Radial Diffusion Research Articles

Brains of endurance athletes differ in the association areas but not in the primary areas.

Regular participation in sports results in a series of physiological adaptations. However, little is known about the brain adaptations to physical activity. Here we aimed to investigate whether young endurance athletes and non-athletes differ in the gray and white matter of the brain and whether cardiorespiratory fitness (CRF) is associated with these differences. We assessed the CRF, volumes of the gray and white matter of the brain using structural magnetic resonance imaging (sMRI), and brain white matter connections using diffusion magnetic resonance imaging (dMRI) in 20 young male endurance athletes and 21 healthy non-athletes. While total brain volume was similar in both groups, the white matter volume was larger and the gray matter volume was smaller in the athletes compared to non-athletes. The reduction of gray matter was located in the association areas of the brain that are specialized in processing of sensory stimuli. In the microstructure analysis, significant group differences were found only in the association tracts, for example, the inferior occipito-frontal fascicle (IOFF) showing higher fractional anisotropy and lower radial diffusivity, indicating stronger myelination in this tract. Additionally, gray and white matter brain volumes, as well as association tracts correlated with CRF. No changes were observed in other brain areas or tracts. In summary, the brain signature of the endurance athlete is characterized by changes in the integration of sensory and motor information in the association areas.

Imaginary Poynting forces on a magnetodielectric particle under cylindrical vector lights

Particles with magnetodielectric dual responses endure the unique imaginary Poynting force, attributed to the crossed interference between electric and magnetic dipoles. In this work, we theoretically demonstrate that for illumination of cylindrical vector light with azimuthal or radial polarization, the imaginary Poynting force has a radial diffusion or centripetal trapping characteristic exerted on a magnetodielectric particle. Moreover, with a superposition of linearly-polarized light on the cylindrical vector light, an extra transverse force will emerge with a unidirectional characteristic. Our work reveals the unique role of imaginary Poynting force for optical manipulations on magnetodielectric particles by cylindrical vector lights, including radial diffusion, centripetal trapping, and transverse conveying.

Microstructural changes of peripheral nerves in early multiple sclerosis: A prospective magnetic resonance neurography study.

Multiple sclerosis (MS) is a demyelinating disorder of the central nervous system (CNS). However, there is increasing evidence of peripheral nerve involvement. This study aims to characterize the pattern of peripheral nerve changes in patients with newly diagnosed MS using quantitative magnetic resonance (MR) neurography. In this prospective study, 25 patients first diagnosed with MS according to the revised McDonald criteria (16 female, mean age = 32.8 ± 10.6 years) and 14 healthy controls were examined with high-resolution 3-T MR neurography of the sciatic nerve using diffusion kurtosis imaging (DKI; 20 diffusional directions, b = 0, 700, 1200 s/mm2 ) and magnetization transfer imaging (MTI). In total, 15 quantitative MR biomarkers were analyzed and correlated with clinical symptoms, intrathecal immunoglobulin synthesis, electrophysiology, and lesion load on brain and spine MR imaging. Patients showed decreased fractional anisotropy (mean = 0.51 ± 0.04 vs. 0.56 ± 0.03, p < 0.001), extra-axonal tortuosity (mean = 2.32 ± 0.17 vs. 2.49 ± 0.17, p = 0.008), and radial kurtosis (mean = 1.40 ± 0.23 vs. 1.62 ± 0.23, p = 0.014) and higher radial diffusivity (mean = 1.09 ∙ 10-3 mm2 /s ± 0.16 vs. 0.98 ± 0.11 ∙ 10-3 mm2 /s, p = 0.036) than controls. Groups did not differ in MTI. No significant association was found between MR neurography markers and clinical/laboratory parameters or CNS lesion load. This study provides further evidence of peripheral nerve involvement in MS already at initial diagnosis. The characteristic pattern of DKI parameters indicates predominant demyelination and suggests a primary coaffection of the peripheral nervous system in MS. This first human study using DKI for peripheral nerves shows its potential and clinical feasibility in providing novel biomarkers.

