Is there an effect of flat-panel-based imaging systems on quantitative coronary and vascular angiography?

Objectives: To study the possible effects on quantitative coronary or vascular analyses (QCA and QVA) on images of a flat-panel-based (FP-based) system. Background: Since a few years, more and more cardiovascular X-ray imaging systems are equipped with flat-panel detectors, replacing the conventional image intensifiers in combination with CCD cameras for the creation of the angiographic images. Methods: To assess any differences in QCA and QVA results from these two types of digital X-ray imaging systems, we performed a quantitative comparison study on images of the Medis coronary and vascular phantom, respectively. All phantom images were acquired on both a FP-based and an image intensifier-based (II-based) imaging system with different system settings (3 different kV-levels and 4 field of view sizes). Results: The QCA and QVA results showed that all the systematic and random errors for the subsets of the FP-based and II-based systems were very small and satisfy the QCA and QVA reference guidelines, though some of the subsets of the FP-based and II-based coronary and vascular phantom images demonstrate a statistically significant difference. However, given the small magnitude of these under- and overestimations under phantom conditions, these differences are considered clinically irrelevant. Conclusions: The image characteristics of the FP-based images do not have any significant influence on the results of QCA and QVA analyses. As a consequence, a further optimization of the contour detection algorithm is not necessary for FP-based images, and data from both II-based and FP-based X-ray imaging systems can be used collectively in (multicenter) clinical trials.