Facing privacy in neuroimaging: removing facial features degrades performance of image analysis methods.

BACKGROUND: Recent studies have created awareness that facial features can be reconstructed from high-resolution MRI. Therefore, data sharing in neuroimaging requires special attention to protect participants' privacy. Facial features removal (FFR) could alleviate these concerns. We assessed the impact of three FFR methods on subsequent automated image analysis to obtain clinically relevant outcome measurements in three clinical groups. METHODS: FFR was performed using QuickShear, FaceMasking, and Defacing. In 110 subjects of Alzheimer's Disease Neuroimaging Initiative, normalized brain volumes (NBV) were measured by SIENAX. In 70 multiple sclerosis patients of the MAGNIMS Study Group, lesion volumes (WMLV) were measured by lesion prediction algorithm in lesion segmentation toolbox. In 84 glioblastoma patients of the PICTURE Study Group, tumor volumes (GBV) were measured by BraTumIA. Failed analyses on FFR-processed images were recorded. Only cases in which all image analyses completed successfully were analyzed. Differences between outcomes obtained from FFR-processed and full images were assessed, by quantifying the intra-class correlation coefficient (ICC) for absolute agreement and by testing for systematic differences using paired t tests. RESULTS: Automated analysis methods failed in 0-19% of cases in FFR-processed images versus 0-2% of cases in full images. ICC for absolute agreement ranged from 0.312 (GBV after FaceMasking) to 0.998 (WMLV after Defacing). FaceMasking yielded higher NBV (p = 0.003) and WMLV (p ≤ 0.001). GBV was lower after QuickShear and Defacing (both p < 0.001). CONCLUSIONS: All three outcome measures were affected differently by FFR, including failure of analysis methods and both "random" variation and systematic differences. Further study is warranted to ensure high-quality neuroimaging research while protecting participants' privacy. KEY POINTS: • Protecting participants' privacy when sharing MRI data is important. • Impact of three facial features removal methods on subsequent analysis was assessed in three clinical groups. • Removing facial features degrades performance of image analysis methods.

Association of asymptomatic spinal cord lesions and atrophy with disability 5 years after a clinically isolated syndrome.

BACKGROUND: Spinal cord pathology is an important substrate for long-term disability in multiple sclerosis (MS). OBJECTIVE: To investigate longitudinal changes in spinal cord lesions and atrophy in patients with a non-spinal clinically isolated syndrome (CIS), and how they relate to the development of disability. METHODS: In all, 131 patients with a non-spinal CIS had brain and spinal cord imaging at the time of CIS and approximately 5 years later (median: 5.2 years, range: 3.0-7.9 years). Brain magnetic resonance imaging (MRI) measures consisted of T2-hyperintense and T1-hypointense lesion loads plus brain atrophy. Spinal cord MRI measures consisted of lesion number and the upper cervical cord cross-sectional area (UCCA). Disability was measured using the Expanded Disability Status Scale (EDSS). Multiple linear regression was used to identify independent predictors of disability after 5 years. RESULTS: During follow-up, 93 (71%) patients were diagnosed with MS. Baseline spinal cord lesion number, change in cord lesion number and change in UCCA were independently associated with EDSS ( R2 = 0.53) at follow-up. Including brain T2 lesion load and brain atrophy only modestly increased the predictive power of the model ( R2 = 0.64). CONCLUSION: Asymptomatic spinal cord lesions and spinal cord atrophy contribute to the development of MS-related disability over the first 5 years after a non-spinal CIS.

Regional cortical thinning in multiple sclerosis and its relation with cognitive impairment: A multicenter study.

