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1.
Mol Psychiatry ; 2020 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-33051605

RESUMO

Neuropsychiatric manifestations are highly prevalent in systemic lupus erythematosus (SLE)-patients. We aimed to unravel the substrates of these manifestations by investigating abnormalities of resting state (RS) functional connectivity (FC) and their correlations with neuropsychiatric variables in SLE-patients. Thirty-two SLE-patients and 32 age- and sex-matched healthy controls (HC) underwent brain 3T RS fMRI. Neuropsychological assessment was performed for all SLE-patients. The main large-scale cognitive and psychiatric functional networks were derived and between-group comparisons and correlations with neuropsychological measures were performed. Compared to HC, SLE-patients exhibited increased RS FC in the right middle cingulate cortex and decreased RS FC in the left precuneus within default-mode network (DMN). They also showed increased RS FC in the left cerebellar crus I and left posterior cingulate cortex, and decreased RS FC in the left angular gyrus within working-memory networks (WMN). Compared to HC, SLE-patients exhibited increased RS FC in the left insular cortex and decreased RS FC in the right anterior cingulate cortex within salience network (SN), as well as decreased RS FC in the right middle frontal gyrus within executive-control network (ECN). Correlation analysis indicated a maladaptive role for left angular gyrus and cerebellar RS FC abnormalities in WMN, affecting memory and executive functions; and for precuneus and insular abnormalities in DMN and SN for psychiatric symptoms. Cingulate cortex modifications within DMN and SN correlated with better memory and global cognitive performance. Significant RS FC alterations in relevant cognitive and psychiatric networks occur in SLE-patients and participate in the pathophysiology of neuropsychiatric symptoms.

2.
Mult Scler ; : 1352458520958356, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32924846

RESUMO

BACKGROUND: Hand-motor impairment affects a large proportion of multiple sclerosis (MS) patients; however, its substrates are still poorly understood. OBJECTIVES: To investigate the association between global disability, hand-motor impairment, and alterations in motor-relevant structural and functional magnetic resonance imaging (MRI) networks in MS patients with different clinical phenotypes. METHODS: One hundred thirty-four healthy controls (HC) and 364 MS patients (250 relapsing-remitting MS (RRMS) and 114 progressive MS (PMS)) underwent Expanded Disability Status Scale (EDSS) rating, nine-hole peg test (9HPT), and electronic finger tapping rate (EFTR). Structural and resting state (RS) functional MRI scans were used to perform a source-based morphometry on gray matter (GM) components, to analyze white matter (WM) tract diffusivity indices and to perform a RS seed-based approach from the primary motor cortex involved in hand movement (hand-motor cortex). Random forest analyses identified the predictors of clinical impairment. RESULT: In RRMS, global measures of atrophy and lesions together with measures of structural damage of motor-related regions predicted EDSS (out-of-bag (OOB)-R2 = 0.19, p-range = <0.001-0.04), z9HPT (right: OOB-R2 = 0.14; left: OOB-R2 = 0.24, p-range = <0.001-0.03). No RS functional connectivity (FC) abnormalities were identified in RRMS models. In PMS, cerebellar and sensorimotor regions atrophy, cerebellar peduncles integrity and increased RS FC between left hand-motor cortex and right inferior frontal gyrus predicted EDSS (OBB-R2 = 0.16, p-range = 0.02-0.04). CONCLUSION: In RRMS, only measures of structural damage contribute to explain motor impairment, whereas both structural and functional MRI measures predict clinical disability in PMS. A multiparametric MRI approach could be relevant to investigate hand-motor impairment in different MS phenotypes.

3.
J Neurol ; 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32617658

RESUMO

INTRODUCTION: The substrates of cognitive impairment in benign MS (BMS) still need to be identified. We investigated whether cognitive impairment in BMS patients is associated with specific patterns of brain structural and functional abnormalities. METHODS: Thirty-seven BMS patients (EDSS score ≤ 3.0 and disease duration ≥ 15 years) and 50 healthy controls (HC) were studied. In BMS patients, a cognitive impairment index (CII) was derived. Gray matter (GM) volumes, white matter (WM) fractional anisotropy (FA) and resting-state (RS) functional connectivity (FC) were investigated for whole-brain relevant regions (cortex, lobes, subcortical nuclei, fiber tracts) and functional networks. Univariate and multivariate analyses identified independent predictors of cognitive impairment. RESULTS: In BMS, median CII was 9 (IQR: 4-16). Compared to HC, BMS patients showed reduced WM FA, GM atrophy and increased RS FC in fronto-temporo-parietal regions. At multivariate analysis, percentage of T2-lesions of the corpus callosum, reduced posterior corona radiata (PCR) FA and caudate nucleus atrophy were independent predictors of worse CII. A multivariate model identified reduced PCR FA (R2 = 0.39; p = 0.001) as the only predictor of CII. CONCLUSIONS: Cognitive impairment in BMS is associated with structural damage of relevant brain areas. WM damage of parietal regions was the predominant predictor of worse cognitive performance in these patients.