Simulation test study on filling flow law of gangue slurry in goaf

The disposal and utilization of solid waste of coal gangue is one of the main problems in coal mining in China. Injecting coal gangue into goaf in the form of slurry can effectively solve the problems of ground stacking and environmental pollution prevention. In order to obtain the flow law of gangue slurry in the void of the accumulated rock in the goaf, a visualization simulation test device for gangue slurry permeation grouting in the goaf was independently designed. The flow and diffusion characteristics, flow and diffusion velocity changes, void pressure changes, and viscosity changes of three mass concentrations (76%, 78%, 80%) of gangue slurry in the void between caved rock blocks in goaf were studied by visual grouting simulation test. The results show that: (1) The seepage process of gangue slurry in the goaf simulation test is divided into three diffusion forms, namely radial diffusion, axial diffusion, and bidirectional diffusion. The three diffusion forms are interrelated and inseparable. (2) The initial flow velocity of the slurry with different concentrations is different under the same permeation grouting pressure, and the higher the slurry concentration, the smaller the initial flow velocity of the slurry. The velocity of the slurry has a nonlinear relationship with the diffusion distance of the slurry. (3) With the permeation and diffusion of slurry, pressure sensors at different positions are subjected to pressure from bottom to top and enter the pressure boost stage, gradually forming stress peaks. When the slurry exceeds the position of the pressure sensor, the pressure on the pressure sensor is weakened and begins to enter the pressure relief stage, and the stress decline trend gradually becomes gentle with time. (4) The water loss effect occurs during slurry flow interaction with rock mass, resulting in slurry viscosity increasing. The viscosity of the slurry affects the difference in the amount of viscosity change. The research results can provide a certain theoretical basis for the goaf gangue slurry filling project.

Rapid white matter changes in children with conduct problems during a parenting intervention

Studies report that the microstructural integrity of the uncinate fasciculus (UF; connecting the anterior temporal lobe to the orbitofrontal cortex) is abnormal in adults with psychopathy and children with conduct problems (CP), especially those with high callous-unemotional (CU) traits. However, it is unknown if these abnormalities are ‘fixed’ or ‘reversible’. Therefore, we tested the hypothesis that a reduction in CP symptoms, following a parenting intervention, would be associated with altered microstructural integrity in the UF. Using diffusion tensor imaging tractography we studied microstructural differences (mean diffusivity (MD) and radial diffusivity (RD)) in the UF of 43 typically developing (TD) and 67 boys with CP before and after a 14-week parenting intervention. We also assessed whether clinical response in CP symptoms or CU traits explained changes in microstructure following the intervention. Prior to intervention, measures of MD and RD in the UF were increased in CP compared to TD boys. Following intervention, we found that the CP group had a significant reduction in RD and MD. Further, these microstructural changes were driven by the group of children whose CU traits improved (but not CP symptoms as hypothesized). No significant microstructural changes were observed in the TD group. Our findings suggest, for the first time, that microstructural abnormalities in the brains of children with CP may be reversible following parenting intervention.

Neural correlates of mental state decoding and mental state reasoning in schizophrenia

Theory of mind skills are disrupted in schizophrenia. However, various theory of mind tasks measure different neurocognitive domains. This multimodal neuroimaging study aimed to investigate the neuroanatomical correlates of mental state decoding and reasoning components of theory of mind in schizophrenia and healthy controls (HCs) using T1-weighted and diffusion-weighted (DTI) magnetic resonance imaging (MRI). Sixty-two patients with schizophrenia and 34 HCs were included. The Reading the Mind in the Eyes (RMET) and Hinting tests were used to evaluate mental state decoding and reasoning, respectively. Correlations between social cognition and cortical parameters (thickness, volume, surface area), or DTI scalars (fractional anisotropy, axial diffusivity, radial diffusivity) were cluster-based corrected for multiple comparisons. In schizophrenia, RMET scores showed positive correlations in 3 clusters, including left insula thickness, right superior-temporal thickness, left superior-temporal-sulcus volume, and DTI analysis revealed that fractional anisotropy showed positive correlations in 3 clusters, including right inferior-fronto-occipital fasciculus, left forceps-major, left inferior-fronto-occipital fasciculus. In schizophrenia, Hinting test scores showed positive correlations in 3 clusters in T1-weighted MRI, including left superior-temporal-sulcus volume, left superior-temporal-sulcus surface area, left pars-orbitalis volume. In conclusion, this study provided evidence for the involvement of particular cortical regions and white matter tracts in mental state decoding and reasoning.

