- 作者：Stefan Bulla ; Philipp Blanke ; Frederike Hassepass ; Tobias Krauss ; Jan Thorsten Winterer ; Christine Breunig ; Mathias Langer ; Gregor Pache
- 关键词：Computed tomography ; Head and neck ; Paranasal sinus ; Low dose ; Dose reduction
- 刊名：European Journal of Radiology
- 出版年：2012
- 出版时间：September, 2012
- 年：2012
- 卷：81
- 期：9
- 页码：2246-2250
- 全文大小：569 K
Purpose
To evaluate image quality of dose-reduced CT of the paranasal-sinus using an iterative reconstruction technique.Methods
In this study 80 patients (mean age: 46.9 ¡À 18 years) underwent CT of the paranasalsinus (Siemens Definition, Forchheim, Germany), with either standard settings (A: 120 kV, 60 mAs) reconstructed with conventional filtered back projection (FBP) or with tube current-time product lowering of 20 % , 40 % and 60 % (B: 48 mAs, C: 36 mAs and D: 24 mAs) using iterative reconstruction (n = 20 each). Subjective image quality was independently assessed by four blinded observers using a semiquantitative five-point grading scale (1 = poor, 5 = excellent). Effective dose was calculated from the dose-length product. Mann-Whitney-U-test was used for statistical analysis.
Results
Mean effective dose was 0.28 ¡À 0.03 mSv(A), 0.23 ¡À 0.02 mSv(B), 0.17 ¡À 0.02 mSv(C) and 0.11 ¡À 0.01 mSv(D) resulting in a maximum dose reduction of 60 % with iterative reconstruction technique as compared to the standard low-dose CT. Best image quality was observed at 48 mAs (mean 4.8; p < 0.05), whereas standard low-dose CT (A) and maximum dose reduced scans (D) showed no significant difference in subjective image quality (mean 4.37 (A) and 4.31 (B); p = 0.72). Interobserver agreement was excellent (¦Ê values 0.79-0.93).
Conclusion
As compared to filtered back projection, the iterative reconstruction technique allows for significant dose reduction of up to 60 % for paranasal-sinus CT without impairing the diagnostic image quality.