Publications by authors named "Seres P"

Purpose: The purpose of this study was to investigate microstructural changes in the aging adult prostate by comparing the effects of varying diffusion times using diffusion MRI, and to provide an age-related benchmark for future prostate cancer studies.

Methods: The prostates of normal male volunteers (n = 70, 19-69 years) were scanned at 3 T with an oscillating gradient spin echo (OGSE: 6 ms), pulsed gradient spin echo (PGSE: 40 ms) and pulsed gradient stimulated echo (PGSTE: 100 ms), and anatomical T-weighted image. Volume and mean diffusivity (MD) were measured in the peripheral (PZ) and transition zones (TZ), which were assessed versus age.

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Autosomal dominant Fanconi syndrome due to a variant (GATM-FS), causes accumulation of misfolded arginine-glycine amidinotransferase (AGAT) in proximal renal tubules leading to cellular injury. GATM-FS presents during childhood and progresses to end-stage kidney disease (ESKD) in adults. We study creatine metabolism in two individuals of unrelated families with a known variant and the effect of creatine supplementation in kidney organoids.

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Postural orthostatic tachycardia syndrome (POTS) is characterized by an excessive heart rate (HR) response upon standing and symptoms indicative of inadequate cerebral perfusion. We tested the hypothesis that during lower body negative pressure (LBNP), individuals with POTS would have larger decreases in cardiac and cerebrovascular function measured using magnetic resonance (MR) imaging. Eleven patients with POTS and 10 healthy controls were studied at rest and during 20 min of -25 mmHg LBNP.

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Background: Multiple sclerosis (MS) lesion evolution may involve changes in diamagnetic myelin and paramagnetic iron. Conventional quantitative susceptibility mapping (QSM) can provide net susceptibility distribution, but not the discrete paramagnetic and diamagnetic components.

Purpose: To apply susceptibility separation (χ separation) to follow lesion evolution in MS with comparison to R*/R /QSM.

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Background: T1 mapping of the liver is confounded by the presence of fat. Multiparametric T1 mapping combines fat-water separation with T1-weighting to enable imaging of water-specific T1 (T1), proton density fat fraction (PDFF), and T2* values. However, normative T1 values in the liver and its dependence on age/sex is unknown.

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Article Synopsis
  • This study explored how brain degeneration correlates with the progression of amyotrophic lateral sclerosis (ALS) by analyzing brain scans of 149 ALS patients and 144 healthy controls.
  • Researchers used a texture analysis method on MRI scans to identify "autocorrelation," a biomarker indicating brain degeneration, focusing on different stages of the disease.
  • Results showed that brain changes varied significantly depending on the criteria used for patient classification, suggesting that standard clinical trial measures may not fully capture the extent of brain degeneration in ALS patients.
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Purpose: Measure the changes in relative lung water density (rLWD), lung volume, and total lung water content as a function of time after supine body positioning.

Methods: An efficient ultrashort-TE pulse sequence with a yarnball k-space trajectory was used to measure water density-weighted lung images for 25 min following supine body positioning (free breathing, 74-s acquisitions, 3D images at functional residual capacity, 18 time points) in 9 healthy volunteers. Global and regional (10 chest-to-back positions) rLWD, lung volume, and total lung water volume were measured in all subjects at all time points.

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Objectives: The role played by medial prefrontal cortex (MPFC) glutamate (Glu) and gamma-aminobutyric acid (GABA) in the pathophysiology and the treatment of major depression (MD) is increasingly recognized. Although measurements of MPFC GABA and Glu have been shown to be sensitive to physiological fluctuations of female hormones, none of the magnetic resonance spectroscopy (MRS) investigations of MPFC Glu and GABA in MD have controlled for possible bias effect of the reproductive stage of the women included.

Methods: MPFC Glu and GABA+ (which include homocarnosine and macromolecules) referenced to creatine and phosphocreatine, were measured via magnetic resonance spectroscopy (MRS) using a 3-Tesla magnet in 24 women with MD and 24 healthy women paired for reproductive status.

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Background: It has been suggested that the dorsolateral prefrontal cortex (DLPFC), especially the left DLPFC, has an important role in the pathophysiology and the treatment of major depressive disorder (MDD); furthermore, the contributory and antidepressant role of γ-aminobutyric acid (GABA) is increasingly recognized. Given that most female patients with MDD are of reproductive age, we sought to assess in vivo baseline GABA levels in the left DLPFC among unmedicated females of reproductive age with depression.

Methods: We compared healthy females and females with MDD.

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Amyotrophic Lateral Sclerosis (ALS) is a complex neurodegenerative disorder characterized by motor neuron degeneration. Significant research has begun to establish brain magnetic resonance imaging (MRI) as a potential biomarker to diagnose and monitor the state of the disease. Deep learning has emerged as a prominent class of machine learning algorithms in computer vision and has shown successful applications in various medical image analysis tasks.

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Article Synopsis
  • The study aimed to assess the degeneration of the corticospinal tract (CST) and corpus callosum (CC) in motor neuron disease patients using diffusion kurtosis imaging (DKI).
  • It involved 27 patients and 33 healthy controls, utilizing MRI and clinical assessments to analyze differences in brain microstructure and disease correlation.
  • Results showed significant differences in diffusion metrics between patients and controls, indicating potential use of DKI as a biomarker for cerebral degeneration in conditions like amyotrophic lateral sclerosis.
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Three-dimensional fast spin echo imaging with long echo trains combines high resolution with reasonable acquisition times and reduced specific absorption rate due to low refocusing flip angles. Typically, an entire volume is encoded (nonselective excitation) or localization can be performed with slab select excitation, which uses a long 90° pulse for precise localization, followed by a preliminary nonselective 180° pulse bounded by spoiler gradients to destroy signal outside of the volume of interest. Subsequent flip angles in the train are nonselective and identical between the two methods.

