Effect of coronary CT angiography in evaluation of in-stent restenosis based on intravascular ultrasound

Objective To explore the accuracy of coronary CT angiography (CCTA) in evaluation of postoperative in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) taking intravascular ultrasound (IVUS) as golden criteria.

Methods The basic information and imaging data of 60 patients (80 target vessels with intravascular stents) with coronary stent implantation who underwent CCTA and IVUS within 4 weeks in the same period were retrospectively collected.According to the diameter of stents, target vessels were divided into group A (stent diameter>3.0 mm) and group B (stent diameter≤ 3.0 mm).Group A and group B were further divided into group A1 and group B1(internal stent lesion), and group A2 and group B2(edge lesion) according to the lesion segment (inside stent or within 5 mm of stent edge).Group 1 included group A1 and group B1, and group 2 included group A2 and group B2.The IVUS results were taken as "gold standard" to evaluate the results of CCTA in quantitative detection of in-stent lesions and its accuracy in diagnosing in-stent lesions with different inner diameters and in different ISR segments.

Results The quantitative results of CCTA in in-stent lesions (minimum lumen diameter, mean vessel diameter, minimum lumen area, plaque area, plaque length, external elastic membrane area, plaque load and plaque volume) had significant positive correlations with the quantitative results of IVUS (P < 0.001).The specificity (92.86%), sensitivity (92.59%) and accuracy (92.68%) of ISR by CCTA in group A (n=41) were higher, and were consistent with the results of IVUS (Kappa=0.840, P < 0.001).The specificity (88.24%), sensitivity (86.36%) and accuracy (87.18%) of ISR by CCTA in the group B were lower than those of the group A, which had moderate consistence with the results of IVUS (Kappa=0.741, P < 0.001).There was no significant difference in the diagnosis of identifying ISR between group A and B (P=0.523), between group 1 and group 2(P=0.212) and between group A2 and group B2(P=0.484).However, there was significant difference in the diagnosis of identifying ISR between group A1 and B1 by CCTA (P=0.011).

Conclusion CCTA has good accuracy in quantitative detection of ISR, and has higher reliability in identification of ISR in in-stent with diameter >3.0 mm and at the edge of stents with different inner diameters, but the diagnosis of internal stent ISR with diameter ≤3.0 mm is inaccurate.