Criteria for the use of 1D and 2D models in catalytic membrane reactor modeling

A criterion was developed to determine the necessity of using 1D or 2D methods for modeling a concentric tubular membrane reactor for hydrogen-producing reactions. Four dimensionless parameters were defined to provide a complete description of the physical and chemical systems, and the effects of each parameter on the difference between a 1D and 2D model were explored. The membrane reactor geometry consisted of a tube-and-shell configuration with a catalyst bed in the tubular section and a perm-selective membrane in the interphase. The four dimensionless parameters consisted of the Damköhler number (Da), which relates the reaction and axial convection rates, the Péclet number (Pe), which relates the radial diffusion and axial convection rates, the transport parameter (θ), which relates the axial convection and membrane permeation rates, and the equilibrium parameter (ε), which is a measure of the favorability of the reaction. A cutoff at which 1D and 2D model results have less than a 1% difference in final concentrations was used to define a critical Pe value, or Pecrit. Then, a criterion equation was fitted using non-linear regression so that any system can be calculated and compared against Pecrit. Using this criterion, a model above the cutoff (Pe > Pecrit) can reduce computation time by selectively calculating a simple 1D model for conditions, while a model below the cutoff (Pe ≤ Pecrit) should use a more computationally expensive 2D model to assure accuracy. The final criterion was validated against literature data for both 1D and 2D models.

Mismatch of MRI White Matter Hyperintensities and Gait Function in Patients With Cerebral Small Vessel Disease.

Cerebral small vessel disease (CSVD) is closely related to gait disorders. Previous studies have found a negative correlation between the severity of MRI white matter hyperintensities (WMH) and gait speed. However, not every individual with WMH experiences a gait disorder. To investigate the mechanisms underlying the mismatch between the severity of MRI WMH and gait impairment, in particular in subjects with severe WMH (Fazekas 3, scale 0-3) resulting from vascular disease. Cohort. 54 subjects with severe WMH and gait disorder (WMH-GD; 29 males) and 114 subjects with severe WMH with no gait disorder (WMH-nGD; 60 males). 3T/diffusion tensor imaging (DTI), and T1-weighted, T2-weighted, FLAIR, DWI, SWI. Trace-based spatial statistics analysis (TBSS) approach (fractional anisotropy, FA; mean diffusivity; radial diffusivity; axial diffusivity); Cognitive assessment; Conventional MRI markers of CSVD (WMH, enlarged perivascular spaces, lacunae, and cerebral microbleeds); Gait parameters (gait speed; cadence; stride length; gait cycle duration; step duration; time-up-and-go test, TUG). Gait disorder was defined as a TUG time exceeding 12 sec. The t-tests, Mann-Whitney U tests, Chi-square tests, and partial correlation analysis (Pearson or Spearman) were used. P < 0.05 with threshold-free cluster enhancement corrected was considered statistically significant for TBSS. After adjusting for age, sex, height, and other conventional MRI markers of CSVD, the WMH-nGD group showed significantly decreased FA values in the corpus callosum, bilateral superior longitudinal fasciculus, left corona radiata, and left posterior thalamic radiation. There was a significant association between FA values and TUG time, gait speed, and stride length in multiple WM tracts, independent of other conventional CSVD markers. This study provides evidence for microstructural damage of specific fibers in WMH-GD subjects compared to WMH-nGD subjects. This may explain the mismatch between WMH and gait impairment in subjects with severe WMH. 1 TECHNICAL EFFICACY: Stage 3.

