New radiation dose saving technologies for 256-slice cardiac computed tomography angiography

  • Matthew J. Walker
  • Mark E. Olszewski
  • Milind Y. Desai
  • Sandra S. Halliburton
  • Scott D. Flamm
Original Paper


Purpose This paper aims to evaluate the dose reductions conferred by spiral dynamic z-collimation and axial adaptive z-collimation for retrospectively and prospectively ECG-referenced cardiac CTA, respectively, on a wide coverage, 256-slice CT scanner. Methods Using typical data presented in the literature, a distribution of cardiac CT scan lengths was synthesized. To isolate the effect of z-overscan on effective radiation dose, 1,000 simulated patient scan lengths were then randomly sampled from this distribution and used for subsequent analysis. Results Retrospectively ECG-gated spiral scans with dynamic z-collimation resulted in a mean relative effective dose reduction of 11.7 and 24.3% for MDCT with 40 and 80 mm z-axis detector coverage, respectively. Mean relative dose reduction of prospectively ECG-triggered axial scans with adaptive z-collimation on an 80 mm coverage scanner was 10.0%. Conclusion Dynamic z-collimation for retrospectively ECG-gated spiral scanning and adaptive z-collimation for prospectively ECG-triggered axial scanning are both associated with a significant dose reduction on a wide coverage, 256-slice CT scanner.


256-Slice MDCT Prospective triggering Retrospective gating Radiation exposure Radiation reduction Coronary CT angiography Step-and-shoot Low dose Dose efficiency 


Conflict of interest

Matthew J. Walker and Mark E. Olszewski are employees of Philips Healthcare (Cleveland, OH, USA) and led the data simulation and statistical analysis. All authors reviewed and confirmed the results, and Scott D. Flamm takes scientific responsibility for data integrity.


