European Radiology

, Volume 27, Issue 7, pp 2717–2725 | Cite as

Radiation dose reduction using 100-kVp and a sinogram-affirmed iterative reconstruction algorithm in adolescent head CT: Impact on grey–white matter contrast and image noise

  • Yasunori Nagayama
  • Takeshi Nakaura
  • Akinori Tsuji
  • Joji Urata
  • Mitsuhiro Furusawa
  • Hideaki Yuki
  • Kenichiro Hirarta
  • Masafumi Kidoh
  • Seitaro Oda
  • Daisuke Utsunomiya
  • Yasuyuki Yamashita
Head and Neck



To retrospectively evaluate the image quality and radiation dose of 100-kVp scans with sinogram-affirmed iterative reconstruction (IR) for unenhanced head CT in adolescents.


Sixty-nine patients aged 12–17 years underwent head CT under 120- (n = 34) or 100-kVp (n = 35) protocols. The 120-kVp images were reconstructed with filtered back-projection (FBP), 100-kVp images with FBP (100-kVp-F) and sinogram-affirmed IR (100-kVp-S). We compared the effective dose (ED), grey–white matter (GM–WM) contrast, image noise, and contrast-to-noise ratio (CNR) between protocols in supratentorial (ST) and posterior fossa (PS). We also assessed GM–WM contrast, image noise, sharpness, artifacts, and overall image quality on a four-point scale.


ED was 46% lower with 100- than 120-kVp (p < 0.001). GM–WM contrast was higher, and image noise was lower, on 100-kVp-S than 120-kVp at ST (p < 0.001). CNR of 100-kVp-S was higher than of 120-kVp (p < 0.001). GM–WM contrast of 100-kVp-S was subjectively rated as better than of 120-kVp (p < 0.001). There were no significant differences in the other criteria between 100-kVp-S and 120-kVp (p = 0.072–0.966).


The 100-kVp with sinogram-affirmed IR facilitated dramatic radiation reduction and better GM–WM contrast without increasing image noise in adolescent head CT.

Key points

100-kVp head CT provides 46% radiation dose reduction compared with 120-kVp.

100-kVp scanning improves subjective and objective GMWM contrast.

Sinogram-affirmed IR decreases head CT image noise, especially in supratentorial region.

100-kVp protocol with sinogram-affirmed IR is suited for adolescent head CT.


Paediatrics Computed tomography X-ray Cranial irradiation Radiation protection Image processing 



Automatic exposure control


Automated tube voltage selection


Contrast-to-noise ratio


Filtered back-projection


Grey matter


Iterative reconstruction


Region of interest


Sinogram-affirmed iterative reconstruction


White matter



The scientific guarantor of this publication is Yasuyuki Yamashita. The authors of this manuscript declare no relationships with any companies. 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 obtained. Written informed consent was waived by the Institutional Review Board. No study subjects or cohorts have been previously reported. Methodology: retrospective, case-control study, performed at one institution.


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Copyright information

© European Society of Radiology 2016

Authors and Affiliations

  • Yasunori Nagayama
    • 1
    • 2
  • Takeshi Nakaura
    • 2
  • Akinori Tsuji
    • 1
  • Joji Urata
    • 1
  • Mitsuhiro Furusawa
    • 1
  • Hideaki Yuki
    • 2
  • Kenichiro Hirarta
    • 2
  • Masafumi Kidoh
    • 2
  • Seitaro Oda
    • 2
  • Daisuke Utsunomiya
    • 2
  • Yasuyuki Yamashita
    • 2
  1. 1.Department of RadiologyKumamoto City HospitalKumamotoJapan
  2. 2.Department of Diagnostic Radiology, Graduate School of Medical SciencesKumamoto UniversityKumamotoJapan

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