Histological Properties of a Chemically Fixed Human Embryo Visualized with Quantitative Susceptibility Mapping.

A chemically fixed Carnegie stage 23 (approximately 56 days of gestation) human embryo specimen was imaged using 3D spin-echo and gradient-echo sequences in a static magnetic field strength of 4.74T, and a quantitative susceptibility map was calculated using the 3D gradient-echo image. The acquired 3D microscopic images (90 μm cube voxel size) clarified the relationship between R (transverse relaxation rate), R* (apparent transverse relaxation rate), and magnetic susceptibility in the heart, liver, kidney, and spinal cord.

Brain Structures in a Human Embryo Imaged with MR Microscopy.

Purpose: To delineate brain microstructures in human embryos during the formation of the various major primordia by MR microscopy, with different contrasts appropriate for each target.

Methods: We focused mainly on the internal structures in the cerebral cortex and the accessory nerves of the brain. To find appropriate sequence parameters, we measured nuclear magnetic resonance (NMR) parameters and created kernel density plots of T1 and T2 values.

Amelioration of Tumor-promoting Microenvironment via Vascular Remodeling and CAF Suppression Using E7130: Biomarker Analysis by Multimodal Imaging Modalities.

E7130 is a novel anticancer agent created from total synthetic study of the natural compound norhalichondrin B. In addition to inhibiting microtubule dynamics, E7130 also ameliorates tumor-promoting aspects of the tumor microenvironment (TME) by suppressing cancer-associated fibroblasts (CAF) and promoting remodeling of tumor vasculature. Here, we demonstrate TME amelioration by E7130 using multi-imaging modalities, including multiplexed mass cytometry [cytometry by time-of-flight (CyTOF)] analysis, multiplex IHC analysis, and MRI.

High-resolution MRI for human embryos with isotropic 10 μm resolution at 9.4 T.

Magnetic resonance (MR) microscopy of human embryos has contributed significantly to the development of human embryology. Higher-resolution MR microscopy will have obvious benefits, for example, in visualizing small structures that are blurred or lost in lower-resolution images, providing detailed information on the development and growth of various organs, and improving the accuracy of MR volumetry. However, high-resolution MR microscopy has yet to be realized because of many technical challenges.

Numerical and Clinical Evaluation of the Robustness of Open-source Networks for Parallel MR Imaging Reconstruction.

Purpose: Deep neural networks (DNNs) for MRI reconstruction often require large datasets for training. Still, in clinical settings, the domains of datasets are diverse, and how robust DNNs are to domain differences between training and testing datasets has been an open question. Here, we numerically and clinically evaluate the generalization of the reconstruction networks across various domains under clinically practical conditions and provide practical guidance on what points to consider when selecting models for clinical application.

Sodium Magnetic Resonance Imaging Shows Impairment of the Counter-current Multiplication System in Diabetic Mice Kidney.

Key Points: Na MRI allows us to noninvasively assess sodium distribution. We propose the utility of Na MRI for evaluating functional changes in diabetic kidney disease and not as a marker reflecting structural damage. Na MRI may be an early marker for structures beyond the glomeruli, enabling prompt intervention with novel efficacious tubule-targeting therapies.

New Cluster Analysis Method for Quantitative Dynamic Contrast-Enhanced MRI Assessing Tumor Heterogeneity Induced by a Tumor-Microenvironmental Ameliorator (E7130) Treatment to a Breast Cancer Mouse Model.

Background: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can provide insight into tumor perfusion. However, a method that can quantitatively measure the intra-tumor distribution of tumor voxel clusters with a distinct range of K and v values remains insufficiently explored.

Hypothesis: Two-dimensional cluster analysis may quantify the distribution of a tumor voxel subregion with a distinct range of K and v values in human breast cancer xenografts.

Implementation of the QRAPMASTER data analysis using dictionary matching and quantitative evaluation of the magnetization transfer effect.

