David H Miller

UCL Eastman Dental Institute, Londinium, England, United Kingdom

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Publications (159)1424.28 Total impact

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    ABSTRACT: To investigate whether spinal cord (SC) lesion load, when quantified on axial images with high in-plane resolution, is associated with disability in multiple sclerosis (MS). Twenty-eight healthy controls and 92 people with MS had cervical SC 3T MRI with axial phase sensitive inversion recovery, T2, and magnetization transfer (MT) sequences. We outlined all visible focal lesions from C2 to C4 to obtain lesion load and also measured upper cervical cord area. We measured MT ratio in normal-appearing cord tissue and in lesions. Disability was recorded using the Expanded Disability Status Scale (EDSS) and MS Functional Composite. We used linear regression models to determine associations with disability. SC lesion load was significantly higher in both secondary progressive MS (SPMS) (p = 0.008) and primary progressive MS (PPMS) (p = 0.02) compared to relapsing-remitting MS (RRMS); in each comparison, adjustment was made for age, sex, and brain volume. These differences were not evident when EDSS was added as a covariate. SC area was significantly lower in both SPMS (p < 0.001) and PPMS (p = 0.009) compared to RRMS. In a multiple regression model, cord lesion load (p < 0.001), cord area (p = 0.003), age (p < 0.001), and sex (p = 0.001) were independently associated with EDSS (R(2) = 0.58). Cord lesion load (p = 0.003), cord area (p = 0.034), and brain parenchymal fraction (p = 0.007) were independently associated with the 9-hole peg test (R(2) = 0.42). When quantified on axial MRI with high in-plane resolution, upper cervical cord lesion load is significantly and independently correlated with physical disability and is higher in progressive forms of MS than RRMS. © 2014 American Academy of Neurology.
    Neurology 12/2014; · 8.30 Impact Factor
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    ABSTRACT: Visual impairment is a key manifestation of multiple sclerosis. Acute optic neuritis is a common, often presenting manifestation, but visual deficits and structural loss of retinal axonal and neuronal integrity can occur even without a history of optic neuritis. Interest in vision in multiple sclerosis is growing, partially in response to the development of sensitive visual function tests, structural markers such as optical coherence tomography and magnetic resonance imaging, and quality of life measures that give clinical meaning to the structure-function correlations that are unique to the afferent visual pathway. Abnormal eye movements also are common in multiple sclerosis, but quantitative assessment methods that can be applied in practice and clinical trials are not readily available. We summarize here a comprehensive literature search and the discussion at a recent international meeting of investigators involved in the development and study of visual outcomes in multiple sclerosis, which had, as its overriding goals, to review the state of the field and identify areas for future research. We review data and principles to help us understand the importance of vision as a model for outcomes assessment in clinical practice and therapeutic trials in multiple sclerosis. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain.
    Brain : a journal of neurology. 11/2014;
  • Journal of Neurology Neurosurgery & Psychiatry 11/2014; · 4.92 Impact Factor
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    ABSTRACT: To investigate whether (1) there were differences between HLA-DRB1*15-positive and -negative patients at baseline, and (2) HLA-DRB1*15-positive patients showed a greater development of brain and spinal cord damage, as assessed by MRI, and greater progression of disability, during a 5-year follow-up, compared with HLA-DRB1*15-negative patients.
