Influence factors on accuracy of CT attenuation measurement of non-calcified coronary plaque:preliminary ex vivo study / 中华放射学杂志

ABSTRACT

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 follows1/200,1/50,1/40,1/30,and 1/20.CT scans were performed after intracoronary iniection 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 vslues.plaque attenuations on 1/40 and 1/30 solutions that can imitate lumen attenuation in clinical practice were increased.Conclusions Intraeoronary attenuation and window settings had significant effeet 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.