Dual-source CT angiography for detection and quantification of in-stent restenosis in the left main coronary artery: comparison with intracoronary ultrasound and coronary angiography.

Objectives: The aim of this study was to evaluate the diagnostic accuracy of dual-source computed tomography coronary angiography (CTCA) compared to coronary angiography (CAG) and intravascular ultrasound (IVUS) for detection and quantification of in-stent restenosis after left main (LM) coronary artery stenting.
Materials and Methods: Fifty-one patients with percutaneous coronary intervention of the LM were prospectively evaluated. Thirty-four of them underwent 56 complete follow-up examinations (CTCA, CAG, and IVUS as gold standard examination) that focused on detection and quantification of restenosis.
Results: Sensitivity, specificity, and positive and negative predictive values were 100%, 94%, 50%, and 100% for CAG, respectively, and 100%, 74%, 18%, and 100% for CTCA, respectively. There was a correlation between the minimal luminal areas (MLA) measured by CTCA and IVUS (r = 0.63; P<.01). A Bland-Altman analysis showed that the MLA measured by CTCA was underestimated (mean difference, 2.14 ± 2.24 mm²).
Conclusion: Dual-source CTCA has a high negative predictive value and might be considered a less invasive alternative to CAG for exclusion of LM in-stent restenosis. However, there was only a moderate correlation between the MLA measurements by IVUS and CTCA in the stented LMs. Moreover, the present results suggest a systematic underestimation of MLAs measured by CTCA. Therefore, finding of any restenosis according to CTCA should be re-evaluated by CAG or, better, by subsequent IVUS.