High-resolution T1-relaxation time mapping displays subtle, clinically relevant, gray matter damage in long-standing multiple sclerosis

Background:

Gray matter (GM) pathology has high clinical relevance in multiple sclerosis (MS), but conventional magnetic resonance imaging (MRI) is insufficiently sensitive to visualize the rather subtle damage.

Objective:

To investigate whether high spatial resolution T1-relaxation time (T1-RT) measurements can detect changes in the normal-appearing GM of patients with long-standing MS and whether these changes are associated with physical and cognitive impairment.

Methods:

High spatial resolution (1.05 × 1.05 × 1.2 mm3) T1-RT measurements were performed at 3 T in 156 long-standing MS patients and 54 healthy controls. T1-RT histogram parameters in several regions were analyzed to investigate group differences. Stepwise linear regression analyses were used to assess the relation of T1-RT with physical and cognitive impairment.

Results:

In both thalamus and cortex, T1-RT histogram skewness was higher in patients than controls. In the cortex, this was driven by the frontal and temporal lobes. No differences were found in other GM histogram parameters. Cortical skewness, thalamus volume, and average white matter (WM) lesion T1-RT emerged as the strongest predictors for cognitive performance (adjusted R2 = 0.39).

Conclusion:

Subtle GM damage was present in the cortex and thalamus of MS patients, as indicated by increased T1-RT skewness. Increased cortical skewness emerged as an independent predictor of cognitive dysfunction.

Widespread cortical thinning in patients with neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Studies on cortical involvement and its relationship with cognitive function in patients with neuromyelitis optica spectrum disorder (NMOSD) remain scarce. The objective of this study was to compare cortical thickness on magnetic resonance imaging (MRI) between patients with NMOSD and multiple sclerosis (MS) and to investigate its relationship with clinical features and cognitive function.

METHODS

This observational clinical imaging study of 91 patients with NMOSD, 52 patients with MS and 44 healthy controls was conducted from 1 December 2013 to 30 April 2015 at the institutional referral center. Three tesla MRI of the brain and neuropsychological tests were performed. Cortical thickness was measured using three-dimensional surface-based analysis.

RESULTS

Both sets of patients exhibited cortical thinning throughout the entire brain cortex. Patients with MS showed a significantly greater reduction in cortical thickness over broad regions of the bilateral frontal and parieto-temporal cortices and the left precuneus compared to those with NMOSD. Memory functions in patients with MS were correlated with broad regional cortical thinning, whereas no significant associations were observed between cortical thickness and cognitive function in patients with NMOSD.

CONCLUSIONS

Widespread cortical thinning was observed in patients with NMOSD and MS, but the extent of cortical thinning was greater in patients with MS. The more severe cortical atrophy may contribute to memory impairment in patients with MS but not in those with NMOSD. These results provide in vivo evidence that the severity and clinical relevance of cortical thinning differ between NMOSD and MS.

Fatigue Management in Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory-demyelinating disease of the central nervous system that may entail severe levels of disability in the long term. However, independently of the level of disability, MS patients frequently experience severe fatigue that can be as disabling as objective neurological deficits. For that reason, it is mandatory to perform an early diagnosis of MS-related fatigue and start a suitable treatment as soon as possible. In clinical practice, MS-related fatigue should be assessed and managed by a multidisciplinary team involving neurologists, MS nurses, occupational therapists, and physiotherapists. When assessing a person with MS-related fatigue, the first step is to rule out potential triggers or causes of fatigue, which may be related to MS, such as urinary dysfunction, pain, or muscular spasms leading to a sleep disorder, or unrelated to it. Once these causes have been ruled out and appropriately tackled, a careful therapeutic intervention needs to be decided. Therapeutic interventions for MS-related fatigue can be pharmacological or non-pharmacological. Regarding the pharmacological treatments, although many drugs have been tested in clinical trials, only amantadine is currently recommended for this indication. Regarding the non-pharmacological approaches, they can be broadly divided into physical, psychological, and mixed physical/psychological interventions. Several studies, many of them randomised clinical trials, support the use of all these types of non-pharmacological interventions to treat MS-related fatigue. Recent publications suggest that the implementation of mixed approaches, which have a naturally comprehensive nature, may have excellent results in clinical practice, in relation not only to fatigue levels but also to more general aspects of MS.

