Diagnostic Accuracy Of 64-Slice Multidetector Computed Tomography In The Assessment Of Coronary In-Stent Restenosis And The Patency Of Coronary Artery Bypass Grafts

Objective:By comparing the images between 64-slice multidetector computed tomography(MDCT) and selective coronary angiography,we expect to evaluate the visualization of coronary stents and its affecting factors,as well as to assess the diagnostic accuracy of 64-slice MDCT on coronary in-stent restenosis(ISR).Material and Methods:The study population consisted of 124 stents implanted in native coronary arteries in 67 consecutive patients(52 men,15 women) who underwent quantitive selective coronary angiography(QCA) preceded by 64-slice MDCT performed within 3 months period before QCA.With QCA as golden reference standard,ISR defined as percent diameter stenosis≥50%,two experienced observers evaluated the image quality and ISR analysis independently.Sensitivity, specificity,negative predictive value(NPV),and diagnostic accuracy of 64-slice MDCT are calculated,as well as the Kappa test between two observers.We compared ISR occurance between bare metallic stents(BMS) and drug eluting stents(DES),and also among different DESs.We also measured CT values in and peri assessable stent on 64-slice MDCT and draw the ROC curve.Results:Of 110 stents counted on CT(with overlapped stents counted as one,a total of 14 overlapped and 96 single stents),105(94.5%) were considered assessable. Among the 105 stented segments,64-slice MDCT correctly detected 15 in-stent restenosis and 3 in-stent occlusions.Yet 6 were false-positive.Sensitivity,specificity, positive predictive value,negative predictive value,and diagnostic accuracy were 72%(18/25),93%(74/8),75%(18/24),91%(74/81),and 88%(92/105).The ISR incidence of BMS was higher than that of DES,and there's no statistical difference among various types of DES.The CT values in hyperplastic stents were significantly lower than those patent stents.The ROC curve drawn from overall CT values in stents showed the area below the curve as 0.720.When the CT threshold value of ISR was 442.1HU,the sensivity and specificity of 64-slice MDCT of detecting significant ISR was 72 and 62%respectively.Conclusions:1.For selected patients with previous stent implantation,64-slice MDCT can be used to evaluate in-stent restenosis with high accuracy,which can be regular application of the follow-up of post PCI patients.2.Quantitative analysis by measuring CT values was less accurate than qualitative analysis,and can thus only be used as assistant method.Objectives:Comparing the images of 64-slice MDCT and selective coronary angiography,we discussed the ability of 64-slice MDCT imaging of coronary artery bypass grafts,and evaluated its diagnostic accuracy.Materials and Methods:46 patients(41 men,5 women) after bypass surgery with a total of 83 bypass grafts have underwent selective coronary angiography preceded by 64-slice MDCT performed within 3 months period before coronary angiography. With coronary angiography as golden reference standard,bypass grafts stenosis was defined as percent diameter stenosis≥50%.Two experienced observers evaluated the image quality and bypass grafts stenosis independently.Sensitivity,specificity, negative predictive value(NPV),and diagnostic accuracy of 64-slice MDCT are calculated,as well as the Kappa test between two observers.Results:Of 83 bypass grafts,82(98.8%) were considered assessable on 64-slice MDCT images.The only unassessable bypass graft was left internal mammary artery. Of 40 arterial bypass grafts,64-slice MDCT correctly detected 1 stenosis and 4 occlusions without false positive or false negative cases.Sensitivity,specificity, positive predictive value,negative predictive value,and diagnostic of 64-slice MDCT evaluating arterial bypass grafts were 100%(5/5),100%(35/35),100%(5/5),100% (35/35),and 100%(40/40) respectively.Of the rest 42 saphenous vein bypass grafts,6 stenosis and 8 occlusions were correctly detected by 64-slice MDCT.But there was one false negative case.Sensitivity,specificity,positive predictive value,negative predictive value,and diagnostic accuracy of 64-slice MDCT to detect signicant stenosis of saphenous vein bypass grafts were 93%(14/15),100%(27/27), 100%(14/14),96%(27/28),and 98%(41/42) respectively.Kappa analysis showed excellent interobserver agreement(k=0.89).Conclusions:For selected patients who have underwent coronary artery bypass grafts surgery,64-slice MDCT had high diagnostic accuracy and reliability,and can be the priority of regular non-invasive diagnostic technologies to evaluate the patency of bypass grafts.