scholarly journals Myelin and axon pathology in multiple sclerosis assessed by myelin water and multi-shell diffusion imaging

Brain ◽  
2021 ◽  
Author(s):  
Reza Rahmanzadeh ◽  
Po-Jui Lu ◽  
Muhamed Barakovic ◽  
Matthias Weigel ◽  
Pietro Maggi ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
White Matter Lesions ◽  
Healthy Controls ◽  
Neurofilament Light Chain ◽  
Water Fraction ◽  
Neurite Density ◽  
Relapsing Remitting ◽  
Density Index ◽  
Myelin Water Fraction

Abstract Damage to the myelin sheath and the neuroaxonal unit is a cardinal feature of multiple sclerosis; however, a detailed characterization of the interaction between myelin and axon damage in vivo remains challenging. We applied myelin water and multi-shell diffusion imaging to quantify the relative damage to myelin and axons (i) among different lesion types; (ii) in normal-appearing tissue; and (iii) across multiple sclerosis clinical subtypes and healthy controls. We also assessed the relation of focal myelin/axon damage with disability and serum neurofilament light chain as a global biological measure of neuroaxonal damage. Ninety-one multiple sclerosis patients (62 relapsing-remitting, 29 progressive) and 72 healthy controls were enrolled in the study. Differences in myelin water fraction and neurite density index were substantial when lesions were compared to healthy controls and normal-appearing MS tissue: both white matter and cortical lesions exhibited a decreased myelin water fraction and neurite density index compared with healthy (P < 0.0001) and peri-plaque white matter (P < 0.0001). Periventricular lesions showed decreased myelin water fraction and neurite density index compared with lesions in the juxtacortical region (P < 0.0001 and P < 0.05). Similarly, lesions with paramagnetic rims showed decreased myelin water fraction and neurite density index relative to lesions without a rim (P < 0.0001). Also, in 75% of white matter lesions, the reduction in neurite density index was higher than the reduction in the myelin water fraction. Besides, normal-appearing white and grey matter revealed diffuse reduction of myelin water fraction and neurite density index in multiple sclerosis compared to healthy controls (P < 0.01). Further, a more extensive reduction in myelin water fraction and neurite density index in normal-appearing cortex was observed in progressive versus relapsing-remitting participants. Neurite density index in white matter lesions correlated with disability in patients with clinical deficits (P < 0.01, beta=-10.00); and neurite density index and myelin water fraction in white matter lesions were associated to serum neurofilament light chain in the entire patients cohort (P < 0.01, beta=-3.60 and P < 0.01, beta=0.13, respectively). These findings suggest that (i) myelin and axon pathology in multiple sclerosis is extensive in both lesions and normal-appearing tissue; (ii) particular types of lesions exhibit more damage to myelin and axons than others; (iii) progressive patients differ from relapsing-remitting because of more extensive axon/myelin damage in the cortex; and (iv) myelin and axon pathology in lesions is related to disability in patients with clinical deficits and global measures of neuroaxonal damage.

Non-invasive quantification of inflammation, axonal and myelin injury in multiple sclerosis

Brain ◽  
2020 ◽  
Author(s):  
Simona Schiavi ◽  
Maria Petracca ◽  
Peng Sun ◽  
Lazar Fleysher ◽  
Sirio Cocozza ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Black Holes ◽  
White Matter ◽  
Corpus Callosum ◽  
Fractional Anisotropy ◽  
White Matter Lesions ◽  
Healthy Controls ◽  
Normal Appearing White Matter ◽  
Relapsing Remitting ◽  
Spectrum Imaging