    Neurology 10/2014; · 8.30 Impact Factor
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    ABSTRACT: Objective Some previous studies suggest modest to strong effects of 25-hydroxyvitamin D (25(OH)D) on multiple sclerosis (MS) activity. The objective of this study was to explore the mechanistic rationale that may explain potential clinical effects of 25(OH)D.Methods This study measured serum 25(OH)D levels and global gene expression profiles over a course of up to 2 years in patients starting treatment with interferon beta-1b (IFNB-1b) after a clinically isolated syndrome. MS disease activity was assessed by the number of gadolinium-enhancing lesions present on repeated magnetic resonance imaging (MRIs).ResultsThe number of gadolinium-enhancing lesions was highly significantly associated with 25(OH)D levels. Conducting various systems-level analyses on the molecular level, multiple lines of evidence indicated that 25(OH)D regulates expression dynamics of a large gene–gene interaction system which primarily regulates immune modulatory processes modulating MS activity. The vitamin D response element was significantly enriched in this system, indicating a direct regulation of this gene interaction network through the vitamin D receptor. With increasing 25(OH)D levels, resulting regulation of this system was associated with a decrease in MS activity. Within the complex network of genes that are regulated by 25(OH)D, well-described targets of IFNB-1b and a regulator of sphingosine-1-phosphate bioavailability were found. The 25(OH)D effects on MS activity were additively enhanced by IFNB-1b.InterpretationHere, we provide mechanistic evidence that an unbalanced 25(OH)D gene expression system may affect MS activity. Our findings support a potential benefit of monitoring and managing vitamin D levels (e.g., through supplementation) in early MS patients treated with IFN-beta-1b.
    Annals of Clinical and Translational Neurology. 08/2014;
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    ABSTRACT: Neuropathological studies in multiple sclerosis have suggested that meningeal inflammation in the brain may be linked to disease progression. Inflammation in the spinal cord meninges has been associated with axonal loss, a pathological substrate for disability. Quantitative magnetic resonance imaging facilitates the investigation of spinal cord microstructure by approximating histopathological changes. We acquired structural and quantitative imaging of the cervical spinal cord from which we calculated magnetization transfer ratio in the outer spinal cord-an area corresponding to the expected location of the pia mater and subpial region-and in spinal cord white and grey matter. We studied 26 healthy controls, 22 people with a clinically isolated syndrome, 29 with relapsing-remitting, 28 with secondary-progressive and 28 with primary-progressive multiple sclerosis. Magnetization transfer ratio values in the outermost region of the spinal cord were higher than the white matter in controls and patients: controls (51.35 ± 1.29 versus 49.87 ± 1.45, P < 0.01), clinically isolated syndrome (50.46 ± 1.39 versus 49.13 ± 1.19, P < 0.01), relapsing-remitting (48.86 ± 2.89 versus 47.44 ± 2.70, P < 0.01), secondary-progressive (46.33 ± 2.84 versus 44.75 ± 3.10, P < 0.01) and primary-progressive multiple sclerosis (46.99 ± 3.78 versus 45.62 ± 3.40, P < 0.01). In linear regression models controlling for cord area and age, higher outer spinal cord magnetization transfer ratio values were seen in controls than all patient groups: clinically isolated syndrome (coefficient = -0.32, P = 0.03), relapsing-remitting (coefficient = -0.48, P < 0.01), secondary-progressive (coefficient = -0.51, P < 0.01) and primary-progressive multiple sclerosis (coefficient = -0.38, P < 0.01). In a regression analysis correcting for age and cord area, magnetization transfer ratio values in the outer cord were lower in relapsing-remitting multiple sclerosis compared with clinically isolated syndrome (coefficient = -0.28, P = 0.02), and both primary and secondary-progressive compared to relapsing-remitting multiple sclerosis (coefficients = -0.29 and -0.24, respectively, P = 0.02 for both). In the clinically isolated syndrome and relapsing-remitting multiple sclerosis groups, outer cord magnetization transfer ratio was decreased in the absence of significant cord atrophy. In a multivariate regression analysis an independent association was seen between outer cord magnetization transfer ratio and cord atrophy (coefficient = 0.40, P < 0.01). Our in vivo imaging observations suggest that abnormalities in a region involving the pia mater and subpial cord occur early in the course of multiple sclerosis and are more marked in those with a progressive course.