Reduced cerebral cortical thickness in Non-cirrhotic patients with hepatitis C

Hepatitis C virus (HCV) infection is associated with fatigue, depression, and cognitive impairment even in the absence of severe liver fibrosis or cirrhosis. HCV has been hypothesised to cause neurodegenerative changes through low-grade neuroinflammation. Our aim was to examine whether cortical thickness (CTh) differs between chronic HCV patients and healthy controls, suggestive of cortical atrophy. In this case-control study 43 HCV patients without severe liver fibrosis, substance abuse, or comorbid HIV or hepatitis B virus infection, and 43 age and sex matched controls underwent MRI. Cortical thickness was measured using a surface based approach. Participants underwent semi-structured psychiatric interview and fatigue was assessed using the fatigue severity scale. HCV was associated with higher fatigue scores, and 58 % of HCV patients suffered from significant fatigue (p < 0.0001). Depression was observed in 16 % of patients. Areas of significantly reduced CTh were found in both left and right occipital cortex and in the left frontal lobe after correction for multiple comparisons (p < 0.05). No association between fatigue, former substance abuse, or psychotropic medication and CTh was found. No overall difference in cerebral white and grey matter volume was found. The findings support the hypothesis that HCV is associated with neurodegenerative changes.

Different cortical underpinnings for fatigue and depression in MS?

BACKGROUND

Fatigue is a common complaint in MS patients but its origins are still not fully understood. A major difficulty is that fatigue seems strongly correlated with depression.

METHODS

95 MS patients and 15 healthy control subjects were included. The Fatigue Severity Scale and Beck's Depression Inventory were used to assess symptom-severity and to determine group membership for five groups: MS patients with and without fatigue, and with or without depressive mood, healthy controls. Participants were scanned using high-resolution structural 3D T1-weighted imaging. Cortical thickness for 84 areas was calculated using the NeuroQLab software in combination with the atlas for the Automated Anatomical Labeling software. A stepwise forward regression analysis was performed to predict group membership of the MS patients by thickness of cortical areas. We also performed a series of post-hoc ANOVAs to explore differences between the four patients groups and the healthy controls.

RESULTS

About 20% of the patients suffered only from fatigue or only from depressive mood. Regression analysis explained 17.3% of the variance and thickness of the right inferior parietal cortex, middle temporal pole and parahippocampus contributed significantly to the model. Patients with pure fatigue showed a specific decrease in cortical thickness in the inferior parietal lobe, patients with both depressive mood and fatigue in the right middle temporal pole. Additional ANOVAs revealed cortical thinning in the right middle cingulate cortex in the group with pure fatigue as well as the groups with depression.

CONCLUSION

Fatigue and depression can be dissociated in larger MS-patient groups using questionnaires and cortical thickness measures, but the cortical thickness measures only explain a small portion of variance of these neuropsychiatric symptoms.

Classification, diagnosis, and differential diagnosis of multiple sclerosis

PURPOSE OF REVIEW

The increasing availability of effective therapies for multiple sclerosis as well as research demonstrating the benefits of early treatment highlights the importance of expedient and accurate multiple sclerosis diagnosis. This review will discuss the classification, diagnosis, and differential diagnosis of multiple sclerosis.

RECENT FINDINGS

An international panel of multiple sclerosis experts, the MS Phenotype Group, recently revised the multiple sclerosis phenotypic classifications and published their recommendations in 2014. Recent research developments have helped improve the accuracy of multiple sclerosis diagnosis, especially with regard to differentiating multiple sclerosis from neuromyelitis optica spectrum disorders.

