The use of combined T2-weighted and FLAIR synthetic magnetic resonance images to improve white matter region contrast: a feasibility study

  • Yasuhiro FujiwaraEmail author
  • Yumi Inoue
  • Masayuki Kanamoto
  • Shota Ishida
  • Toshiki Adachi
  • Hirohiko Kimura


Synthetic magnetic resonance imaging (MRI) allows the production of images with any contrast from a single scan after quantification. The combined T2-weighted image (T2WI) and fluid-attenuated inversion recovery (FLAIR) image is expected to have an improved contrast between the normal-appearing white matter (WM) and WM lesion (WML). The purpose of this study was to determine whether optimal T2 contrast-weighted images (SyFLAIR3) comprising the combined T2WI and FLAIR image generated using synthetic MRI could improve contrast in the WM region. Numerical simulations were performed to estimate the contrast-to-noise ratio (CNR) between the WM and WML and cerebrospinal fluid (CSF) ratio at any echo time (TE) using SyFLAIR3. The CNR and CSF ratio for SyFLAIR3 was compared with those for FLAIR and double inversion recovery (DIR) images in ten volunteers. In numerical simulations, the CNR for SyFLAIR3 was increased in the T2WI and FLAIR images with long TEs, and the CSF ratio was decreased on those with short TEs. An in vivo study indicated that the CNR for SyFLAIR3 using T2WI and FLAIR images with an optimized combination of TEs was significantly higher than those for FLAIR and DIR images; whereas, the CSF ratio for the optimized SyFLAIR3 was not significantly different from that for the FLAIR images. The use of SyFLAIR3 improves the contrast within the region of the WM without the need for additional scanning in synthetic MRI.


Magnetic resonance imaging (MRI) Synthetic MRI Quantitative MRI White matter lesion Multiple sclerosis 



The authors would like to thank Yoshiyuki Ishimori, PhD, for his useful suggestions. This study was supported in part by Grant-in-Aid for Scientic Research (C) from Japan Society for the Promotion of Science (Grant no. 15K09916).

Compliance with ethical standards

Conflict of interest

The authors declare no conflict of interest.

Ethical approval

Statements of human rights: All procedures performed in studies involving human participants were in accordance with the ethical standards of our Institutional Review Board (IRB) and 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Statements of animal rights: This article does not contain any studies performed on animals.

Informed consent

Informed consent was obtained from each participant included in this study.


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Copyright information

© Japanese Society of Radiological Technology and Japan Society of Medical Physics 2019

Authors and Affiliations

  • Yasuhiro Fujiwara
    • 1
    Email author
  • Yumi Inoue
    • 2
  • Masayuki Kanamoto
    • 3
  • Shota Ishida
    • 3
  • Toshiki Adachi
    • 3
  • Hirohiko Kimura
    • 4
  1. 1.Department of Medical Imaging, Faculty of Life SciencesKumamoto UniversityKumamotoJapan
  2. 2.Course of Radiological Science, School of Health SciencesKumamoto UniversityKumamotoJapan
  3. 3.Radiological CenterUniversity of Fukui HospitalFukuiJapan
  4. 4.Department of RadiologyUniversity of FukuiFukuiJapan

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