Publications by authors named "Lehericy S"

Article Synopsis
  • In medial temporal lobe epilepsy (MTLE), surgery can improve symptoms but may lead to memory decline, making it crucial to predict post-operative outcomes using fMRI tasks.
  • A study of 46 MTLE patients assessed the effectiveness of fMRI language tasks in predicting memory outcomes after surgery; results showed memory fMRI had higher sensitivity in detecting hippocampal activity.
  • Language fMRI, while less sensitive, provided better accuracy in predicting memory performance when hippocampal activation occurred, suggesting a need for combining both tasks to improve post-operative outcome predictions.
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Background And Purpose: Isocitrate dehydrogenase () mutation and 1p/19q codeletion classify adult-type diffuse gliomas into 3 tumor subtypes with distinct prognoses. We aimed to evaluate the performance of edited MR spectroscopy for glioma subtyping in a clinical setting, via the quantification of D-2-hydroxyglutarate (2HG) and cystathionine. The delay between this noninvasive classification and the integrated histomolecular analysis was also quantified.

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  • Deep learning is used for medical image segmentation, but it struggles with small training datasets and can produce inaccurate results; anatomical knowledge can help improve this process.
  • A new loss function based on projected pooling introduces soft topological constraints by highlighting smaller parts of the structure to ensure they aren't overlooked during segmentation.
  • When applied to segment the red nucleus in QSM data, this method achieved high accuracy (Dice 89.9%) and minimized topological errors, making it a promising approach for efficient and accurate medical image segmentation.
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Magnetic resonance guided transcranial focused ultrasound holds great promises for treating neurological disorders. This technique relies on skull aberration correction which requires computed tomography (CT) scans of the skull of the patients. Recently, ultra-short time-echo (UTE) magnetic resonance (MR) sequences have unleashed the MRI potential to reveal internal bone structures.

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Background: Transcranial ultrasound stimulation (TUS) is a non-invasive brain stimulation technique; when skull aberrations are compensated for, this technique allows, with millimetric accuracy, circumvention of the invasive surgical procedure associated with deep brain stimulation (DBS) and the limited spatial specificity of transcranial magnetic stimulation.

Objective: /hypothesis: We hypothesize that MR-guided low-power TUS can induce a sustained decrease of tremor power in patients suffering from medically refractive essential tremor.

Methods: The dominant hand only was targeted, and two anatomical sites were sonicated in this exploratory study: the ventral intermediate nucleus of the thalamus (VIM) and the dentato-rubro-thalamic tract (DRT).

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Asymptomatic Leucine-Rich Repeat Kinase 2 Gene (LRRK2) carriers are at risk for developing Parkinson's disease (PD). We studied presymptomatic substantia nigra pars compacta (SNc) regional neurodegeneration in asymptomatic LRRK2 carriers compared to idiopathic PD patients using neuromelanin-sensitive MRI technique (NM-MRI). Fifteen asymptomatic LRRK2 carriers, 22 idiopathic PD patients, and 30 healthy controls (HCs) were scanned using NM-MRI.

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Background: The locus coeruleus (LC) and the nucleus basalis of Meynert (NBM) are altered in early stages of Alzheimer's disease (AD). Little is known about LC and NBM alteration in limbic-predominant age-related TDP-43 encephalopathy (LATE) and frontotemporal dementia (FTD). The aim of the present study is to investigate in vivo LC and NBM integrity in patients with suspected-LATE, early-amnestic AD and FTD in comparison with controls.

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Background: In early-stage Parkinson's disease (PD), rapid eye movement (REM) sleep behavior disorder (RBD) predicts poor cognitive and motor outcome. However, the baseline significance and disease evolution associated with isolated REM sleep without atonia (iRWA, ie, enhanced muscle tone during 8.7% of REM sleep, but no violent behavior) are not well understood.

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Article Synopsis
  • * It involved 113 patients with diagnoses like Parkinson's disease and progressive supranuclear palsy, analyzing the accuracy of clinical criteria, MRI readings, and a machine-learning algorithm.
  • * Results indicated that MRI visual reading significantly enhanced diagnostic accuracy by 14.3%, and combining it with clinical criteria further improved accuracy to 85.4%, suggesting MRI is beneficial in early diagnoses.
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  • In early-stage Parkinson's disease (PD), a study found that sleep disorders such as insomnia, REM sleep behavior disorder (RBD), excessive daytime sleepiness (EDS), and restless legs syndrome (RLS) are common, affecting 71% of participants.
  • Insomnia was the most prevalent disorder at 41%, and these sleep disorders often occurred in combination, particularly as disease duration increased.
  • The research revealed that factors like gender, age, and dysautonomia were linked to specific sleep disorders, indicating that the causes of these disturbances are likely more physical than psychological.
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Background: Clinical presentation and progression dynamics are variable in patients with Parkinson's disease (PD). Disease course mapping is an innovative disease modelling technique that summarizes the range of possible disease trajectories and estimates dimensions related to onset, sequence, and speed of progression of disease markers.

Objective: To propose a disease course map for PD and investigate progression profiles in patients with or without rapid eye movement sleep behavioral disorders (RBD).

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Background: Clinical exam is the goldstandard for surgical indication. ENMG and conventional MRI are insufficient to understand the highly variable clinical presentation of brachial plexus (BP) lesions. DTI is based on motion of water molecules and can explore nerve function.

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Background Noninvasive identification of glioma subtypes is important for optimizing treatment strategies. Purpose To compare the in vivo neurochemical profiles between isocitrate dehydrogenase (IDH) 1-mutant 1p/19q codeleted gliomas and their noncodeleted counterparts measured by MR spectroscopy at 3.0 T with a point-resolved spectroscopy (PRESS) sequence optimized for D-2-hydroxyglutarate (2HG) detection.