4.
Radiology ; 297(1): 154-163, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32720869

RESUMO

Background The spinal cord is commonly involved in patients with neuromyelitis optica spectrum disorders (NMOSDs). However, the relationship between inflammation and atrophy remains unclear. Purpose To characterize the spatial distribution of T1-hypointense lesions in the spinal cord at MRI, its association with cord atrophy, and its correlation with disability in participants with NMOSDs. Materials and Methods This prospective study evaluated three-dimensional T1-weighted spinal cord MRI scans in seropositive participants with NMOSDs and in age-matched healthy control participants acquired between February 2010 and July 2018. Binary masks of T1-hypointense lesions and lesion probability maps were produced. Cross-sectional area of the cervical and upper thoracic cord (down to T3 level) was calculated with the active-surface method. Full factorial models were used to assess cord atrophy in participants with NMOSDs. Correlations between cord atrophy and clinical and brain MRI measures were investigated with multiple regression models. Results A total of 52 participants with NMOSDs (mean age ± standard deviation, 44 years ± 15; 45 women) and 28 age-matched healthy control participants (mean age, 44 years ± 13; 16 women) were evaluated. Thirty-eight of 52 (73%) participants with NMOSDs had T1-hypointense cord lesions. No cord lesions were detected in the healthy control participants. Lesion probability maps showed a predominant involvement of the upper cervical (C2-C4) and upper thoracic (T1-T3 level) cord. The greater involvement of C1-C4 survived Bonferroni correction (P value range, .007-.04), with a higher percentage lesion extent in the gray matter (P < .001). Atrophy colocalized with focal cord lesions and correlated with pyramidal subscore (r ranging from -0.53 to -0.40; P < .001) and sensitive subscore (r ranging from -0.48 to -0.46; P = .001) of the Expanded Disability Status Scale. Participants without cord lesions had no cord atrophy. Conclusion In participants with neuromyelitis optica spectrum disorders, focal areas of spinal cord atrophy at MRI were topographically associated with lesions and correlated to motor and sensory disability. Participants without visible cord lesions had no atrophy. © RSNA, 2020 Online supplemental material is available for this article.

5.
Mult Scler ; : 1352458520940548, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32662748

RESUMO

BACKGROUND: Longitudinal evolution of cortical thickness (CTh) in different MS phenotypes has been rarely studied. AIM: To investigate the regional pattern and 1-year progression of cortical thinning in relapsing-remitting (RR) and progressive (P) MS. METHODS: 3T high-resolution T1-weighted magnetic resonance imaging (MRI) was obtained from 86 patients (75 RRMS, 11 PMS) and 34 healthy controls (HC) at three European sites at baseline and 1-year follow-up. Using FreeSurfer, baseline CTh between-group differences, longitudinal CTh changes and their correlations with clinical and MRI variables were assessed. RESULTS: Baseline frontal, parietal and sensorimotor atrophy was found in MS versus HC. Such pattern was driven by RRMS, while PMS showed additional parietal, insular and sensorimotor cortical atrophy versus RRMS. At 1-year versus baseline, additional frontal and temporal cortical thinning was detected in RRMS patients, while a widespread CTh reduction was found in PMS patients (significant at time-by-group interaction vs RRMS). In MS, baseline fronto-parietal atrophy correlated with more severe disability and higher lesion volume. Baseline inferior parietal CTh decrease and 1-year temporal cortical thinning correlated with more severe disability. CONCLUSION: Parieto-temporal baseline CTh abnormalities and thinning pattern over time characterized the main MS clinical phenotypes and were associated with 1-year disability worsening.

