scholarly journals A tractometry investigation of white matter tract network structure and relationships with cognitive function in relapsing-remitting multiple sclerosis

2021 ◽  
Author(s):  
Danka Jandric ◽  
Geoff JM Parker ◽  
Hamied Haroon ◽  
Valentina Tomassini ◽  
Nils Muhlert ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Cognitive Function ◽  
White Matter ◽  
Cognitive Dysfunction ◽  
Network Structure ◽  
Test Performance ◽  
Cognitive Domains ◽  
Normal Appearing White Matter ◽  
Relapsing Remitting ◽  
The Brain

Understanding the brain changes underlying cognitive dysfunction is a key priority in multiple sclerosis to improve monitoring and treatment of this debilitating symptom. Functional connectivity network changes are associated with cognitive dysfunction, but it is less well understood how changes in normal appearing white matter relate to cognitive symptoms. If white matter tracts share a similar network structure it would be expected that tracts within a network are similarly affected by MS pathology. In the present study, we used a tractometry approach to explore patterns of variance in diffusion metrics across white matter (WM) tracts. We investigated whether separate networks, based on normal variation or pathology, appear, and how this relates to neuropsychological test performance across cognitive domains. A sample of 102 relapsing-remitting MS patients and 27 healthy controls underwent MRI and neuropsychological testing. Tractography was performed on diffusion MRI data to extract 40 WM tracts and microstructural measures were extracted from each tract. Principal component analysis (PCA) was used to decompose metrics from all tracts to assess the presence of any co-variance structure among the tracts. Similarly, PCA was applied to cognitive test scores to identify the main cognitive domains. Finally, we assessed the ability of tract components to predict test performance across cognitive domains. We found that a single component which captured pathology across all tracts explained the most variance and that there was little evidence for separate, smaller network patterns of pathology. WM tract components were weak, but significant, predictors of cognitive function in MS. These findings highlight the need to investigate the relationship between the normal appearing white matter and cognitive impairment further and on a more granular level, to improve the understanding of the network structure of the brain in MS.

scholarly journals Magnetization transfer and adiabatic T1ρ MRI reveal abnormalities in normal-appearing white matter of subjects with multiple sclerosis

2013 ◽  
Vol 20 (8) ◽  
pp. 1066-1073 ◽  
Author(s):  
Silvia Mangia ◽  
Adam F Carpenter ◽  
Andy E Tyan ◽  
Lynn E Eberly ◽  
Michael Garwood ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Magnetization Transfer ◽  
Magnetic Resonance Images ◽  
Relaxation Methods ◽  
Normal Appearing White Matter ◽  
Relaxation Parameters ◽  
Relapsing Remitting ◽  
Cortical Gray Matter ◽  
The Brain

Background: Diffuse abnormalities are known to occur within the brain tissue of multiple sclerosis (MS) patients that is “normal appearing” on T1-weighted and T2-weighted magnetic resonance images. Objectives: With the goal of exploring the sensitivity of novel MRI parameters to detect such abnormalities, we implemented an inversion-prepared magnetization transfer (MT) protocol and adiabatic T1ρ and T2ρ rotating frame relaxation methods. Methods: Nine relapsing–remitting MS patients and seven healthy controls were recruited. Relaxation parameters were measured in a single slice just above the lateral ventricles and approximately parallel to the AC-PC line. Results: The MT ratio of regions encompassing the normal-appearing white matter (NAWM) was different in MS patients as compared with controls ( p = 0.043); however, the T1 measured during off-resonance irradiation (T1sat) was substantially more sensitive than the MT ratio for detecting differences between groups ( p = 0.0006). Adiabatic T1ρ was significantly prolonged in the NAWM of MS patents as compared to controls (by 6%, p = 0.026), while no differences were found among groups for T2ρ. No differences among groups were observed in the cortical gray matter for any relaxation parameter. Conclusions: The results suggest degenerative processes occurring in the NAWM of MS, likely not accompanied by significant abnormalities in iron content.

scholarly journals A higher proportion of ermin-immunopositive oligodendrocytes in areas of remyelination

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256155
Author(s):  
Intakhar Ahmad ◽  
Stig Wergeland ◽  
Eystein Oveland ◽  
Lars Bø
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Corpus Callosum ◽  
Mouse Model ◽  
Grey Matter ◽  
Early Stage ◽  
Relative Proportion ◽  
Normal Appearing White Matter ◽  
The Brain

Incomplete remyelination is frequent in multiple sclerosis (MS)-lesions, but there is no established marker for recent remyelination. We investigated the role of the oligodendrocyte/myelin protein ermin in de- and remyelination in the cuprizone (CPZ) mouse model, and in MS. The density of ermin+ oligodendrocytes in the brain was significantly decreased after one week of CPZ exposure (p < 0.02). The relative proportion of ermin+ cells compared to cells positive for the late-stage oligodendrocyte marker Nogo-A increased at the onset of remyelination in the corpus callosum (p < 0.02). The density of ermin-positive cells increased in the corpus callosum during the CPZ-phase of extensive remyelination (p < 0.0001). In MS, the density of ermin+ cells was higher in remyelinated lesion areas compared to non-remyelinated areas both in white- (p < 0.0001) and grey matter (p < 0.0001) and compared to normal-appearing white matter (p < 0.001). Ermin immunopositive cells in MS-lesions were not immunopositive for the early-stage oligodendrocyte markers O4 and O1, but a subpopulation was immunopositive for Nogo-A. The data suggest a relatively higher proportion of ermin immunopositivity in oligodendrocytes compared to Nogo-A indicates recent or ongoing remyelination.