OBJECTIVES: The objectives of this paper are to compare in a multicenter setting patterns of regional cortical thickness in patients with relapsing-remitting multiple sclerosis (RRMS) and cognitive impairment (CI) and those cognitively preserved (CP), and explore the relationship between cortical thinning and cognitive performance. METHODS: T1-weighted isotropic brain scans were collected at 3T from seven European centers in 60 RRMS patients and 65 healthy controls (HCs). Patients underwent clinical and neuropsychological examinations. Cortical thickness (CTh) measures were calculated using FreeSurfer (failing in four) and both lobar and vertex-based general linear model (GLM) analyses were compared between study groups. RESULTS: Twenty (36%) MS patients were classified as CI. Mean global CTh was smaller in RRMS patients compared to HCs (left 2.43 vs. 2.53 mm, right 2.44 vs. 2.54 mm, p < 0.001). Multivariate GLM regional analysis showed significantly more temporal thinning in CI compared to CP patients. Verbal memory scores correlated to regional cortical thinning in the insula whereas visual memory scores correlated to parietal thinning. CONCLUSIONS: This multicenter study showed mild global cortical thinning in RRMS. The extent of thinning is less pronounced than previously reported. Only subtle regional differences between CI and CP patients were observed, some of which related to specific cognitive domains.

Spinal cord grey matter abnormalities are associated with secondary progression and physical disability in multiple sclerosis.

BACKGROUND: In multiple sclerosis (MS), pathological studies have identified substantial demyelination and neuronal loss in the spinal cord grey matter (GM). However, there has been limited in vivo investigation of cord GM abnormalities and their possible functional effects using MRI combined with clinical evaluation. METHODS: We recruited healthy controls (HC) and people with a clinically isolated syndrome (CIS), relapsing remitting (RR) and secondary progressive (SP) MS. All subjects had 3 T spinal cord MRI with measurement of cord cross-sectional area and diffusion tensor imaging metrics in the GM and posterior and lateral column white matter tracts using region of interest analysis. Physical disability was assessed using the expanded disability status scale (EDSS) and motor components of the MS functional composite scale. We calculated differences between MS and HC using a ANOVA and associations with disability using linear regression. RESULTS: 113 people were included in this study: 30 controls, 21 CIS, 33 RR and 29 SPMS. Spinal cord radial diffusivity (RD), fractional anisotropy and mean diffusivity in the GM and posterior columns were significantly more abnormal in SPMS than in RRMS. Spinal cord GM RD (ß=0.33, p<0.01) and cord area (ß=-0.45, p<0.01) were independently associated with EDSS (R(2)=0.77); spinal cord GM RD was also independently associated with a 9-hole peg test (ß=-0.33, p<0.01) and timed walk (ß=-0.20, p=0.04). CONCLUSIONS: The study findings suggest that pathological involvement of the spinal cord GM contributes significantly to physical disability in relapse-onset MS and SPMS in particular.

The current state-of-the-art of spinal cord imaging: methods.

A first-ever spinal cord imaging meeting was sponsored by the International Spinal Research Trust and the Wings for Life Foundation with the aim of identifying the current state-of-the-art of spinal cord imaging, the current greatest challenges, and greatest needs for future development. This meeting was attended by a small group of invited experts spanning all aspects of spinal cord imaging from basic research to clinical practice. The greatest current challenges for spinal cord imaging were identified as arising from the imaging environment itself; difficult imaging environment created by the bone surrounding the spinal canal, physiological motion of the cord and adjacent tissues, and small cross-sectional dimensions of the spinal cord, exacerbated by metallic implants often present in injured patients. Challenges were also identified as a result of a lack of "critical mass" of researchers taking on the development of spinal cord imaging, affecting both the rate of progress in the field, and the demand for equipment and software to manufacturers to produce the necessary tools. Here we define the current state-of-the-art of spinal cord imaging, discuss the underlying theory and challenges, and present the evidence for the current and potential power of these methods. In two review papers (part I and part II), we propose that the challenges can be overcome with advances in methods, improving availability and effectiveness of methods, and linking existing researchers to create the necessary scientific and clinical network to advance the rate of progress and impact of the research.

The current state-of-the-art of spinal cord imaging: applications.