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Article Synopsis
  • - The study investigates the risk of major depressive episodes during perimenopause and how biological changes, specifically GABA and glutamate levels in the dorsolateral prefrontal cortex (DLPFC), might contribute to this risk.
  • - Eighteen perimenopausal and twenty reproductive-aged women were compared using magnetic resonance spectroscopy to analyse their DLPFC GABA+ and glutamate ratios, finding no significant differences between the two groups.
  • - Results indicate that, contrary to previous studies, perimenopausal women do not show decreased GABA+ or glutamate ratios in the DLPFC, suggesting that different brain areas may play distinct roles in depression risk during perimenopause.
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Objective: To identify structural and neurochemical properties that underlie functional connectivity impairments of the primary motor cortex (PMC) and how these relate to clinical findings in amyotrophic lateral sclerosis (ALS).

Methods: 52 patients with ALS and 52 healthy controls, matched for age and sex, were enrolled from 5 centres across Canada for the Canadian ALS Neuroimaging Consortium study. Resting-state functional MRI, diffusion tensor imaging and magnetic resonance spectroscopy data were acquired.

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Background: Quantitative susceptibility mapping (QSM) demonstrates elevated iron content in Parkinson's disease (PD) patients within the basal ganglia, though it has infrequently been studied in relation to gait difficulties including freezing of gait (FOG). Our purpose was to relate QSM of basal ganglia and extra-basal ganglia structures with qualitative and quantitative gait measures in PD.

Methods: This case-control study included PD and cognitively unimpaired (CU) participants from the Comprehensive Assessment of Neurodegeneration and Dementia study.

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Objective: Perimenopause is associated with an increased risk of developing a major depressive (MD) episode. A significant number of women develop their first MD episode during perimenopause, suggesting a unique pathophysiology of perimenopausal (PM) depression. Previous research has shown that depression is associated with decreased gamma-aminobutyric acid (GABA) levels in the medial prefrontal cortex (MPFC) of MD patients.

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T2 mapping from 2D proton density and T2-weighted images (PD-T2) using Bloch equation simulations can be time consuming and introduces a latency between image acquisition and T2 map production. A fast T2 mapping reconstruction method is investigated and compared with a previous modeling approach to reduce computation time and allow inline T2 maps on the MRI console. Brain PD-T2 images from five multiple sclerosis patients were used to compare T2 map reconstruction times between the new subtraction method and the Euclidean norm minimization technique.

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Objective: To determine differences in diffusion metrics in key white matter (WM) tracts between women with chronic temporomandibular disorders (TMDs) and age- and sex-matched healthy controls.

Design: Cross sectional study compared diffusion metrics between groups and explored their associations with clinical variables in subjects with TMDs.

Methods: In a total of 33 subjects with TMDs and 33 healthy controls, we performed tractography to obtain diffusion metrics (fractional anisotropy [FA], mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) from the cingulum near the cingulate gyrus (CGC), the cingulum near the hippocampus (CGH), the fornix, the anterior limb of the internal capsule (ALIC), the posterior limb of the internal capsule (PLIC), and the uncinate fasciculus (UF).

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Iron concentration in the human brain plays a crucial role in several neurodegenerative diseases and can be monitored noninvasively using quantitative susceptibility mapping (QSM) and effective transverse relaxation rate (R *) mapping from multiecho T *-weighted images. Large population studies enable better understanding of pathologies and can benefit from pooling multisite data. However, reproducibility may be compromised between sites and studies using different hardware and sequence protocols.

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Background: The substantial female hormone fluctuations associated with pregnancy and postpartum have been linked to a greater risk of developing depressive symptoms, particularly in high-risk women (HRW), i.e. those with histories of mood sensitivity to female hormone fluctuations.

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Brain magnetic resonance imaging (MRI) studies of clinical populations often require comparison to a normative 'control' cohort, usually of similar age/sex, scanned with the same protocol. The goal here was to create a normative brain MRI database of common quantitative methods to be used in comparisons with a variety of neurological disorders across the lifespan. 378 neurotypical controls (aged 5-90 years; median 31 years; 216 females, 162 males) completed brain MRI, cognitive testing, clinical assessment, and a demographics questionnaire.

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There is an increased risk of experiencing depression during perimenopause (PM), a period of rapidly changing female hormone concentrations. Women at particular risk of developing major depression (MD) during PM are those with history of mood sensitivity to female hormone fluctuations i.e.

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Purpose: The transmit field at 3 T in brain affects the spatial uniformity and contrast of most image acquisitions. Here, spatial variation in brain at 3 T is characterized in a large healthy population.

Methods: Bloch-Siegert maps were acquired at 3 T from 385 healthy subjects aged 5-90 years on a single MRI system.

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Objective: To evaluate progressive cerebral degeneration in amyotrophic lateral sclerosis (ALS) by assessing alterations in -acetylaspartate (NAA) ratios in the motor and prefrontal cortex within clinical subgroups of ALS.

Methods: Seventy-six patients with ALS and 59 healthy controls were enrolled in a prospective, longitudinal, multicenter study in the Canadian ALS Neuroimaging Consortium. Participants underwent serial clinical evaluations and magnetic resonance spectroscopy at baseline and 4 and 8 months using a harmonized protocol across 5 centers.

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Very little is known about maternal cerebral changes during pregnancy. Since there is an increased risk for major depression during pregnancy and postpartum, it is important to understand the structural and neurochemical changes that occur in the brain during pregnancy. Using proton magnetic resonance spectroscopy (H-MRS) (3 T field strength), glutamate (Glu) levels were measured in the medial prefrontal cortex (MPFC) of 21 healthy gravid subjects 2-3 weeks before their due date (6.

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