White matter integrity assessment in spinocerebellar ataxia type 2 (SCA2) patients

To assess the burden of white matter (WM) damage in the cerebrum and cerebellum of spinocerebellar ataxia type 2 (SCA2) patients in an attempt to identify key regions affected by the neurodegenerative processes using diffusion tensor imaging (DTI). Nine SCA2 patients and 16 age-matched healthy controls were examined twice (SCA2 patients 3.6±0.7 years and controls 3.3±1.0 years apart) on the same 1.5 T scanner by acquiring T1-weighted and diffusion-weighted (b-value=1,000 s/mm2) images. Using tract-based spatial statistics, DTI analysis on fractional anisotropy (FA), mean diffusivity (MD), axial (AD)/radial (RD) diffusivity was performed. At baseline magnetic resonance imaging (MRI), FA was significantly decreased in SCA2 patients in the corticospinal tracts, inferior and superior cerebellar peduncles, middle cerebellar peduncles, cerebral peduncles, right superior and posterior corona radiata. RD was only significantly increased in SCA2 patients in the middle cerebellar peduncles. No significant AD and MD changes were observed. Tract-based spatial statistics (TBSS) analysis between SCA2 patients at baseline and at follow-up showed no significant changes in any of the DTI metrics. DTI is a sensitive tool for following the progression of WM neurodegeneration and severity assessment in patients with SCA2. These findings add to a better understanding of the neurological underpinnings of the symptoms experienced by SCA2 patients.

Novel Computational Chemistry Infrastructure for Simulating Astatide in Water: From Basis Sets to Force Fields Using Particle Swarm Optimization.

Using the example of astatine, the heaviest naturally occurring halogen whose isotope At-211 has promising medical applications, we propose a new infrastructure for large-scale computational models of heavy elements with strong relativistic effects. In particular, we focus on developing an accurate force field for At- in water based on reliable relativistic density functional theory (DFT) calculations. To ensure the reliability of such calculations, we design novel basis sets for relativistic DFT, via the particle swarm optimization algorithm to optimize the coefficients of the new basis sets and the polarization-consistent basis set idea's extension to heavy elements to eliminate the basis set error from DFT calculations. The resulting basis sets enable the well-grounded evaluation of relativistic DFT against "gold-standard" CCSD(T) results. Accounting for strong relativistic effects, including spin-orbit interaction, via our redesigned infrastructure, we elucidate a noticeable dissimilarity between At- and I- in halide-water force field parameters, radial distribution functions, diffusion coefficients, and hydration energies. This work establishes the framework for the systematic development of polarization-consistent basis sets for relativistic DFT and accurate force fields for molecular dynamics simulations to be used in large-scale models of complex molecular systems with elements from the bottom of the periodic table, including actinides and even superheavy elements.

4 Interactions of Inflammation and Psychosocial Stress on White Matter Integrity Over Time in Older Black Adults

Objective:Higher levels of inflammation are associated with risk factors for Alzheimer’s disease and related dementias (ADRD) in older Black adults including psychosocial stressors (e.g., discrimination and early life adversity) and white matter alterations. Yet, limited work has investigated these risk factors together in a longitudinal neuroimaging study, despite the well-known ADRD disparity in older Black adults. Using data from the Minority Aging Research Study and African American Clinical Core of the Rush Alzheimer’s Disease Center, we examined interactions of psychosocial stressors and change in inflammation on changes in white matter integrity as measured via diffusion tensor imaging (DTI).Participants and Methods:Older Black adults (n=102) without known dementia at baseline (age=75.8±6.1 years; 87.3% female; education=15.4±2.7 years) completed blood draws at two time points (follow-up=2.4±0.7 years), neuroimaging at two or more time points (follow-up=3.7±1.8 years), and psychosocial questionnaires at one time point coinciding with the first blood draw/neuroimaging. Blood serum was assayed using highly-sensitive multiplexed sandwich ELISA for interleukin-6, c-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-a) and a change score was calculated for each inflammatory marker (T2 - T1). The Williams Everyday Discrimination Scale quantified experiences of discrimination in all participants and a 16-item questionnaire of emotional and physical trauma from age 0-18 assessed early life adversity in a participant subset (n=63). DTI-derived tract-based spatial statistics (TBSS) slope change measures for trace of the diffusion tensor, fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) were calculated, with the first two scans matched in time to blood assays. Linear regression models investigated interactions of each inflammatory marker change score (separately) and either discrimination or early life adversity (separately) on trace, FA, AD, and RD slopes as individual outcomes adjusting for age, sex, education, white matter hyperintensities (total volume and voxelwise), cardiovascular risk factors, statin and analgesic medications, thyroid conditions, and depression. Statistical significance was determined at p&lt;0.05 using family wise error correction and threshold free cluster enhancement.Results:Discrimination moderated the relationship between TNF-a and AD whereby those with increasing TNF-a and higher levels of discrimination had increasing levels of AD over time in white matter tracts connecting the left and right cerebellum, the left pallidum and medulla, and the left superior frontal gyrus and left thalamus. Both discrimination and early life adversity moderated associations between CRP and AD, where increases in CRP and higher psychosocial stressors (of either type) resulted in decreasing AD over time in tracts involving cingulate, frontal, and parietal regions. Discrimination and early life adversity also moderated associations between CRP and RD, where increasing CRP combined with greater psychosocial stressors resulted in decreasing RD in right hemisphere association and projection tracts connecting frontal, parietal, central, and subcortical regions.Conclusions:TNF-a and CRP interacted with measures of psychosocial stress to associate with DTI-derived TBSS slope change measures of AD and RD in differential, and at times, paradoxical ways. Findings suggest that both risk and resilience as related to brain connectivity may be co-occurring in the presence of psychosocial stressors for older Black adults.