A first-ever spinal cord imaging meeting was sponsored by the International Spinal Research Trust and the Wings for Life Foundation with the aim of identifying the current state-of-the-art of spinal cord imaging, the current greatest challenges, and greatest needs for future development. This meeting was attended by a small group of invited experts spanning all aspects of spinal cord imaging from basic research to clinical practice. The greatest current challenges for spinal cord imaging were identified as arising from the imaging environment itself; difficult imaging environment created by the bone surrounding the spinal canal, physiological motion of the cord and adjacent tissues, and small crosssectional dimensions of the spinal cord, exacerbated by metallic implants often present in injured patients. Challenges were also identified as a result of a lack of "critical mass" of researchers taking on the development of spinal cord imaging, affecting both the rate of progress in the field, and the demand for equipment and software to manufacturers to produce the necessary tools. Here we define the current state-of-the-art of spinal cord imaging, discuss the underlying theory and challenges, and present the evidence for the current and potential power of these methods. In two review papers (part I and part II), we propose that the challenges can be overcome with advances in methods, improving availability and effectiveness of methods, and linking existing researchers to create the necessary scientific and clinical network to advance the rate of progress and impact of the research.

Magnetic resonance imaging correlates of physical disability in relapse onset multiple sclerosis of long disease duration.

BACKGROUND: Understanding long-term disability in multiple sclerosis (MS) is a key goal of research; it is relevant to how we monitor and treat the disease. OBJECTIVES: The Magnetic Imaging in MS (MAGNIMS) collaborative group sought to determine the relationship of brain lesion load, and brain and spinal cord atrophy, with physical disability in patients with long-established MS. METHODS: Patients had a magnetic resonance imaging (MRI) scan of their brain and spinal cord, from which we determined brain grey (GMF) and white matter (WMF) fractional volumes, upper cervical spinal cord cross-sectional area (UCCA) and brain T2-lesion volume (T2LV). We assessed patient disability using the Expanded Disability Status Scale (EDSS). We analysed associations between EDSS and MRI measures, using two regression models (dividing cohort by EDSS into two and four sub-groups). RESULTS: In the binary model, UCCA (p < 0.01) and T2LV (p = 0.02) were independently associated with the requirement of a walking aid. In the four-category model UCCA (p < 0.01), T2LV (p = 0.02) and GMF (p = 0.04) were independently associated with disability. CONCLUSIONS: Long-term physical disability was independently linked with atrophy of the spinal cord and brain T2 lesion load, and less consistently, with brain grey matter atrophy. Combinations of spinal cord and brain MRI measures may be required to capture clinically-relevant information in people with MS of long disease duration.

Tissue- and column-specific measurements from multi-parameter mapping of the human cervical spinal cord at 3 T.

The aim of this study was to quantify a range of MR parameters [apparent proton density, longitudinal relaxation time T1, magnetisation transfer (MT) ratio, MT saturation (which represents the additional percentage MT saturation of the longitudinal magnetisation caused by a single MT pulse) and apparent transverse relaxation rate R2*] in the white matter columns and grey matter of the healthy cervical spinal cord. The cervical cords of 13 healthy volunteers were scanned at 3 T using a protocol optimised for multi-parameter mapping. Intra-subject co-registration was performed using linear registration, and tissue- and column-specific parameter values were calculated. Cervical cord parameter values measured from levels C1-C5 in 13 subjects are: apparent proton density, 4822 ± 718 a.u.; MT ratio, 40.4 ± 1.53 p.u.; MT saturation, 1.40 ± 0.12 p.u.; T1 = 1848 ± 143 ms; R2* = 22.6 ± 1.53 s(-1). Inter-subject coefficients of variation were low in both the cervical cord and tissue- and column-specific measurements, illustrating the potential of this method for the investigation of changes in these parameters caused by pathology. In summary, an optimised cervical cord multi-parameter mapping protocol was developed, enabling tissue- and column-specific measurements to be made. This technique has the potential to provide insight into the pathological processes occurring in the cervical cord affected by neurological disorders.