6.
Brain ; 143(7): 2089-2105, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32572488

RESUMO

Despite important efforts to solve the clinico-radiological paradox, correlation between lesion load and physical disability in patients with multiple sclerosis remains modest. One hypothesis could be that lesion location in corticospinal tracts plays a key role in explaining motor impairment. In this study, we describe the distribution of lesions along the corticospinal tracts from the cortex to the cervical spinal cord in patients with various disease phenotypes and disability status. We also assess the link between lesion load and location within corticospinal tracts, and disability at baseline and 2-year follow-up. We retrospectively included 290 patients (22 clinically isolated syndrome, 198 relapsing remitting, 39 secondary progressive, 31 primary progressive multiple sclerosis) from eight sites. Lesions were segmented on both brain (T2-FLAIR or T2-weighted) and cervical (axial T2- or T2*-weighted) MRI scans. Data were processed using an automated and publicly available pipeline. Brain, brainstem and spinal cord portions of the corticospinal tracts were identified using probabilistic atlases to measure the lesion volume fraction. Lesion frequency maps were produced for each phenotype and disability scores assessed with Expanded Disability Status Scale score and pyramidal functional system score. Results show that lesions were not homogeneously distributed along the corticospinal tracts, with the highest lesion frequency in the corona radiata and between C2 and C4 vertebral levels. The lesion volume fraction in the corticospinal tracts was higher in secondary and primary progressive patients (mean = 3.6 ± 2.7% and 2.9 ± 2.4%), compared to relapsing-remitting patients (1.6 ± 2.1%, both P < 0.0001). Voxel-wise analyses confirmed that lesion frequency was higher in progressive compared to relapsing-remitting patients, with significant bilateral clusters in the spinal cord corticospinal tracts (P < 0.01). The baseline Expanded Disability Status Scale score was associated with lesion volume fraction within the brain (r = 0.31, P < 0.0001), brainstem (r = 0.45, P < 0.0001) and spinal cord (r = 0.57, P < 0.0001) corticospinal tracts. The spinal cord corticospinal tracts lesion volume fraction remained the strongest factor in the multiple linear regression model, independently from cord atrophy. Baseline spinal cord corticospinal tracts lesion volume fraction was also associated with disability progression at 2-year follow-up (P = 0.003). Our results suggest a cumulative effect of lesions within the corticospinal tracts along the brain, brainstem and spinal cord portions to explain physical disability in multiple sclerosis patients, with a predominant impact of intramedullary lesions.

7.
Mol Psychiatry ; 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32322087

RESUMO

Here, we explored trajectories of sub-regional thalamic resting state (RS) functional connectivity (FC) modifications occurring in clinically isolated syndrome (CIS) patients early after their first clinical episode, and assessed their relationship with disability over 7 years. RS fMRI and clinical data were prospectively acquired from 59 CIS patients and 13 healthy controls (HC) over 2 years. A clinical re-assessment was performed in 53 (89%) patients after 7 years. Using a structural connectivity-based atlas, five thalamic sub-regions (frontal, motor, postcentral, occipital, and temporal) were used for seed-based RS FC. Thalamic RS FC abnormalities and their longitudinal changes were correlated with disability. Thirty-nine (66.1%) patients suffered a second clinical relapse, but the median EDSS remained stable over time. At baseline, CIS patients vs HC showed reduced RS FC (p < 0.001, uncorrected) with: (1) frontal cortices, for the whole thalamus, occipital, postcentral, and temporal thalamic sub-regions, (2) occipital cortices, for the occipital thalamic sub-region. In CIS, the longitudinal analysis revealed at year 2 vs baseline: (1) no significant whole-thalamic RS FC changes; (2) reduction of motor, postcentral, and temporal sub-regional RS FC with occipital cortices (p < 0.05, corrected); (3) an increase (p < 0.001, uncorrected) of postcentral and occipital sub-regional thalamic RS FC with frontal cortices, left putamen, and ipsi- and contralateral thalamus, this latter correlating with less severe clinical disability at year 7. Thalamo-cortical disconnections were present in CIS mainly in thalamic sub-regions closer to the third ventricle early after the demyelinating event, evolved in the subsequent 2 years, and were associated with long-term clinical disability.

8.
J Neurol ; 267(3): 760-769, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31745724

RESUMO

Resting state (RS) functional connectivity (FC) abnormalities of brain networks involved in pain- and multisensory processing have been disclosed in adult-migraine patients. We explored RS FC of large-scale brain networks in pediatric-migraine patients and their correlation with patients' clinical characteristics. RS functional MRI data was acquired from 13 pediatric-migraine patients and 14 age- and sex-matched controls. Intra- and inter-network RS FC differences between patients and controls were evaluated. Correlations between RS FC abnormalities and patients' clinical characteristics were also assessed. Compared to controls, pediatric-migraine patients had a decreased RS FC of the left parieto-occipital junction of the default mode network (DMN) and left-dorsolateral prefrontal cortex of the executive control network (ECN). They also experienced an increased RS FC of the right frontopolar cortex of the right frontoparietal network (FPN) and the right-middle occipital gyrus of the secondary visual network. A significant stronger connectivity between the ECN and primary visual network and between the right FPN and primary sensorimotor, primary visual and auditory networks were found in migraine patients compared to controls. A significant weaker connectivity between the DMN and right FPN was revealed in migraineurs compared to controls. No correlation was found between intra- and inter-network RS FC abnormalities and patients' clinical characteristics. Pediatric-migraine patients harbor significant RS FC abnormalities in brain networks involved in multisensory processing and in the cognitive control of pain. An early dysregulation of multisensory processing, including pain, might represent a phenotypic biomarker of the disease.