Abstract The aim of this study was to determine the feasibility of diffusion basis spectrum imaging in multiple sclerosis at 7 T and to investigate the pathological substrates of tissue damage in lesions and normal-appearing white matter. To this end, 43 patients with multiple sclerosis (24 relapsing-remitting, 19 progressive), and 21 healthy control subjects were enrolled. White matter lesions were classified in T1-isointense, T1-hypointense and black holes. Mean values of diffusion basis spectrum imaging metrics (fibres, restricted and non-restricted fractions, axial and radial diffusivities and fractional anisotropy) were measured from whole brain white matter lesions and from both lesions and normal appearing white matter of the corpus callosum. Significant differences were found between T1-isointense and black holes (P ranging from 0.005 to <0.001) and between lesions’ centre and rim (P < 0.001) for all the metrics. When comparing the three subject groups in terms of metrics derived from corpus callosum normal appearing white matter and T2-hyperintense lesions, a significant difference was found between healthy controls and relapsing-remitting patients for all metrics except restricted fraction and fractional anisotropy; between healthy controls and progressive patients for all metrics except restricted fraction and between relapsing-remitting and progressive multiple sclerosis patients for all metrics except fibres and restricted fractions (P ranging from 0.05 to <0.001 for all). Significant associations were found between corpus callosum normal-appearing white matter fibres fraction/non-restricted fraction and the Symbol Digit Modality Test (respectively, r = 0.35, P = 0.043; r = −0.35, P = 0.046), and between black holes radial diffusivity and Expanded Disability Status Score (r = 0.59, P = 0.002). We showed the feasibility of diffusion basis spectrum imaging metrics at 7 T, confirmed the role of the derived metrics in the characterization of lesions and normal appearing white matter tissue in different stages of the disease and demonstrated their clinical relevance. Thus, suggesting that diffusion basis spectrum imaging is a promising tool to investigate multiple sclerosis pathophysiology, monitor disease progression and treatment response.

Comparison of myelin water fraction values in periventricular white matter lesions between multiple sclerosis and neuromyelitis optica spectrum disorder

2016 ◽  
Vol 22 (12) ◽  
pp. 1616-1620 ◽  
Author(s):  
In Hye Jeong ◽  
Joon Yul Choi ◽  
Su-Hyun Kim ◽  
Jae-Won Hyun ◽  
AeRan Joung ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Neuromyelitis Optica ◽  
White Matter Lesions ◽  
Spectrum Disorder ◽  
Periventricular White Matter ◽  
Neuromyelitis Optica Spectrum Disorder ◽  
Water Fraction ◽  
Myelin Water Fraction ◽  
The Central Nervous System

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are inflammatory autoimmune diseases of the central nervous system. We hypothesized that the degree of demyelination within lesions in MS and NMOSD would differ as the pathophysiology of the two diseases do. We used myelin water imaging to compare the myelin water fraction (MWF) in 106 periventricular white matter (PVWM) lesions in 27 MS patients and 51 PVWM lesions in 20 NMOSD patients. The MWF was significantly reduced in the MS compared with the NMOSD lesions, suggesting that myelin loss was more severe in MS than in NMOSD.

scholarly journals Restriction spectrum imaging of white matter and its relation to neurological disability in multiple sclerosis

2018 ◽  
Vol 25 (5) ◽  
pp. 687-698 ◽  
Author(s):  
Piotr Sowa ◽  
Hanne F Harbo ◽  
Nathan S White ◽  
Elisabeth G Celius ◽  
Hauke Bartsch ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Fractional Anisotropy ◽  
Free Water ◽  
White Matter Lesions ◽  
Neurological Disability ◽  
Water Fraction ◽  
Neurite Density ◽  
Normal Appearing White Matter ◽  
Spectrum Imaging

Background: Restriction spectrum imaging (RSI) is a recently introduced magnetic resonance imaging diffusion technique. The utility of RSI in multiple sclerosis (MS) is unknown. Objective: To investigate the association between RSI-derived parameters and neurological disability in MS. Methods: Seventy-seven relapsing–remitting MS patients were scanned with RSI on a 3-T scanner. RSI-derived parameters: fast and slow apparent diffusion coefficient (sADC), fractional anisotropy, restricted fractional anisotropy, neurite density (ND), cellularity, extracellular water fraction, and free water fraction, were obtained in white matter lesions (WML) and normal appearing white matter (NAWM). Patients were divided into three groups according to their expanded disability status scale (EDSS): with minimal, low, and substantial disability (<2.5, 2.5–3, and >3, respectively). Group comparisons and correlation analyses were performed. Results: All tested RSI-derived parameters differed between WML and NAWM ( p < 0.001 for all pairwise comparisons). The sADC in WML showed largest difference across disability subgroups (analysis of variance (ANOVA): F = 5.1, η2 = 0.12, p = 0.008). ND in NAWM showed strongest correlation with disability (ϱ = –0.39, p < 0.001). Conclusion: The strongest correlation with EDSS of ND obtained in NAWM indicates that processes outside lesions are important for disability in MS. Our study suggests that RSI-derived parameters may help understand the “clinico-radiological paradox” and improve disease monitoring in MS.