Purpose: To clarify the magnetization transfer (MT) effect on T and T values obtained with the QRAPMASTER sequence.

Methods: A phantom consisting of MnCl aqueous solution with various proton relaxation times and a chicken breast sample was imaged with the QRAPMASTER sequence and a multislice multiple spin-echo (MSMSE) sequence that was the basis of the QRAPMASTER sequence using a 1.5 T MRI system.

Development of an Add-on Na-MRI Radiofrequency Platform for a H-MRI System Using a Crossband Repeater: Proof-of-concept.

Na-MRI provides information on Na content, and its application in the medical field has been highly anticipated. However, for existing clinical H-MRI systems, its implementation requires an additional broadband RF transmitter, dedicated transceivers, and RF coils for Na imaging. However, a standard medical MRI system cannot often be modified to perform Na imaging.

Bloch Simulation of a Three-point Dixon Experiment Using a Four-dimensional Numerical Phantom.

A 4D numerical phantom, which is defined in the 3D spatial axes and the resonance frequency axis, is indispensable for Bloch simulations of biological tissues with complex distribution of materials. In this study, a 4D numerical phantom was created using MR image datasets of a biological sample containing water and fat, and the Bloch simulations were performed using the 4D numerical phantom. As a result, 3D images of the sample containing water and fat were successfully reproduced, which demonstrated the usefulness of the concept of the 4D numerical phantom.

Development of a method for the Bloch image simulation of biological tissues.

Purpose: The purpose of this study is to develop a method for the Bloch image simulation of biological tissues including various chemical components and T* distribution.

Methods: The nuclear spins in the object material were modeled as a spectral intensity function Sr→ω defined by superposition of Lorentz functions with various central precession frequencies and the half width of 1/(πT'), where 1/T' is a relaxation rate attributable to microscopic field inhomogeneity in a voxel. Four-dimensional numerical phantoms were created to simulate Sr→ω and used for MRI simulations of the phantoms containing water and fat protons.

SET/TAF1 forms a distance-dependent feedback loop with Aurora B and Bub1 as a tension sensor at centromeres.

During mitosis, spatiotemporal regulation of phosphorylation at the kinetochore is essential for accurate chromosome alignment and proper chromosome segregation. Aurora B kinase phosphorylates kinetochore substrates to correct improper kinetochore-microtubule (KT-MT) attachments, whereas tension across the centromeres inactivates Aurora B kinase, and PP2A phosphatase dephosphorylates the kinetochore proteins to stabilize the attachments. However, the molecular entity of the tension sensing mechanism remains elusive.

Dynamics of xylem and phloem sap flow in an outdoor zelkova tree visualized by magnetic resonance imaging.

Xylem and phloem sap flows in an intact, young Japanese zelkova tree (Zelkova serrata (Thunb.) Makino) growing outdoors were measured using magnetic resonance imaging (MRI). Two propagator-based sequences were developed for q-space imaging: pulse field gradient (PFG) with spin echo (PFG-SE) and stimulated echo (PFG-STE), which were used for xylem and phloem flow measurements, respectively.

Relationship between Li diffusion and ion conduction for single-crystal and powder garnet-type electrolytes studied by Li PGSE NMR spectroscopy.

Ion-conducting garnets are important candidates for use in all-solid Li batteries and numerous materials have been synthesized with high ionic conductivities. For understanding ion conduction mechanisms, knowledge on Li diffusion behaviour is essential. The proposed nano-scale lithium pathways are composed of tortuous and narrow Li channels.

Aurora B kinase activity is regulated by SET/TAF1 on Sgo2 at the inner centromere.

The accurate regulation of phosphorylation at the kinetochore is essential for establishing chromosome bi-orientation. Phosphorylation of kinetochore proteins by the Aurora B kinase destabilizes improper kinetochore-microtubule attachments, whereas the phosphatase PP2A has a counteracting role. Imbalanced phosphoregulation leads to error-prone chromosome segregation and aneuploidy, a hallmark of cancer cells.

