Abstract
Objectives
To analyse the effects of radiation dose reduction and iterative reconstruction (IR) algorithms on coronary calcium scoring (CCS).
Methods
Fifteen ex vivo human hearts were examined in an anthropomorphic chest phantom using computed tomography (CT) systems from four vendors and examined at four dose levels using unenhanced prospectively ECG-triggered protocols. Tube voltage was 120 kV and tube current differed between protocols. CT data were reconstructed with filtered back projection (FBP) and reduced dose CT data with IR. CCS was quantified with Agatston scores, calcification mass and calcification volume. Differences were analysed with the Friedman test.
Results
Fourteen hearts showed coronary calcifications. Dose reduction with FBP did not significantly change Agatston scores, calcification volumes and calcification masses (P > 0.05). Maximum differences in Agatston scores were 76, 26, 51 and 161 units, in calcification volume 97, 27, 42 and 162 mm3, and in calcification mass 23, 23, 20 and 48 mg, respectively. IR resulted in a trend towards lower Agatston scores and calcification volumes with significant differences for one vendor (P < 0.05). Median relative differences between reference FBP and reduced dose IR for Agatston scores remained within 2.0–4.6 %, 1.0–5.3 %, 1.2–7.7 % and 2.6–4.5 %, for calcification volumes within 2.4–3.9 %, 1.0–5.6 %, 1.1–6.4 % and 3.7–4.7 %, for calcification masses within 1.9–4.1 %, 0.9–7.8 %, 2.9–4.7 % and 2.5–3.9 %, respectively. IR resulted in increased, decreased or similar calcification masses.
Conclusions
CCS derived from standard FBP acquisitions was not affected by radiation dose reductions up to 80 %. IR resulted in a trend towards lower Agatston scores and calcification volumes.
Key points
• In this ex vivo study, radiation dose could be reduced by 80 % for coronary calcium scoring
• Iterative reconstruction resulted in a trend towards lower Agatston scores and calcification volumes
• Caution should be taken for coronary calcium scoring with iterative reconstruction
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Abbreviations
- AIDR 3D:
-
adaptive iterative dose reduction 3D
- ASIR:
-
adaptive statistical iterative reconstruction
- CCS:
-
coronary calcium score
- CT:
-
computed tomography
- CTDIvol :
-
volumetric CT dose index
- ECG:
-
electrocardiogram
- FBP:
-
filtered back projection
- HU:
-
Hounsfield units
- ICC:
-
intraclass correlation coefficient
- IR:
-
iterative reconstruction
- SAFIRE:
-
sinogram-affirmed iterative reconstruction
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Acknowledgments
The scientific guarantor of this publication is Dr. Tim Leiner. The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article. The authors state that this work has not received any funding. No complex statistical methods were necessary for this paper. Institutional review board approval was not required because the hearts were from deceased subjects who donated their bodies to science, approval by a research ethics committee was not necessary. These hearts were from deceased subjects who donated their bodies to science. Written informed consent on using their entire body for research and educational purposes was obtained during life. Methodology: prospective, experimental, multicentre study.
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Willemink, M.J., Takx, R.A.P., de Jong, P.A. et al. The impact of CT radiation dose reduction and iterative reconstruction algorithms from four different vendors on coronary calcium scoring. Eur Radiol 24, 2201–2212 (2014). https://doi.org/10.1007/s00330-014-3217-7
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DOI: https://doi.org/10.1007/s00330-014-3217-7