Eur Radiol (2012) 22:1278–1286 coronary artery assessment. These PHVs are mainly com- posed of titanium alloys that are associated with only limited artefacts on MDCT [8]. The biological PHVs and annuloplasty rings produced fewer PHV artefacts than mechanical PHVs on MDCT. Some biological PHVs have a radiopaque frame that sup- ports the valve leaflets, but this does not generally induce many artefacts [2, 9]. In our study, no PHV-related artefacts that interfered with diagnostic coronary assessment were found in biological PHVs or annuloplasty rings. Prosthetic heart valves in the aortic position may show mainly artefacts in the proximal RCA (segments 1 and 2) because of the close relationship between the aortic PHV and the proximal RCA. Interestingly, the left main branch, which also has a close relationship with the aortic PHV, did not show any PHV-related artefacts. The reason for the absence of PHV- related artefacts in this segment may be the angulation of the PHV with respect to the X-ray beam of the gantry. In the mitral position, PHV-related artefacts occurred in the LCX and MO branches. The close relationship between these segments and the mitral PHV position is a likely explanation for the presence of the PHV-related artefacts in these specific segments. Limitations Our study contains many different PHV types. A few PHV types are only represented in small numbers. However the most commonly implanted PHVs (Carbomedics, St Jude, Medtronic Hall and the Perimount biological PHVs) are present in considerable numbers. The mean heart rate of 73 ± 18 bpm is relatively high for CT coronary assessment because 79 of 82 CTAs (96%) were performed for other clinical indications without a specific heart rate reduction. High heart rates may cause considerable motion artefacts that influence diagnostic CAD assessment. However, the specific interest of this study was to address the question: do PHV-related artefacts disturb coronary assessment? Other reports emphasised the importance of an optimal heart rate and the restricted diagnostic value of MDCT in the detection of CAD in distal coronary segments [13]. To optimize coronary image quality, beta-blockers and nitro- glycerin should be routinely administered in patients with- out contraindications for these drugs. In this study, CT coronary angiography was not compared with conventional coronary angiography. Further prospective studies are re- quired to determine the diagnostic accuracy of CT coronary angiography in patients after PHV implantation. However, as most commonly implanted PHV types generate only limited artefacts, we would expect the diagnostic accuracy to be close to published results in patients who have not yet undergone PHV implantation [13]. Consensus reading was performed. Interobserver variability has to be investigated in 1285 further studies to validate the PHV-related artefacts scoring system. Axial CT images only were assessed for the presence of PHV-related artefacts. Multiplanar reconstructions were not separately assessed because PHV-related artefacts were pres- ent in both axial and multiplanar reconstructions. In conclusion, the most commonly implanted PHVs do not cause artefacts that prohibit coronary artery assessment of at least one coronary segment by MDCT. Carbomedics, Med- tronic Hall and ON-X mechanical PHVs, bioprosthesis, and annuloplasty rings virtually never hamper coronary artery as- sessment by MDCT. However, in patients with a Björk–Shiley or Sorin tilting PHV, coronary artery assessment by MDCT is virtually always hampered by PHV induced artefacts. Acknowledgement We thank K.A. van Rijnbach (Department of Radi- ology, University Medical Center Utrecht) for her help with the final edition of the Figures and I.G. Janssen (Department of Multimedia Pro- duction, University Medical Center Utrecht) for designing Figure 1 and 6. The present study was supported by a grant from the Netherlands Heart Foundation [Grant number 2009B014] Open Access This article is distributed under the terms of the Crea- tive Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. References 1. Meijboom WB, Meijs MF, Schuijf JD et al (2008) Diagnostic accuracy of 64-slice computed tomography coronary angiography: a prospective, multicenter, multivendor study. J Am Coll Cardiol 52:2135–2144 2. Chenot F, Montant P, Goffinet C et al (2010) Evaluation of anatomic valve opening and leaflet morphology in aortic valve bioprosthesis by using multidetector CT: comparison with transthoracic echocar- diography. Radiology 255:377–385 3. 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