1396 additional diagnostic value of MDCT in evaluation of PHV dysfunction, (3) and the best imaging protocols for PHV with special attention to dose reduction. Limitations The study has a retrospective study design. In addition to dedicated cardiac CT, 18 ECG-gated aortic CT studies with a lower mAs setting were included. The lower mAs setting may have negatively influenced image quality. However, the aortic scan protocol was not associated with a significant lower image quality score. Some PHVs were present in small numbers. However, MDCT scans of the currently most commonly implanted PHVs (Carbomedics, St Jude, ON-X, Sorin and Perimount) were available for at least 7 valves each. Despite a mean heart rate of 58 bpm during scanning there was a relatively wide range of heart rates (48–139). Although heart rates were not significantly correlated with a lesser CT image quality in our series, motion artefacts at higher heart rates may decrease image quality. In addition, aggressive heart rate lowering using beta blockers during scanning is contraindicated in some PHV patients as they may have poor left ventricular function and conduction abnormalities. Although no correlation between image quality and heart rate, type of CT system and CT protocol were found, it should be noted that this retrospective study was not specifically designed for this. Conclusion MDCT is a promising imaging technique to evaluate PHV dysfunction. Currently implanted PHVs generate only limited artefacts and are suitable for evaluation with MDCT. CT assessment of Björk-Shiley and Sorin mono- leaflet tilting disc PHVs is hampered by severe artefacts. Acknowledgements The present study was supported by a grant of the Netherlands Heart Foundation [Grant number 2009B014] Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which per- mits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Eur Radiol (2011) 21:1390–1396 References 1. Zoghbi WA, Chambers JB, Dumesnil JG, Foster E, Gottdiener JS, Grayburn PA, Khandheria BK, Levine RA, Marx GR, Miller FA Jr, Nakatani S, Quinones MA, Rakowski H, Rodriguez LL, Swaminathan M, Waggoner AD, Weissman NJ, Zabalgoitia M (2009) Recommendations for evaluation of prosthetic valves with echocardiography and doppler ultrasound: a report From the American Society of Echocardiography’s Guidelines and Standards Committee and the Task Force on Prosthetic Valves, developed in conjunction with the American College of Cardiology Cardiovascular Imaging Committee, Cardiac Imaging Committee of the American Heart Association, the European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography and the Canadian Society of Echocardiogra- phy, endorsed by the American College of Cardiology Founda- tion, American Heart Association, European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography, and Canadian Society of Echocardiography. J Am Soc Echocardiogr 22:975–1014 2. Girard SE, Miller FA Jr, Orszulak TA, Mullany CJ, Montgomery S, Edwards WD, Tazelaar HD, Malouf JF, Tajik AJ (2001) Reoper- ation for prosthetic aortic valve obstruction in the era of echocardiography: trends in diagnostic testing and comparison with surgical findings. J Am Coll Cardiol 37:579–584 3. Konen E, Goitein O, Feinberg MS, Eshet Y, Raanani E, Rimon U, Di-Segni E (2008) The role of ECG-gated MDCT in the evaluation of aortic and mitral mechanical valves: initial experience. Am J Roentgenol 191:26–31 4. Symersky P, Budde RPJ, de Mol BAJM, Prokop M (2009) Comparison of multidetector-row computed tomography to echocar- diography and fluoroscopy for evaluation of patients with mechanical prosthetic valve obstruction. Am J Cardiol 104:1128–1134 5. Teshima H, Hayashida N, Fukunaga S, Tayama E, Kawara T, Aoyagi S, Uchida M (2004) Usefulness of a multidetector-row computed tomography scanner for detecting pannus formation. Ann Thorac Surg 77:523–526 6. Tsai IC, Lin YK, Chang Y, Fu YC, Wang CC, Hsieh SR, Wei HJ, Tsai HW, Jan SL, Wang KY, Chen MC, Chen CC (2009) Correctness of multi-detector-row computed tomography for diagnosing mechanical prosthetic heart valve disorders using operative findings as a gold standard. Eur Radiol 19:857–867 7. Chenot F, Montant P, Goffinet C, Pasquet A, Vancraeynest D, Coche E, Vanoverschelde JL, Gerber BL (2010) Evaluation of anatomic valve opening and leaflet morphology in aortic valve bioprosthesis by using multidetector CT: comparison with trans- thoracic echocardiography. Radiology 255:377–385 8. Symersky P, Budde RPJ, Prokop M, de Mol BAJM (2009) Abstract 541: prosthetic valve evaluation using prospective triggering with 256-detector row computed tomography reduces radiation dose. Circulation 120:S355