Combined Use of Automatic Tube Potential Selection with Tube Current Modulation and Iterative Reconstruction Technique in Coronary CT Angiography

Abstract

To analyze the effect of automatic tube potential selection with tube current modulation (APSCM) and iterative reconstruction on image quality, diagnostic accuracy, and radiation dose at computed tomographic (CT) angiography and compare it with APSCM-only and body mass index (BMI)-based examination protocols. This study was approved by the institutional review board, and informed consent was obtained from all patients. Images from 185 patients who underwent a BMI-based protocol and 197 patients who underwent an APSCM protocol with filtered back projection (FBP) and an APSCM protocol with sinogram-affirmed iterative reconstruction (SAFIRE) were retrospectively evaluated. Diagnostic performance was compared with that of conventional coronary angiography in a subgroup of 51 patients. Statistical analysis was performed by using the independent or paired t test, Mann-Whitney U test, Wilcoxon signed rank test, χ(2) statistics, linear weighted κ statistics, and generalized estimating equation. The APSCM group with SAFIRE had a significant reduction in image noise and a significant increase in CT number, contrast enhancement, signal-to-noise ratio, and contrast-to-noise ratio compared with the APSCM group with FBP (P < .0001) and the BMI-based group (P < .001, except P = .002 for image noise). Image quality and diagnostic accuracy showed no significant difference between the three groups. The use of APSCM resulted in a significant reduction in radiation dose compared with the BMI-based protocol. The combination of SAFIRE and APSCM at coronary CT angiography significantly improves objective image quality while maintaining diagnostic accuracy and reduced radiation dose. Online supplemental material is available for this article.