Diffusion tensor imaging in multiple sclerosis: a tool for monitoring changes in normal-appearing white matter

2004 ◽  
Vol 10 (2) ◽  
pp. 188-196 ◽  
Author(s):  
Emmanuelle Cassol ◽  
Jean-Philippe Ranjeva ◽  
Danielle Ibarrola ◽  
Claude Mékies ◽  
Claude Manelfe ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Lesion Load ◽  
Normal Appearing White Matter ◽  
Relapsing Remitting ◽  
One Year ◽  
Diffusion Tensor Imaging Dti

Our objectives were to determine the reproducibility of diffusion tensor imaging (DTI) in volunteers and to evaluate the ability of the method to monitor longitudinal changes occurring in the normal-appearing white matter (NAWM) of patients with multiple sclerosis (MS). DTI was performed three-mo nthly for one year in seven MS patients: three relapsing-remitting (RRMS), three secondary progressive (SPMS) and one relapsing SP. They were selected with a limited cerebral lesion load. Seven age- and sex-matched controls also underwent monthly examinations for three months. Diffusivity and anisotropy were quantified over the segmented whole supratentorial white matter, with the indices of trace (Tr) and fractional anisotropy (FA). Results obtained in volunteers show the reproducibility of the method. Patients had higher trace and lower anisotropy than matched controls (P B-0.0001). O ver the follow-up, both Tr and FA indicated a recovery after the acute phase in RRMS and a progressive shift towards abnormal values in SPMS. A lthough this result is not statistically significant, it suggests that DTI is sensitive to microscopic changes occurring in tissue of normal appearance in conventional images and could be useful for monitoring the course of the disease, even though it was unable to clearly distinguish between the various physiopathological processes involved.

T1 relaxation maps allow differentiation between pathologic tissue subsets in relapsing-remitting and secondary progressive multiple sclerosis

2004 ◽  
Vol 10 (5) ◽  
pp. 556-561 ◽  
Author(s):  
A Castriota-Scanderbeg ◽  
F Fasano ◽  
M Filippi ◽  
C Caltagirone
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Relaxation Times ◽  
Brain Regions ◽  
Progressive Multiple Sclerosis ◽  
Clinical Group ◽  
Secondary Progressive ◽  
Normal Appearing White Matter ◽  
Relapsing Remitting ◽  
Normal White Matter

In an attempt to clarify whether T1 relaxation time mapping may assist in characterizing the pathological brain tissue substrate of multiple sclerosis (MS), we compared the T1 relaxation times of lesions, areas of normal-appearing white matter (NAWM) located proximal to lesions, and areas of NAWM located distant from lesions in 12 patients with the relapsing-remitting and 12 with the secondary progressive (SP) subtype of disease. Nine healthy volunteers served as controls. Calculated mean T1 values were averaged across all patients within each clinical group, and comparisons were made by means of the Mann-Whitney U-test. Significant differences were found between all investigated brain regions within each clinical subgroup. Significant differences were also detected for each investigated brain region among clinical subgroups. While T1 values of NAWM were significantly higher in patients with SP disease than in normal white matter (NWM) of controls, no differences were detected when corresponding brain areas of patients with RR MS were compared with NWM of controls. T1 maps identify areas of the brain that are damaged to a different extent in patients with MS, and may be of help in monitoring disease progression.

scholarly journals Pittsburgh compound-B PET white matter imaging and cognitive function in late multiple sclerosis

2017 ◽  
Vol 24 (6) ◽  
pp. 739-749 ◽  
Author(s):  
Burcu Zeydan ◽  
Val J Lowe ◽  
Christopher G Schwarz ◽  
Scott A Przybelski ◽  
Nirubol Tosakulwong ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Cognitive Function ◽  
White Matter ◽  
Conditional Logistic Regression ◽  
Standardized Uptake Value ◽  
Population Based ◽  
Large Network ◽  
Pittsburgh Compound B ◽  
Normal Appearing White Matter ◽  
Positron Emission

