摘要
目的探讨管腔密度、扫描层厚和窗设置对非钙化性斑块CT值测量准确性的影响。方法选用20个心脏标本，配制1：50、1：40、1：30、1：20和1：200的5种浓度对比剂（300mgI/ml的碘海醇），注入血管内行CT扫描。1：200浓度对比剂用作斑块基准状态CT值测量，其余4种浓度对比剂模拟不同管腔密度。采用兴趣区法分别测量4种管腔密度、2种扫描层厚（0．625mm和1．250mm）和2种窗设置（窗宽1000HU、窗位150HU和窗宽500HU、窗位200HU）下的斑块CT值。对管腔密度、层厚和窗设置对斑块CT值测量影响的比较采用析因设计的方差分析，对斑块CT值与3个因素之间的相关关系进行偏相关分析。结果符合纳入标准的斑块24个。2种窗设置下斑块基准状态CT值分别为（23．90±6．87）HU和（29．00±7．26）HU。管腔密度和窗设置对斑块CT值测量的影响有统计学意义（F值分别为45．674和79．094，P值均〈0．01），而2种层厚的影响无统计学意义（F=1．033，P〉0．05）。斑块的CT值随管腔密度的增加而升高。结论管腔密度和窗设置影响斑块CT值测量，而0．625mm层厚和1．250mm层厚的影响不显著。斑块CT值随管腔密度增加而升高。
Objective To assess the effect of intracoronary attenuation, slice thickness, and window setting on CT attenuation measurement of non-calcified coronary plaque in ex vivo specimen. Methods Twenty adult cadaver heart specimens were used. Five solutions of contrast medium diluted with saline were prepared as follows： 1/200, 1/50, 1/40, 1/30, and 1/20. CT scans were performed after intracoronary injection of each solution. The solution of 1/200 was used to measure baseline values of plaques, and the other four solutions were used to imitate the different intracoronary attenuation. The plaque attenuations were measured with region of interest under four intracoronary attenuations, two slice thickness （0. 625 mm and 1. 250 mm）, and two window settings （WW 1000 HU,WL 150 HU and WW 500 HU ,WL 200 HU）, respectively. The result was compared with factor analysis and partial correlation analysis. Results Twenty four plaques met the study criteria. The baseline CT attenuation of plaques under two window settings were （23. 90 ± 6. 87） HU （ setting 1 ） and （ 29. 00 ± 7. 26） HU （ setting 2） respectively. Intracoronary attenuation and window settings had significant effect on CT attenuation measurement of non- calcified plaques （F = 45. 674 and 79. 094, P 〈 0. 01 ）, whereas slice thickness of 0. 625 mm and 1. 250 mm showed no significant effect on CT attenuation measurement （ F = 1. 033,P 〉 0. 05 ）. Comparing with baseline values, plaque attenuations on 1/40 and 1/30 solutions that can imitate lumen attenuation in clinical practice were increased. Conclusions Intracoronary attenuation and window settings had significant effect on CT attenuation measurement of non-calcified plaques, while slice thickness of 0. 625 mm and 1. 250 mm had no significant effect. Plaque attenuation would increase with the increase of intracoronary attenuation.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2008年第5期489-492,共4页
Chinese Journal of Radiology
