Objectives: The aim of this study was to quantify image quality gains of a moving coronary plaque phantom using dual-source computed tomography (DSCT) providing 83 milliseconds temporal resolution in direct comparison to 64 slice single-source multidetector CT (MDCT) with a temporal resolution of 165 milliseconds. Materials and Methods: Three cardiac vessel phantoms with fixed 50% stenosis and changing plaque configurations were mounted on a moving device simulating cardiac motion. Scans were performed at a simulated heart frequency of 60 to 120 bpm. Image quality assessment was performed in different anatomic orientations inside a thoracic phantom. Results: A significant improvement of image quality using the DSCT could be found (P = 0.0002). Relevant factors influencing image quality aside from frequency (P = 0.0002) are plaque composition (P < 0.0001), as well as orientation (P < 0.0001). Conclusion: Scanning with 83 milliseconds temporal resolution improved image quality of coronary plaque at higher heart frequencies.