Longitudinal evolution of diffusion metrics after left hemisphere ischaemic stroke

Abstract White matter is often severely affected after human ischaemic stroke. While animal studies have suggested that various factors may contribute to white matter structural damage after ischaemic stroke, the characterization of damaging processes to the affected hemisphere after human stroke remains poorly understood. Thus, the present study aims to thoroughly describe the longitudinal pattern of evolution of diffusion magnetic resonance imaging metrics in different parts of the ipsilesional white matter after stroke. We acquired diffusion and anatomical images in 17 patients who had suffered from a single left hemisphere ischaemic stroke, at 24–72 h, 8–14 days and 6 months post-stroke. For each patient, we created three regions of interest: (i) the white matter lesion; (ii) the perilesional white matter; and (iii) the remaining white matter of the left hemisphere. We extracted diffusion metrics (fractional anisotropy, mean, axial and radial diffusivities) for each region and conducted two-way repeated measures ANOVAs with stage post-stroke (acute, subacute and chronic) × regions of interest (white matter lesion, perilesional white matter and remaining white matter). Fractional anisotropy values stayed consistent across time-points, with significantly lower values in the white matter lesion compared to the perilesional white matter and remaining white matter tissue. Fractional anisotropy values of the perilesional white matter were also significantly lower than that of the remaining white matter. Mean, axial and radial diffusivities in the white matter lesion were all decreased in the acute stage compared to perilesional white matter and remaining white matter, but significantly increased in both the subacute and chronic stages. Significant increases in mean and radial diffusivities in the perilesional white matter were seen in the later stages of stroke. Our findings suggest that various physiological processes are at play in the acute, subacute and chronic stages following ischaemic stroke, with the infarct territory and perilesional white matter affected by ischaemia at different rates and to different extents throughout the stroke recovery stages. The examination of multiple diffusivity metrics may inform us about the mechanisms occurring at different time-points, i.e. focal swelling, axonal damage or myelin loss.

7 P-Tau and Education as Moderators of the Relation between APOE4 and Memory Performance in Older Adults with Varying Cognitive Status