  1. 1.
    Budoff MJ, Dowe D, Jollis JG et al (2008) Diagnostic performance of 64-multidetector row coronary computed tomographic angiography for evaluation of coronary artery stenosis in individuals without known coronary artery disease: results from the prospective multicenter ACCURACY (Assessment by Coronary Computed Tomographic Angiography of Individuals Undergoing Invasive Coronary Angiography) trial. J Am Coll Cardiol 52:1724–1732. doi: 10.1016/j.jacc.2008.07.031 PubMedCrossRefGoogle Scholar
  2. 2.
    Watkins MW, Hesse B, Green CE et al (2007) Detection of coronary artery stenosis using 40-channel computed tomography with multi-segment reconstruction. Am J Cardiol 99:175–181. doi: 10.1016/j.amjcard.2006.07.081 PubMedCrossRefGoogle Scholar
  3. 3.
    Garcia MJ, Lessick J, Hoffmann MHK et al (2006) Accuracy of 16-row multidetector computed tomography for the assessment of coronary artery stenosis. JAMA 296:403–411. doi: 10.1001/jama.296.4.403 PubMedCrossRefGoogle Scholar
  4. 4.
    Leschka S, Alkadhi H, Plass A et al (2005) Accuracy of MSCT coronary angiography with 64-slice technology: first experience. Eur Heart J 26:1482–1487. doi: 10.1093/eurheartj/ehi261 PubMedCrossRefGoogle Scholar
  5. 5.
    Miller JM, Rochitte CE, Dewey M et al (2008) Diagnostic performance of coronary angiography by 64-row CT. N Engl J Med 359:2324–2336. doi: 10.1056/NEJMoa0806576 PubMedCrossRefGoogle Scholar
  6. 6.
    Phurrough SE, Salive ME, Baldwin J et al. (2008) Decision memo for computed tomographic angiography (CAG-00385 N). In: Medicare National Coverage Determinations Manual. Sect. 220.1F. CMS publication 100-03. Centers for Medicare & Medicaid Services, Baltimore, MD, USA. Accessed December 7, 2008
  7. 7.
    Brenner DJ, Hall EJ (2007) Computed tomography—an increasing source of radiation exposure. N Engl J Med 357:2277–2284. doi: 10.1056/NEJMra072149 PubMedCrossRefGoogle Scholar
  8. 8.
    Budoff MJ, Achenbach S, Blumenthal RS et al (2006) Assessment of coronary artery disease by cardiac computed tomography: a scientific statement from the American Heart Association Committee on Cardiovascular Imaging and Intervention, Council on Cardiovascular Radiology and Intervention, and Committee on Cardiac Imaging, Council on Clinical Cardiology. Circulation 114:1761–1791. doi: 10.1161/CIRCULATIONAHA.106.178458 PubMedCrossRefGoogle Scholar
  9. 9.
    Einstein AJ, Moser KW, Thompson RC et al (2007) Radiation dose to patients from cardiac diagnostic imaging. Circulation 116:1290–1305. doi: 10.1161/CIRCULATIONAHA.107.688101 PubMedCrossRefGoogle Scholar
  10. 10.
    Paul JF, Abada HT (2007) Strategies for reduction of radiation dose in cardiac multislice CT. Eur Radiol 17:2028–2037. doi: 10.1007/s00330-007-0584-3 PubMedCrossRefGoogle Scholar
  11. 11.
    Coles DR, Smail MA, Negus IS et al (2006) Comparison of radiation doses from multislice computed tomography coronary angiography and conventional diagnostic angiography. J Am Coll Cardiol 47:1840–1845. doi: 10.1016/j.jacc.2005.11.078 PubMedCrossRefGoogle Scholar
  12. 12.
    Greess H, Nömayr A, Wolf H et al (2002) Dose reduction in CT examination of children by an attenuation-based on-line modulation of tube current (CARE Dose). Eur Radiol 12:1571–1576. doi: 10.1007/s00330-001-1255-4 PubMedCrossRefGoogle Scholar
  13. 13.
    Kalra MK, Maher MM, Toth TL et al (2004) Comparison of Z-axis automatic tube current modulation technique with fixed tube current CT scanning of abdomen and pelvis. Radiology 232:347–353. doi: 10.1148/radiol.2322031304 PubMedCrossRefGoogle Scholar
  14. 14.
    Deetjen A, Möllmann S, Conradi G et al (2007) Use of automatic exposure control in multislice computed tomography of the coronaries: comparison of 16-slice and 64-slice scanner data with conventional coronary angiography. Heart 93:1040–1043. doi: 10.1136/hrt.2006.103838 PubMedCrossRefGoogle Scholar
  15. 15.
    Kalra MK, Maher MM, Toth TL et al (2004) Techniques and applications of automatic tube current modulation for CT. Radiology 233:649–657. doi: 10.1148/radiol.2333031150 PubMedCrossRefGoogle Scholar
  16. 16.
    Kalender WA, Wolf H, Suess C et al (1999) Dose reduction in CT by on-line tube current control: principles and validation on phantoms and cadavers. Eur Radiol 9:323–328. doi: 10.1007/s003300050674 PubMedCrossRefGoogle Scholar
  17. 17.
    Gies M, Kalender WA, Wolf H et al (1999) Dose reduction in CT by anatomically adapted tube current modulation. I. Simulation studies. Med Phys 26:2235–2247. doi: 10.1118/1.598779 Google Scholar
  18. 18.
    Greess H, Lutze J, Nömayr A et al (2004) Dose reduction in subsecond multislice spiral CT examination of children by online tube current modulation. Eur Radiol 14:995–999. doi: 10.1007/s00330-004-2301-9 PubMedCrossRefGoogle Scholar