    Brain 06/2014; · 10.23 Impact Factor
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    ABSTRACT: The prevalence of MS in New Zealand in 2006 was 73.2 (age standardized per 100,000) while for those with indigenous Māori ancestry it was 3.6 times lower at 20.6. Earlier regional surveys (1968-2001) all reported much lower, or zero, prevalence for Māori than European. There was no evidence for differences in MS between those with and without Māori ancestry in either clinical features or latitude, confirming that Māori ancestry does not produce the reported increase in prevalence with latitude. It is likely that prevalence is increasing in low risk Māori; however, MS prognosis is independent of Māori ancestry.
    Multiple sclerosis (Houndmills, Basingstoke, England). 05/2014;
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    ABSTRACT: Trials of potential neuroreparative agents are becoming more important in the spectrum of multiple sclerosis research. Appropriate imaging outcomes are required that are feasible from a time and practicality point of view, as well as being sensitive and specific to myelin, while also being reproducible and clinically meaningful. Conventional MRI sequences have limited specificity for myelination. We evaluate the imaging modalities which are potentially more specific to myelin content in vivo, such as magnetisation transfer ratio (MTR), restricted proton fraction f (from quantitative magnetisation transfer measurements), myelin water fraction and diffusion tensor imaging (DTI) metrics, in addition to positron emission tomography (PET) imaging. Although most imaging applications to date have focused on the brain, we also consider measures with the potential to detect remyelination in the spinal cord and in the optic nerve. At present, MTR and DTI measures probably offer the most realistic and feasible outcome measures for such trials, especially in the brain. However, no one measure currently demonstrates sufficiently high sensitivity or specificity to myelin, or correlation with clinical features, and it should be useful to employ more than one outcome to maximise understanding and interpretation of findings with these sequences. PET may be less feasible for current and near-future trials, but is a promising technique because of its specificity. In the optic nerve, visual evoked potentials can indicate demyelination and should be correlated with an imaging outcome (such as optic nerve MTR), as well as clinical measures.
    Journal of neurology, neurosurgery, and psychiatry 04/2014; · 4.87 Impact Factor
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    ABSTRACT: Pathological abnormalities including demyelination and neuronal loss are reported in the outer cortex in multiple sclerosis (MS). We investigated for in vivo evidence of outer cortical abnormalities by measuring the magnetisation transfer ratio (MTR) in MS patients of different subgroups. Forty-four relapsing-remitting (RR) (mean age 41.9 years, median Expanded Disability Status Scale (EDSS) 2.0), 25 secondary progressive (SP) (54.1 years, EDSS 6.5) and 19 primary progressive (PP) (53.1 years, EDSS 6.0) MS patients and 35 healthy control subjects (mean age 39.2 years) were studied. Three-dimensional (3D) 1×1×1mm(3) T1-weighted images and MTR data were acquired. The cortex was segmented, then subdivided into outer and inner bands, and MTR values were calculated for each band. In a pairwise analysis, mean outer cortical MTR was lower than mean inner cortical MTR in all MS groups and controls (p<0.001). Compared with controls, outer cortical MTR was decreased in SPMS (p<0.001) and RRMS (p<0.01), but not PPMS. Outer cortical MTR was lower in SPMS than PPMS (p<0.01) and RRMS (p<0.01). Lower outer than inner cortical MTR in healthy controls may reflect differences in myelin content. The lowest outer cortical MTR was seen in SPMS and is consistent with more extensive outer cortical (including subpial) pathology, such as demyelination and neuronal loss, as observed in post-mortem studies of SPMS patients.
    Multiple Sclerosis 02/2014; · 4.47 Impact Factor
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    ABSTRACT: Multiple sclerosis (MS) is influenced by pregnancy, sex and hormonal factors. A comprehensive understanding of the role of pregnancy, sex and hormonal factors can provide insights into disease mechanisms, and new therapeutic developments and can provide improved patient care and treatment. Based on an international conference of experts and a comprehensive PubMed search for publications on these areas in MS, we provide a review of what is known about the impact of these factors on disease demographics, etiology, pathophysiology and clinical course and outcomes. Recommendations are provided for counseling and management of people with MS before conception, during pregnancy and after delivery. The use of disease-modifying and symptomatic therapies in pregnancy is problematic and such treatments are normally discontinued. Available knowledge about the impact of treatment on the mother, fetus and newborn is discussed. Recommendations for future research to fill knowledge gaps and clarify inconsistencies in available data are made.
