| Objective: To evaluate the effect of energy spectrum CT on in-stent restenosis after coronary stent implantation,and to analyze the effect of stent diameter,stent thickness and heart rate on its diagnostic efficacy.Background: With the development of coronary atherosclerotic heart disease(CAHD)and the development of coronary stenting,more and more patients underwent coronary stent implantation.One of the important problems facing patients after surgery is in-stent restenosis(ISR).The gold standard in the diagnosis of ISR is coronary angiography(CAG).However,CAG operation has more stringent requirements,there may be more complications,the price is more expensive,the patients' psychological pressure is greater,and other shortcomings.In recent years,coronary CT imaging technology has made great progress,in which energy spectrum CT can effectively reduce the artifacts caused by metal stents.It has a great advantage in follow-up after stent implantation.Materials and Methods: A total of 90 patients underwent coronary stent implantation in Affiliated Hospital of Qingdao University Medical College between January 2012 and December 2014,including 63 males and 27 females aged 45-68 years.A total of 174 stents were implanted.The actual number of stents may be evaluated as 134.All patients underwent CT coronary angiography and coronary angiography.The two methods were separated by 1-2 weeks.To evaluate the effect of energy spectrum CT on in-stent restenosis after coronary stent implantation,and to analyze the effect of stent diameter,stent thickness and heart rate on its diagnostic efficacy.Result:(1)Stents imaging score of energy spectrum CT: The average score of all 134 stents was 2.60 ± 0.80.Energy spectrum CT imaging score of stents with 2.5mm,2.75 mm,3.0mm,3.5mm and 4.0mm in diameter are 2.24 ± 0.89,2.42 ± 0.75,2.76 ± 0.74,2.83 ± 0.79,3.00 ± 0.82 points.The variance analysis showed that there was a statistically significant difference(F= 2.91,P= 0.02)between CT imaging scores of different diameter stents.CT imaging score of stents with strut thickness?0.09 mm is 2.52 ± 0.79 points,CT imaging score of stents with strut thickness<0.09 mm is 2.62 ± 0.80 points.There was no statistically significant difference between the two groups(t= 0.68,P= 0.50).The heart rate of all patients enrolled in this study was <75 beats / min.Heart rate ? 60 times / min: stents imaging score is 2.52 ± 0.82 points,heart rate <60 times / min: stents imaging score is 2.66 ± 0.78 points.There was no statistically significant difference between the two groups(t = 1.01,P = 0.31).(2)Evaluation of ISR by energy spectrum CT: The sensitivity of energy spectrum CT to evaluate ISR in patients was 100%,the specificity was 96.72%,the positive predictive value was 93.55%,the negative predictive value was 100% and the accuracy was 97.78%.X2 test shows that there is no significant differences between spectral CT imaging and coronary angiography for the assessment of ISR(P> 0.05).The sensitivity,specificity,positive predictive value and negative predictive value of energy spectrum CT to evaluate ISR in stents with 2.5mm in diameter were 66.67%,75.00%,66.67% and 75.00% respectively,and the accuracy was 71.43%.The sensitivity,specificity,positive predictive value and negative predictive value of energy spectrum CT to evaluate ISR in stents with 2.75 mm in diameter were 75.00%,79.17%,70.59% and 82.61% respectively,and the accuracy was 77.50%.The sensitivity,specificity,positive predictive value and negative predictive value of energy spectrum CT to evaluate ISR in stents with 3.0mm in diameter were 90.91%,97.50%,90.91% and 97.50% respectively,and the accuracy was 96.08%.The sensitivity,specificity,positive predictive value and negative predictive value of energy spectrum CT to evaluate ISR in stents with 3.5 and 4.0mm in diameter were 100%,100%,100% and 100% respectively,and the accuracy was 100%.X2 test showed that there were no statistically significant differences between the two methods(P> 0.05).The sensitivity of energy spectrum CT to evaluate ISR in stents with strut thickness ?0.09 mm was 75.00%,the specificity was 84.38%,the positive predictive value is 64.29%,the negative predictive value was 90.00% and the accuracy was 81.82%.The sensitivity of energy spectrum CT to evaluate ISR in stents with strut thickness ?0.09 mm is 80.77%,the specificity was 93.75%,the positive predictive value was 84.00%,the negative predictive value was 92.31%,and the accuracy was 90.00%.The heart rate of all patients enrolled in this study was <75 beats / min.Heart rate ? 60 times / min: The sensitivity of energy spectrum CT to evaluate ISR was 81.25%,the specificity was 88.10%,the positive predictive value was 72.22%,and the negative predictive value was 92.50%.Heart rate <60 times / min: The sensitivity of energy spectrum CT to evaluate ISR was 77.27%,the specificity was 92.59%,the positive predictive value was 80.95% and the negative predictive value was 90.91%.Conclusion: The imaging quality of stents evaluated by 128-slice energy spectrum CT is affected by the diameter of the stent,and is not affected by the heart rate(heart rate <75 times / min)and the thickness of the stent strut.The energy spectrum CT has excellent specificity for assessing in-stent restenosis.The 128-slice energy spectrum CT can be used as an important means for the follow-up of patients PCI with stent diameter ? 3.0mm.The 128-slice energy spectrum CT can be used as a primary screening tool for patients underwent PCI with stent diameter <3.0mm. |
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