Scholarlink

Objective <p>Quantifying myelin is essential for understanding demyelinating disease, yet myelin water fraction (MWF) varies across studies due to sequence choice, acquisition parameters, and field inhomogeneities. A major limitation is the lack of a phantom with a known structural reference. This study aimed to develop an electron microscopy (EM)–derived numerical MRI phantom representing structural tissue water fractions and to evaluate how acquisition and field conditions influence simulated MWF estimates. Here, simulated MWF refers to the short-T<sub>2</sub> component recovered from EM-derived structural fractions and should be distinguished from in-vivo biological MWF.</p> Materials and methods <p>EM images of CNS tissue were segmented into myelin, axons, and intra-/extracellular water (29%, 41%, 30%). Relaxation times were assigned from the literature, and simulated MWF was defined as the short-T<sub>2</sub> component estimated using non-negative least squares. Multi-echo spoiled gradient echo signals were simulated across TR, flip angle, and synthetic B<sub>0</sub>/B<sub>1</sub> inhomogeneity.</p> Results <p>The phantom produced compartment-specific decay curves and enabled controlled evaluation of acquisition-dependent behavior. MWF increased with flip angle, decreased with longer TR, and showed systematic bias under B<sub>0</sub>/B<sub>1</sub> variation. The framework further visualized mixing among compartments and sensitivity to relaxation- and field-driven changes.</p> Discussion <p>This tissue water fraction phantom provides a structural ground truth for reproducible evaluation of simulated MWF and supports optimization and future methodological standardization of quantitative MRI.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

A structural tissue water fraction phantom derived from electron microscopy for simulation-based evaluation in MRI

  • 期刊论文

  • 发表日期：

    2026年3月26日

查看全文
  • Ryuji Ohshiro,
  • Yuki Kanazawa,
  • Akihiro Haga,
  • Takeshi Ohno,
  • Motoharu Sasaki,
  • Masafumi Harada

摘要

Objective

Quantifying myelin is essential for understanding demyelinating disease, yet myelin water fraction (MWF) varies across studies due to sequence choice, acquisition parameters, and field inhomogeneities. A major limitation is the lack of a phantom with a known structural reference. This study aimed to develop an electron microscopy (EM)–derived numerical MRI phantom representing structural tissue water fractions and to evaluate how acquisition and field conditions influence simulated MWF estimates. Here, simulated MWF refers to the short-T2 component recovered from EM-derived structural fractions and should be distinguished from in-vivo biological MWF.

Materials and methods

EM images of CNS tissue were segmented into myelin, axons, and intra-/extracellular water (29%, 41%, 30%). Relaxation times were assigned from the literature, and simulated MWF was defined as the short-T2 component estimated using non-negative least squares. Multi-echo spoiled gradient echo signals were simulated across TR, flip angle, and synthetic B0/B1 inhomogeneity.

Results

The phantom produced compartment-specific decay curves and enabled controlled evaluation of acquisition-dependent behavior. MWF increased with flip angle, decreased with longer TR, and showed systematic bias under B0/B1 variation. The framework further visualized mixing among compartments and sensitivity to relaxation- and field-driven changes.

Discussion

This tissue water fraction phantom provides a structural ground truth for reproducible evaluation of simulated MWF and supports optimization and future methodological standardization of quantitative MRI.