    Multiple Sclerosis 01/2014; · 4.47 Impact Factor
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    ABSTRACT: IMPORTANCE It remains unclear whether vitamin D insufficiency, which is common in individuals with multiple sclerosis (MS), has an adverse effect on MS outcomes. OBJECTIVES To determine whether serum concentrations of 25-hydroxyvitamin D (25[OH]D), a marker of vitamin D status, predict disease activity and prognosis in patients with a first event suggestive of MS (clinically isolated syndrome). DESIGN, SETTING, AND PARTICIPANTS The Betaferon/Betaseron in Newly Emerging multiple sclerosis For Initial Treatment study was a randomized trial originally designed to evaluate the impact of early vs delayed interferon beta-1b treatment in patients with clinically isolated syndrome. Serum 25(OH)D concentrations were measured at baseline and 6, 12, and 24 months. A total of 465 of the 468 patients randomized had at least 1 25(OH)D measurement, and 334 patients had them at both the 6- and 12-month (seasonally asynchronous) measurements. Patients were followed up for 5 years clinically and by magnetic resonance imaging. MAIN OUTCOMES AND MEASURES New active lesions, increased T2 lesion volume, and brain volume on magnetic resonance imaging, as well as MS relapses and disability (Expanded Disability Status Scale score). RESULTS Higher 25(OH)D levels predicted reduced MS activity and a slower rate of progression. A 50-nmol/L (20-ng/mL) increment in average serum 25(OH)D levels within the first 12 months predicted a 57% lower rate of new active lesions (P < .001), 57% lower relapse rate (P = .03), 25% lower yearly increase in T2 lesion volume (P < .001), and 0.41% lower yearly loss in brain volume (P = .07) from months 12 to 60. Similar associations were found between 25(OH)D measured up to 12 months and MS activity or progression from months 24 to 60. In analyses using dichotomous 25(OH)D levels, values greater than or equal to 50 nmol/L (20 ng/mL) at up to 12 months predicted lower disability (Expanded Disability Status Scale score, -0.17; P = .004) during the subsequent 4 years. CONCLUSIONS AND RELEVANCE Among patients with MS mainly treated with interferon beta-1b, low 25(OH)D levels early in the disease course are a strong risk factor for long-term MS activity and progression.
    JAMA neurology. 01/2014;
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    ABSTRACT: Glutamate is the principal excitatory neurotransmitter and is involved in normal brain function. Cognitive impairment is common in multiple sclerosis (MS), and understanding its mechanisms is crucial for developing effective treatments. We used structural and metabolic brain imaging to test two hypotheses: (i) glutamate levels in grey matter regions are abnormal in MS, and (ii) patients show a relationship between glutamate concentration and memory performance. Eighteen patients with relapsing-remitting MS and 17 healthy controls were cognitively assessed and underwent (1)H-magnetic resonance spectroscopy at 3 T to assess glutamate levels in the hippocampus, thalamus, cingulate and parietal cortices. Regression models investigated the association between glutamate concentration and memory performance independently of magnetisation transfer ratio values and grey matter lesions withint he same regions, and whole-brain grey matter volume. Patients had worse visual and verbal memory than controls. A positive relationship between glutamate levels in the hippocampal, thalamic and cingulate regions and visuospatial memory was detected in patients, but not in healthy controls. The relationship between memory and glutamate concentration, which is unique to MS patients, suggests the reliance of memory on glutamatergic systems in MS.
