Helical prospective ECG-gating in cardiac computed tomography: radiation dose and image quality

  • Tony DeFrance
  • Eric Dubois
  • Dan Gebow
  • Alex Ramirez
  • Florian Wolf
  • Gudrun M. Feuchtner
Original Paper


Helical prospective ECG-gating (pECG) may reduce radiation dose while maintaining the advantages of helical image acquisition for coronary computed tomography angiography (CCTA). Aim of this study was to evaluate helical pECG–gating in CCTA in regards to radiation dose and image quality. 86 patients undergoing 64-multislice CCTA were enrolled. pECG-gating was performed in patients with regular heart rates (HR) < 65 bpm; with the gating window set at 70–85% of the cardiac cycle. All patients received oral and some received additional IV beta-blockers to achieve HR < 65 bpm. In patients with higher or irregular HR, or for functional evaluation, retrospective ECG-gating (rECG) was performed. The average X-ray dose was estimated from the dose length product. Each arterial segment (modified AHA/ACC 17-segment-model) was evaluated on a 4-point image quality scale (4 = excellent; 3 = good, mild artefact; 2 = acceptable, some artefact, 1 = uninterpretable). pECG-gating was applied in 57 patients, rECG-gating in 29 patients. There was no difference in age, gender, body mass index, scan length or tube output settings between both groups. HR in the pECG-group was 54.7 bpm (range, 43–64). The effective radiation dose was significantly lower for patients scanned with pECG-gating with mean 6.9 mSv ± 1.9 (range, 2.9–10.7) compared to rECG with 16.9 mSv ± 4.1 (P < 0.001), resulting in a mean dose reduction of 59.2%. For pECG-gating, out of 969 coronary segments, 99.3% were interpretable. Image quality was excellent in 90.2%, good in 7.8%, acceptable in 1.3% and non-interpretable in 0.7% (n = 7 segments). For patients with steady heart rates <65 bpm, helical prospective ECG-gating can significantly lower the radiation dose while maintaining high image quality.


Computed tomography Coronary arteries Radiation dose 



Computed tomography


Cardiac computed tomography angiography




Beats per minute


Prospective ECG-gating


Retrospective ECG-gating



Conflict of interest statement

TD is member of the Speakers Bureau for Toshiba Medical Systems.


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Copyright information

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

Authors and Affiliations

  • Tony DeFrance
    • 1
    • 2
  • Eric Dubois
    • 5
  • Dan Gebow
    • 1
  • Alex Ramirez
    • 1
  • Florian Wolf
    • 4
  • Gudrun M. Feuchtner
    • 3
  1. 1.CVCTA EducationSan FranciscoUSA
  2. 2.Department of CardiologyStanford UniversityPalo AltoUSA
  3. 3.Department of Radiology IIInnsbruck Medical UniversityInnsbruckAustria
  4. 4.Department of RadiologyVienna Medical UniversityViennaAustria
  5. 5.Ikazia HospitalRotterdamThe Netherlands

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