Publications by authors named "Tales Santini"

Central sensitization plays a crucial role in chronic pain experienced by individuals with sickle cell disease, yet current pain assessment tools fail to capture the complex, multidimensional nature of this pain. Disrupted neural communication serves as a key marker of central sensitization. Thus, this study investigated whether Painimation, a novel electronic visualization tool for pain assessment, correlates with functional connectivity in brain networks using enhanced resolution 7-Tesla imaging, potentially offering a simpler method to identify CS in patients with SCD.

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Background And Purpose: White matter lesions are common imaging biomarkers associated with aging and neurodegenerative diseases, yet their underlying pathology remains unclear due to limitations in imaging-based characterization. We aim to develop and validate a comprehensive workflow enabling precise MRI-guided histological sampling of white matter lesions to bridge neuroimaging and neuropathology.

Methods: We establish a workflow integrating agarose-saccharose brain embedding, ultra-high field 7T MRI acquisition, reusable 3D-printed cutting guides, and semi-automated MRI-blockface alignment.

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The rapid advancements in magnetic resonance imaging (MRI) technology have precipitated a new paradigm wherein cross-modality data translation across diverse imaging platforms, field strengths, and different sites is increasingly challenging. This issue is particularly accentuated when transitioning from 3 Tesla (3T) to 7 Tesla (7T) MRI systems. This study proposes a novel solution to these challenges using generative adversarial networks (GANs)-specifically, the CycleGAN architecture-to create synthetic 7T images from 3T data.

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Introduction: Interest has grown in lithium's neuroprotective properties in neurodegenerative illnesses. We discuss the design, rationale, and implementation of a pilot feasibility, double-blind, randomized placebo-controlled trial (RCT) examining whether lithium can delay cognitive decline in older adults with mild cognitive impairment (MCI).

Methods: The study launched in September 2017.

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Purpose: To develop an radiofrequency (RF) shimming approach for operating the 2nd Generation Tic Tac Toe RF coil system (60 transmit channels integrated with 32-channel receive insert) for routine use in 7T neuro MRI on the single transmit mode.

Methods: RF simulations were performed and used to develop non-subject-specific RF shim cases over three anatomically detailed head models: adult male, adult female, and child female. Multi-ROI shimming strategies were developed and implemented.

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Magnetic resonance imaging (MRI) at 7T has a superior signal-to-noise ratio to 3T but also presents higher signal inhomogeneities and geometric distortions. A key knowledge gap is to robustly investigate the sensitivity and accuracy of 3T and 7T MRI in assessing brain morphometrics. This study aims to (a) aggregate a large number of paired 3T and 7T scans to evaluate their differences in quantitative brain morphological assessment using a widely available brain segmentation tool, FreeSurfer, as well as to (b) examine the impact of normalization methods for subject variability and smaller sample sizes on data analysis.

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Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC), is common in elderly brains and often seen in conjunction with Alzheimer's disease neuropathologic change (ADNC). LATE-NC typically begins in the amygdala and spreads to the hippocampus and neocortex. Whether it contributes to hippocampal and amygdala atrophy in Down syndrome (DS) remains unexplored.

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Introduction: Aging adults with Down syndrome (DS) accumulate Alzheimer's disease (AD) neuropathology, including amyloid beta plaques and neurofibrillary tangles, by age 40.

Methods: We present findings from an individual with DS who remained cognitively stable despite AD neuropathology. Clinical assessments, fluid biomarkers, neuroimaging, and neuropathological examinations were conducted to characterize her condition.

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Importance: Emerging evidence suggests that severe acute respiratory syndrome, COVID-19, negatively impacts brain health, with clinical magnetic resonance imaging (MRI) showing a wide range of neurologic manifestations but no consistent pattern. Compared with 3 Tesla (3T) MRI, 7 Tesla (7T) MRI can detect more subtle injuries, including hippocampal subfield volume differences and additional standard biomarkers such as white matter lesions. 7T MRI could help with the interpretation of the various persistent post-acute and distal onset sequelae of COVID-19 infection.