    Journal of neurology, neurosurgery, and psychiatry 01/2014; · 4.87 Impact Factor
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    Wallace J. Brownlee, David H. Miller
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    ABSTRACT: The most common presentation of multiple sclerosis (MS) is with a clinically isolated syndrome (CIS) affecting the optic nerves, brainstem or spinal cord. Two thirds of patients with CIS will have further episodes of neurological dysfunction and convert to relapsing-remitting MS, while the remaining patients have a monophasic illness, at least clinically. Abnormalities on a baseline MRI scan predict the subsequent development of MS in patients with CIS. In the long term, about 80% of patients with an abnormal MRI convert to MS compared with 20% with a normal MRI. For patients who develop MS the long term prognosis is varied. After 20 years, almost half will have developed secondary progressive MS, while around one third have a benign disease course with little physical disability. Disease-modifying treatments delay conversion to MS in selected CIS patients with abnormal MRI but an effect on long term disability has not been demonstrated. In this review we discuss recent advances in the diagnosis, management and prognostication of patients with CIS.
    Journal of Clinical Neuroscience. 01/2014;
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    ABSTRACT: The mechanisms underlying the pathogenesis of multiple sclerosis induce the changes that underpin relapse-associated and progressive disability. Disease mechanisms can be investigated in preclinical models and patients with multiple sclerosis by molecular and metabolic imaging techniques. Many insights have been gained from such imaging studies: persisting inflammation in the absence of a damaged blood–brain barrier, activated microglia within and beyond lesions, increased mitochondrial activity after acute lesions, raised sodium concentrations in the brain, increased glutamate in acute lesions and normal-appearing white matter, different degrees of demyelination in different patients and lesions, early neuronal damage in grey matter, and early astrocytic proliferation and activation in lesions and white matter. Clinical translation of molecular and metabolic imaging and extension of these techniques will enable the assessment of novel drugs targeted at these disease mechanisms, and have the potential to improve health outcomes through the stratification of patients for treatments.
    Lancet neurology. 01/2014;
  • Ahmed T Toosy, Deborah F Mason, David H Miller
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    ABSTRACT: Acute optic neuritis is the most common optic neuropathy affecting young adults. Exciting developments have occurred over the past decade in understanding of optic neuritis pathophysiology, and these developments have been translated into treatment trials. In its typical form, optic neuritis presents as an inflammatory demyelinating disorder of the optic nerve, which can be associated with multiple sclerosis. Atypical forms of optic neuritis can occur, either in association with other inflammatory disorders or in isolation. Differential diagnosis includes various optic nerve and retinal disorders. Diagnostic investigations include MRI, visual evoked potentials, and CSF examination. Optical coherence tomography can show retinal axonal loss, which correlates with measures of persistent visual dysfunction. Treatment of typical forms with high-dose corticosteroids shortens the period of acute visual dysfunction but does not affect the final visual outcome. Atypical forms can necessitate prolonged immunosuppressive regimens. Optical coherence tomography and visual evoked potential measures are suitable for detection of neuroaxonal loss and myelin repair after optic neuritis. Clinical trials are underway to identify potential neuroprotective or remyelinating treatments for acutely symptomatic inflammatory demyelinating CNS lesions.