In vivo gradients of thalamic damage in paediatric multiple sclerosis: a window into pathology

Brain ◽  
2020 ◽  
Author(s):  
Ermelinda De Meo ◽  
Loredana Storelli ◽  
Lucia Moiola ◽  
Angelo Ghezzi ◽  
Pierangelo Veggiotti ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Mean Diffusivity ◽  
White Matter Lesions ◽  
Healthy Controls ◽  
Paediatric Multiple Sclerosis ◽  
Multiple Sclerosis Patients

Abstract The thalamus represents one of the first structures affected by neurodegenerative processes in multiple sclerosis. A greater thalamic volume reduction over time, on its CSF side, has been described in paediatric multiple sclerosis patients. However, its determinants and the underlying pathological changes, likely occurring before this phenomenon becomes measurable, have never been explored. Using a multiparametric magnetic resonance approach, we quantified, in vivo, the different processes that can involve the thalamus in terms of focal lesions, microstructural damage and atrophy in paediatric multiple sclerosis patients and their distribution according to the distance from CSF/thalamus interface and thalamus/white matter interface. In 70 paediatric multiple sclerosis patients and 26 age- and sex-matched healthy controls, we tested for differences in thalamic volume and quantitative MRI metrics—including fractional anisotropy, mean diffusivity and T1/T2-weighted ratio—in the whole thalamus and in thalamic white matter, globally and within concentric bands originating from CSF/thalamus interface. In paediatric multiple sclerosis patients, the relationship of thalamic abnormalities with cortical thickness and white matter lesions was also investigated. Compared to healthy controls, patients had significantly increased fractional anisotropy in whole thalamus (f2 = 0.145; P = 0.03), reduced fractional anisotropy (f2 = 0.219; P = 0.006) and increased mean diffusivity (f2 = 0.178; P = 0.009) in thalamic white matter and a trend towards a reduced thalamic volume (f2 = 0.027; P = 0.058). By segmenting the whole thalamus and thalamic white matter into concentric bands, in paediatric multiple sclerosis we detected significant fractional anisotropy abnormalities in bands nearest to CSF (f2 = 0.208; P = 0.002) and in those closest to white matter (f2 range = 0.183–0.369; P range = 0.010–0.046), while we found significant mean diffusivity (f2 range = 0.101–0.369; P range = 0.018–0.042) and T1/T2-weighted ratio (f2 = 0.773; P = 0.001) abnormalities in thalamic bands closest to CSF. The increase in fractional anisotropy and decrease in mean diffusivity detected at the CSF/thalamus interface correlated with cortical thickness reduction (r range = −0.27–0.34; P range = 0.004–0.028), whereas the increase in fractional anisotropy detected at the thalamus/white matter interface correlated with white matter lesion volumes (r range = 0.24–0.27; P range = 0.006–0.050). Globally, our results support the hypothesis of heterogeneous pathological processes, including retrograde degeneration from white matter lesions and CSF-mediated damage, leading to thalamic microstructural abnormalities, likely preceding macroscopic tissue loss. Assessing thalamic microstructural changes using a multiparametric magnetic resonance approach may represent a target to monitor the efficacy of neuroprotective strategies early in the disease course.

Corticospinal tract integrity is related to primary motor cortex thinning in relapsing–remitting multiple sclerosis

2015 ◽  
Vol 21 (14) ◽  
pp. 1771-1780 ◽  
Author(s):  
Niels Bergsland ◽  
Maria Marcella Laganà ◽  
Eleonora Tavazzi ◽  
Matteo Caffini ◽  
Paola Tortorella ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Motor Cortex ◽  
Linear Regression ◽  
Multiple Linear Regression ◽  
Primary Motor Cortex ◽  
Corticospinal Tract ◽  
Healthy Controls ◽  
Relapsing Remitting ◽  
Relapsing Remitting Multiple Sclerosis

