Air trapping: Comparison of standard-dose and simulated low-dose thin-section CT techniques

被引:40
作者
Bankier, Alexander A.
Schaefer-Prokop, Cornelia
De Maertelaer, Viviane
Tack, Denis
Jaksch, Peter
Klepetko, Walter
Gevenois, Pierre Alain
机构
[1] Med Univ Vienna, Dept Radiol, A-1090 Vienna, Austria
[2] Med Univ Vienna, Dept Cardiothorac Surg, Lung Transplantat Unit, A-1090 Vienna, Austria
[3] Univ Amsterdam, Dept Radiol, NL-1012 WX Amsterdam, Netherlands
[4] Univ Libre Bruxelles, Stat Unit, Inst Interdisciplinary Res Human & Mol Biol, Brussels, Belgium
[5] Univ Libre Bruxelles, Erasme Univ Hosp, Dept Radiol, Brussels, Belgium
[6] RHMS Clin Louis Caty, Dept Radiol, Baudour, Belgium
关键词
D O I
10.1148/radiol.2423060196
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
Purpose: To prospectively investigate the effect of radiation dose reduction on the visual quantification of air trapping at expiratory thin-section computed tomography (CT). Materials and Methods: In this ethical committee-approved study, 27 lung transplant recipients (12 women, 15 men; mean age, 54 years +/- 2 [standard error of the mean]) underwent expiratory thin-section CT at 140 kVp and 80 mAs (effective). All patients gave written informed consent. Dose reduction corresponding to 60, 40, and 20 mAs (effective) was simulated. The extent of air trapping in both original and dose-reduced studies was scored by three independent readers. The effects of tube current-time product, reader, reading session, and body mass index on average air trapping scores were assessed with analysis of variance. Agreements between and within observers were assessed with a weighted kappa statistic. Subjective scores for diagnostic confidence were attributed (3 = high, 2 = medium, 1 = low), and their means were calculated for each tube current time product value. Results: No significant effect on average air trapping scores as a result of tube current-time product (P = .222), reader (P = .217), reading session (P = .705), or body mass index (P = .505) could be detected. At 80 mAs, agreement between readers was excellent; agreement decreased to good or moderate at lower tube current settings. Agreement within readers decreased with a decrease in dose but remained good even at 20 mAs. Confidence also decreased, with mean scores decreasing from 2.33 +/- 0.73 (standard deviation) to 1.04 +/- 0.19 when dose decreased. Conclusion: At 140 kVp, the tube current-time product can be reduced from 80 to 20 mAs without impairing the visual quantification of air trapping at expiratory thin-section CT and with acceptable decreases in agreement between and within readers and in reader confidence. (c) RSNA, 2007.
引用
收藏
页码:898 / 906
页数:9
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