on computed t omography (CT) examination of the kidneys 24 hours after injection of contrast medium. 96 patients undergoing aortography were selected, who were considered ''high risk'' either because of the presence of a bas eline serum creatinine (Cr) of 123.76 mu mol l(-1) (1.4 mg dl(-1)) or higher, or who were 73 or older with or without elevated creatinine le vels. A CT study of the kidneys at approximately 24 h was correlated w ith baseline serum creatinine as well as 24 h Cr (48-72 h Cr when avai lable). Medical history and medications were recorded. Eight of 96 pat ients had RCA of 108-236 HU at 24 h CT and all developed significant C AN of varying degree; 3/96 had RCA ranging from 48 to 67 HU and had tr ansient CAN; two other patients with RCA of 67-90 HU developed CAN; an d there was increased incidence of CAN in patients: (a) with pre-exist ing renal insufficiency; (b) with diabetes with renal insufficiency; ( c) on diuretics; (d) who were older; and (e) had a unilateral atrophic kidney. It was concluded that a 24 h CT study evaluating the RCA had better predictive value for the development of CAN than a 24 h creatin ine level.