- 著者
- Ryoichi Kose Katsumi Kose Koji Fujimoto Tomohisa Okada Daiki Tamada Utaroh Motosugi
- 出版者
- Japanese Society for Magnetic Resonance in Medicine
- 雑誌
- Magnetic Resonance in Medical Sciences (ISSN:13473182)
- 巻号頁・発行日
- pp.tn.2023-0063, (Released:2023-09-09)
- 参考文献数
- 24
- 被引用文献数
- 1
Recent high-performance gradient coils are fabricated mainly at the expense of spatial linearity. In this study, we measured the spatial nonlinearity of the magnetic field generated by the gradient coils of two MRI systems with high-performance gradient coils. The nonlinearity of the gradient fields was measured using 3D gradient echo sequences and a spherical phantom with a built-in lattice structure. The spatial variation of the gradient field was approximated to the 3rd order polynomials. The coefficients of the polynomials were calculated using the steepest descent method. The geometric distortion of the acquired 3D MR images was corrected using the polynomials and compared with the 3D images corrected using the harmonic functions provided by the MRI venders. As a result, it was found that the nonlinearity correction formulae provided by the vendors were insufficient and needed to be verified or corrected using a geometric phantom such as used in this study.
- 著者
- Yoshimasa MATSUDA Shinya ONO Yosuke OTAKE Shinya HANDA Katsumi KOSE Tomoyuki HAISHI Shigeto YAMADA Chikako UWABE Kohei SHIOTA
- 出版者
- 日本磁気共鳴医学会
- 雑誌
- Magnetic Resonance in Medical Sciences (ISSN:13473182)
- 巻号頁・発行日
- vol.6, no.3, pp.139-146, 2007 (Released:2007-11-20)
- 参考文献数
- 15
- 被引用文献数
- 18 38
Using 4 and 8-channel super-parallel magnetic resonance (MR) microscopes with a horizontal bore 2.34T superconducting magnet developed for 3-dimensional MR microscopy of the large Kyoto Collection of Human Embryos, we acquired T1-weighted 3D images of 1204 embryos at a spatial resolution of (40 μm)3 to (150 μm)3 in about 2 years. Similarity of image contrast between the T1-weighted images and stained anatomical sections indicated that T1-weighted 3D images could be used for an anatomical 3D image database for human embryology.