Relativistic impulse approximation-based compton component of mass energy absorption coefficients (cm/g) for few materials of medical interest.

Total, whole-atom, individual and integrated Compton scattering cross sections and Compton energy absorption scattering cross sections are evaluated for light elements, such as, H, C, N, O, P, and Ca, with relativistic impulse approximation methods. Most of the phantom materials composed of these elements, which are the basic constituents of biological soft-tissue and attenuation through them, provides potential source of information. Compton scattering cross-sections for few biological materials, such as, HO, CH, CH, CHO, CHNO, CHO, CHO, [Ca(PO)]Ca (OH) of medical interest, have been evaluated with the use of double differential scattering cross-section based on impulse approximation.

Feasibility study of phase-contrast X-ray laminography using X-ray interferometry.

For fine observation of laminar samples, phase-contrast X-ray laminography using X-ray interferometry was developed. An imaging system fitted with a two-crystal X-ray interferometer was used to perform the observations, and the sectional images were calculated by a three-dimensional iterative reconstruction method. Obtained images of an old flat slab of limestone from the Carnic Alps depicted fusulinids in the Carboniferous period with 3 mg cm density resolution, and those of carbon paper used for a fuel-cell battery displayed the inner fibrous structures clearly.

Combining Segmented Grey and White Matter Images Improves Voxel-based Morphometry for the Case of Dilated Lateral Ventricles.

Purpose: To evaluate the error in segmented tissue images and to show the usefulness of the brain image in voxel-based morphometry (VBM) using Statistical Parametric Mapping (SPM) 12 software and 3D T-weighted magnetic resonance images (3D-TWIs) processed to simulate idiopathic normal pressure hydrocephalus (iNPH).

Materials And Methods: VBM analysis was performed on sagittal 3D-TWIs obtained in 22 healthy volunteers using a 1.5T MR scanner.

Mis-segmentation in voxel-based morphometry due to a signal intensity change in the putamen.

The aims of this study were to demonstrate an association between changes in the signal intensity of the putamen on three-dimensional T1-weighted magnetic resonance images (3D-T1WI) and mis-segmentation, using the voxel-based morphometry (VBM) 8 toolbox. The sagittal 3D-T1WIs of 22 healthy volunteers were obtained for VBM analysis using the 1.5-T MR scanner.

The Effect of Single-Scan and Scan-Pair Intensity Inhomogeneity Correction Methods on Repeatability of Voxel-Based Morphometry With Multiple Magnetic Resonance Scanners.

Objective: The aim of this study was to investigate the effects of single-scan and scan-pair intensity inhomogeneity correction methods on the repeatability of voxel-based morphometry (VBM) using images acquired with multiple magnetic resonance (MR) scanners.

Methods: Three-dimensional T1-weighed MR images of the brain were obtained from 22 healthy participants using each of 5 MR scanners, yielding 110 images (5 scanners × 22 subjects) in total. Six patterns of intensity inhomogeneity corrections (no correction, single-scan corrections, and scan-pair correction, and their combinations) were applied in the VBM procedure to investigate the effect of the corrections on the repeatability of gray and white matter volume measurements.

Cartilage formation in the pelvic skeleton during the embryonic and early-fetal period.

The pelvic skeleton is formed via endochondral ossification. However, it is not known how the normal cartilage is formed before ossification occurs. Furthermore, the overall timeline of cartilage formation and the morphology of the cartilage in the pelvis are unclear.

Positional Changes of the Ocular Organs During Craniofacial Development.

The present study aimed to describe the positional changes of the ocular organs during craniofacial development; moreover, we examined the relationships among the ocular organs and other internal structures. To do this, we traced the positions of the ocular organs in 56 human early fetal samples at different stages of development using high-resolution magnetic resonance imaging and phase-contrast X-ray computed tomography. The eyes were located on the lateral side in the ventral view at Carnegie stage (CS) 16, and then changed their positions medially during development.

Dual-energy fluorescent x-ray computed tomography system with a pinhole design: Use of K-edge discontinuity for scatter correction.

We propose a pinhole-based fluorescent x-ray computed tomography (p-FXCT) system with a 2-D detector and volumetric beam that can suppress the quality deterioration caused by scatter components. In the corresponding p-FXCT technique, projections are acquired at individual incident energies just above and below the K-edge of the imaged trace element; then, reconstruction is performed based on the two sets of projections using a maximum likelihood expectation maximization algorithm that incorporates the scatter components. We constructed a p-FXCT imaging system and performed a preliminary experiment using a physical phantom and an I imaging agent.

CO₂ processing and hydration of fruit and vegetable tissues by clathrate hydrate formation.

CO2 hydrate can be used to preserve fresh fruits and vegetables, and its application could contribute to the processing of carbonated frozen food. We investigated water transformation in the frozen tissue of fresh grape samples upon CO2 treatment at 2-3 MPa and 3°C for up to 46 h. Frozen fresh bean, radish, eggplant and cucumber samples were also investigated for comparison.

Comparison of Reconstruction Algorithms for Decreasing the Exposure Dose During Digital Tomosynthesis for Arthroplasty: a Phantom Study.