9.
Mult Scler ; 26(2): 233-244, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-30657011

RESUMO

BACKGROUND: Hand motor impairment has considerable effects on daily-life activities of patients with multiple sclerosis (pwMS). Understanding its anatomo-functional substrates is relevant to provide more specific therapeutic interventions. OBJECTIVES: To investigate the association between hand motor performance and anatomo-functional magnetic resonance imaging (MRI) abnormalities in pwMS. METHODS: A total of 134 healthy controls (HC) and 366 pwMS underwent the Nine-Hole-Peg-Test (9HPT), structural and resting state (RS) functional MRI. Multivariate analyses identified the independent predictors of hand motor performance. RESULTS: PwMS versus HC showed widespread gray matter atrophy, microstructural white matter abnormalities, and decreased RS functional connectivity in motor and cognitive networks. Predictors of worse right-9HPT (R2 = 0.52) were decreased right superior cerebellar peduncle and right lemniscus fractional anisotropy (FA) (p ⩽ 0.02), left angular gyrus atrophy (p < 0.003), decreased RS connectivity in left superior frontal gyrus, and left posterior cerebellum (p < 0.001). Worse left 9HPT (R2 = 0.56) was predicted by decreased right corticospinal FA (p = 0.003), atrophy of left anterior cingulum and left cerebellum (p ⩽ 0.02), decreased RS connectivity of left lingual gyrus and right posterior cerebellum in cerebellar and executive networks (p ⩽ 0.02). CONCLUSION: Structural and functional abnormalities of regions involved in motor functions contribute to explain motor disability in pwMS. The integration of clinical and advanced MRI measures contributes to improve our understanding of multiple sclerosis clinical manifestations.

10.
Mult Scler ; 26(4): 476-488, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30887862

RESUMO

BACKGROUND: In multiple sclerosis (MS), abnormalities of brain network dynamics and their relevance for cognitive impairment have never been investigated. OBJECTIVES: The aim of this study was to assess the dynamic resting state (RS) functional connectivity (FC) on 62 relapsing-remitting MS patients and 65 sex-matched healthy controls enrolled at 7 European sites. METHODS: MS patients underwent clinical and cognitive evaluation. Between-group network FC differences were evaluated using a dynamic approach (based on sliding-window correlation analysis) and grouping correlation matrices into recurrent FC states. RESULTS: Dynamic FC analysis revealed, in healthy controls and MS patients, three recurrent FC states: two characterized by strong intra- and inter-network connectivity and one characterized by weak inter-network connectivity (State 3). A total of 23 MS patients were cognitively impaired (CI). Compared to cognitively preserved (CP), CI-MS patients had reduced RS-FC between subcortical and default-mode networks in the low-connectivity State 3 and lower dwell time (i.e. time spent in a given state) in the high-connectivity State 2. CI-MS patients also exhibited a lower number and a less frequent switching between meta-states, as well as a smaller distance traveled through connectivity states. CONCLUSION: Time-varying RS-FC was markedly less dynamic in CI- versus CP-MS patients, suggesting that slow inter-network connectivity contributes to cognitive dysfunction in MS.

11.
Mult Scler ; 26(6): 645-658, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-30887875

RESUMO

BACKGROUND: The features of functional network connectivity reorganization at the earliest stages of MS have not been investigated yet. OBJECTIVE: To combine static and dynamic analysis of resting state (RS) functional connectivity (FC) to identify mechanisms of clinical dysfunction and recovery occurring in clinically isolated syndrome (CIS) patients. METHODS: RS functional magnetic resonance imaging (fMRI) and clinical data were prospectively acquired from 50 CIS patients and 13 healthy controls (HC) at baseline, month 12 and month 24. Between-group differences and longitudinal evolution of network FC were analysed across 41 functionally relevant networks. RESULTS: At follow-up, 47 patients developed MS. Disability remained stable (and relatively low). CIS and HC exhibited two recurring RS FC states (states 1 and 2, showing low and high internetwork connectivity, respectively). At baseline, patients showed reduced state 2 connectivity strength in the default-mode and cerebellar networks, and no differences in global dynamism versus HC. A selective FC reduction in networks affected by the clinical attack was also detected. At follow-up, increased state 2 connectivity strength and global connectivity dynamism was observed in patients versus HC. CONCLUSION: Longitudinal FC modifications occurring relatively early in the course of multiple sclerosis may represent a protective mechanism contributing to preserve clinical function over time.

