Dynamic topography of the contrast enhancement of the spleen.

Topographic variations of the contrast enhancement (CE) with time were studied in 74 dynamic CT scans of the spleen. After an 8-10 second bolus of urographic contrast medium containing 18.5 g. iodine, six scans per minute were done through the same section for two minutes, and single scan at 3, 4 and 5 minutes with a scanning time of 5.5 seconds. Early inhomogeneous CE of the normal spleen appearing 0-20 seconds after the peak CE of the aorta was found in 38 of 70 patients due to inhomogeneous parenchymal opacification (capillary phase) (19), delayed opacification of intrasplenic veins (8) or both (10) or due to other causes (1). Inhomogeneous CE in normal structures disappeared after 40 seconds from the aortic peak CE had elapsed, while all four pathological focal splenic lesions of different histology appeared as low density areas in postcontrast scans up to four minutes.