Toward understanding the anomalous Li diffusion in inorganic solid electrolytes by studying a single-crystal garnet of LLZO-Ta by pulsed-gradient spin-echo nuclear magnetic resonance spectroscopy.

Li diffusion was observed by Li nuclear magnetic resonance (NMR) spectroscopy in three single-crystal samples of LLZO-Ta (LiLaZrTaO) grown by the floating zone melting method as well as a crushed sample in this study. Previously, the pulsed-gradient spin-echo Li NMR method was applied to Li diffusion measurements in inorganic solid electrolyte powder samples. Anomalous Li diffusion behaviors were observed such as dependence of the observing time (Δ) and pulsed-field-gradient strength (g), and the diffusive-diffraction patterns in short Δ in the echo-attenuation plots.

Development of a small car-mounted magnetic resonance imaging system for human elbows using a 0.2 T permanent magnet.

Portable magnetic resonance imaging (MRI) scanners can provide opportunities for mobile operation in many environments including disease screening and primary care suites. Here, we develop a new, compact transportable MRI system for imaging small joints of the extremities using a 0.2 T, 200 kg permanent magnet.

Diffusion-weighting Caused by Spoiler Gradients in the Fast Imaging with Steady-state Precession Sequence May Lead to Inaccurate T Measurements in MR Fingerprinting.

Magnetic resonance fingerprinting (MRF) is a promising framework that allows the quantification of multiple magnetic resonance parameters with a single scan. MRF using fast imaging with steady-state precession (MRF-FISP) has robustness to off-resonance artifacts and has many applications in inhomogeneous fields. However, the spoiler gradient used in MRF-FISP is sensitive to diffusion motion, and may lead to quantification errors when the spoiler moment increases.

Identification of Cep169-interacting proteins and the in vivo modification sites of Cep169 via proteomic analysis.

Cep169 is a microtubule plus-end tracking and centrosomal protein that interacts with CDK5RAP2. Cep169 is known to regulate microtubule dynamics and stability; however, its other cellular functions remain largely elusive. In this study, we identified novel Cep169-interacting proteins from HeLa cell extracts.

Advanced Imaging Techniques of the Wrist.

Objective: This article covers the technical aspects and clinical applications of recent advancements in wrist MRI techniques, including T2 and T1rho mapping, compressed sensing, and isotropic 3D imaging using driven equilibrium sequences, variable-flip-angle refocusing pulse sequences, and parallel imaging. The clinical applications of these techniques include the quantitative analysis of cartilage and triangular fibrocartilaginous complex (TFCC) degeneration, faster scanning times, and improved resolution of complex wrist anatomy, allowing differentiation of degenerative from traumatic TFCC tears and improved morphologic evaluation of chondromalacia.

Conclusion: MRI of the wrist and of the musculoskeletal system has had multiple novel and exciting advancements in recent years.

Oval gradient coils for an open magnetic resonance imaging system with a vertical magnetic field.

Existing open magnetic resonance imaging (MRI) systems use biplanar gradient coils for the spatial encoding of signals. We propose using novel oval gradient coils for an open vertical-field MRI. We designed oval gradients for a 0.

Analysis of Rhizome Development in Oryza longistaminata, a Wild Rice Species.

Vegetative reproduction is a form of asexual propagation in plants. A wide range of plants develop rhizomes, modified stems that grow underground horizontally, as a means of vegetative reproduction. In rhizomatous species, despite their distinct developmental patterns, both rhizomes and aerial shoots derive from axillary buds.

Development of an outdoor MRI system for measuring flow in a living tree.

An outdoor MRI system for noninvasive, long-term measurements of sap flow in a living tree in its natural environment has been developed. An open-access, 0.2 T permanent magnet with a 160 mm gap was combined with a radiofrequency probe, planar gradient coils, electromagnetic shielding, several electrical units, and a waterproofing box.