Background: The relationship between white matter injury and cortical atrophy development in relapsing–remitting multiple sclerosis (RRMS) remains unclear. Objectives: To investigate the associations between corticospinal tract integrity and cortical morphology measures of the primary motor cortex in RRMS patients and healthy controls. Methods: 51 RRMS patients and 30 healthy controls underwent MRI examination for cortical reconstruction and assessment of corticospinal tract integrity. Partial correlation and multiple linear regression analyses were used to investigate the associations of focal and normal appearing white matter (NAWM) injury of the corticospinal tract with thickness and surface area measures of the primary motor cortex. Relationships between MRI measures and clinical disability as assessed by the Expanded Disability Status Scale and disease duration were also investigated. Results: In patients only, decreased cortical thickness was related to increased corticospinal tract NAWM mean, axial and radial diffusivities in addition to corticospinal tract lesion volume. The final multiple linear regression model for PMC thickness retained only NAWM axial diffusivity as a significant predictor (adjusted R2= 0.270, p= 0.001). Clinical measures were associated with NAWM corticospinal tract integrity measures. Conclusions: Primary motor cortex thinning in RRMS is related to alterations in connected white matter and is best explained by decreased NAWM integrity.

scholarly journals 7 T imaging reveals a gradient in spinal cord lesion distribution in multiple sclerosis

Brain ◽  
2020 ◽  
Vol 143 (10) ◽  
pp. 2973-2987 ◽  
Author(s):  
Russell Ouellette ◽  
Constantina A Treaba ◽  
Tobias Granberg ◽  
Elena Herranz ◽  
Valeria Barletta ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Spinal Cord ◽  
White Matter ◽  
Cervical Spinal Cord ◽  
White Matter Lesions ◽  
Progressive Multiple Sclerosis ◽  
Secondary Progressive Multiple Sclerosis ◽  
Spinal Cord Lesions ◽  
Secondary Progressive ◽  
Relapsing Remitting

Abstract We used 7 T MRI to: (i) characterize the grey and white matter pathology in the cervical spinal cord of patients with early relapsing-remitting and secondary progressive multiple sclerosis; (ii) assess the spinal cord lesion spatial distribution and the hypothesis of an outside-in pathological process possibly driven by CSF-mediated immune cytotoxic factors; and (iii) evaluate the association of spinal cord pathology with brain burden and its contribution to neurological disability. We prospectively recruited 20 relapsing-remitting, 15 secondary progressive multiple sclerosis participants and 11 age-matched healthy control subjects to undergo 7 T imaging of the cervical spinal cord and brain as well as conventional 3 T brain acquisition. Cervical spinal cord imaging at 7 T was used to segment grey and white matter, including lesions therein. Brain imaging at 7 T was used to segment cortical and white matter lesions and 3 T imaging for cortical thickness estimation. Cervical spinal cord lesions were mapped voxel-wise as a function of distance from the inner central canal CSF pool to the outer subpial surface. Similarly, brain white matter lesions were mapped voxel-wise as a function of distance from the ventricular system. Subjects with relapsing-remitting multiple sclerosis showed a greater predominance of spinal cord lesions nearer the outer subpial surface compared to secondary progressive cases. Inversely, secondary progressive participants presented with more centrally located lesions. Within the brain, there was a strong gradient of lesion formation nearest the ventricular system that was most evident in participants with secondary progressive multiple sclerosis. Lesion fractions within the spinal cord grey and white matter were related to the lesion fraction in cerebral white matter. Cortical thinning was the primary determinant of the Expanded Disability Status Scale, white matter lesion fractions in the spinal cord and brain of the 9-Hole Peg Test and cortical thickness and spinal cord grey matter cross-sectional area of the Timed 25-Foot Walk. Spinal cord lesions were localized nearest the subpial surfaces for those with relapsing-remitting and the central canal CSF surface in progressive disease, possibly implying CSF-mediated pathogenic mechanisms in lesion development that may differ between multiple sclerosis subtypes. These findings show that spinal cord lesions involve both grey and white matter from the early multiple sclerosis stages and occur mostly independent from brain pathology. Despite the prevalence of cervical spinal cord lesions and atrophy, brain pathology seems more strongly related to physical disability as measured by the Expanded Disability Status Scale.

scholarly journals Neurite density is reduced in the presymptomatic phase of C9orf72 disease

2018 ◽  
Vol 90 (4) ◽  
pp. 387-394 ◽  
Author(s):  
Junhao Wen ◽  
Hui Zhang ◽  
Daniel C Alexander ◽  
Stanley Durrleman ◽  
Alexandre Routier ◽  
...  
Keyword(s):  
White Matter ◽  
Effect Size ◽  
Grey Matter ◽  
Free Water ◽  
Chromosome 9 ◽  
Grey Matter Volume ◽  
Water Fraction ◽  
White Matter Abnormalities ◽  
Neurite Density ◽  
Density Index