12.
Mult Scler ; : 1352458519887332, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31686577

RESUMO

We investigated modifications of resting state dynamic functional network connectivity (dFNC) following a 2-week action observation training (AOT) in 46 right-handed healthy controls (HC) and 41 patients with multiple sclerosis (pwMS) and dominant-hand motor impairment, who were randomized to AOT or control (C) training. PwMS had decreased baseline dFNC versus HC. After training, MS groups improved in right upper limb functions, mainly in AOT, and showed dFNC increase (larger in MS-AOT vs MS-C) in sensorimotor and cognitive networks (p range, ⩽0.001-0.01). Both HC groups showed decreased dFNC over time (p range, ⩽0.001-0.01). Clinical improvements following interventions correlated with sensorimotor and cognitive dFNC changes, suggesting their possible role in motor recovery.

13.
Neurology ; 93(20): e1852-e1866, 2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31611336

RESUMO

OBJECTIVE: To characterize the distribution and regional evolution of cervical cord atrophy in patients with multiple sclerosis (MS) in a multicenter dataset. METHODS: MRI and clinical evaluations were acquired from 179 controls and 435 patients (35 clinically isolated syndromes [CIS], 259 relapsing-remitting multiple sclerosis [RRMS], 99 secondary progressive multiple sclerosis [SPMS], and 42 primary progressive multiple sclerosis [PPMS]). Sixty-nine controls and 178 patients underwent a 1-year MRI and clinical follow-up. Patients were classified as clinically stable/worsened according to their disability change. Longitudinal changes of cord atrophy were investigated with linear mixed-effect models. Sample size calculations were performed using age-, sex- and site-adjusted annualized percentage normalized cord cross-sectional area (CSAn) changes. RESULTS: Baseline CSAn was lower in patients with MS vs controls (p < 0.001), but not different between controls and patients with CIS or between patients with early RRMS (disease duration ≤5 years) and patients with CIS. Patients with late RRMS (disease duration >5 years) showed significant cord atrophy vs patients with early RRMS (p = 0.02). Patients with progressive MS had decreased CSAn (p < 0.001) vs patients with RRMS. Atrophy was located between C1/C2 and C5 in patients with RRMS vs patients with CIS, and widespread along the cord in patients with progressive MS vs patients with RRMS, with an additional C5/C6 involvement in patients with SPMS vs patients with PPMS. At follow-up, CSAn decreased in all phenotypes (p < 0.001), except CIS. Cord atrophy rates were highest in patients with early RRMS and clinically worsened patients, who had a more widespread cord involvement than stable patients. The sample size per arm required to detect a 50% treatment effect was 118 for patients with early RRMS. CONCLUSIONS: Cord atrophy increased in MS during 1 year, except for CIS. Faster atrophy contributed to explain clinical worsening.


Assuntos
Esclerose Múltipla Crônica Progressiva/diagnóstico por imagem , Esclerose Múltipla Recidivante-Remitente/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Adolescente , Adulto , Idoso , Atrofia , Vértebras Cervicais , Doenças Desmielinizantes/diagnóstico por imagem , Doenças Desmielinizantes/patologia , Doenças Desmielinizantes/fisiopatologia , Progressão da Doença , Feminino , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/patologia , Esclerose Múltipla/fisiopatologia , Esclerose Múltipla Crônica Progressiva/patologia , Esclerose Múltipla Crônica Progressiva/fisiopatologia , Esclerose Múltipla Recidivante-Remitente/patologia , Esclerose Múltipla Recidivante-Remitente/fisiopatologia , Medula Espinal/patologia , Adulto Jovem
14.
Ann Neurol ; 86(5): 704-713, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31385358