SUMMARY

Current multiple sclerosis phenotypic classifications include relapsing-remitting multiple sclerosis, clinically isolated syndrome, radiologically isolated syndrome, primary-progressive multiple sclerosis, and secondary-progressive multiple sclerosis. The McDonald 2010 diagnostic criteria provide formal guidelines for the diagnosis of relapsing-remitting multiple sclerosis and primary-progressive multiple sclerosis. These require demonstration of dissemination in space and time, with consideration given to both clinical findings and imaging data. The criteria also require that there exist no better explanation for the patient's presentation. The clinical history, examination, and MRI should be most consistent with multiple sclerosis, including the presence of features typical for the disease as well as the absence of features that suggest an alternative cause, for a diagnosis of multiple sclerosis to be proposed.

Regional Neocortical Gray Matter Structure and Sleep Fragmentation in Older Adults

STUDY OBJECTIVES

To test the hypothesis that greater sleep fragmentation is associated with regionally decreased cortical gray matter volume in older community-dwelling adults without cognitive impairment.

METHODS

We studied 141 community-dwelling older adults (median age 82.9; 73% female) without cognitive impairment or stroke, and not using sedative/ hypnotic medications, participating in the Rush Memory and Aging Project. We quantified sleep fragmentation from 7 d of actigraphy using the metric kRA and related this to total cortical gray matter volume, and regional gray matter volume in 34 cortical regions quantified by automated segmentation of magnetic resonance imaging data. We determined statistical significance and accounted for multiple comparisons by empirically estimating the false discovery rate by permutation.

RESULTS

Lower total cortical gray matter volume was associated with higher sleep fragmentation (coefficient +0.23, standard error [SE] 0.11, P = 0.037). Lower gray matter volumes in four cortical regions were accompanied by higher sleep fragmentation with a false discovery rate < 0.05: the left (coefficient +0.36, SE 0.10, P = 2.7 × 10(-4)) and right (coefficient +0.31, SE 0.10, P = 4.0 × 10(-3)) lateral orbitofrontal cortices, and the adjacent left (coefficient +0.31, SE 0.10, 5.4 × 10(-4)) and right (coefficient +0.39, SE 0.10, P = 1.2 × 10(-4)) inferior frontal gyri pars orbitalis. These associations were unchanged after accounting for age, sex, education, depression, cognitive function, and a number of medical comorbidities.

CONCLUSIONS

Lower cortical gray matter volume in the lateral orbitofrontal cortex and inferior frontal gyrus pars orbitalis is associated with greater sleep fragmentation in older community-dwelling adults. Further work is needed to clarify whether this is a consequence of or contributor to sleep fragmentation.

COMMENTARY

A commentary on this article appears in this issue on page 15.

Quantitative validation of a visual rating scale for frontal atrophy: associations with clinical status, APOE e4, CSF biomarkers and cognition

OBJECTIVES

To validate a visual rating scale of frontal atrophy with quantitative imaging and study its association with clinical status, APOE ε4, CSF biomarkers, and cognition.

METHODS

The AddNeuroMed and ADNI cohorts were combined giving a total of 329 healthy controls, 421 mild cognitive impairment patients, and 286 Alzheimer's disease (AD) patients. Thirty-four patients with frontotemporal dementia (FTD) were also included. Frontal atrophy was assessed with the frontal sub-scale of the global cortical atrophy scale (GCA-F) on T1-weighted images. Automated imaging markers of cortical volume, thickness, and surface area were evaluated. Manual tracing was also performed.

RESULTS

The GCA-F scale reliably reflects frontal atrophy, with orbitofrontal, dorsolateral, and motor cortices being the regions contributing most to the GCA-F ratings. GCA-F primarily reflects reductions in cortical volume and thickness, although it was able to detect reductions in surface area too. The scale showed significant associations with clinical status and cognition.