ObjectiveTo assess the added value of neurite orientation dispersion and density imaging (NODDI) compared with conventional diffusion tensor imaging (DTI) and anatomical MRI to detect changes in presymptomatic carriers of chromosome 9 open reading frame 72 (C9orf72) mutation.MethodsThe PREV-DEMALS (Predict to Prevent Frontotemporal Lobar Degeneration and Amyotrophic Lateral Sclerosis) study is a prospective, multicentre, observational study of first-degree relatives of individuals carrying the C9orf72 mutation. Sixty-seven participants (38 presymptomatic C9orf72 mutation carriers (C9+) and 29 non-carriers (C9−)) were included in the present cross-sectional study. Each participant underwent one single-shell, multishell diffusion MRI and three-dimensional T1-weighted MRI. Volumetric measures, DTI and NODDI metrics were calculated within regions of interest. Differences in white matter integrity, grey matter volume and free water fraction between C9+ and C9− individuals were assessed using linear mixed-effects models.ResultsCompared with C9−, C9+ demonstrated white matter abnormalities in 10 tracts with neurite density index and only 5 tracts with DTI metrics. Effect size was significantly higher for the neurite density index than for DTI metrics in two tracts. No tract had a significantly higher effect size for DTI than for NODDI. For grey matter cortical analysis, free water fraction was increased in 13 regions in C9+, whereas 11 regions displayed volumetric atrophy.ConclusionsNODDI provides higher sensitivity and greater tissue specificity compared with conventional DTI for identifying white matter abnormalities in the presymptomatic C9orf72 carriers. Our results encourage the use of neurite density as a biomarker of the preclinical phase.Trial registration numberNCT02590276.

scholarly journals GAMER-MRI in Multiple Sclerosis Identifies the Diffusion-Based Microstructural Measures That Are Most Sensitive to Focal Damage: A Deep-Learning-Based Analysis and Clinico-Biological Validation

2021 ◽  
Vol 15 ◽  
Author(s):  
Po-Jui Lu ◽  
Muhamed Barakovic ◽  
Matthias Weigel ◽  
Reza Rahmanzadeh ◽  
Riccardo Galbusera ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Deep Learning ◽  
Bayesian Approach ◽  
Disease Diagnosis ◽  
Response To Therapy ◽  
Imaging Data ◽  
Neurofilament Light Chain ◽  
Biological Validation ◽  
Neurite Density ◽  
Density Index

Conventional magnetic resonance imaging (cMRI) in multiple sclerosis (MS) patients provides measures of focal brain damage and activity, which are fundamental for disease diagnosis, prognosis, and the evaluation of response to therapy. However, cMRI is insensitive to the damage to the microenvironment of the brain tissue and the heterogeneity of MS lesions. In contrast, the damaged tissue can be characterized by mathematical models on multishell diffusion imaging data, which measure different compartmental water diffusion. In this work, we obtained 12 diffusion measures from eight diffusion models, and we applied a deep-learning attention-based convolutional neural network (CNN) (GAMER-MRI) to select the most discriminating measures in the classification of MS lesions and the perilesional tissue by attention weights. Furthermore, we provided clinical and biological validation of the chosen metrics—and of their most discriminative combinations—by correlating their respective mean values in MS patients with the corresponding Expanded Disability Status Scale (EDSS) and the serum level of neurofilament light chain (sNfL), which are measures of disability and neuroaxonal damage. Our results show that the neurite density index from neurite orientation and dispersion density imaging (NODDI), the measures of the intra-axonal and isotropic compartments from microstructural Bayesian approach, and the measure of the intra-axonal compartment from the spherical mean technique NODDI were the most discriminating (respective attention weights were 0.12, 0.12, 0.15, and 0.13). In addition, the combination of the neurite density index from NODDI and the measures for the intra-axonal and isotropic compartments from the microstructural Bayesian approach exhibited a stronger correlation with EDSS and sNfL than the individual measures. This work demonstrates that the proposed method might be useful to select the microstructural measures that are most discriminative of focal tissue damage and that may also be combined to a unique contrast to achieve stronger correlations to clinical disability and neuroaxonal damage.

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