Background: There is growing interest in white matter (WM) imaging with positron emission tomography (PET). Objectives: We studied the association of cognitive function in late multiple sclerosis (MS) with cortical and WM Pittsburgh compound-B PET (PiB-PET) binding. Methods: In the population-based Mayo Clinic Study of Aging, 24 of 4869 participants had MS (12 underwent PiB-PET). Controls were age and sex matched (5:1). We used automated or semi-automated processing for quantitative image analyses and conditional logistic regression for group differences. Results: MS patients had lower memory ( p = 0.03) and language ( p = 0.02) performance; smaller thalamic volumes ( p = 0.003); and thinner temporal ( p = 0.001) and frontal ( p = 0.045) cortices on magnetic resonance imaging (MRI) than controls. There was no difference in global cortical PiB standardized uptake value ratios between MS and controls ( p = 0.35). PiB uptake was lower in areas of WM hyperintensities compared to normal-appearing white matter (NAWM) in MS ( p = 0.0002). Reduced PiB uptake in both the areas of WM hyperintensities ( r = 0.65; p = 0.02) and NAWM ( r = 0.69; p = 0.01) was associated with decreased visuospatial performance in MS. Conclusion: PiB uptake in the cortex in late MS is not different from normal age-matched controls. PiB uptake in the WM in late MS may be a marker of the large network structures’ integrity such as those involved in visuospatial performance.

White matter tract abnormalities are associated with cognitive dysfunction in secondary progressive multiple sclerosis

2016 ◽  
Vol 22 (11) ◽  
pp. 1429-1437 ◽  
Author(s):  
Kim A Meijer ◽  
Nils Muhlert ◽  
Mara Cercignani ◽  
Varun Sethi ◽  
Maria A Ron ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Progressive Multiple Sclerosis ◽  
Secondary Progressive Multiple Sclerosis ◽  
Cognitive Domains ◽  
Secondary Progressive ◽  
Relapsing Remitting ◽  
Magnetic Resonance Imaging Mri ◽  
Relapsing Remitting Multiple Sclerosis ◽  
Tract Damage

Background: While our knowledge of white matter (WM) pathology underlying cognitive impairment in relapsing remitting multiple sclerosis (MS) is increasing, equivalent understanding in those with secondary progressive (SP) MS lags behind. Objective: The aim of this study is to examine whether the extent and severity of WM tract damage differ between cognitively impaired (CI) and cognitively preserved (CP) secondary progressive multiple sclerosis (SPMS) patients. Methods: Conventional magnetic resonance imaging (MRI) and diffusion MRI were acquired from 30 SPMS patients and 32 healthy controls (HC). Cognitive domains commonly affected in MS patients were assessed. Linear regression was used to predict cognition. Diffusion measures were compared between groups using tract-based spatial statistics (TBSS). Results: A total of 12 patients were classified as CI, and processing speed was the most commonly affected domain. The final regression model including demographic variables and radial diffusivity explained the greatest variance of cognitive performance ( R2 = 0.48, p = 0.002). SPMS patients showed widespread loss of WM integrity throughout the WM skeleton when compared with HC. When compared with CP patients, CI patients showed more extensive and severe damage of several WM tracts, including the fornix, superior longitudinal fasciculus and forceps major. Conclusion: Loss of WM integrity assessed using TBSS helps to explain cognitive decline in SPMS patients.

Cognitive dysfunction in patients with relapsing-remitting multiple sclerosis

2006 ◽  
Vol 12 (1) ◽  
pp. 77-87 ◽  
Author(s):  
U Nocentini ◽  
P Pasqualetti ◽  
S Bonavita ◽  
M Buccafusca ◽  
M F De Caro ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Information Processing ◽  
Cognitive Dysfunction ◽  
Processing Speed ◽  
Sample Selection ◽  
Large Sample Size ◽  
Clinical Markers ◽  
Information Processing Speed ◽  
Cognitive Domains ◽  
Relapsing Remitting

Cognitive dysfunction is considered one of the clinical markers of multiple sclerosis (MS). However, in the literature there are inconsistent reports on the prevalence of cognitive dysfunction, and separate data for the relapsing-remitting (RR) type of the disease are not always presented. In this study, we submitted 461 RRMS patients to a battery of neuropsychological tests to investigate their impairment in various cognitive domains. As a consequence of the exclusion criteria, the sample is not fully representative of the entire population of RRMS patients. In this selected sample, when only the eight scores of a core battery (Mental Deterioration Battery) were considered (with respective cutoffs), it emerged that 31% of the patients were affected by some degree of cognitive deficit. In particular, 15% had mild, 11.2% moderate and 4.8% had severe impairment. Information processing speed was the most frequently impaired area, followed by memory. When two other tests (SDMT and MCST) were added and cognitive domains were considered, it emerged that 39.3% of the patients were impaired in two or more domains. When four subgroups were obtained by means of cluster analysis and then compared, it emerged that information processing speed and memory deficits differentiated the still cognitively unimpaired from the mildly impaired MS patients. Significant associations were found between cognitive and clinical characteristics. However, due to the large sample size, clinically irrelevant relationships may also have emerged. Even with the limitations imposed by the sample selection and the possible underestimation of the prevalence and severity of cognitive dysfunction, these results seem to provide further evidence that information processing speed deficit may be an early and important marker of cognitive impairment in MS patients.

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