European Radiology

, Volume 29, Issue 1, pp 161–167 | Cite as

Neointimal formation after carotid artery stenting: phantom and clinical evaluation of model-based iterative reconstruction (MBIR)

  • Kazushi YokomachiEmail author
  • Fuminari Tatsugami
  • Toru Higaki
  • Shinji Kume
  • Shigeyuki Sakamoto
  • Takahito Okazaki
  • Kaoru Kurisu
  • Yuko Nakamura
  • Yasutaka Baba
  • Makoto Iida
  • Kazuo Awai
Computed Tomography



The objective of this study was to investigate the usefulness of model-based iterative reconstruction (IR) for detecting neointimal formations after carotid artery stenting.


In a cervical phantom harbouring carotid artery stents, we placed simulated neointimal formations measuring 0.40, 0.60, 0.80 and 1.00 mm along the stent wall. The thickness of in-stent neointimal formations was measured on images reconstructed with filtered-back projection (FBP), hybrid IR (AIDR 3D), and model-based IR (FIRST). The clinical study included 43 patients with carotid stents. Cervical computed tomography (CT) images obtained on a 320-slice scanner were reconstructed with AIDR 3D and FIRST. Five blinded observers visually graded the likelihood of neointimal formations on AIDR 3D and AIDR 3D plus FIRST images. Carotid ultrasound images were the reference standard. We analysed results of visual grading by using a Jack-knife type receiver observer characteristics analysis software.


In the phantom study, the difference between the measured and the true diameter of the neointimal formations was smaller on FIRST than FBP or AIDR 3D images. In the clinical study, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of AIDR 3D were 58%, 88%, 83%, 67% and 73%, respectively. For AIDR 3D plus FIRST images they were 84%, 78%, 80%, 82% and 81%, respectively. The mean area under the curve was significantly higher on AIDR 3D plus FIRST than AIDR 3D images (0.82 vs 0.72; p < 0.01).


The model-based IR algorithm helped to improve diagnostic performance for the detection of neointimal formations after carotid artery stenting.

Key Points

• Neointimal formations can be visualised more accurately with model-based IR.

• Model-based IR improves the detection of neointimal formations after carotid artery stenting.

• Model-based IR is suitable for follow up after carotid artery stenting.


CT angiography Carotid artery stenosis Image reconstruction Multidetector computed tomography Image quality enhancement 



Three-dimensional adaptive iterative dose reduction


Carotid artery stenting


Filtered-back projection


Forward-projected model-based iterative reconstruction solution


Iterative reconstruction



The authors state that this work has not received any funding.

Compliance with ethical standards


The scientific guarantor of this publication is Kazuo Awai.

Conflict of interest

Kazuo Awai, Professor of Hiroshima University, obtained a research grant from Canon Medical Systems. The other authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

One of the authors (F.T.) who has skill for statistics performed the statistical analyses.

Informed consent

Written informed consent was obtained from all subjects in this study.

Ethical approval

Institutional Review Board approved this study.


• retrospective

• diagnostic or prognostic study

• performed at one institution


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Copyright information

© European Society of Radiology 2018

Authors and Affiliations

  • Kazushi Yokomachi
    • 1
    • 2
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  • Fuminari Tatsugami
    • 2
  • Toru Higaki
    • 2
  • Shinji Kume
    • 1
  • Shigeyuki Sakamoto
    • 3
  • Takahito Okazaki
    • 3
  • Kaoru Kurisu
    • 3
  • Yuko Nakamura
    • 2
  • Yasutaka Baba
    • 2
  • Makoto Iida
    • 2
  • Kazuo Awai
    • 2
  1. 1.Department of RadiologyHiroshima University HospitalHiroshimaJapan
  2. 2.Department of Diagnostic Radiology, Graduate School of Biomedical and Health SciencesHiroshima UniversityHiroshimaJapan
  3. 3.Department of NeurosurgeryHiroshima University HospitalHiroshimaJapan

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