Linking white matter tracts to associated cortical grey matter: a tract extension methodology.

Quantitative diffusion analysis of white matter (WM) tracts has been utilised in many diseases for determining damage to, and changes in, WM tracts throughout the brain. However, there are limited studies investigating associations between quantitative measures in WM tracts and anatomically linked grey matter (GM), due to the difficulty in determining GM regions connected with a given WM tract. This work describes a straightforward method for extending a WM tract through GM based on geometry. The tract is extended by following a straight line from each point on the tract boundary to the outer boundary of the cortex. A comparison between a multiplanar 2D approach and a 3D method was made. This study also tested an analysis pipeline from tracking WM tracts to quantifying magnetisation transfer ratios (MTR) in the associated cortical GM, and assessed the applicability of the method to healthy control subjects. Tract and associated cortical volumes and MTR values for the cortico-spinal tracts, genu and body of the corpus callosum were extracted; the between-subjects standard deviation was calculated. It was found that a multiplanar 2D approach produced a more anatomically plausible volume of GM than a 3D approach, at the expense of possible overestimation of the GM volume. The between-subjects standard deviation of the tract specific quantitative measurements (from both the WM and GM masks) ranged between 1.2 and 7.3% for the MTR measures, and between 10 and 45% for the absolute volume measures. The results show that the method can be used to produce anatomically plausible extensions of the WM tracts through the GM, and regions defined in this way yield reliable estimates of the MTR from the regions.

Feasibility of grey matter and white matter segmentation of the upper cervical cord in vivo: a pilot study with application to magnetisation transfer measurements.

Spinal cord pathology can be functionally very important in neurological disease. Pathological studies have demonstrated the involvement of spinal cord grey matter (GM) and white matter (WM) in several diseases, although the clinical relevance of abnormalities detected histopathologically is difficult to assess without a reliable way to assess cord GM and WM in vivo. In this study, the feasibility of GM and WM segmentation was investigated in the upper cervical spinal cord of 10 healthy subjects, using high-resolution images acquired with a commercially available 3D gradient-echo pulse sequence at 3T. For each healthy subject, tissue-specific (i.e. WM and GM) cross-sectional areas were segmented and total volumes calculated from a 15 mm section acquired at the level of C2-3 intervertebral disc and magnetisation transfer ratio (MTR) values within the extracted volumes were also determined, as an example of GM and WM quantitative measurements in the cervical cord. Mean (± SD) total cord cross-sectional area (TCA) and total cord volume (TCV) of the section studied across 10 healthy subjects were 86.9 (± 7.7) mm(2) and 1302.8 (± 115) mm(3), respectively; mean (±SD) total GM cross-sectional area (TGMA) and total GM volume (TGMV) were 14.6 (± 1.1) mm(2) and 218.3 (± 16.8) mm(3), respectively; mean (± SD) GM volume fraction (GMVF) was 0.17 (± 0.01); mean (± SD) MTR of the total WM volume (WM-MTR) was 51.4 (± 1.5) and mean (± SD) MTR of the total GM volume (GM-MTR) was 49.7 (± 1.6). The mean scan-rescan, intra- and inter-observer % coefficient of variation for measuring the TCA were 0.7%, 0.5% and 0.5% and for measuring the TGMA were 6.5%, 5.4% and 12.7%. The difference between WM-MTR and GM-MTR was found to be statistically significant (p=0.00006). This study has shown that GM and WM segmentation in the cervical cord is possible and the MR imaging protocol and analysis method presented here in healthy controls can be potentially extended to study the cervical cord in disease states, with the option to explore further quantitative measurements alongside MTR.

The role of mitochondria in axonal degeneration and tissue repair in MS.

