Published online before print August 12, 2002, 10.1148/radiol.2251010930
Renal Cyst Pseudoenhancement: Evaluation with an Anthropomorphic Body CT Phantom1
Bernard A. Birnbaum, MD,
Daniel D. Maki, MD,
Dev P. Chakraborty, PhD,
Jill E. Jacobs, MD and
James S. Babb, PhD
1 From the Department of Radiology, New York University Medical Center, 560 First Ave, New York, NY 10016 (B.A.B., J.E.J., J.S.B.); Department of Radiology, Scottsdale Memorial Hospitals, Ariz (D.D.M.); and Department of Radiology, University of Pennsylvania Medical Center, Philadelphia (D.P.C.). From the 2000 RSNA scientific assembly. Received May 15, 2001; revision requested June 26; final revision received May 29, 2002; accepted June 5. Address correspondence to B.A.B. (e-mail: bernard.birnbaum@med.nyu.edu).
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Figure 1a. (a) Transverse slice of anthropomorphic CT phantom used to study pseudoenhancement effect. (b) Transverse helical CT image of phantom demonstrates internal components simulating normal anatomic structures, renal insert (arrowheads), and both intrarenal (black arrow) and exophytic (white arrow) renal cysts.
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Figure 1b. (a) Transverse slice of anthropomorphic CT phantom used to study pseudoenhancement effect. (b) Transverse helical CT image of phantom demonstrates internal components simulating normal anatomic structures, renal insert (arrowheads), and both intrarenal (black arrow) and exophytic (white arrow) renal cysts.
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Figure 2. Bar graph of phantom attenuation data for a 7-mm intrarenal cyst imaged with a HiSpeed Advantage scanner demonstrates both pseudoenhancement and volume-averaging effects. At any given choice of section collimation, there is an increase in CT attenuation values as background attenuation increases because of cyst pseudoenhancement (solid arrows). At any given choice of background attenuation, there is also a generalized increase in cyst attenuation values as section collimation increases because of volume averaging (dashed arrow). White bars represent 40 HU, black bars represent 140 HU, and gray bars represent 240 HU.
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Figure 3a. (a) Graph demonstrates mean cyst enhancement and 95% CI, as determined with the least-squares method, plotted according to scanner type at the 140-HU attenuation level. No significant differences exist between the scanners at this level of background renal attenuation. (b) Graph demonstrates mean cyst enhancement and 95% CI, as determined by the least-squares method, plotted according to scanner type at the 240-HU attenuation level. Less cyst enhancement is noted with the Siemens Somatom Plus 4 scanner; however, the 95% CI shows substantial overlap with the other scanners tested. HSA = HiSpeed Advantage, SP4 = Somatom Plus 4.
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Figure 3b. (a) Graph demonstrates mean cyst enhancement and 95% CI, as determined with the least-squares method, plotted according to scanner type at the 140-HU attenuation level. No significant differences exist between the scanners at this level of background renal attenuation. (b) Graph demonstrates mean cyst enhancement and 95% CI, as determined by the least-squares method, plotted according to scanner type at the 240-HU attenuation level. Less cyst enhancement is noted with the Siemens Somatom Plus 4 scanner; however, the 95% CI shows substantial overlap with the other scanners tested. HSA = HiSpeed Advantage, SP4 = Somatom Plus 4.
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Copyright © 2002 by the Radiological Society of North America.