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Background: Longitudinal measures of structural brain changes using MRI in relation to clinical features and progression patterns in PD have been assessed in previous studies, but few were conducted in well-defined and large cohorts, including prospective clinical assessments of both motor and non-motor symptoms.

Objective: We aimed to identify brain volumetric changes characterizing PD patients, and determine whether regional brain volumetric characteristics at baseline can predict motor, psycho-behavioral and cognitive evolution at one year in a prospective cohort of PD patients.

Methods: In this multicentric 1 year longitudinal study, PD patients and healthy controls from the MPI-R2* cohort were assessed for demographical, clinical and brain volumetric characteristics.

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  • A study involving 20 COVID-19 cases identified cerebral microangiopathy in six patients, marked by changes in white matter and small artery diseases as seen on MRI.
  • The condition featured perivascular alterations such as vacuolization, macrophage clusters, and large axonal swellings, suggesting blood-brain barrier disruption without evidence of direct viral presence in the brain.
  • Detection of the SARS-CoV-2 spike protein in brain endothelial cells, particularly within the Golgi apparatus, indicates a unique interaction that might affect vascular permeability and contribute to long-term neurological effects of COVID-19.
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Introduction: Gait disorders and falls occur early in progressive supranuclear palsy (PSP-RS) and Caribbean atypical parkinsonism (Caribbean AP). However, the link between these signs and brain lesions has never been explored in these patient populations. Here, we investigate and compare the imaging factors that relate to gait and balance disorders in Caribbean AP and PSP-RS patients.

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Article Synopsis
  • Isolated rapid eye movement sleep behavior disorder (iRBD) involves abnormal movements and vocalizations during REM sleep, serving as an early indicator of neurodegenerative diseases like Parkinson's and Lewy body dementia.
  • This study analyzed data from 171 iRBD patients and 238 healthy controls using advanced imaging techniques to understand the genetic and structural brain changes associated with iRBD.
  • Key findings highlighted significant alterations in gene expression related to mitochondrial function and brain atrophy, suggesting possible underlying mechanisms for these neurodegenerative processes.
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Introduction: Quantitative biomarkers for clinical differentiation of parkinsonian syndromes are still lacking. Our aim was to evaluate the value of combining clinically feasible manual measurements of R2* relaxation rates and mean diffusivity (MD) in subcortical regions and brainstem morphometric measurements to improve the discrimination of parkinsonian syndromes.

Methods: Twenty-two healthy controls (HC), 25 patients with Parkinson's disease (PD), 19 with progressive supranuclear palsy (PSP) and 27 with multiple system atrophy (MSA, 21 with the parkinsonian variant -MSAp, 6 with the cerebellar variant -MSAc) were recruited.

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Background: The locus coeruleus/subcoeruleus complex (LC/LsC) is a structure comprising melanized noradrenergic neurons.

Objective: To study the LC/LsC damage across Parkinson's disease (PD) and atypical parkinsonism in a large group of subjects.

Methods: We studied 98 healthy control subjects, 47 patients with isolated rapid eye movement sleep behavior disorder (RBD), 75 patients with PD plus RBD, 142 patients with PD without RBD, 19 patients with progressive supranuclear palsy (PSP), and 19 patients with multiple system atrophy (MSA).

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Background: Parkinson's disease (PD) demonstrates neurodegenerative changes in the substantia nigra pars compacta (SNc) using neuromelanin-sensitive (NM)-MRI. As SNc manual segmentation is prone to substantial inter-individual variability across raters, development of a robust automatic segmentation framework is necessary to facilitate nigral neuromelanin quantification. Artificial intelligence (AI) is gaining traction in the neuroimaging community for automated brain region segmentation tasks using MRI.

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Background: Iron content is increased in the substantia nigra of persons with Parkinson's disease and may contribute to the pathophysiology of the disorder. Early research suggests that the iron chelator deferiprone can reduce nigrostriatal iron content in persons with Parkinson's disease, but its effects on disease progression are unclear.

Methods: We conducted a multicenter, phase 2, randomized, double-blind trial involving participants with newly diagnosed Parkinson's disease who had never received levodopa.

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Background The time course of cellular damage after acute ischemic stroke (IS) is currently not well known, and specific noninvasive markers of microstructural alterations linked to inflammation are lacking, which hinders the monitoring of anti-inflammatory treatment. Purpose To evaluate the temporal pattern of neuronal and glial microstructural changes after stroke using in vivo single-voxel diffusion-weighted MR spectroscopy. Materials and Methods In this prospective longitudinal study, participants with IS and healthy volunteers (HVs) underwent MRI at 3.

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Article Synopsis
  • The study examined misfolded alpha-Synuclein (α-Syn) in salivary gland biopsies from patients with isolated REM sleep behavior disorder (iRBD), Parkinson's disease (PD), and healthy controls.
  • Deposits of α-Syn were found in various percentages across all groups, but no significant difference in substantia nigra damage was observed between those with or without α-Syn deposits.
  • The results suggest that detecting α-Syn in biopsies is not an effective biomarker for predicting PD, lacking both sensitivity and specificity.
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Several postmortem studies have shown iron accumulation in the substantia nigra of Parkinson's disease patients. Iron concentration can be estimated via MRI-R mapping. To assess the changes in R occurring in Parkinson's disease patients compared to controls, a multicentre transversal study was carried out on a large cohort of Parkinson's disease patients (n = 163) with matched controls (n = 82).

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