    The Lancet Neurology 01/2014; 13(1):83-99. · 23.92 Impact Factor
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    ABSTRACT: Histopathological studies have demonstrated the involvement of spinal cord grey matter (GM) and white matter (WM) in several diseases and recent research has suggested the use of magnetic resonance imaging (MRI) as a promising tool for in vivo assessment of the upper spinal cord. However, many neurological conditions would benefit from quantitative assessment of tissue integrity at different levels and relatively little work has been done, mainly due to technical challenges associated with imaging the lower spinal cord. In this study, the value of the lumbosacral enlargement (LSE) as an intrinsic imaging biomarker was determined by exploring the feasibility of obtaining within it reliable GM and WM cross-sectional area (CSA) measurements by means of a commercially available MRI system at 3 tesla (T). 10 healthy volunteers (mean age 27.5 years, 6 female) gave written informed consent and high resolution images of the LSE were acquired and analysed using an optimised MRI acquisition and analysis protocol. GM and WM mean CSA measurements were obtained from a 15 mm section at the level of the LSE and the reproducibility of the measurements was determined by means of scan-rescan, intra- and inter-observer assessments. Mean (±SD) LSE cross-sectional area (LSE-CSA) was 62.3 (±4.1) mm2 and mean (±SD) LSE grey matter cross-sectional area (LSE-GM-CSA) was 19.8 (±3.3) mm2. The mean scan-rescan, intra- and inter-observer % coefficient of variation (COV) for measuring the LSE-CSA were 2%, 2% and 2.5%, respectively and for measuring the LSE-GM-CSA were 7.8%, 8% and 8.6%, respectively. This study has shown that the LSE can be used reliably as an intrinsic imaging biomarker. The method presented here can be potentially extended to study the LSE in the diseased state and could provide a solid foundation for subsequent multi-parametric MRI investigations.
    PLoS ONE 01/2014; 9(8):e105544. · 3.53 Impact Factor
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    ABSTRACT: Cortical grey matter lesions (CGM) in MS are associated with cognitive impairment and progressive disability.(1 2) Histopathology studies have shown a predominantly fronto-temporal cortical lesion location,(3) but these are based mainly on post mortem study of patients with end stage progressive MS. The phase sensitive inversion recovery (PSIR) MRI sequence is sensitive in detecting MS CGM lesions in vivo,(4) and thus has potential to characterise their regional distribution in patients with both relapsing remitting and progressive MS. To study the lobar distribution of CGM lesions and their relationship to clinical course. Thirty MS patients [16 Relapsing remitting (RR), 9 primary progressive (PP) and 5 (SP) MS] were scanned using a Philips 3T Achieva system. PSIR scans (0.5×0.5×2 mm) were acquired. CGM lesions were divided into intracortical (IC, only involving cortex) and leucocortical (LC, mixed GM-WM lesions). Lobar lesion counts were determined in the frontal, parietal, temporal, occipital and insular lobes. For this NiftyReg ((http://sourceforge.net/projects/niftyreg) was used to register the MNI 152 brain template to each participants' PSIR image in a series of steps. 1) A study-specific T1-weighted template was generated by iteratively registering each participants' T1 image together to a common image, with repeated iterations. 2) the MNI template was nonlinearly registered to this T1-template. 3) the T1-template was nonlinearly registered to each participants' T1-weighted image. 4) the T1-weighted image was rigidly registered to the PSIR image for each participant 5) The transformation parameters from steps 2 to 4 were combined and used to transform the lobar parcellations from the Oxford-Harvard atlas into each participants' PSIR space. 6) A maximum likelihood algorithm was then used to remove any overlap between the parcellations in PSIR space. The number and volume of lesions falling within each parcellation was measured based on lesion-type. Multivariate ANOVA was performed using patient type as the fixed grouping factor. In the whole MS cohort, the mean number (±standard deviation) of CGM lesions (IC+LC) was 7.7±5.1, 7.4±5.8, 5.1±3.6, 0.9±1.7 and 2.1±1.8 in the frontal, temporal, parietal, occipital and insular regions. The total volume of lesion was 0.3±0.2, 0.2±0.2, 0.1±0.08, 0.01±0.02 and 0.09±0.1 (in cc) in these regions respectively. No preferential regional distribution of lesions was noted among the clinical subgroups. Using PSIR at 3T, lesions involving CGM were visible in all lobes. A higher number of CGM lesions were noted in the frontal and temporal lobes both relapsing remitting and progressive MS subgroups. Occipital CGM lesions were uncommon.