Axonal injury is a key feature of multiple sclerosis (MS) pathology and is currently seen as the main correlate for permanent clinical disability. Although little is known about the pathogenetic mechanisms that drive axonal damage and loss, there is accumulating evidence highlighting the central role of mitochondrial dysfunction in axonal degeneration and associated neurodegeneration. The aim of this topical review is to provide a concise overview on the involvement of mitochondrial dysfunction in axonal damage and destruction in MS. Hereto, we will discuss putative pathological mechanisms leading to mitochondrial dysfunction and recent imaging studies performed in vivo in patients with MS. Moreover, we will focus on molecular mechanisms and novel imaging studies that address the role of mitochondrial metabolism in tissue repair. Finally, we will briefly review therapeutic strategies aimed at improving mitochondrial metabolism and function under neuroinflammatory conditions.

Brain lesion location and clinical status 20 years after a diagnosis of clinically isolated syndrome suggestive of multiple sclerosis.

BACKGROUND/OBJECTIVES: The objective of this study was to investigate associations between the spatial distribution of brain lesions and clinical outcomes in a cohort of people followed up 20 years after presentation with a clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS). METHODS: Brain lesion probability maps (LPMs) of T1 and T2 lesions were generated from 74 people who underwent magnetic resonance imaging (MRI) and clinical assessment a mean of 19.9 years following a CIS. One-tailed t-test statistics were used to compare LPMs between the following groups: clinically definite (CD) MS and those who remained with CIS, with an abnormal MRI; people with MS and an Expanded Disability Status Scale (EDSS) ≤3 and >3; people with relapsing-remitting (RR) and secondary progressive (SP) MS. The probability of each voxel being lesional was analysed adjusting for age and gender using a multiple linear regression model. RESULTS: People with CDMS were significantly more likely than those with CIS and abnormal scan 20 years after onset to have T1 and T2 lesions in the corona radiata, optic radiation, and splenium of the corpus callosum (periventricularly) and T2 lesions in the right fronto-occipital fasciculus. People with MS EDSS >3, compared with those with EDSS ≤3, were more likely to have optic radiation and left internal capsule T2 lesions. No significant difference in lesion distribution was noted between RRMS and SPMS. CONCLUSION: This work demonstrates that lesion location characteristics are associated with CDMS and disability after long-term follow-up following a CIS. The lack of lesion spatial distribution differences between RRMS and SPMS suggests focal pathology affects similar regions in both subgroups.

Intrahepatic Portal Vein Aneurysm: A Case Report of an Uncanny Late Complication of Liver Transplantation.

BACKGROUND: Whereas chronic rejection, opportunistic infections, post-transplant lymphoproliferative disorder, hemophagocytic lymphohistiocytosis, biliary tract issues, and cardiovascular side effects of immunosuppressive drugs are frequently reported as late complications in liver transplanted patients, intrahepatic portal venous aneurysm following liver transplantation remains exceptional and unusual. CASE REPORT: We report the case of a 25-year-old man who underwent a liver transplantation in 1997 because he had glycogen storage disease type 4. The patient developed a late postoperative complication, an intrahepatic portal aneurysm, and 2 episodes of acute cholangitis. DISCUSSION: By reviewing and scoping the literature, we tried to spotlight the best therapeutic attitude concerning the management of this rare complication.

Exceptional manifestation of Madelung's disease after liver transplantation.

Unlike simple obesity, Madelung's disease (MD) is a rare disease characterized by symmetric accumulation of massive adipose tissue on the neck, the superior part of the trunk and limbs, leading to a pathognomonic cosmetic deformity. Here, we report an extremely rare case of MD associated with bilateral gynecomastia in a 61-year-old man, with a history of recent liver transplantation for alcoholic liver disease (ALD).

Complementary roles of grey matter MTR and T2 lesions in predicting progression in early PPMS.

