Tales Santini

• PhD
• PostDoc Position at University of Pittsburgh

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 7...

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...

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 neur...

Background Brain fluid flow plays a crucial role in maintaining brain health by eliminating potentially harmful waste products like amyloid‐beta and tau [1‐2]. This process is potentially facilitated by pulsations in the perivascular space, influenced by the neurovascular unit and autonomic nervous system, which may vary in brain diseases such as A...

Background White matter hyperintensities are associated with vascular diseases, while amyloid deposition serves as an early indicator of Alzheimer's disease (AD). Despite both pathologies contributing to cognitive decline, the ability to distinguish between them is crucial in selecting the appropriate course of treatment or management of these cond...

Background Employing a custom 60‐channel single‐transmit/32‐channel receive Tic‐Tac‐Toe (TTT) coil in 7T MRI imaging has enhanced the resolution and contrast for identifying White Matter Hyperintensities (WMHs), which are critical markers in Alzheimer’s disease and related dementias (AD/ADRD). Method The method involves resecting the left hemisphe...

Background High‐resolution and high‐contrast postmortem MRI can unveil structural abnormalities overlooked by antemortem MRI, making it well‐suited for targeted pathology assessments. In community cohorts, limbic‐predominant age‐related TDP‐43 encephalopathy (LATE) pathology is linked with smaller amygdala [Makkinejad 2019 Neurobiol Aging] and hipp...

Background White matter hyperintensities are associated with vascular diseases, while amyloid deposition serves as an early indicator of Alzheimer's disease (AD). Despite both pathologies contributing to cognitive decline, the ability to distinguish between them is crucial in selecting the appropriate course of treatment or management of these cond...

Background Brain fluid flow plays a crucial role in maintaining brain health by eliminating potentially harmful waste products like amyloid‐beta and tau [1‐2]. This process is potentially facilitated by pulsations in the perivascular space, influenced by the neurovascular unit and autonomic nervous system, which may vary in brain diseases such as A...

Background During normal aging, it has been observed that brain regional volume and thickness can be altered due to atrophy. While both 3 Tesla (3T) and 7 Tesla (7T) MRI are used to study such changes, it is unknown how individual brain morphology is characterized differently when 7T MRI allows for higher‐resolution and higher tissue contrast image...

Background Employing a custom 60‐channel single‐transmit/32‐channel receive Tic‐Tac‐Toe (TTT) coil in 7T MRI imaging has enhanced the resolution and contrast for identifying White Matter Hyperintensities (WMHs), which are critical markers in Alzheimer’s disease and related dementias (AD/ADRD). Method The method involves resecting the left hemisphe...

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...

Purpose: To develop and shim a 60-channel transmit 32-channel receive RF coil system for routine use in 7T neuro MRI based on the Tic-Tac-Toe antenna design. Methods: RF simulations were performed and used to optimize three non-subject-specific RF shim cases over three anatomically detailed head models: adult male, adult female, and child female. D...

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 a...

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. Th...

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 an...

In this neuropathology case report, we present findings from an individual with Down syndrome (DS) who remained cognitively stable despite Alzheimer's disease (AD) neuropathology. Clinical assessments, fluid biomarkers, neuroimaging, and neuropathological examinations were conducted to characterize her condition. Notably, her ApoE genotype was E2/3...

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 structu...

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...

This protocol describes the steps taken to assess whether MR signal noise and distortion is introduced by utilization of a 3D printed plastic stereotaxic frame. The computer-aided design files and engineering drawings for the frame used in this protocol are publicly available, with the modular design allowing for low cost and manageable manufacturi...

Highlights We present a compact MRI-compatible stereotaxic frame for large nonhuman primates. The design is 3D printable, inexpensive, and matches size of an adult human head. Enabled real-time, accurate, MRI-guided deep-brain viral vector injection. Facilitated multimodal alignment for deep-brain electrophysiology planning. All computer-aided-desi...

Background Hippocampal formation atrophy is a well‐established imaging biomarker of several neurological diseases, including Alzheimer’s disease, temporal lobe epilepsy, and schizophrenia. The hippocampus is divided into subfields that have different functions and vary in sensitivity to different diseases. This study investigates the potential inte...

Background As the usage of MRI for biomedical research increases, an ongoing goal for extending the usefulness of MRIs has been the increase of the magnet’s field strength to 3T, 7T, and beyond. The 7T field strength has recently been given FDA‐approval for clinical use, due to recognition of its safety and ability to characterize “smaller structur...