    Journal of neurology, neurosurgery, and psychiatry 11/2013; 84(11):e2. · 4.87 Impact Factor
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    ABSTRACT: Alterations in the overall cerebral hemodynamics have been reported in multiple sclerosis (MS); however, their cause and significance is unknown. While potential venous causes have been examined, arterial causes have not. In this study, a multiple delay time arterial spin labeling magnetic resonance imaging sequence at 3T was used to quantify the arterial hemodynamic parameter bolus arrival time (BAT) and cerebral blood flow (CBF) in normal-appearing white matter (NAWM) and deep gray matter in 33 controls and 35 patients with relapsing-remitting MS. Bolus arrival time was prolonged in MS in NAWM (1.0±0.2 versus 0.9±0.2 seconds, P=0.031) and deep gray matter (0.90±0.18 versus 0.80±0.14 seconds, P=0.001) and CBF was increased in NAWM (14±4 versus 10±2 mL/100 g/min, P=0.001). Prolonged BAT in NAWM (P=0.042) and deep gray matter (P=0.01) were associated with higher expanded disability status score. This study demonstrates alteration in cerebral arterial hemodynamics in MS. One possible cause may be widespread inflammation. Bolus arrival time was longer in patients with greater disability independent of atrophy and T2 lesion load, suggesting alterations in cerebral arterial hemodynamics may be a marker of clinically relevant pathology.Journal of Cerebral Blood Flow & Metabolism advance online publication, 18 September 2013; doi:10.1038/jcbfm.2013.161.
    Journal of cerebral blood flow and metabolism: official journal of the International Society of Cerebral Blood Flow and Metabolism 09/2013; · 5.46 Impact Factor
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    ABSTRACT: Grey matter (GM) pathology in multiple sclerosis (MS) is associated with progressive long-term disability. Detection of GM abnormalities in early MS may therefore be valuable in understanding and predicting the long-term course. However, structural MRI measures such as volume loss have shown only modest abnormalities in early relapsing-remitting MS (RRMS). We therefore investigated for evidence of abnormality in GM perfusion, consistent with metabolic dysfunction, in early RRMS. 25 RRMS patients with ≤5 years disease duration and 25 age-matched healthy controls underwent 3 Tesla MRI with a pseudo-continuous arterial spin labelling sequence to quantify GM perfusion and a volumetric T1-weighted sequence to measure GM volume. Neurological status was assessed in patients and neuropsychological evaluation undertaken in all subjects. Voxel-based analysis was used to compare regional GM perfusion and volume measures in patients and controls. There was reduced global GM perfusion in patients versus controls (50.6±5.8 mL/100 g/min vs 54.4±7.6 mL/100 g/min, p=0.04). Voxel-based analysis revealed extensive regions of decreased cortical and deep GM perfusion in MS subjects. Reduced perfusion was associated with impaired memory scores. There was no reduction in global or regional analysis of GM volume in patients versus controls. The decrease in GM perfusion in the absence of volume loss is consistent with neuronal metabolic dysfunction in early RRMS. Future studies in larger cohorts and longitudinal follow-up are needed to investigate the functional and prognostic significance of the early GM perfusion deficits observed.
