| Objective: To analyzed the diagnostic value of coronary artery occlusions by measuring occluded lesion length,the CT density of the two sides of the coronary artery occlusions and the attenuation gradient distal to the occlusions of coronary artery tomography(CCTA)with using catheterization coronary angiography as the standard of reference.Methods: A total of 100 coronary artery branches divided into total occlusion and subtotal occlusion that confirmed as coronary artery occlusions with using catheterization coronary angiography suspected with coronary artery disease and detected by coronary CT angiography(CCTA),and then underwent catheterization coronary angiography examination from October 2011 to December 2015.CCTA using retrospective ECG-gated spiral scan mode or prospective-ECG triggered sequential scan mode on a second generation DSCT system.Acquisition parameters were as follows: 0.28 s gantry rotation time,2×64×0.6 mm detector collimation,2×128×0.6 mm Z-flying focal spot technique.The tube voltage was set as 120 k V and the tube current was 330-420 m As every round.Parameters for image reconstruction include time resolution of 75 ms,a slice thickness of 0.75 mm,increment of 0.7 mm.Images were reconstructed with filtered back projection(FBP)and a medium soft convolution kernel(B26f).Contrast medium enhancement was achieved by injecting70-85 ml of iodinated contrast material and injected at 5-6 ml/s followed by 30-50 ml of saline though intravenous antecubital catheter.A test bolus was first injected and the region of interest was placed within the ascending aorta to determine the required delayed time,which was defined as 6 s when the CT value of interest of the ascending aorta was equal or over 100 HU.Cross-sectional images reconstructed at multiple phases of the interal between R-R electrocardiograms,curved planar reformation(CPR),multiplanar reconstruction(MPR)and maximum intensity projection(MIP)were reconstructed,and selected the best image for assessment.Measuring the CT density and of the two sides of the coronary artery occlusions and comparing the CT density and corrected coronary opacification(CCO)difference of the two sides of occlusions coronary artery and the attenuation gradient distal to the occlusions of coronary artery tomography(CCTA)with using catheterization coronary angiography as the standard of reference.Results: Total occlusion and subtotal occlusion amount of 50 coronary artery branches respectively,and the two groups of left anterior descending,left circumflex branch and right coronary artery involve of 25/26?7/7?18/17.The total occlusion of lesion length is greater significantly than the subtotal occlusion group(18.7±13.6mm and 5.8±3.8mm,P<0.01);The sensitivity and specificity was 80.0%,72.0% of lesion length for diagnosing the coronary artery occlusions.The proximal CCO difference of the total occlusion is greater significantly than the distal(1.03±0.12?0.77±0.17,P< 0.01);The proximal CCO difference of the subtotal occlusion is greater significantly than the distal(1.03±0.12?0.92±0.19,P<0.01);The CCO difference between proximal and distal of the total occlusion is greater significantly than that of the subtotal occlusion(0.26 ± 0.20 and 0.11 ± 0.19,P<0.01).The optimal cutoff in CCO difference of occlusion was 0.15,the sensitivity and specificity was 78.0%,68.0%.The optimal cutoff occlusioned lesion length was 6.85,the sensitivity and specificity was 82.0%,80.0%.Two groups of attenuation gradient: there are 11branches(22%)appearing reverse attenuation gradient in the diatal lumen of total occlusion,while there are 20 branches(40%)appearing positive attenuation gradient in the diatal lumen of total occlusion.There are 3 branches(6%)appearing reverse attenuation gradient in the distal lumen of total occlusion,while there are 26 branches(52%)appearing positive attenuation gradient of the CT density in the diatal lumen of total occlusion.Conclusion:(1)The total occlusion of lesion length is greater significantly than the subtotal occlusion group in CCTA;it can be used as important signs of the diagnosis of coronary artery total occlusion.(2)The CCO difference across coronary artery occlusions enhance the accuracy of diagnosis which can be as important supplement of the coronary artery occlusions.(3)The reverse attenuation gradient distal to the occlusions was an important CT symptom of coronary artery occlusions,which have important value to the diagnosis and the differential diagnosis of total occlusion and subtotal occlusion. |
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