PURPOSE: To investigate the utility of dual-energy (DE) CT using virtual noncontrast (VNC) and iodine overlay (IO) images to assess therapeutic response to radiofrequency ablation (RFA) for renal cell carcinomas (RCCs).
MATERIALS AND METHODS: In this institutional review board-approved study (with waiver of informed consent), 47 patients with RCCs that underwent DECT after RFA were enrolled in this study. DECT protocols included true noncontrast (TNC), linearly blended DE corticomedullary and late nephrographic phase imaging. Two types of VNC and IO images were derived from corticomedullary and late nephrographic phases, respectively. To predict local tumor progression at RFA site, linearly blended and IO images were analyzed both qualitatively and quantitatively. Contrast-to-noise ratios (CNR) of renal cortex-to-RFA zones were calculated. The overall imaging quality of VNC images was compared with TNC images.
RESULTS: The IO images from corticomedullary and late nephrographic phases showed excellent diagnostic performance (each sensitivity 100% and each specificity 91.5%) for predicting local tumor progression. The degree of enhancement of local tumor progression was not significantly different between linearly blended and IO images (P>0.05). The mean CT numbers were not significantly different between TNC and VNC images (P>0.05). In renal cortex-to-RFA site, CNR between linearly blended and IO images was not significantly different (P>0.05). The VNC imaging quality from the two phases was given a good rating.
CONCLUSION: VNC and IO images from DECT may allow acceptable diagnostic performance with less radiation exposure as a follow-up imaging tool after RFA for RCC, compared to the linearly blended CT images.
Written by:
Park SY, Kim CK, Park BK. Are you the author?
Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Reference: Eur J Radiol. 2014 Feb;83(2):e73-9.
doi: 10.1016/j.ejrad.2013.11.022
PubMed Abstract
PMID: 24345460
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