    Journal of neurology, neurosurgery, and psychiatry 09/2013; · 4.87 Impact Factor
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    ABSTRACT: Neuroaxonal loss is a major substrate of irreversible disability in multiple sclerosis, however, its cause is not understood. In multiple sclerosis there may be intracellular sodium accumulation due to neuroaxonal metabolic dysfunction, and increased extracellular sodium due to expansion of the extracellular space secondary to neuroaxonal loss. Sodium magnetic resonance imaging measures total sodium concentration in the brain, and could investigate this neuroaxonal dysfunction and loss in vivo. Sodium magnetic resonance imaging has been examined in small cohorts with relapsing-remitting multiple sclerosis, but has not been investigated in patients with a progressive course and high levels of disability. We performed sodium magnetic resonance imaging in 27 healthy control subjects, 27 patients with relapsing-remitting, 23 with secondary-progressive and 20 with primary-progressive multiple sclerosis. Cortical sodium concentrations were significantly higher in all subgroups of multiple sclerosis compared with controls, and deep grey and normal appearing white matter sodium concentrations were higher in primary and secondary-progressive multiple sclerosis. Sodium concentrations were higher in secondary-progressive compared with relapsing-remitting multiple sclerosis in cortical grey matter (41.3 ± 4.2 mM versus 38.5 ± 2.8 mM, P = 0.008), normal appearing white matter (36.1 ± 3.5 mM versus 33.6 ± 2.5 mM, P = 0.018) and deep grey matter (38.1 ± 3.1 mM versus 35.7 ± 2.4 mM, P = 0.02). Higher sodium concentrations were seen in T1 isointense (44.6 ± 7.2 mM) and T1 hypointense lesions (46.8 ± 8.3 mM) compared with normal appearing white matter (34.9 ± 3.3 mM, P < 0.001 for both comparisons). Higher sodium concentration was observed in T1 hypointense lesions in secondary-progressive (49.0 ± 7.0 mM) and primary-progressive (49.3 ± 8.0 mM) compared with relapsing-remitting multiple sclerosis (43.0 ± 8.5 mM, P = 0.029 for both comparisons). Independent association was seen of deep grey matter sodium concentration with expanded disability status score (coefficient = 0.24, P = 0.003) and timed 25 ft walk speed (coefficient = -0.24, P = 0.01), and of T1 lesion sodium concentration with the z-scores of the nine hole peg test (coefficient = -0.12, P < 0.001) and paced auditory serial addition test (coefficient = -0.081, P < 0.001). Sodium concentration is increased within lesions, normal appearing white matter and cortical and deep grey matter in multiple sclerosis, with higher concentrations seen in secondary-progressive multiple sclerosis and in patients with greater disability. Increased total sodium concentration is likely to reflect neuroaxonal pathophysiology leading to clinical progression and increased disability.
    Brain 07/2013; 136(Pt 7):2305-2317. · 10.23 Impact Factor

Publication Stats

7k Citations
1,424.28 Total Impact Points

Institutions

  • 2009–2014
    • UCL Eastman Dental Institute
      Londinium, England, United Kingdom
    • UK Department of Health
      Londinium, England, United Kingdom
  • 1999–2014
    • University College London
      • • Department of Brain Repair and Rehabilitation
      • • Department of Neuroinflammation
      • • Institute of Neurology
      Londinium, England, United Kingdom
  • 2013
    • The National Institute of Neurology and Neurosurgery
      Tlalpam, The Federal District, Mexico
  • 2010–2013
    • The Bracton Centre, Oxleas NHS Trust
      Дартфорде, England, United Kingdom
    • Aristotle University of Thessaloniki
      Saloníki, Central Macedonia, Greece
  • 2012
    • Autonomous University of Barcelona
      Cerdanyola del Vallès, Catalonia, Spain
    • Universität Basel
      Bâle, Basel-City, Switzerland
  • 2002–2012
    • London Research Institute
      Londinium, England, United Kingdom
  • 2006–2011
    • San Raffaele Scientific Institute
      Milano, Lombardy, Italy
  • 2007–2009
    • Universitätsspital Basel
      Bâle, Basel-City, Switzerland
    • University of London
      Londinium, England, United Kingdom
    • University of Texas Southwestern Medical Center
      • Division of Neuro-oncology
      Dallas, TX, United States
  • 2007–2008
    • VU University Amsterdam
      Amsterdamo, North Holland, Netherlands
  • 2003
    • The University of Sheffield
      • School of Health and Related Research (ScHARR)
      Sheffield, ENG, United Kingdom
    • University of Leicester
      • Department of Cardiovascular Sciences
      Leiscester, England, United Kingdom
    • The University of Manchester
      Manchester, England, United Kingdom