OBJECTIVE: To investigate whether T2 lesion load and magnetisation transfer ratio (MTR) in the normal-appearing white matter (NAWM) and grey matter (GM) at study entry are independent predictors of progression and whether their changes correlate with the accrual of disability, over 5 years in early primary progressive multiple sclerosis (PPMS). METHODS: Forty-seven patients with early PPMS and 18 healthy controls were recruited at baseline and invited to attend clinical 6-monthly assessments for 3 years, and after 5 years. Patients were scored on the Expanded Disability Status Scale and multiple sclerosis functional composite subtests (25-foot timed walk test (TWT), nine-hole peg test and paced auditory serial addition test). At each time point, all subjects underwent brain MRI including T2-weighted, magnetisation transfer and volumetric sequences. T2 lesion load (T2LL), MTR histogram parameters and volumes for NAWM and GM were calculated. Statistical analyses identified predictors of progression and correlations between MRI changes and clinical changes over time. RESULTS: Baseline T2LL and GM peak location and peak height MTR were independent predictors of progression, as measured by TWT; a model including these three predictors explained 91% of the variance of the progression on TWT, a significantly higher percentage than that obtained when the predictors were modelled individually (80%, 74% and 68%, respectively). A greater progression rate correlated with a steeper increase in T2LL and a faster decline in GM mean and peak location MTR. CONCLUSIONS: The combined assessment of both visible white matter damage and GM involvement is useful in predicting progression in PPMS.

Early pericalcarine atrophy in acute optic neuritis is associated with conversion to multiple sclerosis.

BACKGROUND: Previous work showed that pericalcarine cortical volume loss is evident early after presentation with acute clinically isolated optic neuritis (ON). The aims of this study were: (1) to determine whether pericalcarine atrophy in patients with ON is associated with conversion to multiple sclerosis (MS); (2) to investigate whether regional atrophy preferentially affects pericalcarine cortex; and (3) to investigate potential causes of early pericalcarine atrophy using MRI. METHODS: 28 patients with acute ON and 10 controls underwent structural MRI (brain and optic nerves) and were followed-up over 12 months. Associations between the development of MS, optic nerve, optic radiation and pericalcarine cortical damage measures were investigated using multiple linear regression models. Regional cortical volumetric differences between patients and controls were calculated using t tests. RESULTS: The development of MS at 12 months was associated with greater whole brain and optic radiation lesion loads, shorter acute optic nerve lesions and smaller pericalcarine cortical volume at baseline. Regional atrophy was not evident in other sampled cortical regions. Pericalcarine atrophy was not directly associated with whole brain lesion load, optic radiation measures or optic nerve lesion length. However, the association between pericalcarine atrophy and MS was not independent of these parameters. CONCLUSIONS: Reduced pericalcarine cortical volumes in patients with early clinically isolated ON were associated with the development of MS but volumes of other cortical regions were not. Hence pericalcarine cortical regions appear particularly susceptible to early damage. These findings could be explained by a combination of pathological effects to visual grey and white matter in patients with ON.

T2 lesion location really matters: a 10 year follow-up study in primary progressive multiple sclerosis.

OBJECTIVES: Prediction of long term clinical outcome in patients with primary progressive multiple sclerosis (PPMS) using imaging has important clinical implications, but remains challenging. We aimed to determine whether spatial location of T2 and T1 brain lesions predicts clinical progression during a 10-year follow-up in PPMS. METHODS: Lesion probability maps of the T2 and T1 brain lesions were generated using the baseline scans of 80 patients with PPMS who were clinically assessed at baseline and then after 1, 2, 5 and 10 years. For each patient, the time (in years) taken before bilateral support was required to walk (time to event (TTE)) was used as a measure of progression rate. The probability of each voxel being 'lesional' was correlated with TTE, adjusting for age, gender, disease duration, centre and spinal cord cross sectional area, using a multiple linear regression model. To identify the best, independent predictor of progression, a Cox regression model was used. RESULTS: A significant correlation between a shorter TTE and a higher probability of a voxel being lesional on T2 scans was found in the bilateral corticospinal tract and superior longitudinal fasciculus, and in the right inferior fronto-occipital fasciculus (p<0.05). The best predictor of progression rate was the T2 lesion load measured along the right inferior fronto-occipital fasciculus (p=0.016, hazard ratio 1.00652, 95% CI 1.00121 to 1.01186). CONCLUSION: Our results suggest that the location of T2 brain lesions in the motor and associative tracts is an important contributor to the progression of disability in PPMS, and is independent of spinal cord involvement.