Objective:White matter microstructure (WMM) potentially mediates the relation between APOE4 and memory performance. This study’s purpose was to understand whether p-tau effects this mediation model and whether education level differentially impacts the relations between these genetic and biological biomarkers’ influence on memory.Participants and Methods:Participants included 161 older adults (M=74 years, 40.4% female, 92% White, 74 e4 non-carriers, 87 e4 carriers) with subjective and objective cognitive impairment from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). A composite memory score created by ADNI was used as the outcome variable. Mean fractional anisotropy (FA) and radial diffusivity (RD) values of white matter tracts within regions of interest (i.e., fornix (FX), hippocampal cingulum (CGH)) were individually used as the measures of WMM. A moderated mediation was run to examine whether p-tau was a moderator of the mediation between APOE4, white matter microstructure, and memory. An exploratory dual moderated mediation analysis examined education as a moderator of the moderated mediation. Indirect effects were tested using bootstrapping procedures.Results:In the FA moderated mediation model, APOE4 was significantly related to FA of the fornix and memory performance. FA of the CGH and FX were also related to memory performance. With FA of the fornix as the mediator, the conditional indirect effect was not significant (95% CI[-.0009, .0070]). There was a trend suggesting at low (95% CI[-.2421, -.0140]) and average (95% CI[-.1658, -.0083]) levels of p-tau, FA of the fornix was a significant mediator but was non-significant at high levels of p-tau (95% CI [-.1322, .0341]). The RD moderated mediation model was non-significant. The FA and RD exploratory dual moderated mediation models were non-significant. However, the APOE4 x p-tau interaction with FA of the fornix as the mediator suggested a trend. At low levels of p-tau, increased education was related to a significant moderated mediation.Conclusions:Results suggest that FA of the fornix is a significant mediator between the relation of APOE4 and memory, and this may be dependent upon p-tau levels. When p-tau burden load was high, the path by which APOE4 impacts memory performance was not through white matter microstructure degradation. Additionally, the potential buffering effects of education may be most robust at lower levels of p-tau burden.

Severity of white matter microstructural damage in a Brazilian relapsing-remitting multiple sclerosis cohort: A possible window to optimize treatment.

Multiple sclerosis (MS) is an important cause of acquired neurological disability in young adults, characterized by multicentric inflammation, demyelination, and axonal damage. The objective is to investigate white matter (WM) damage progression in a Brazilian MS patient cohort, using diffusion tensor imaging (DTI) post-processed by tract-based spatial statistics (TBSS). DTI scans were acquired from 76 MS patients and 37 sex-and-age matched controls. Patients were divided into three groups based on disease duration. DTI was performed along 30 non-collinear directions by using a 1.5T imager. For TBSS analysis, the WM skeleton was created, and a 5000 permutation-based inference with a threshold of p < .05 was used, to enable the identification of abnormalities in fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). Decreased FA and increased RD, MD, and AD were seen in patients compared to controls and a decreased FA and increased MD and RD were seen, predominantly after the first 5years of disease, when compared between groups. Progressive WM deterioration is seen over time with a more prominent pattern after 5years of disease onset, providing evidence that the early years might be a window to optimize treatment and prevent disability.

Alterations in Diffusion Tensor Imaging-derived Indices of Auditory Pathway-related Fiber Tracts in Children With Sensorineural Hearing Loss.

Hearing loss is the most common sensory-neurological defect in humans. The most common hearing impairment is sensorineural hearing loss (SNHL) caused by the inner ear and related nerves. Diffusion tensor imaging (DTI) is an advanced MRI technique that can provide valuable information about auditory neural pathways and their microstructural changes. The present study was designed to investigate the microstructural changes in auditory pathways-related fiber tracts in children with SNHL. Twenty-two children including 11 subjects with SNHL aged 1-4 years and 11 healthy children were examined as controls. Then, DTI-derived parameters, such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AxD), and radial diffusivity (RD), and volume of fiber tracts were extracted from the inferior longitudinal fasciculus, acoustic radiation, and uncinate fasciculus. The results showed an increase in MD, RD, and AxD as well as a decrease in FA, volume, and diameter of auditory-pathway-related fiber tracts. Interestingly, there was an increase in the FA of acoustic radiation. White matter connections in the auditory canal decrease and AR integrity increases due to compensatory effects. These probably reflect atrophy or degradation as well as compensatory cross-modal reorganization in the absence of auditory input and the use of sign language. Diffusion tensor imaging (DTI) plays an important role in preoperative planning.Anatomical knowledge of the auditory tract is essential for lacrimal drainage surgeries, such as cochlear implantation.DTI-based biomarkers for brain changes and allows us to better understand the pathophysiological changes of auditory tract.Microstructural changes in the fiber tracts associated with the auditory pathway can distinguish sensorineural hearing loss (SNHL) from healthy subjects. Sensorineural hearing loss (SNHL) is the most common type and accounts for the majority of all hearing loss. SNHL is a congenital deficit and refers to any cause of hearing loss due to a pathology of the cochlea, auditory nerve, or central nervous system. One of the chief treatment planning is cochlear implant for these patients. So, it is necessary to evaluate the auditory system by imaging devices such as MRI (magnetic resonance imaging) before treatment. Diffusion tensor imaging tractography, or diffusion tensor imaging (DTI) tractography, is an MRI technique that measures the rate of water diffusion between cells to understand and create a map of the body's internal structures; it is most commonly used to provide imaging of the brain. The purpose of the present research was to assess the auditory system and its nerve routs in children before cochlear implant. This study showed that DT imaging is a novel approach for assessment of children with SNHL before and treatment.