Background 7T MRI allows implementation of high‐resolution quantitative susceptibility mapping (QSM) which can be used to assess the cerebral microvascular/hypoperfusion pathogenic hypothesis in Alzheimer’s disease (AD) and in the post‐SARS‐CoV2 setting to explore if there may be similarities in brain changes in these two conditions. The magnetic s...

Background Emerging evidence indicates that COVID‐19 can negatively impact patient’s brain health (Douaud et al., 2022) (Cecchetti et al., 2022). Common clinical symptoms include brain fog, headaches, difficulty concentrating, and loss of sense of smell or taste. Some studies suggest that SARS‐CoV‐2 infection can damage the blood brain barrier eith...

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 e...

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 a...

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, wh...

Altered gene expressions may mechanistically link genetic factors with brain morphometric alterations. Existing gene expression studies have examined selected morphometric features using low-resolution atlases in medicated schizophrenia. We examined the relationship of gene expression with cortical thickness (CT), surface area (SA), and gray matter...

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...

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‐resolu...

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 pa...

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 volumes, cortical thickness, and surface area using the Human Connectome Project atlas-based parcellation...

Purpose: The expanded encoding model incorporates spatially- and time-varying field perturbations for correction during reconstruction. So far, 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-resolu...

The guidelines and recommendations contained in this document are intended to assist experts in MRI scanner hardware with obtaining local research ethics approvals for radio frequency (RF) devices built at the research site. Such devices are typically used on research subjects and not on the general patient population, in which case additional requ...

Neurovascular complications are a common and major cause of morbidity and mortality in patients with sickle cell disease (SCD). Prior studies have demonstrated cortical thinness (Kim et al. 2016) as well as reduced cerebral volume in children with SCD (Kawadler et al. 2013) when compared to age-matched controls. There is very limited data regarding...

Sickle cell disease (SCD) is complicated by accelerated brain aging and cerebrovascular complications leading to structural brain damage and altered resting state functional connectivity (RS-FC). Investigation of the Default Mode Network (DMN), the most studied of the RS-FC networks, by functional MRI may provide insight into the neurological and n...

Objective Structural brain alterations are consistently observed in schizophrenia. However, divergent findings suggest that often-observed regions exist within a network of susceptible regions. We conducted structural covariance analysis of multiple morphometric features of 358 regions from 79 first-episode anti-psychotic-naive psychosis patients (...

Background: Magnetic resonance (MR) scans are routine clinical procedures for monitoring people with multiple sclerosis (PwMS). Patient discomfort, timely scheduling, and financial burden motivate the need to accelerate MR scan time. We examined the clinical application of a deep learning (DL) model in restoring the image quality of accelerated rou...

Sickle cell disease (SCD) is an inherited hemoglobinopathy that causes organ dysfunction, including cerebral vasculopathy and neurological complications. Hippocampal segmentation with newer and advanced 7 Tesla (7T) MRI protocols has revealed atrophy in specific subregions in other neurodegenerative and neuroinflammatory diseases, however, there is...

Recently cleared by the FDA, 7 Tesla (7 T) MRI is a rapidly growing technology that can provide higher resolution and enhanced contrast in human MRI images. However, the increased operational frequency (~ 297 MHz) hinders its full potential since it causes inhomogeneities in the images and increases the power deposition in the tissues. This work de...

Electromagnetic simulations are an important tool for the safety assessment of RF coils. They are a useful resource for MRI RF coil designers, especially when complemented with experimental measurements and testing using physical phantoms. Regular‐shaped (spherical/cylindrical) homogeneous phantoms are the MRI standard for RF testing but are somewh...

Recently cleared by the FDA, 7 Tesla (7T) MRI is a rapidly growing technology that can provide higher resolution and enhanced contrast in human MRI images. However, the increased operational frequency (~297 MHz) hinders its full potential since it causes inhomogeneities in the images and increases the power deposition in the tissues. This work desc...

Sickle cell disease (SCD) is an inherited hemoglobinopathy that causes organ dysfunction, including cerebral vasculopathy and neurological complications. Hippocampal segmentation with newer and advanced 7 Tesla (7T) MRI protocols has revealed atrophy in specific subregions in other neurodegenerative and neuroinflammatory diseases, however, there is...

Objective: We sought to determine whether the aspects of white matter connectivity implicated in major depression also relate to mild depressive symptoms in family dementia caregivers (dCGs). Methods: Forty-one dCGs (average age=69 years, standard deviation=6.4) underwent a 7 Tesla 64-direction (12-minute) diffusion-weighted imaging sequence. We...

Cerebral small vessel disease is associated with late-life depression, cognitive impairment, executive dysfunction, distress, and loss of life for older adults. Late-life depression is becoming a substantial public health burden, and a considerable number of older adults presenting to primary care have significant clinical depression. Even though w...

