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Virtual monoenergetic dual-layer, dual-energy CT enterography: optimization of keV settings and its added value for Crohn’s disease

  • Gastrointestinal
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Abstract

Objectives

To determine the optimal keV on dual-layer, dual-energy CT enterography (dlDE-CTE) and to investigate the added value of virtual monoenergetic images (VMIs) for the diagnosis of active Crohn’s disease (CD).

Methods

We collected 76 patients (including 45 CD patients) who underwent dlDE-CTE. CD was diagnosed using ileocolonoscopy. Conventional polychromatic images (PCI) were reconstructed using an iterative reconstruction algorithm at 120 kVp, and VMI at 40 keV (VMI40), 55 keV (VMI55), and 70 keV (VMI70). Contrast-to-noise ratio (CNR) was compared using Kruskal-Wallis test. Three radiologists independently reviewed PCI and subsequently combined PCI and the optimized VMI for the diagnosis of active CD using a 5-point scale. Multi-reader multi-case receiver operating characteristic analysis was performed.

Results

Mean ± standard deviation of CNRs for both normal (13.6±6.5, 6.1±3.2, 2.0±2.1, 1.9±1.6; P<0.001) and abnormal (9.4±7.3, 6.5±4.8, 4.9±3.1, 3.7±2.3; P<0.001) bowels were significantly greatest on VMI40, followed by VMI55, VMI70, and PCI. When VMI40 were added to PCI, overall area-under-the-curve of the three radiologists was significantly improved from 0.891 to 0.951 for diagnosing active CD (P=0.009).

Conclusions

The lowest monoenergetic images (VMI40) provided the best CNR on dlDE-CTE. Furthermore, the diagnostic performance for diagnosing active CD can be significantly improved with the addition of VMI40.

Key Points

• CNR for both normal and abnormal bowel walls is greatest on VMI 40 .

• Subjective image quality on VMI 40 is better than those on PCI.

• When VMI 40 images are added to PCI, radiologists’ diagnostic performance can be improved.

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Abbreviations

MDCT:

Multidetector CT

CTE:

CT enterography

DE:

Dual energy

SDCT:

Spectral detector CT

dlDE-CTE:

Dual-layer dual-energy CTE

PCI:

Polychromatic image

VMI:

Virtual monoenergetic image

CNR:

Contrast-to-noise ratio

ROC:

Receiver operating characteristic

AUC:

Area under the curve

ANOVA:

One-way analysis of variance

SD:

Standard deviation

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Funding

This study was supported by the Basic Science Research Program through the National Research Foundation of Korea [NRF] funded by the Ministry of Science, ICT & Future Planning (2016R1A2B4007762) and by the Research Program 2017 funded by Seoul National University College of Medicine Research Foundation (800-20170128).

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Authors and Affiliations

  1. Department of Radiology, Hallym University Sacred Heart Hospital, Anyang, South Korea

    Sang Min Lee

  2. Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul, 03080, Korea

    Se Hyung Kim, Su Joa Ahn, Hyo-Jin Kang, Ji Hee Kang & Joon Koo Han

  3. Department of Radiology, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul, 03080, Korea

    Se Hyung Kim, Su Joa Ahn, Hyo-Jin Kang & Joon Koo Han

  4. Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea

    Joon Koo Han

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  1. Sang Min Lee
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Correspondence to Se Hyung Kim.

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The scientific guarantor of this publication is Se Hyung Kim.

Conflict of interest

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.

Statistics and biometry

No complex statistical methods were necessary for this paper.

Informed consent

Written informed consent was waived by the Institutional Review Board.

Ethical approval

Institutional Review Board approval was obtained.

Methodology

• retrospective

• observational

• performed at one institution

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Lee, S.M., Kim, S.H., Ahn, S.J. et al. Virtual monoenergetic dual-layer, dual-energy CT enterography: optimization of keV settings and its added value for Crohn’s disease. Eur Radiol 28, 2525–2534 (2018). https://doi.org/10.1007/s00330-017-5215-z

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  • DOI: https://doi.org/10.1007/s00330-017-5215-z

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