  19. 19.
    Poll LW, Cohnen M, Brachten S et al (2002) Dose reduction in multi-slice CT of the heart by use of ECG-controlled tube current modulation (“ECG pulsing”): phantom measurements. Rofo 174:1500–1505PubMedGoogle Scholar
  20. 20.
    Hausleiter J, Meyer T, Hadamitzky M et al (2006) Radiation dose estimates from cardiac multislice computed tomography in daily practice: impact of different scanning protocols on effective dose estimates. Circulation 113:1305–1310. doi: 10.1161/CIRCULATIONAHA.105.602490 PubMedCrossRefGoogle Scholar
  21. 21.
    Gutstein A, Dey D, Cheng V et al (2008) Algorithm for radiation dose reduction with helical dual source coronary computed tomography angiography in clinical practice. J Cardiovasc Comput Tomogr 2:311–322. doi: 10.1016/j.jcct.2008.07.003 PubMedCrossRefGoogle Scholar
  22. 22.
    Nakayama Y, Awai K, Funama Y et al (2005) Abdominal CT with low tube voltage: preliminary observations about radiation dose, contrast enhancement, image quality, and noise. Radiology 237:945–951. doi: 10.1148/radiol.2373041655 PubMedCrossRefGoogle Scholar
  23. 23.
    Earls JP, Berman EL, Urban BA et al (2008) Prospectively gated transverse coronary CT angiography versus retrospectively gated helical technique: improved image quality and reduced radiation dose. Radiology 246:742–753. doi: 10.1148/radiol.2463070989 PubMedCrossRefGoogle Scholar
  24. 24.
    Gutstein A, Wolak A, Lee C et al (2008) Predicting success of prospective and retrospective gating with dual-source coronary computed tomography angiography: development of selection criteria and initial experience. J Cardiovasc Comput Tomogr 2:81–90PubMedCrossRefGoogle Scholar
  25. 25.
    Hirai N, Horiguchi J, Fujioka C et al (2008) Prospective versus retrospective ECG-gated 64-detector coronary CT angiography: assessment of image quality, stenosis, and radiation dose. Radiology 248:424–430. doi: 10.1148/radiol.2482071804 PubMedCrossRefGoogle Scholar
  26. 26.
    Husmann L, Valenta I, Gaemperli O et al (2008) Feasibility of low-dose coronary CT angiography: first experience with prospective ECG-gating. Eur Heart J 29:191–197. doi: 10.1093/eurheartj/ehm613 PubMedCrossRefGoogle Scholar
  27. 27.
    Klass O, Jeltsch M, Feuerlein S et al. (2008) Prospectively gated axial CT coronary angiography: preliminary experiences with a novel low-dose technique. Eur Radiol. doi: 10.1007/s00330-008-1222-4 Google Scholar
  28. 28.
    Rybicki FJ, Otero HJ, Steigner ML et al (2008) Initial evaluation of coronary images from 320-detector row computed tomography. Int J Cardiovasc Imaging 24:535–546. doi: 10.1007/s10554-008-9308-2 PubMedCrossRefGoogle Scholar
  29. 29.
    Scheffel H, Alkadhi H, Leschka S et al (2008) Low-dose CT coronary angiography in the step-and-shoot mode: diagnostic performance. Heart 94:1132–1137. doi: 10.1136/hrt.2008.149971 PubMedCrossRefGoogle Scholar
  30. 30.
    Shuman WP, Branch KR, May JM et al (2008) Prospective versus retrospective ECG gating for 64-detector CT of the coronary arteries: comparison of image quality and patient radiation dose. Radiology 248:431–437. doi: 10.1148/radiol.2482072192 PubMedCrossRefGoogle Scholar
  31. 31.
    Stolzmann P, Leschka S, Scheffel H et al (2008) Dual-source CT in step-and-shoot mode: noninvasive coronary angiography with low radiation dose. Radiology 249:71–80. doi: 10.1148/radiol.2483072032 PubMedCrossRefGoogle Scholar
  32. 32.
    Hsieh J, Londt J, Vass M et al (2006) Step-and-shoot data acquisition and reconstruction for cardiac x-ray computed tomography. Med Phys 33:4236–4248. doi: 10.1118/1.2361078 PubMedCrossRefGoogle Scholar
  33. 33.
    Toth TL, Cesmeli E, Ikhlef A et al. (2005) Image quality and dose optimization using novel x-ray source filters tailored to patient size. In: Flynn MJ (ed) Proceedings of the SPIE. Medical Imaging 2005: Physics of Medical Imaging, vol 5745. SPIE Press, Bellingham, WA, USA, pp 283–291Google Scholar
  34. 34.
    Kalender W (2008) Cardiac and thoracic CT should be carried out at low voltages. In: Glazer GM, Rubin GD (eds) Proceedings of the 10th Annual International Symposium on Multidetector-row CT. Available online at
  35. 35.
    Flohr TG, Schaller S, Stierstorfer K et al (2005) Multi-detector row CT systems and image-reconstruction techniques. Radiology 235:756–773. doi: 10.1148/radiol.2353040037 PubMedCrossRefGoogle Scholar
  36. 36.
    Nicholson R, Fetherston S (2002) Primary radiation outside the imaged volume of a multislice helical CT scan. Br J Radiol 75:518–522PubMedGoogle Scholar
  37. 37.
    Goodman-Mumma C (2006) CT dose optimization. Med Imaging Accessed 12 Dec 2008
