The International Journal of Cardiovascular Imaging

, Volume 29, Issue 7, pp 1565–1574 | Cite as

Image quality of low-dose CCTA in obese patients: impact of high-definition computed tomography and adaptive statistical iterative reconstruction

  • Cathérine Gebhard
  • Tobias A. Fuchs
  • Michael Fiechter
  • Julia Stehli
  • Barbara E. Stähli
  • Oliver Gaemperli
  • Philipp A. Kaufmann
Original Paper


The accuracy of coronary computed tomography angiography (CCTA) in obese persons is compromised by increased image noise. We investigated CCTA image quality acquired on a high-definition 64-slice CT scanner using modern adaptive statistical iterative reconstruction (ASIR). Seventy overweight and obese patients (24 males; mean age 57 years, mean body mass index 33 kg/m2) were studied with clinically-indicated contrast enhanced CCTA. Thirty-five patients underwent a standard definition protocol with filtered backprojection reconstruction (SD-FBP) while 35 patients matched for gender, age, body mass index and coronary artery calcifications underwent a novel high definition protocol with ASIR (HD-ASIR). Segment by segment image quality was assessed using a four-point scale (1 = excellent, 2 = good, 3 = moderate, 4 = non-diagnostic) and revealed better scores for HD-ASIR compared to SD-FBP (1.5 ± 0.43 vs. 1.8 ± 0.48; p < 0.05). The smallest detectable vessel diameter was also improved, 1.0 ± 0.5 mm for HD-ASIR as compared to 1.4 ± 0.4 mm for SD-FBP (p < 0.001). Average vessel attenuation was higher for HD-ASIR (388.3 ± 109.6 versus 350.6 ± 90.3 Hounsfield Units, HU; p < 0.05), while image noise, signal-to-noise ratio and contrast-to noise ratio did not differ significantly between reconstruction protocols (p = NS). The estimated effective radiation doses were similar, 2.3 ± 0.1 and 2.5 ± 0.1 mSv (HD-ASIR vs. SD-ASIR respectively). Compared to a standard definition backprojection protocol (SD-FBP), a newer high definition scan protocol in combination with ASIR (HD-ASIR) incrementally improved image quality and visualization of distal coronary artery segments in overweight and obese individuals, without increasing image noise and radiation dose.


Cardiac computed tomography Adaptive statistical iterative reconstruction Obesity 



The study was supported by grants from the Swiss National Science Foundation (SNSF) to P.A.K., C.G. and to M.F.

Ethical standard

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008. The need for written informed consent in this study was waived by the institutional review board (local ethics committee) since, according to Swiss law on clinical investigations, informed consent is not required if the nature of the study is purely retrospective.

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Cathérine Gebhard
    • 1
  • Tobias A. Fuchs
    • 1
  • Michael Fiechter
    • 1
  • Julia Stehli
    • 1
  • Barbara E. Stähli
    • 1
  • Oliver Gaemperli
    • 1
  • Philipp A. Kaufmann
    • 1
    • 2
  1. 1.Department of Radiology, Cardiac ImagingUniversity Hospital ZurichZurichSwitzerland
  2. 2.Zurich Center for Integrative Human Physiology (ZIHP)University of ZurichZurichSwitzerland

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