Grey matter damage and overall cognitive impairment in primary progressive multiple sclerosis.

OBJECTIVES: To identify associations between cognitive impairment and imaging measures in a cross-sectional study of patients with primary progressive multiple sclerosis (PPMS). METHODS: Neuropsychological tests were administered to 27 patients with PPMS and 31 controls. Patients underwent brain conventional magnetic resonance imaging (MRI) sequences, volumetric scans and magnetization transfer (MT) imaging; MT ratio (MTR) parameters, grey matter (GM) and normal-appearing white matter (NAWM) volumes, and WM T2 lesion load (T2LL) were obtained. In patients, multiple linear regression models identified the imaging measure associated with the abnormal cognitive tests independently from the other imaging variables. Partial correlation coefficients (PCC) were reported. RESULTS: Patients performed worse on tests of attention/speed of visual information processing, delayed verbal memory, and executive function, and had a worse overall cognitive performance index, when compared with controls. In patients, a lower GM peak location MTR was associated with worse overall cognitive performance (p < 0.001, PCC = 0.77). GM mean and peak height MTR showed the strongest association with the estimated verbal intelligence quotient (IQ) decline (p < 0.001, PCC = -0.62), and executive function (p < 0.001, PCC = 0.79). NAWM volume was associated with attention/speed of visual information processing (p < 0.001, PCC = 0.74), while T2LL was associated with delayed verbal memory (p = 0.007, PCC = -0.55). CONCLUSIONS: The finding of strong associations between GM MTR, NAWM volume and T2LL and specific cognitive impairments suggests that models that predict cognitive impairment in PPMS should include comprehensive MRI assessments of both GM and WM. However, GM MTR appears to be the main correlate of overall cognitive dysfunction, underlining the role of abnormal GM integrity in determining cognitive impairment in PPMS.

A comprehensive assessment of cerebellar damage in multiple sclerosis using diffusion tractography and volumetric analysis.

BACKGROUND: White matter (WM) and grey matter (GM) brain damage in multiple sclerosis (MS) is widespread, but the extent of cerebellar involvement and impact on disability needs to be clarified. OBJECTIVE: This study aimed to assess cerebellar WM and GM atrophy and the degree of fibre coherence in the main cerebellar connections, and their contribution to disability in relapsing-remitting MS (RRMS) and primary progressive MS (PPMS). METHODS: Fourteen patients with RRMS, 12 patients with PPMS and 16 healthy controls were recruited. Cerebellar WM and GM volumes and tractography-derived measures from the middle and superior cerebellar peduncles, including fractional anisotropy (FA), mean diffusivity (MD), and directional diffusivities, were quantified from magnetic resonance imaging (MRI). Patients were assessed on clinical scores, including the MS Functional Composite score subtests. Linear regression models were used to compare imaging measures between 12 RRMS, 11 PPMS and 16 controls, and investigate their association with clinical scores. RESULTS: Patients with PPMS showed reduced FA and increased radial diffusivity in the middle cerebellar peduncle compared with controls and patients with RRMS. In PPMS, lower cerebellar WM volume was associated with worse performance on the upper limb test. In the same patient group, we found significant relationships between superior cerebellar peduncle FA and upper limb function, and between superior cerebellar peduncle FA, MD and radial diffusivity and speed of walking. CONCLUSION: These findings indicate reduced fibre coherence in the main cerebellar connections, and link damage in the whole cerebellar WM, and, in particular, in the superior cerebellar peduncle, to motor deficit in PPMS.