Magnetic Resonance Microscopy of Chemically Fixed Human Embryos Performed in University of Tsukuba Since 1999 to 2015

Abstract

Magnetic resonance (MR) microscopy of chemically fixed human embryos performed in University of Tsukuba since 1999 to 2015 was reviewed. More than 1,000 chemically fixed human embryos stored in the Congenital Anomaly Research Center of Kyoto University were used throughout the MR microscopy project, which was divided into three terms. In the first term (1999-2005), 3D MR images of 1,204 embryo specimens were acquired with 128 × 128 × 256 voxels by a super-parallel MR microscope using a 2.35 T horizontal-bore superconducting magnet. In the second term (2005-2006), 3D MR images of seven embryo specimens were acquired with 256 × 256 × 512 voxels by an MR microscope using a 9.4 T vertical wide-bore superconducting magnet. In the third term (2013-2015), 3D MR images of a Carnegie Stage (CS) 21 specimen were acquired with 512 × 512 × 1024 voxels by an MR microscope using a 4.7 T vertical wide-bore superconducting magnet and nuclear magnetic resonance parameters of a CS23 specimen were measured with 128 × 128 × 256-256 × 256 × 512 voxels by an MR microscope using a 9.4 T vertical narrow-bore superconducting magnet. Based on the results obtained in this project, the author has proposed the future MR microscopy project in which a number of embryo specimens will be imaged with 256 × 256 × 512-512 × 512 × 1024 voxels using a newly designed super-parallel MR microscope. Anat Rec, 301:987-997, 2018. © 2018 Wiley Periodicals, Inc.

Brain Structures in a Human Embryo Imaged with MR Microscopy

“…17,18 T1-weighted imaging has also been reported to have the advantage of suppressing the signal from the preservation fluid, allowing clear distinction of structures between adjacent tissues in human embryos. The previous study 16 also discussed the appropriate sequence type for embryo K. Kunieda et al…”

“…Despite these difficulties, many studies have been performed on MR microscopy of human embryos. [14][15][16] The previous study performed MR microscopy of specimens from CS16 to CS22 in 2015. 15 The largest sample used was CS22 with a voxel size of (60 µm) 3 .…”

“…The study performed in 2018 showed that T1 and T2 for human embryos are positively correlated and have a very similar distribution, thus providing similar information. 16 Therefore, it has been argued that since the TR is shorter for T1-weighted imaging than for T2-weighted imaging, T1-weighted imaging is more time efficient and allows more signal averaging in the same measurement time than T2-weighted imaging. Taking advantage of high SNR per unit time, T1-weighted imaging with high spatial resolution has recently been performed on CS16 specimens.…”

Human fetal virtual histology with X-ray phase contrast imaging

“…Consequently, it would require a large number of samples to study a whole range of pathologies due to the technique's destructiveness. To overcome this issue, Magnetic Resonance (MR) microscopy has been used for embryo imaging [6] allowing for 3D reconstruction. Nevertheless, this technique has limited contrast for hard tissues and has a limited resolution to evaluate the structures at the tissue scale.…”

The Evaluation of the Four-Chamber Cardiac Dissection Method of the Fetal Heart as an Alternative to Conventional Inflow–Outflow Dissection in Small Gestational-Age Fetuses

“…Considering that conventional 1.5T and 3T magnetic resonance imaging (MRI) magnets currently used in clinical setting have shown lower accuracy in examining fetuses below 16 weeks of gestation [ 8 , 9 ], we considered the use of a high-power field magnet of 7T. Significant advances in the development of high-field MRI allowed for important progress in post-mortem fetal imaging [ 10 , 11 ] and numerous published studies have shown good diagnostic accuracy specially for fetal heart examination, describing pm-MRI as an alternative to conventional autopsy [ 12 , 13 , 14 , 15 ].…”