| Objective: To evaluate the accuracy of the second generation dual-source computed tomography(DSCT)in diagnosis of calcified coronary artery stenosis with using coronary angiography(CAG)as the standard of reference.Exploring the value of the measuring and analyzing the CT values across calcified coronary artery in diagnosis of coronary stenosis severity.Methods: A total of 185 patients confirmed or suspected with coronary artery disease and 291 coronary artery were detected with calcification by coronary CT angiography(CCTA),and then underwent CAG examination from October 2011 to December 2015.There were 126 male and 59 female,and age was 40-87(66.5 ± 10.0)years old.The interval between CCTA and CAG was less than 30 days.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: 280 ms 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 injecting 70-85 ml of iodinated contrast material and injected at 5.5-6.0 ml/s followed by 30-50 ml of saline through an 18-G intravenous antecubital catheter by using a dual-syringe injector.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 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 DSCT image for assessment.Evaluating the accuracy by the unit vascular branch independently.Comparing the CCO difference across calcified coronary artery among the different lesion length ratio(LLR).Comparing the CCO difference among the different coronary stenosis severity.Evaluate the accuracy of CCTA and the CCO difference in diagnosis of coronary coronary stenosis.Results:(1)The CT images of 185 patients with 233 calcified coronary arteries were accounted for assessment.The CCO difference across calcified coronary artery of LLR≥2/3(group C)was 0.39 ± 0.17,which was significant higher than LLR < 1/3(group A)(0.10 ± 0.14)and 1/3≤LLR<2/3(group B)(0.25 ± 0.16)(p=0.000).The CCO difference of group B was significant higher than group A(p=0.000).17(11.6%)calcified coronary arteries were total-occlusion in group A,20(39.2%)in group B and 12(48%)in group C.(2)The CCO difference across calcified coronary artery of total-occlusion was 0.39 ± 0.14,which was significant higher than mild stenosis(0.03± 0.10),moderate stenosis(0.14 ± 0.11)and severe stenosis(0.16 ± 0.15)(p=0.000).The CCO difference between severe stenosis and moderate stenosis was no significant difference(p>0.05).The CCO difference of severe stenosis and moderate stenosis was significant higher than mild stenosis(p=0.000).(3)The sensitivity,specificity,positive predictive value and negative predictive value was 73.9%,66.0%,88.1% and 42.7%of CCTA for diagnosing the coronary artery stenosis ≥ 50%.The sensitivity,specificity,positive predictive value and negative predictive value was 76.7%,75.5%,89.4% and 48.8% of CCO difference across calcified coronary artery for diagnosing the coronary artery stenosis ≥50%.The sensitivity,specificity,positive predictive value and negative predictive value was 20.4%,99.5%,90.9% and 82.4% of CCTA for diagnosing the coronary artery total-occlusion.The sensitivity,specificity,positive predictive value and negative predictive value was 91.8%,79.9%,54.9% and 94.2% of CCO difference across calcified coronary artery for diagnosing the coronary artery total-occlusion.Conclusion:(1)The limited diagnostic value of morphology analysis with CCTA in assessmenting the stenosis of calcified coronary artery is its low accuracy of diagnosis.(2)The CCO difference across calcified coronary artery elevated as stenosis severity increased,the result may contribute to the defection of morphology imaging with CCTA,which improve the accuracy of diagnosis of CCTA,there for,it may be helpful by calculating the CCO difference to the morphology analysis with CCTA in assessmenting the stenosis of calcified coronary artery. |
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