RESUMO

OBJECTIVE: Spinal cord atrophy is a clinically relevant feature of multiple sclerosis (MS), but longitudinal assessments on magnetic resonance imaging using segmentation-based methods suffer from measurement variability, especially in multicenter studies. We compared the generalized boundary shift integral (GBSI), a registration-based method, with a standard segmentation-based method. METHODS: Baseline and 1-year spinal cord 3-dimensional T1-weighted images (1mm isotropic) were obtained from 282 patients (52 clinically isolated syndrome [CIS], 196 relapsing-remitting MS [RRMS], 34 progressive MS [PMS]), and 82 controls from 8 MAGNIMS (Magnetic Resonance Imaging in Multiple Sclerosis) sites on multimanufacturer and multi-field-strength scans. Spinal Cord Toolbox was used for C2-5 segmentation and cross-sectional area (CSA) calculation. After cord straightening and registration, GBSI measured atrophy based on the probabilistic boundary-shift region of interest. CSA and GBSI percentage annual volume change was calculated. RESULTS: GBSI provided similar rates of atrophy, but reduced measurement variability compared to CSA in all MS subtypes (CIS: -0.95 ± 2.11% vs -1.19 ± 3.67%; RRMS: -1.74 ± 2.57% vs -1.74 ± 4.02%; PMS: -2.29 ± 2.40% vs -1.29 ± 3.20%) and healthy controls (0.02 ± 2.39% vs -0.56 ± 3.77%). GBSI performed better than CSA in differentiating healthy controls from CIS (area under the curve [AUC] = 0.66 vs 0.53; p = 0.03), RRMS (AUC = 0.73 vs 0.59; p < 0.001), PMS (AUC = 0.77 vs 0.53; p < 0.001), and patients with disability progression from patients without progression (AUC = 0.59 vs 0.50; p = 0.04). Sample size to detect 60% treatment effect on spinal cord atrophy over 1 year was lower for GBSI than CSA (CIS: 106 vs 830; RRMS: 95 vs 335; PMS: 44 vs 215; power = 80%; alpha = 5%). INTERPRETATION: The registration-based method (GBSI) allowed better separation between MS patients and healthy controls and improved statistical power, when compared with a conventional segmentation-based method (CSA), although it is still far from perfect. ANN NEUROL 2019 ANN NEUROL 2019;86:704-713.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Esclerose Múltipla/diagnóstico por imagem , Neuroimagem/métodos , Medula Espinal/diagnóstico por imagem , Adulto , Atrofia/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/patologia , Estudos Retrospectivos , Medula Espinal/patologia
15.
Front Neurosci ; 13: 618, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354402

RESUMO

Functional magnetic resonance imaging (fMRI) at resting state (RS) has been widely used to characterize the main brain networks. Functional connectivity (FC) has been mostly assessed assuming that FC is static across the whole fMRI examination. However, FC is highly variable at a very fast time-scale, as demonstrated by neurophysiological techniques. Time-varying functional connectivity (TVC) is a novel approach that allows capturing reoccurring patterns of interaction among functional brain networks. Aim of this review is to provide a description of the methods currently used to assess TVC on RS fMRI data, and to summarize the main results of studies applying TVC in healthy controls and patients with multiple sclerosis (MS). An overview of the main results obtained in neurodegenerative and psychiatric conditions is also provided. The most popular TVC approach is based on the so-called "sliding windows," in which the RS fMRI acquisition is divided in small temporal segments (windows). A window of fixed length is shifted over RS fMRI time courses, and data within each window are used to calculate FC and its variability over time. Sliding windows can be combined with clustering techniques to identify recurring FC states or used to assess global TVC properties of large-scale functional networks or specific brain regions. TVC studies have used heterogeneous methodologies so far. Despite this, similar results have been obtained across investigations. In healthy subjects, the default-mode network (DMN) exhibited the highest degree of connectivity dynamism. In MS patients, abnormal global TVC properties and TVC strengths were found mainly in sensorimotor, DMN and salience networks, and were associated with more severe structural MRI damage and with more severe physical and cognitive disability. Conversely, abnormal TVC measures of the temporal network were correlated with better cognitive performances and less severe fatigue. In patients with neurodegenerative and psychiatric conditions, TVC abnormalities of the DMN, attention and executive networks were associated to more severe clinical manifestations. TVC helps to provide novel insights into fundamental properties of functional networks, and improves the understanding of brain reorganization mechanisms. Future technical advances might help to clarify TVC association with disease prognosis and response to treatment.