49 Longitudinal White Matter Changes in First Time Mild Traumatic Brain Injury in Relationship with Cognitive Performance: A Diffusion Tensor Imaging Study

Objective:The objective of the study was to examine longitudinal changes in the white matter tracts with diffusion tensor imaging (DTI), neuropsychological performance, and the associate between the two in adults with a mild traumatic brain injury (mTBI).Participants and Methods:Sixteen adult patients (age = 38.5(12.8); 75% female) seeking medical care at an emergency department for their first mTBI and 15 healthy adults (age = 30.5(11.3); 33% female) from the community were recruited. DTI and the neuropsychological evaluation were performed at 7 days and 4-months post-injury. The neuropsychological evaluation consisted of the CNS Vital Signs computerized neurocognitive test battery and 2 trials of the Paced Auditory Serial-Addition Test.Results:Results showed a significant decrease in fractional anisotropy (FA) and an increase in radial diffusivity (RD) of the right uncinate fasciculus as well as a significant decrease in FA and axial diffusivity (AD) of the right inferior fronto-occipital fasciculus over the 4-month follow-up period in the mTBI group compared to the Control group.The FA of multiple white matter tracts at baseline were positively associated with working memory, sustained attention, and complex attention at baseline in the mTBI group but not the Control group. The global mean cerebral diffusivity for FA at baseline was positively associated with working memory and sustained attention at 4-months post-injury.Conclusions:The current findings of abnormal white matter suggest an oxidative stress reaction as a result of mTBI altering the diffusivity of some white matter tracts. Furthermore, the disruption of the white matter tracts at baseline may serve as a biomarker for identifying mTBI and those who may have prolonged cognitive difficulties in working memory and attention as a result of the mTBI.

The preservation of right cingulum fibers in subjective cognitive decline of preclinical phase of Alzheimer's disease.

Subjective cognitive decline (SCD) with a positive amyloid burden has been recognized as the earliest clinical symptom of the preclinical phase of Alzheimers disease (AD), providing invaluable opportunities to improve our understanding of the natural history of AD and determine strategies for early therapeutic interventions. The microstructure of white matter in patients showing SCD in the preclinical phase of AD (SCD of pre-AD) was evaluated using diffusion images, and voxel-wise fractional anisotropy (FA), mean diffusivity (MD), and axial and radial diffusivities were assessed and compared among participant groups. Significant clusters in the tracts were extracted to determine their associations with alterations in the cognitive domains. We found that individuals with SCD of pre-AD may have subclinical episodic memory impairment associated with the global amyloid burden. Meanwhile, we found significantly reduced FA and λ1 in the right cingulum (cingulate and hippocampus) in AD dementia, while significantly increased FA and decreased MD as well as λ23 in the SCD of pre-AD group in comparison with the HC group. In conclusion, increased white matter microstructural integrity in the right cingulum (cingulate and hippocampus) may indicate compensation for short-term episodic memory in individuals with SCD of pre-AD in comparison with individuals with AD and healthy elderly individuals.