To explore the possibility of decreasing the radiation dose during digital tomosynthesis (DT) for arthroplasty, we compared the image qualities of several reconstruction algorithms, such as filtered back projection (FBP) and two iterative reconstruction (IR), methods maximum likelihood expectation maximization (MLEM) and the simultaneous iterative reconstruction technique (SIRT) under different radiation doses. The three algorithms were implemented using a DT system and experimentally evaluated by contrast-to-noise ratio (CNR), artifact spread function (ASF), and power spectrum measurements on a prosthesis phantom. The CNR and ASF data were statistically analyzed by a one-way analysis of variance.

Repeatability of Brain Volume Measurements Made with the Atlas-based Method from T-weighted Images Acquired Using a 0.4 Tesla Low Field MR Scanner.

Purpose: An understanding of the repeatability of measured results is important for both the atlas-based and voxel-based morphometry (VBM) methods of magnetic resonance (MR) brain volumetry. However, many recent studies that have investigated the repeatability of brain volume measurements have been performed using static magnetic fields of 1-4 tesla, and no study has used a low-strength static magnetic field. The aim of this study was to investigate the repeatability of measured volumes using the atlas-based method and a low-strength static magnetic field (0.

Head Motion and Correction Methods in Resting-state Functional MRI.

Resting-state functional magnetic resonance imaging (RS-fMRI) is used to investigate brain functional connectivity at rest. However, noise from human physiological motion is an unresolved problem associated with this technique. Following the unexpected previous result that group differences in head motion between control and patient groups caused group differences in the resting-state network with RS-fMRI, we reviewed the effects of human physiological noise caused by subject motion, especially motion of the head, on functional connectivity at rest detected with RS-fMRI.

Three-dimensional imaging of palatal muscles in the human embryo and fetus: Development of levator veli palatini and clinical importance of the lesser palatine nerve.

Background: After palatoplasty, incomplete velopharyngeal closure in speech articulation sometimes persists, despite restoration of deglutition function. The levator veli palatini (LVP) is believed to be significantly involved with velopharyngeal function in articulation; however, the development and innervation of LVP remain obscure. The development of LVP in human embryos and fetuses has not been systematically analyzed using the Carnegie stage (CS) to standardize documentation of development.

A Novel Strategy to Reveal the Latent Abnormalities in Human Embryonic Stages from a Large Embryo Collection.

The cause of spontaneous abortion of normal conceptuses remains unknown in most cases. The study was aimed to reveal the latent abnormalities by using a large collection of embryo images from a magnetic resonance imaging (MRI) database and novel phase-contrast radiographic computed tomography (PXCT). MRI from 1,156 embryos between Carnegie stage (CS) 14 and CS23 from the Kyoto Collection were screened by using the volume of the liver as the target organ.

Morphogenesis of the inner ear at different stages of normal human development.

This study examined the external morphology and morphometry of the human embryonic inner ear membranous labyrinth and documented its three-dimensional position in the developing embryo using phase-contrast X-ray computed tomography and magnetic resonance imaging. A total of 27 samples between Carnegie stage (CS) 17 and the postembryonic phase during trimester 1 (approximately 6-10 weeks after fertilization) were included. The otic vesicle elongated along the dorso-ventral axis and differentiated into the end lymphatic appendage and cochlear duct (CD) at CS 17.

Enhanced renal image contrast by ethanol fixation in phase-contrast X-ray computed tomography.

Phase-contrast X-ray imaging using a crystal X-ray interferometer can depict the fine structures of biological objects without the use of a contrast agent. To obtain higher image contrast, fixation techniques have been examined with 100% ethanol and the commonly used 10% formalin, since ethanol causes increased density differences against background due to its physical properties and greater dehydration of soft tissue. Histological comparison was also performed.

Comparison of chest dual-energy subtraction digital tomosynthesis and dual-energy subtraction radiography for detection of pulmonary nodules: initial evaluations in human clinical cases.

Rationale And Objectives: To compare initial evaluations of chest dual-energy subtraction digital tomosynthesis (DES-DT) and dual-energy subtraction radiography (DES-R) for detection of pulmonary nodules.

Materials And Methods: DES-DT and DES-R systems with pulsed x-rays and rapid kV switching were used to evaluate pulmonary nodules (>4-6 mm, 2 nodules; >6-8 mm, 2 nodules; >8 mm, 32 nodules). Multidetector computed tomography was used as a reference.

Diffraction-enhanced X-ray imaging under low-temperature conditions: non-destructive observations of clathrate gas hydrates.

Diffraction-enhanced imaging (DEI) is a phase-contrast X-ray imaging technique suitable for visualizing light-element materials. The method also enables observations of sample-containing regions with large density gradients. In this study a cryogenic imaging technique was developed for DEI-enabled measurements at low temperature from 193 K up to room temperature with a deviation of 1 K.

Embedded soft-tissue image mechanism of a small animal shell with synchrotron-based micro-CT.

Synchrotron-based micro-CT was utilized to image the embedded biological soft-tissue of a small animal shell. Micro-CT images of the biological soft-tissue were acquired using 20, 25, and 27 keV synchrotron X-rays with contrast agents, such as water, physiological saline and iodine. Visualized the complex features of the animal at the above energies with water, physiological saline and iodine.

Synchrotron-based DEI for bio-imaging and DEI-CT to image phantoms with contrast agents.

The introduction of water, physiological, or iodine as contrast agents is shown to enhance minute image features in synchrotron-based X-ray diffraction radiographic and tomographic imaging. Anatomical features of rat kidney, such as papillary ducts, ureter, renal artery and renal vein are clearly distinguishable. Olfactory bulb, olfactory tact, and descending bundles of the rat brain are visible with improved contrast.