Investigation on the factors affecting the image quality of 64-director spiral CT coronary angiography after coronary stent im-plantation

PENG Feng-he; PENG Ru-chen; MA Guo-wu; WA NG Xiao-yan; ZHOU Hong; ZHA NG Dian-ping

Abstract：Objective To investigate factors affecting the image quality of coronary angiography (CTA) with 64‐detector spiral CT after coronary stent implantation .Methods 41 consecutive patients with previous cononary stent implantation with 82 stainless steel drug‐eluting stents were included in this study to analyze whether the patient’s heart rate ,the stent diameter and the stent wall thickness affected the CTA image quality .And then ,we evaluated the accuracy of CTA in the diagnosis of in‐stent restenosis (ISR) compared with the coronary angiography (CAG) as the“gold standard” .Results 10 ISRs were detected by CAG in the 82 stents ,14 stents could not be evaluated by CTA because of poor image quality .Of 68 evaluable stents ,there were 65 stents (95 .6% ) with the paten’s heart rate <70 beats per minute(bpm) ,54 stents (79.4% ) with stent diameter ≥3 .0 mm ,and 53 stents (77 .9% ) with stent wall thickness <140μm .14 stents were un‐evaluable ,of which there were 12 stents (85 .7% ) in patients with heart rate≥70 bpm and 12 with stent diameter <3.0 mm ,13 stents (92 .9% ) with wall thickness ≥140μm .Of 68 stents which could be assessed by CTA ,6 ISRs were detec‐ted by CAG ,and 7 by CTA which included 2 false positive and 1 false negative ,and the diagnostic sensitivity ,specificity , positive predictive value and negative predictive value of ISR with CTA were 83 .3% ,96 .8% ,71 .4% and 98 .4% ,and the difference was no statistically significant ( P >0 .05) compared with CAG .Conclusion 64‐detector Spiral CT Coronary Angiography can accurately evaluate in‐stent restenosis of coronary artery .The heart rate of the patient ,stent diameter and wall thickness of stent can affect image quality ,the slower heart rate ,thinner‐walled and large diameter stent can be better assessed .