DELAYED CT OF THE KIDNEYS AFTER IOPENTOL (IMAGOPAQUE(R)-350) INJECTION IN PATIENTS WITH NORMAL RENAL-FUNCTION - AN ASSESSMENT OF THE GRADUAL DECREASE IN OPACIFICATION OVER 32 H AFTER INJECTION

The elimination of the non-ionic contrast medium iopentol (Imagopaque( R), Nycomed Imaging AS, Oslo, Norway) from the kidneys was investigate d in adult patients with normal renal function referred for cerebral c omputed tomography (CT). Twenty-four patients were included in the stu dy. Each patient was given one intravenous injection of 50 ml iopentol 350 mg I/ml. CT scans of the kidneys were taken before, immediately a fter, 8 h after and 32 h after the injection of contrast medium. To as sess the rate of iopentol disappearance, calculations were made for th e cortex, medulla and aorta, based on changes from the baseline (pre-c ontrast) measurements, in Hounsfield units (HU). The median estimated time for disappearance was 28 h from the cortex, 32 h from the medulla and 8 h from the aorta. Thus, a small retention of contrast medium ca n usually be seen after normalization of aortic HU values.