Past research shows that major depression is associated with lower white matter integrity in fronto-limbic and other areas. But it is not known whether the integrity of these white matter connections is associated with subsyndromal depression symptoms, a marker of risk for major depression, in family dementia caregivers (dCGs) who reported stress....

OBJECTIVE: To develop and test a beat-to-beat blood pressure monitoring device during coronary angiography, and compare it with invasive blood pressure monitoring. METHODS: Twenty-eight patients with an indication for hemodynamic study were selected for this investigation, and kept in supine position. Before starting the coronary angiography, they...

A variety of 7 Tesla RF coil systems have been proposed to produce spin excitation (B1⁺ field) and MR image acquisition. Different groups have attempted to mitigate the challenges at high and ultra-high field MRI by proposing novel hardware and software solutions to obtain uniformly high spin excitation at acceptable RF absorption levels. In this s...

Radio-frequency (RF) field inhomogeneities and higher levels of specific absorption rate (SAR) still present great challenges in ultrahigh-field (UHF) MRI. In this study, an in-depth analysis of the eigenmodes of a 20-channel transmit Tic-Tac-Toe (TTT) RF array for 7T neuro MRI is presented. The eigenmodes were calculated for five different Z level...

Objectives Hippocampal hyperactivation marks pre-clinical dementia pathophysiology, potentially due to differences in the connectivity of specific medial temporal lobe structures. Our aims were to characterize the resting-state functional connectivity of medial temporal lobe sub-structures in older adults, and evaluate whether specific sub-structur...

[This corrects the article DOI: 10.1371/journal.pone.0183168.].

A four-channel Tic-Tac-Toe (TTT) transmit RF coil was designed and constructed for foot and ankle imaging at 7T MRI. Numerical simulations using an in-house developed FDTD package and experimental analyses using a homogenous phantom show an excellent agreement in terms of B1(+) field distribution and s-parameters. Simulations performed on an anatom...

Objective The purpose of this study is to design an anthropomorphic heterogeneous head phantom that can be used for MRI and other electromagnetic applications. Materials and methods An eight compartment, physical anthropomorphic head phantom was developed from a 3T MRI dataset of a healthy male. The designed phantom was successfully built and prel...

Visual representation to construct a physical head anthropomorphic heterogeneous phantom. A visual representation of the 3D printed workflow in Fig 1. This video highlights each step in the process to create an anthropomorphic phantom. (MP4)

Objective The purpose of this study was to explore the efficacy of Ultra-high field [UHF] 7 Tesla [T] MRI as compared to 3T MRI in non-contrast enhanced [nCE] imaging of structural anatomy in the elbow, forearm, and hand [upper extremity]. Materials and method A wide range of sequences including T1 weighted [T1] volumetric interpolate breath-hold...

The purpose of this study is to develop and evaluate a custom‐designed 7 T MRI coil and explore its use for upper extremity applications. An RF system composed of a transverse electromagnetic transmit coil and an eight‐channel receive‐only array was developed for 7 T upper extremity applications. The RF system was characterized and evaluated using...

In ultrahigh-field MRI, such as 7 T, the signal-to-noise ratio (SNR) increases while transmit (Tx) field (B1⁺) can be degraded due to inhomogeneity and elevated specific absorption rate (SAR). By applying new array coil concepts to both Tx and receive (Rx) coils, the B1⁺ homogeneity and SNR can be improved. In this study, we developed and tested in...

Circulators are often used in RF systems; however, their size, cost, and weight increase greatly at lower frequencies (<300 MHz). The development of a load-insensitive active quasi-circulator is presented as an alternative for the traditional circulators to be used in low-frequency systems such as Doppler ultrasound. Major challenges to these activ...

A system for monitoring the hand sanitizing opportunities in hospital wards (1), the system (1) comprising a plurality of sensors (8, 9, 10) arranged inside a ward (2), capable of detecting at least one hand sanitizing action according to a set of hand sanitizing opportunities, the system (1) further comprising at least one indication device (7) of...

Developing a radiofrequency (RF) coil system that produces a uniform B1+ field (circularly polarized component of the transverse magnetic field responsible for excitation) and low specific absorption rate (SAR) is critical for high performance ultrahigh field human imaging. In this study, we provide the design of a new eight channel radiofrequency...

Background Monitoring of hand hygiene is an important part of the improvement of hospital quality indicators. Methods This study was prospectively performed over a 14-week (electronic observer) period from December 3, 2013-March 9, 2014, to evaluate hand hygiene compliance in an adult step-down unit. We compared electronic handwash counters with t...