16.
Mult Scler ; : 1352458519865989, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31347448

RESUMO

BACKGROUND: Mechanisms associated with cervical spinal cord (CSC) and upper thoracic spinal cord (TSC) atrophy in multiple sclerosis (MS) are poorly understood. OBJECTIVE: To assess the influence of brain, CSC and TSC T2-hyperintense lesions on cord atrophy and disability in MS. METHODS: Thirty-four MS patients underwent 3T brain, cervical and thoracic cord magnetic resonance imaging (MRI) and Expanded Disability Status Scale (EDSS) score assessment. CSC/TSC lesion number and volume (LV), whole-brain and cortico-spinal tract (CST) LVs were obtained. Normalized whole CSC and upper TSC cross-sectional areas (CSAn) were also derived. Age- and sex-adjusted regression models assessed associations of brain/cord lesions with CSAn and EDSS and identified variables independently associated with CSAn and EDSS with a stepwise variable selection. RESULTS: CSC CSAn (ß = -0.36, p = 0.03) and TSC CSAn (ß = -0.60, p < 0.001) were associated with CSC T2 LV. EDSS (median = 3.0) was correlated with CSC T2 LV (ß = 0.42, p = 0.01), brain (ß = 0.34, p = 0.04) and CST LV (ß = 0.35, p = 0.03). The multivariate analysis retained CSC LV as significant predictor of CSC CSAn (R2 = 0.20, p = 0.023) and TSC CSAn (R2 = 0.51, p < 0.001) and retained CSC and CST LVs as significant predictors of EDSS (R2 = 0.55, p = 0.001). CONCLUSIONS: CSC LV is an independent predictor of cord atrophy. When neurological impairment is relatively mild, central nervous system (CNS) lesion burden is a better correlate of disability than atrophy.

17.
Mult Scler ; : 1352458519845109, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31079538

RESUMO

BACKGROUND: Functional magnetic resonance imaging (fMRI) correlates of cognitive deficits have not been thoroughly studied in patients with neuromyelitis optica spectrum disorders (NMOSDs). OBJECTIVE: To investigate resting state (RS) functional connectivity (FC) abnormalities within the main cognitive networks in NMOSD patients and their correlation with cognitive performance. METHODS: We acquired RS fMRI from 25 NMOSD patients and 30 healthy controls (HC). Patients underwent an extensive neuropsychological evaluation. Between-group RS FC comparisons and correlations with cognitive performance were assessed on the main cognitive RS networks identified by independent component analysis. RESULTS: NMOSD patients showed higher RS FC versus HC in the precuneus of the default mode network (DMN) and right working memory network (WMN), as well as in several frontoparietal regions of the salience network (SN) and bilateral WMNs. Reduced frontal RS FC in NMOSD versus HC was detected in the left WMN. Increased RS FC in the DMN and right WMN was correlated with better cognitive performance, while decreased RS FC in the left WMN was associated with worse cognitive performance. CONCLUSION: Cognitive-network reorganization occurs in NMOSD. Clinico-imaging correlations suggest an adaptive role of increased RS FC. Conversely, reduced RS FC seems to be a maladaptive mechanism associated with a worse cognitive performance.

18.
Brain ; 142(3): 633-646, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30715195

RESUMO

Spinal cord lesions detected on MRI hold important diagnostic and prognostic value for multiple sclerosis. Previous attempts to correlate lesion burden with clinical status have had limited success, however, suggesting that lesion location may be a contributor. Our aim was to explore the spatial distribution of multiple sclerosis lesions in the cervical spinal cord, with respect to clinical status. We included 642 suspected or confirmed multiple sclerosis patients (31 clinically isolated syndrome, and 416 relapsing-remitting, 84 secondary progressive, and 73 primary progressive multiple sclerosis) from 13 clinical sites. Cervical spine lesions were manually delineated on T2- and T2*-weighted axial and sagittal MRI scans acquired at 3 or 7 T. With an automatic publicly-available analysis pipeline we produced voxelwise lesion frequency maps to identify predilection sites in various patient groups characterized by clinical subtype, Expanded Disability Status Scale score and disease duration. We also measured absolute and normalized lesion volumes in several regions of interest using an atlas-based approach, and evaluated differences within and between groups. The lateral funiculi were more frequently affected by lesions in progressive subtypes than in relapsing in voxelwise analysis (P < 0.001), which was further confirmed by absolute and normalized lesion volumes (P < 0.01). The central cord area was more often affected by lesions in primary progressive than relapse-remitting patients (P < 0.001). Between white and grey matter, the absolute lesion volume in the white matter was greater than in the grey matter in all phenotypes (P < 0.001); however when normalizing by each region, normalized lesion volumes were comparable between white and grey matter in primary progressive patients. Lesions appearing in the lateral funiculi and central cord area were significantly correlated with Expanded Disability Status Scale score (P < 0.001). High lesion frequencies were observed in patients with a more aggressive disease course, rather than long disease duration. Lesions located in the lateral funiculi and central cord area of the cervical spine may influence clinical status in multiple sclerosis. This work shows the added value of cervical spine lesions, and provides an avenue for evaluating the distribution of spinal cord lesions in various patient groups.