CONCLUSION

The GCA-F scale may have implications for clinical practice as supportive diagnostic tool for disorders demonstrating predominant frontal atrophy such as FTD and the executive presentation of AD. We believe that GCA-F is feasible for use in clinical routine for the radiological assessment of dementia and other disorders.

KEY POINTS

• The GCA-F visual rating scale reliably reflects frontal brain atrophy. • Orbitofrontal, dorsolateral, and motor cortices are the most contributing regions. • GCA-F shows significant associations with clinical status and cognition. • GCA-F may be supportive diagnostic tool for disorders demonstrating predominant frontal atrophy. • GCA-F may be feasible for use in radiological routine.

Reduced perfusion in white matter lesions in multiple sclerosis

OBJECTIVE

To investigate dynamic susceptibility contrast (DSC) perfusion weighted imaging (PWI) in white matter lesions (WML) in patients with multiple sclerosis (MS), using automatically generated binary masks of brain tissue.

BACKGROUND

WML in MS have in some studies demonstrated perfusion abnormalities compared to normal appearing white matter (NAWM), however perfusion changes in WML in MS have in general not been well documented.

METHODS

DSC PWI was performed at 1.5 Tesla in 69 newly diagnosed MS patients. Parametric perfusion maps representing cerebral blood volume (CBV), cerebral blood flow (CBF) and mean transit time (MTT) were obtained. Binary masks of WML, white matter (WM) and grey matter (GM) were automatically generated and co-registered to the perfusion maps. The WML mask was manually edited and modified to correct for errors in the automatic lesion detection. Perfusion parameters were derived both from WML and NAWM using the manually modified WML mask, and using the original non-modified WML mask (with and without GM exclusion mask). Differences in perfusion measures between WML and NAWM were analyzed.

RESULTS

CBF was significantly lower (p<0.001) and MTT significantly higher (p<0.001) in WML compared to NAWM. CBV did not show significant difference between WML and NAWM. The non-modified WML mask gave similar results as manually modified WML mask if the GM exclusion mask was used in the analysis.

CONCLUSIONS

DSC PWI revealed lower CBF and higher MTT, consistent with reduced perfusion, in WML compared to NAWM in patients with early MS. Automatically generated binary masks are a promising tool in perfusion analysis of WML.

A Longitudinal Study of Disability, Cognition and Gray Matter Atrophy in Early Multiple Sclerosis Patients According to Evidence of Disease Activity

New treatment options may make “no evidence of disease activity” (NEDA: no relapses or disability progression and no new/enlarging MRI lesions, as opposed to “evidence of disease activity” (EDA) with at least one of the former), an achievable goal in relapsing-remitting multiple sclerosis (RRMS). The objective of the present study was to determine whether early RRMS patients with EDA at one-year follow-up had different disability, cognition, treatment and gray matter (GM) atrophy rates from NEDA patients and healthy controls (HC). RRMS patients (mean age 34 years, mean disease duration 2.2 years) were examined at baseline and one-year follow-up with neurological (n = 72), neuropsychological (n = 56) and structural MRI (n = 57) examinations. Matched HC (n = 61) were retested after three years. EDA was found in 46% of RRMS patients at follow-up. EDA patients used more first line and less second line disease modifying treatment than NEDA (p = 0.004). While the patients groups had similar disability levels at baseline, they differed in disability at follow-up (p = 0.010); EDA patients progressed (EDSS: 1.8–2.2, p = 0.010), while NEDA patients improved (EDSS: 2.0–1.7, p<0.001). Cognitive function was stable in both patient groups. Subcortical GM atrophy rates were higher in EDA patients than HC (p<0.001). These results support the relevance of NEDA as outcome in RRMS and indicate that pathological neurodegeneration in RRMS mainly occur in patients with evidence of disease activity.

Corticospinal tract integrity is related to primary motor cortex thinning in 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.