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Article Synopsis
  • - The study compares brain imaging results from 3 Tesla (3T) and 7 Tesla (7T) MRI to assess differences in brain morphology, focusing on signal quality and accuracy issues associated with each technology.
  • - Using data from 452 healthy participants, the research employed FreeSurfer for brain segmentation, explored normalization methods for accounting variability in head size, and correlated brain measurements with age.
  • - Findings indicate that 7T MRI provided stronger correlations between brain structure and age, although different normalization techniques impacted the results for 3T, with the Residual method showing better age correlation compared to the Proportional method.
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The rapid advancements in magnetic resonance imaging (MRI) technology have precipitated a new paradigm wherein cross-modality data translation across diverse imaging platforms, field strengths, and different sites is increasingly challenging. This issue is particularly accentuated when transitioning from 3 Tesla (3T) to 7 Tesla (7T) MRI systems. This study proposes a novel solution to these challenges using generative adversarial networks (GANs)-specifically, the CycleGAN architecture-to create synthetic 7T images from 3T data.

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Inquiries into properties of brain structure and function have progressed due to developments in magnetic resonance imaging (MRI). To sustain progress in investigating and quantifying neuroanatomical details in vivo, the reliability and validity of brain measurements are paramount. Quality control (QC) is a set of procedures for mitigating errors and ensuring the validity and reliability of brain measurements.

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Purpose: To investigate microstructural alterations induced by perfusion fixation in brain tissues using advanced diffusion MRI techniques and estimate their potential impact on the application of ex vivo models to in vivo microstructure.

Methods: We used oscillating gradient spin echo (OGSE) and b-tensor encoding diffusion MRI to examine in vivo and ex vivo microstructural differences in the marmoset brain. OGSE was used to shorten effective diffusion times, whereas b-tensor encoding allowed for the differentiation of isotropic and anisotropic kurtosis.

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Article Synopsis
  • * Key findings include her ApoE genotype (E2/3) linked to a lower dementia risk, neuroimaging showing stable amyloid and moderate tau levels, and intermediate Alzheimer’s pathology with added Lewy body and cerebrovascular issues.
  • * The study highlights the complex relationship between Alzheimer's symptoms and brain changes in Down syndrome, suggesting the need for more research on factors that contribute to cognitive resilience in this population.
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Numerous research groups worldwide have focused on postmortem imaging to bridge the resolution gap between clinical neuroimaging and neuropathology data. We developed a standardized protocol for brain embedding, imaging, and processing, facilitating alignment between antemortem MRI, postmortem MRI, and pathology to observe brain atrophy and structural damage progression over time. Using 7T postmortem ex vivo MRI, we explore the potential correlation of amygdala and hippocampal atrophy with neuropathological burden in both Down syndrome (DS) and Alzheimer's disease (AD) cohorts.

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The development of innovative non-invasive neuroimaging methods and biomarkers is critical for studying brain disease. Imaging of cerebrospinal fluid (CSF) pulsatility may inform the brain fluid dynamics involved in clearance of cerebral metabolic waste. In this work, we developed a methodology to characterize the frequency and spatial localization of whole brain CSF pulsations in humans.

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Background: High-precision neurosurgical targeting in nonhuman primates (NHPs) often requires presurgical anatomical mapping with noninvasive neuroimaging techniques (MRI, CT, PET), allowing for translation of individual anatomical coordinates to surgical stereotaxic apparatus. Given the varied tissue contrasts that these imaging techniques produce, precise alignment of imaging-based coordinates to surgical apparatus can be cumbersome. MRI-compatible stereotaxis with radiopaque fiducial markers offer a straight-forward and reliable solution, but existing commercial options do not fit in conformal head coils that maximize imaging quality.