Assuntos
Medula Cervical/patologia , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/patologia , Adulto , Encéfalo/patologia , Medula Cervical/diagnóstico por imagem , Medula Cervical/metabolismo , Avaliação da Deficiência , Progressão da Doença , Feminino , Substância Cinzenta/patologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Crônica Progressiva/patologia , Esclerose Múltipla Recidivante-Remitente/patologia , Análise Espacial , Medula Espinal/patologia , Doenças da Medula Espinal , Substância Branca/patologia
19.
Mult Scler ; 25(9): 1232-1242, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30039746

RESUMO

BACKGROUND: Different subregional patterns of hippocampal involvement have been observed in diverse multiple sclerosis (MS) phenotypes. OBJECTIVE: To evaluate the occurrence of regional hippocampal variations in clinically isolated syndrome (CIS) patients, their relationships with focal white matter (WM) lesions, and their prognostic implications. METHODS: Brain dual-echo and three-dimensional (3D) T1-weighted scans were acquired from 14 healthy controls and 36 CIS patients within 2 months from clinical onset and after 3, 12, and 24 months. Radial distance distribution was assessed using 3D parametric surface mesh models. A cognitive screening was also performed. RESULTS: Patients showed clusters of reduced radial distance in the Cornu Ammonis 1 from month 3, progressively extending to the subiculum, negatively correlated with ipsilateral T2 and T1 lesion volume. Increased radial distance appeared in the right dentate gyrus after 3 (p < 0.05), 12, and 24 (p < 0.001) months, and in the left one after 3 and 24 months (p < 0.001), positively correlated with lesional measures. Hippocampal volume variations were more pronounced in patients converting to MS after 24 months and did not correlate with cognitive performance. CONCLUSION: Regional hippocampal changes occur in CIS, are more pronounced in patients converting to MS, and are modulated by focal WM lesions.

20.
Neuroimage ; 184: 901-915, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30300751

RESUMO

The spinal cord is frequently affected by atrophy and/or lesions in multiple sclerosis (MS) patients. Segmentation of the spinal cord and lesions from MRI data provides measures of damage, which are key criteria for the diagnosis, prognosis, and longitudinal monitoring in MS. Automating this operation eliminates inter-rater variability and increases the efficiency of large-throughput analysis pipelines. Robust and reliable segmentation across multi-site spinal cord data is challenging because of the large variability related to acquisition parameters and image artifacts. In particular, a precise delineation of lesions is hindered by a broad heterogeneity of lesion contrast, size, location, and shape. The goal of this study was to develop a fully-automatic framework - robust to variability in both image parameters and clinical condition - for segmentation of the spinal cord and intramedullary MS lesions from conventional MRI data of MS and non-MS cases. Scans of 1042 subjects (459 healthy controls, 471 MS patients, and 112 with other spinal pathologies) were included in this multi-site study (n = 30). Data spanned three contrasts (T1-, T2-, and T2∗-weighted) for a total of 1943 vol and featured large heterogeneity in terms of resolution, orientation, coverage, and clinical conditions. The proposed cord and lesion automatic segmentation approach is based on a sequence of two Convolutional Neural Networks (CNNs). To deal with the very small proportion of spinal cord and/or lesion voxels compared to the rest of the volume, a first CNN with 2D dilated convolutions detects the spinal cord centerline, followed by a second CNN with 3D convolutions that segments the spinal cord and/or lesions. CNNs were trained independently with the Dice loss. When compared against manual segmentation, our CNN-based approach showed a median Dice of 95% vs. 88% for PropSeg (p ≤ 0.05), a state-of-the-art spinal cord segmentation method. Regarding lesion segmentation on MS data, our framework provided a Dice of 60%, a relative volume difference of -15%, and a lesion-wise detection sensitivity and precision of 83% and 77%, respectively. In this study, we introduce a robust method to segment the spinal cord and intramedullary MS lesions on a variety of MRI contrasts. The proposed framework is open-source and readily available in the Spinal Cord Toolbox.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Esclerose Múltipla/diagnóstico por imagem , Esclerose Múltipla/patologia , Redes Neurais de Computação , Medula Espinal/patologia , Humanos , Imagem por Ressonância Magnética/métodos , Variações Dependentes do Observador , Reconhecimento Automatizado de Padrão , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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