Renal cysts: Is attenuation artifactually increased on contrast-enhanced CT images?

K. T. Bae, J. P. Heiken, C. L. Siegel, H. F. Bennett

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


PURPOSE: To determine if the attenuation values of simple renal cysts are artifactually increased on contrast material-enhanced, clinically acquired spiral computed tomographic (CT) images. MATERIALS AND METHODS: Dual-phase renal spiral CT studies (5-mm collimation; pitch, 1.0) were retrospectively analyzed in 24 consecutive patients who had ultrasonographic (US) documentation of simple renal cysts. Forty-eight cysts were identified. The attenuation values of each cyst were measured on nonenhanced, cortical phase, and nephrographic phase images. The size and the location of each cyst in relation to the renal parenchyma were also recorded. RESULTS: The cysts were 0.6-10.8 cm in diameter (mean, 2.6 cm; SD, 2.0). The mean attenuation change in the cysts from nonenhanced to contrast-enhanced images was statistically significant in a comparison of cortical phase and nephrographic phase images (P < .01): +1.8 HU (SD, 3.8) for cortical phase and +3.6 HU (SD, 5.6) for nephrographic phase images. Renal cysts 1.0 cm or smaller showed a higher attenuation increase (mean, +4.0 HU for cortical phase and +11.0 HU for nephrographic phase). None of the renal cysts larger than 1.0 cm demonstrated an increase greater than 10 HU (mean, +1.4 HU for cortical phase and +2.3 HU for nephrographic phase). Intraparenchymal cysts showed higher mean attenuation changes than the exophytic cysts. CONCLUSION: Attenuation values in the renal cysts increased artifactually on contrast-enhanced images, but this pseudoenhancement was not substantial and was less than 10 HU when the cyst was larger than 1.0 cm in diameter.

Original languageEnglish (US)
Pages (from-to)792-796
Number of pages5
Issue number3
StatePublished - 2000


  • Computed tomography (CT), contrast enhancement
  • Computed tomography (CT), helical
  • Kidney, CT
  • Kidney, cysts

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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