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  • Previous studies link thalamic and hippocampal neurodegeneration to clinical decline in Multiple Sclerosis (MS), but more research is needed on specific brain regions involved.
  • Using 7 Tesla MRI technology, this study explored how the volumes and properties of certain thalamic nuclei and hippocampal subfields are related to clinical outcomes in MS patients.
  • Results showed a correlation between smaller anterior thalamus volumes and worse gait performance, while larger thalamic volumes were associated with better cognitive function; however, some associations with hippocampal subfields were not strong enough to be significant after adjustments.
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Development of innovative non-invasive neuroimaging methods and biomarkers are critical for studying brain disease. In this work, we have developed a methodology to characterize the frequency responses and spatial localization of oscillations and movements of cerebrospinal fluid (CSF) flow in the human brain. Using 7 Tesla human MRI and ultrafast echo-planar imaging (EPI), images were obtained to capture CSF oscillations and movements.

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The paraventricular nucleus of the hypothalamus (PVN) is uniquely capable of proximal control over autonomic and neuroendocrine stress responses, and the bed nucleus of the stria terminalis (BNST) directly modulates PVN function, as well as playing an important role in stress control itself. The dorsal BNST (dBNST) is predominantly preautonomic, while the ventral BNST (vBNST) is predominantly viscerosensory, receiving dense noradrenergic signaling. Distinguishing the dBNST and vBNST, along with the PVN, may facilitate our understanding of dynamic interactions among these regions.

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  • The study investigates how altered gene expressions are linked to changes in brain structure, specifically focusing on cortical thickness (CT), surface area (SA), and gray matter volume (GMV) in first-episode antipsychotic-naïve psychosis patients compared to controls.
  • Researchers found that out of 15,633 genes examined, 1,137 genes exhibited a significant correlation with CT, with different sets of genes being unique to specific diagnostic groups such as schizophrenia and non-schizophrenia patients.
  • The identified molecular pathways related to CT included axonal guidance, inflammation, synaptic modulation, and telomere extension, suggesting these pathways could be potential targets for further research and new treatment approaches in psychosis.
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The objective of this study is to evaluate the efficacy of deep learning (DL) techniques in improving the quality of diffusion MRI (dMRI) data in clinical applications. The study aims to determine whether the use of artificial intelligence (AI) methods in medical images may result in the loss of critical clinical information and/or the appearance of false information. To assess this, the focus was on the angular resolution of dMRI and a clinical trial was conducted on migraine, specifically between episodic and chronic migraine patients.

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Structural covariance network (SCN) studies on first-episode antipsychotic-naïve psychosis (FEAP) have examined less granular parcellations on one morphometric feature reporting lower network resilience among other findings. We examined SCNs of volume, cortical thickness, and surface area using the Human Connectome Project atlas-based parcellation (n = 358 regions) from 79 FEAP and 68 controls to comprehensively characterize the networks using a descriptive and perturbational network neuroscience approach. Using graph theoretical methods, we examined network integration, segregation, centrality, community structure, and hub distribution across the small-worldness threshold range and correlated them with psychopathology severity.

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Purpose: The expanded encoding model incorporates spatially- and time-varying field perturbations for correction during reconstruction. To date, these reconstructions have used the conjugate gradient method with early stopping used as implicit regularization. However, this approach is likely suboptimal for low-SNR cases like diffusion or high-resolution MRI.

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Water diffusion anisotropy MRI is sensitive to microstructural changes in the brain that are hallmarks of various neurological conditions. However, conventional metrics like fractional anisotropy are confounded by neuron fiber orientation dispersion, and the relatively low resolution of diffusion-weighted MRI gives rise to significant free water partial volume effects in many brain regions that are adjacent to cerebrospinal fluid. Microscopic fractional anisotropy is a recent metric that can report water diffusion anisotropy independent of neuron fiber orientation dispersion but is still susceptible to free water contamination.

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