Rationale and Objectives
The purpose of this study was to assess the effect of a low-tube-voltage technique
and iterative reconstruction (IR) on the radiation dose and image quality of computed
tomography colonography (CTC).
Materials and Methods
We studied 30 patients (14 women and 16 men; mean age, 64.5 ± 13.1 years; range, 39–90 years)
with colorectal cancer referred for surgical treatment. All underwent CTC with fecal
tagging under a standard 120-kVp protocol in the supine position and a 100-kVp protocol
in the prone position. The 120-kVp images were reconstructed with filtered back projection
(FBP). The 100-kVp images were postprocessed using FBP and a hybrid type of IR (adaptive
iterative dose reduction 3D). The effective radiation dose (ED), image noise, and
contrast-to-noise ratio (CNR) were compared among the three protocols. The visual
image quality was scored on a four-point scale.
Results
The mean ED was significantly lower under the 100-kVp protocol than the 120-kVp protocol,
resulting in a 27% radiation dose decrease (3.5 ± 2.0 vs 2.5 ± 1.5 mSv; P < .01). Image noise decreased by 48%, and the mean attenuation of tagged fluid increased
from 452 to 558 HU on images acquired at 100 kVp with IR compared to that in the 120-kVp
protocol; these differences were significant. The mean CNR was significantly higher
under the 100 kVp with IR than the other two protocols. We found no significant differences
in the visual scores for diagnostic utility between the 100 kVp with IR and the 120
kVp with FBP protocol (P = .10).
Conclusions
Low-tube-voltage CTC reduced the radiation dose by approximately 27% while maintaining
the image quality.
Key Words
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Article Info
Publication History
Published online: April 11, 2015
Accepted:
March 8,
2015
Received:
January 3,
2015
Footnotes
Conflicts of Interest: The authors do not have a direct or indirect financial interest in the products under investigation or subject matter discussed in this article.
Identification
Copyright
© 2016 AUR. Published by Elsevier Inc. All rights reserved.