  38. 38.
    Rydberg J, Buckwalter KA, Caldemeyer KS et al (2000) Multisection CT: scanning techniques and clinical applications. Radiographics 20:1787–1806PubMedGoogle Scholar
  39. 39.
    Dewey M, Hoffmann H, Hamm B (2007) CT coronary angiography using 16 and 64 simultaneous detector rows: intraindividual comparison. Rofo 179:581–586PubMedGoogle Scholar
  40. 40.
    Grass M, Manzke R, Nielsen T et al (2003) Helical cardiac cone beam reconstruction using retrospective ECG gating. Phys Med Biol 48:3069–3084. doi: 10.1088/0031-9155/48/18/308 PubMedCrossRefGoogle Scholar
  41. 41.
    Manzke R, Koken P, Hawkes D et al (2005) Helical cardiac cone beam CT reconstruction with large area detectors: a simulation study. Phys Med Biol 50:1547–1568. doi: 10.1088/0031-9155/50/7/016 PubMedCrossRefGoogle Scholar
  42. 42.
    Grass M, Köhler T, Proksa R (2000) 3D cone-beam CT reconstruction for circular trajectories. Phys Med Biol 45:329–347. doi: 10.1088/0031-9155/45/2/306 PubMedCrossRefGoogle Scholar
  43. 43.
    Hausleiter J, Meyer T, Hermann F et al (2008) International prospective multicenter study on radiation dose estimates of coronary CT angiography in daily practice—the PROTECTION I study. J Am Coll Cardiol 51(suppl A):A137 (abstract)Google Scholar
  44. 44.
    Achenbach S, Ulzheimer S, Baum U et al (2000) Noninvasive coronary angiography by retrospectively ECG-gated multislice spiral CT. Circulation 102:2823–2828PubMedGoogle Scholar
  45. 45.
    Hausleiter J, Meyer T, Hadamitzky M et al (2007) Non-invasive coronary computed tomographic angiography for patients with suspected coronary artery disease: the coronary angiography by computed tomography with the use of a submillimeter resolution (CACTUS) trial. Eur Heart J 28:3034–3041. doi: 10.1093/eurheartj/ehm150 PubMedCrossRefGoogle Scholar
  46. 46.
    Dewey M, Teige F, Laule M et al (2007) Influence of heart rate on diagnostic accuracy and image quality of 16-slice CT coronary angiography: comparison of multisegment and halfscan reconstruction approaches. Eur Radiol 17:2829–2837. doi: 10.1007/s00330-007-0685-z PubMedCrossRefGoogle Scholar
  47. 47.
    Sato Y, Matsumoto N, Kato M et al (2003) Noninvasive assessment of coronary artery disease by multislice spiral computed tomography using a new retrospectively ECG-gated image reconstruction technique. Circ J 67:401–405. doi: 10.1253/circj.67.401 PubMedCrossRefGoogle Scholar
  48. 48.
    Willmann JK, Weishaupt D, Lachat M et al (2002) Electrocardiographically gated multi-detector row CT for assessment of valvular morphology and calcification in aortic stenosis. Radiology 225:120–128. doi: 10.1148/radiol.2251011703 PubMedCrossRefGoogle Scholar
  49. 49.
    Hausleiter J, Meyer T (2008) Tips to minimize radiation exposure. J Cardiovasc Comput Tomogr 2:325–327. doi: 10.1016/j.jcct.2008.08.012 PubMedCrossRefGoogle Scholar
  50. 50.
    Halliburton SS (2008) One-scan protocol does not fit all: responsible cardiovascular imaging with computed tomography. J Cardiovasc Comput Tomogr 2:323–324. doi: 10.1016/j.jcct.2008.08.009 PubMedCrossRefGoogle Scholar
  51. 51.
    McCollough C, Cody D, Edyvean S et al. (2008) The measurement, reporting, and management of radiation dose in CT. Tech. Rep. 96 American Association of Physicists in Medicine, College Park, MD, USAGoogle Scholar
  52. 52.
    Shrimpton PC (2004) Assessment of patient dose in CT. Tech. Rep. NRPB-PE/1/2004 National Radiological Protection Board, Health Protection Agency, London, UKGoogle Scholar
  53. 53.
    Jakobs TF, Becker CR, Ohnesorge B et al (2002) Multislice helical CT of the heart with retrospective ECG gating: reduction of radiation exposure by ECG-controlled tube current modulation. Eur Radiol 12:1081–1086. doi: 10.1007/s00330-001-1278-x PubMedCrossRefGoogle Scholar
  54. 54.
    Leschka S, Scheffel H, Desbiolles L et al (2007) Image quality and reconstruction intervals of dual-source CT coronary angiography: recommendations for ECG-pulsing windowing. Invest Radiol 42:543–549. doi: 10.1097/RLI.0b013e31803b93cf PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, B.V. 2009

Authors and Affiliations

  • Matthew J. Walker
    • 1
  • Mark E. Olszewski
    • 1
  • Milind Y. Desai
    • 2
    • 3
  • Sandra S. Halliburton
    • 3
    • 4
  • Scott D. Flamm
    • 2
    • 3
  1. 1.CT Clinical SciencePhilips HealthcareClevelandUSA
  2. 2.Department of Cardiovascular Medicine, Heart and Vascular InstituteCleveland ClinicClevelandUSA
  3. 3.Cardiovascular Imaging Laboratory, Department of Radiology, Imaging InstituteCleveland ClinicClevelandUSA
  4. 4.Department of Biomedical EngineeringCleveland ClinicClevelandUSA

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