[Computed tomography of the kidney with diuretics--a method for avoiding artifacts due to nonionic contrast media]

We devised a method for avoiding beam-hardening artifacts, which interfere with enhanced CT images of kidney due to nonionic contrast medium. The radiographic effect and the frequency of beam-hardening artifacts on enhanced CT of kidney were studied by prospective comparison among three groups: a group of 20 patients examined with furosemide (f-d. CT), a group of 20 patients examined without diuretics (non-d. CT) and a group of 20 patients examined after water intake (w-d. CT). In all patients of f-d. CT group, the renal parenchyma from the cortex to the papilla was almost evenly enhanced, free from artifacts. The density of the renal papilla and pelvis in non-d. CT and w-d. CT groups was significantly higher than that in f-d. CT group, and artifacts were also observed in 14 (70%) of non-d. CT group and 12 (60%) of w.d. CT group, respectively. Satisfactory CT of kidney free from artifacts was obtained by f-d. CT, providing easy evaluation of renal pelvic or peripelvic lesions. In conclusion, this technique can be used in those pathologic cases of renal pelvis or peripelvic region, that are not clear on routine CT because of artifacts.