Delayed CT of the kidneys after iopentol (Imagopaque 350) injection in patients with normal renal function. An assessment of the gradual decrease in opacification over 32 h after injection.

Abstract

The elimination of the non-ionic contrast medium iopentol (Imagopaque, Nycomed Imaging AS, Oslo, Norway) from the kidneys was investigated in adult patients with normal renal function referred for cerebral computed tomography (CT). Twenty-four patients were included in the study. Each patient was given one intravenous injection of 50 ml iopentol 350 mg I/ml. CT scans of the kidneys were taken before, immediately after, 8 h after and 32 h after the injection of contrast medium. To assess the rate of iopentol disappearance, calculations were made for the cortex, medulla and aorta, based on changes from the baseline (pre-contrast) 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 can usually be seen after normalization of aortic HU values.