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European Radiology

, Volume 29, Issue 12, pp 6439–6442 | Cite as

Temporal subtraction of computed tomography images improves detectability of bone metastases by radiology residents

  • Koji OnoueEmail author
  • Mizuho Nishio
  • Masahiro Yakami
  • Ryo Sakamoto
  • Gakuto Aoyama
  • Keita Nakagomi
  • Yoshio Iizuka
  • Takeshi Kubo
  • Yutaka Emoto
  • Thai Akasaka
  • Kiyohide Satoh
  • Hiroyuki Yamamoto
  • Hiroyoshi Isoda
  • Kaori Togashi
Letter to the Editor
  • 73 Downloads

Abstract

Objective

Temporal subtraction of CT (TS) images improves detection of newly developed bone metastases (BM). We sought to determine whether TS improves detection of BM by radiology residents as well.

Methods

We performed an observer study using a previously reported dataset, consisting of 60 oncology patients, each with previous and current CT images. TS images were calculated using in-house software. Four residents independently interpreted twice the 60 sets of CT images, without and with TS. They identified BM by marking suspicious lesions likely to be BM. Lesion-based sensitivity and number of false positives per patient were calculated. Figure-of-merit (FOM) was calculated. Detectability of BM, with and without TS, was compared between radiology residents and board-certified radiologists, as published previously.

Results

FOM of residents significantly improved by implementing TS (p value < 0.0001). Lesion-based sensitivity, false positives per patients, and FOM were 40.8%, 0.121, and 0.657, respectively, without TS, and 58.1%, 0.0958, and 0.796, respectively, with TS. These findings were comparable with the previously published values for board-certified radiologists without TS (58.0%, 0.19, and 0.758, respectively).

Conclusion

The detectability of BM by residents improved markedly by implementing TS and reached that of board-certified radiologists without TS.

Key Points

• Detectability of bone metastases on CT by residents improved significantly when using temporal subtraction of CT (TS).

• Detections by residents with TS and board-certified radiologists without TS were comparable.

• TS is useful for residents as it is for board-certified radiologists.

Keywords

Tomography X-Ray computed Bone neoplasms Internship and residency 

Abbreviations and acronyms

BM

Newly developed bone metastases

CT

Computed tomography

FOM

Figure-of-merit

TS

Temporal subtraction of CT

Notes

Funding

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

Compliance with ethical standards

Guarantor

The scientific guarantor of this publication is K. Togashi.

Conflict of interest

The authors of this manuscript declare relationships with the following companies: Canon Inc. K. Togashi has received research grants from Canon Inc.

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.

Study subjects or cohorts overlap

For 60 subjects in our study, there is overlap between our study and the previous study (ref. [1]). The purpose of our study (detectability of residents) is totally different from that of the previous study (detectability of board-certified radiologists).

Methodology

• retrospective

• diagnostic or prognostic study

• performed at one institution

Supplementary material

330_2019_6314_MOESM1_ESM.docx (676 kb)
ESM 1 (DOCX 675 kb)

References

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    Sakamoto R, Yakami M, Fujimoto K et al (2017) Temporal subtraction of serial CT images with large deformation diffeomorphic metric mapping in the identification of bone metastases. Radiology 3:161942Google Scholar
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    Onoue K, Nishio M, Yakami M et al (2019) CT temporal subtraction improves early detection of bone metastases compared to SPECT. Eur Radiol.  https://doi.org/10.1007/s00330-019-06107-w
  4. 4.
    Ueno M, Aoki T, Murakami S et al (2018) CT temporal subtraction method for detection of sclerotic bone metastasis in the thoracolumbar spine. Eur J Radiol 107:54–59CrossRefGoogle Scholar
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    Dorfman DD, Berbaum KS, Metz CE (1992) Receiver operating characteristic rating analysis. Generalization to the population of readers and patients with the jackknife method. Invest Radiol 27(9):723–731CrossRefGoogle Scholar
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Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Koji Onoue
    • 1
    Email author
  • Mizuho Nishio
    • 1
    • 2
  • Masahiro Yakami
    • 1
    • 2
  • Ryo Sakamoto
    • 1
    • 2
  • Gakuto Aoyama
    • 3
  • Keita Nakagomi
    • 3
  • Yoshio Iizuka
    • 3
  • Takeshi Kubo
    • 1
  • Yutaka Emoto
    • 4
  • Thai Akasaka
    • 5
  • Kiyohide Satoh
    • 3
  • Hiroyuki Yamamoto
    • 3
  • Hiroyoshi Isoda
    • 1
    • 2
  • Kaori Togashi
    • 1
  1. 1.Department of Diagnostic Imaging and Nuclear MedicineKyoto University Graduate School of MedicineKyotoJapan
  2. 2.Preemptive Medicine and Lifestyle-Related Disease Research CenterKyoto University HospitalKyotoJapan
  3. 3.Medical Imaging System Development CenterR&D Headquarters, Canon Inc.TokyoJapan
  4. 4.Kyoto College of Medical ScienceNantanJapan
  5. 5.Osaka Red Cross HospitalOsakaJapan

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