Research on ash movement law of membrane bin drum slag cooler

For a membrane bin drum slag cooler, the ash movement model is established using the discrete element method. The EDEM software is used to simulate the movement state of the particles. The change of the active layer depth of the particles is analyzed, and the irregular movement of the particles is measured by the radial diffusion coefficient and the mixing degree. The results show that the thickness of the active layer increases linearly with the rotational speed, and the particle size has little effect on it. The diffusion coefficient of the particles in the active layer is large, and in the core area, it is the smallest. It increases from the core to the passive area and decreases near the wall. The particle size has little effect on the diffusion coefficient, but the filling rate dramatically influences it. The increase in rotational speed is beneficial to the diffusion of particles. With the rise of time, the mixing degree of particles increases continuously. The increase in rotational speed and particle size and the decrease in particle filling rate benefit particle mixing.

Prediction of H3K27M Alteration Status in Brainstem Glioma Using Multi-Shell Diffusion MRI Metrics.

Multi-shell diffusion characteristics may help characterize brainstem gliomas (BSGs) and predict H3K27M status. To identify the diffusion characteristics of BSG patients and investigate the predictive values of various diffusion metrics for H3K27M status in BSG. Prospective. Eighty-four BSG patients (median age 10.5 years [IQR 6.8-30.0 years]) were included, of whom 56 were pediatric and 28 were adult patients. 3 T, multi-shell diffusion imaging. Diffusion kurtosis imaging and neurite orientation dispersion and density imaging analyses were performed. Age, gender, and diffusion metrics, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, radial diffusivity (RD), mean kurtosis (MK), axial kurtosis (AK), radial kurtosis, intracellular volume fraction (ICVF), orientation dispersion index, and isotropic volume fraction (ISOVF), were compared between H3K27M-altered and wildtype BSG patients. Chi-square test, Mann-Whitney U test, multivariate analysis of variance (MANOVA), step-wise multivariable logistic regression. P-values <0.05 were considered significant. 82.4% pediatric and 57.1% adult patients carried H3K27M alteration. In the whole group, the H3K27M-altered BSGs demonstrated higher FA, AK and lower RD, ISOVF. The combination of age and median ISOVF showed fair performance for H3K27M prediction (AUC = 0.78). In the pediatric group, H3K27M-altered BSGs showed higher FA, AK, MK, ICVF and lower RD, MD, ISOVF. The combinations of median ISOVF, 5th percentile of FA, median MK and median MD showed excellent predictive power (AUC = 0.91). In the adult group, H3K27M-altered BSGs showed higher ICVF and lower RD, MD. The 75th percentile of RD demonstrated fair performance for H3K27M status prediction (AUC = 0.75). Different alteration patterns of diffusion measures were identified between H3K27M-altered and wildtype BSGs, which collectively had fair to excellent predictive value for H3K27M alteration status, especially in pediatric patients. 2 TECHNICAL EFFICACY: Stage 3.

Sensation seeking correlates with increased white matter integrity of structures associated with visuospatial processing in healthy adults.

The ability to process sensory information is an essential adaptive function, and hyper- or hypo-sensitive maladaptive profiles of responses to environmental stimuli generate sensory processing disorders linked to cognitive, affective, and behavioral alterations. Consequently, assessing sensory processing profiles might help research the vulnerability and resilience to mental disorders. The research on neuroradiological correlates of the sensory processing profiles is mainly limited to the young-age population or neurodevelopmental disorders. So, this study aims to examine the structural MRI correlates of sensory profiles in a sample of typically developed adults. We investigated structural cortical thickness (CT) and white matter integrity, through Diffusion Tensor Imaging (DTI), correlates of Adolescent/Adult Sensory Profile (AASP) questionnaire subscales in 57 typical developing subjects (34F; mean age: 32.7 ± 9.3). We found significant results only for the sensation seeking (STS) subscale. Positive and negative correlations emerged with fractional anisotropy (FA) and radial diffusivity (RD) in anterior thalamic radiation, optic radiation, superior longitudinal fasciculus, corpus callosum, and the cingulum bundle. No correlation between sensation seeking and whole brain cortical thickness was found. Overall, our results suggest a positive correlation between sensation seeking and higher white matter structural integrity in those tracts mainly involved in visuospatial processing but no correlation with gray matter structure. The enhanced structural integrity associated with sensation seeking may reflect a neurobiological substrate linked to active research of sensory stimuli and resilience to major psychiatric disorders like schizophrenia, bipolar disorder, and depression.