Myelin-weighted imaging derived from quantitative parameter mapping

Yuki Kanazawa; Masafumi Harada; Yo Taniguchi; Hiroaki Hayashi; Takashi Abe; Maki Otomo; Yuki Matsumoto; Masaharu Ono; Kosuke Ito; Yoshitaka Bito; Akihiro Haga

doi:10.1016/j.ejrad.2022.110525

Myelin-weighted imaging derived from quantitative parameter mapping

Eur J Radiol. 2022 Nov:156:110525. doi: 10.1016/j.ejrad.2022.110525. Epub 2022 Sep 16.

Authors

Yuki Kanazawa¹, Masafumi Harada², Yo Taniguchi³, Hiroaki Hayashi⁴, Takashi Abe⁵, Maki Otomo⁶, Yuki Matsumoto⁷, Masaharu Ono⁸, Kosuke Ito⁹, Yoshitaka Bito¹⁰, Akihiro Haga¹¹

Affiliations

¹ Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan. Electronic address: yk@tokushima-u.ac.jp.
² Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan. Electronic address: masafumi@tokushima-u.ac.jp.
³ FUJIFILM Healthcare Corporation, Tokyo 107-0052, Japan. Electronic address: yo.taniguchi.tk@fujifilm.com.
⁴ College of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Ishikawa 920-0942, Japan. Electronic address: hayashi.hiroaki@staff.kanazawa-u.ac.jp.
⁵ Department of Radiology, Nagoya University Hospital, Aichi 466-8550, Japan. Electronic address: abe-takashi@med.nagoya-u.ac.jp.
⁶ Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan. Electronic address: maki.o@tokushima-u.ac.jp.
⁷ Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan. Electronic address: lakaisbmtyk@gmail.com.
⁸ FUJIFILM Healthcare Corporation, Tokyo 107-0052, Japan. Electronic address: masaharu.ono.fn@fujifilm.com.
⁹ FUJIFILM Healthcare Corporation, Tokyo 107-0052, Japan. Electronic address: kosuke.ito.qb@fujifilm.com.
¹⁰ FUJIFILM Healthcare Corporation, Tokyo 107-0052, Japan. Electronic address: yoshitaka.bito.dn@fujifilm.com.
¹¹ Graduate School of Biomedical Sciences, Tokushima University, Tokushima 770-8503, Japan. Electronic address: haga@tokushima-u.ac.jp.

PMID: 36166986
DOI: 10.1016/j.ejrad.2022.110525

Abstract

Purpose: We developed a novel method which is applicable to visualize contrast according to myelin components in the human brain using relaxation time derived from quantitative parameter mapping magnetic resonance imaging (QPM-MRI).

Materials and methods: Using healthy volunteer data (n = 10), we verified that our method demonstrated that the myelin-weighted contrast increased proportionally by products R₁ and R₂*, i.e., QPM-myelin-weighted image, in which modified T₁-weighted/T₂-weighted (T₁w/T₂w) ratio mapping method was applied. We compared measurement values in white matter (WM) and gray matter (GM) regions of the T₁w/T₂w ratio and R₁·R₂* product maps of healthy volunteers. Linear regression analysis between each value. Mann Whitney U test between WM and GM signals in each myelin map. In addition, Additionally, QPM-myelin-weighted image was applied to a 32-year-old female MS patient.

Results: Linear regression analysis showed a highly significant correlation between conventional T₁w/T₂w ratios and R₁·R₂* products derived from QPM (R = 0.73, P < 0.0001). Moreover, there is a significant difference between WM and GM structures in each myelin images (both, P < 0.0001). Additionally, in a clinical case, MS lesions enabled observation of not only MS plaques but also heterogeneous myelin signal loss associated with demyelination more clearly than T₂w image and conventional T₁w/T₂w ratio image.

Conclusion: Our myelin-weighted imaging technique using QPM may be useful for myelin visualization and is expected to become independent of measurement conditions due to having quantitative characteristics of QPM itself.

Keywords: Magnetic resonance imaging (MRI); Multiple sclerosis; Myelin content; Myelin water fraction; Quantitative parameter mapping (QPM); Relaxometry; Voxel based morphometry (VBM); White matter.