Effect of hybrid iterative reconstruction technique on quantitative and qualitative image analysis at 256-slice prospective gating cardiac CT

摘要

Objectives To evaluate the effect of hybrid iterative reconstruction on qualitative and quantitative parameters at 256- slice cardiac CT. Methods Prospective cardiac CT images from 20 patients were analysed. Paired image sets were created using 3 reconstructions, i.e. filtered back projection (FBP) and moderate- and high-level iterative reconstructions. Quantitative parameters including CT-attenuation, noise, and contrast-to-noise ratio (CNR) were determined in both proximal- and distal coronary segments. Image quality was graded on a 4-point scale. Results Coronary CT attenuation values were similar for FBP, moderate- and high-level iterative reconstruction at 293±74-, 290±75-, and 283±78 Hounsfield units (HU), respectively. CNR was significantly higher with moderate- and high-level iterative reconstructions (10.9±3.5 and 18.4±6.2, respectively) than FBP (8.2±2.5) as was the visual grading of proximal vessels. Visualisation of distal vessels was better with highlevel iterative reconstruction than FBP. The mean number of assessable segments among 289 segments was 245, 260, and 267 for FBP, moderate- and high-level iterative reconstruction, respectively; the difference between FBP and high-level iterative reconstruction was significant. Interobserver agreement was significantly higher for moderate- and high-level iterative reconstruction than FBP. Conclusions Cardiac CT using hybrid iterative reconstruction yields higher CNR and better image quality than FBP. Key Points ? Cardiac CT helps clinicians to assess patients with coronary artery disease ? Hybrid iterative reconstruction provides improved cardiac CT image quality ? Hybrid iterative reconstruction improves the number of assessable coronary segments ? Hybrid iterative reconstruction improves interobserver agreement on cardiac CT.