Sodium Intensity Changes Differ Between Relaxation- and Density-Weighted MRI in Multiple Sclerosis

Introduction: The source of Tissue Sodium Concentration (TSC) increase in Multiple Sclerosis (MS) remains unclear, and could be attributed to altered intracellular sodium concentration or tissue microstructure. This paper investigates sodium in MS using three new MRI sequences.Methods: Three sodium scans were acquired at 4.7 T from 30 patients (11 relapsing-remitting, 10 secondary-progressive, 9 primary-progressive) and 9 healthy controls including: Density-Weighted (NaDW), with very short 30° excitation for more accurate TSC measurement; Projection Acquisition with Coherent MAgNetization (NaPACMAN), designed for enhanced relaxation-based contrast; and Soft Inversion Recovery FLuid Attenuation (NaSIRFLA), developed to reduce fluid space contribution. Signal was measured in both lesions (n = 397) and normal appearing white matter (NAWM) relative to controls in the splenium of corpus callosum and the anterior and posterior limbs of internal capsule. Correlations with clinical and cognitive evaluations were tested over all MS patients.Results: Sodium intensity in MS lesions was elevated over control WM by a greater amount for NaPACMAN (75%) than NaDW (35%), the latter representing TSC. In contrast, NaSIRFLA exhibited lower intensity, but only for region specific analysis in the SCC (−7%). Sodium intensity in average MS NAWM was not significantly different than control WM for either of the three scans. NaSIRFLA in the average NAWM and specifically the posterior limb of internal capsules positively correlated with the Paced Auditory Serial Addition Test (PASAT).Discussion: Lower NaSIRFLA signal in lesions and ~2× greater NaPACMAN signal elevation over control WM than NaDW can be explained with a demyelination model that also includes edema. A NAWM demyelination model that includes tissue atrophy suggests no signal change for NaSIRFLA, and only slightly greater NAWM signal than control WM for both NaDW and NaPACMAN, reflecting experimental results. Models were derived from previous total and myelin water fraction study in MS with T2-relaxometry, and for the first time include sodium within the myelin water space. Reduced auditory processing association with lower signal on NaSIRFLA cannot be explained by greater demyelination and its modeled impact on the three sodium MRI sequences. Alternative explanations include intra- or extracellular sodium concentration change. Relaxation-weighted sodium MRI in combination with sodium-density MRI may help elucidate microstructural and metabolic changes in MS.

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Abstract TP75: Normal Appearing White Matter Integrity and Motor Impairment Severity in Acute Ischemic Stroke

Stroke ◽

10.1161/str.51.suppl_1.tp75 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Carson Ingo ◽

Chen Lin ◽

James Higgins ◽

Yurany Arevalo ◽

Shyam Prabhakaran

Keyword(s):

Ischemic Stroke ◽

White Matter ◽

Acute Ischemic Stroke ◽

Motor Function ◽

Motor Impairment ◽

Internal Capsule ◽

Posterior Limb ◽

Normal Appearing White Matter ◽

Stroke Group ◽

Microstructural Integrity

Introduction: The effect of white matter hyperintensities (WMH) as measured by fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging on functional impairment and recovery after ischemic stroke has been investigated thoroughly. However, there has been growing interest to investigate normal-appearing white matter (NAWM) microstructural integrity following ischemic stroke onset with techniques such as diffusion tensor imaging (DTI). Methods: 52 patients with acute ischemic stroke and 36 without stroke were evaluated with a DTI and FLAIR imaging protocol and clinically assessed for severity of motor impairment using the Motricity Index within 72 hours of suspected symptom onset. Results: There were widespread decreases in fractional anisotropy (FA) and increases in mean diffusivity (MD) and radial diffusivity (RD) for the acute stroke group compared to the non-stroke group. As shown in the abstract figure with the blue voxels, there was a significant positive association between FA and motor function and a significant negative association between MD/RD and motor function. The NAWM regions of interest that were most sensitive to the Motricity Index were the anterior/posterior limb of the internal capsule in the infarcted hemisphere and the splenium of the corpus callosum, external capsule, posterior limb/retrolenticular part of the internal capsule, superior longitudinal fasciculus, and cingulum (hippocampus) of the intra-/contralateral hemisphere. Conclusion: The microstructural integrity of NAWM is a significant parameter to identify neural differences not only between those individuals with and without acute ischemic stroke, but also correlated with severity of acute motor impairment.

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A 24-month advanced magnetic resonance imaging study of multiple sclerosis patients treated with alemtuzumab

Multiple Sclerosis Journal ◽

10.1177/1352458518770085 ◽

2018 ◽

Vol 25 (6) ◽

pp. 811-818 ◽

Cited By ~ 8

Author(s):

Irene M Vavasour ◽

Roger Tam ◽

David KB Li ◽

Cornelia Laule ◽

Carolyn Taylor ◽

...

Keyword(s):

Multiple Sclerosis ◽

Magnetic Resonance ◽

Cortical Thickness ◽

Diffusion Tensor ◽

Imaging Study ◽

Water Fraction ◽

Normal Appearing White Matter ◽

Brain Parenchymal Fraction ◽

Brain Parenchymal ◽

Multiple Sclerosis Patients

Background: Tissue damage in both multiple sclerosis (MS) lesions and normal-appearing white matter (NAWM) are important contributors to disability and progression. Specific aspects of MS pathology can be measured using advanced imaging. Alemtuzumab is a humanised monoclonal antibody targeting CD52 developed for MS treatment. Objective: To investigate changes over 2 years of advanced magnetic resonance (MR) metrics in lesions and NAWM of MS patients treated with alemtuzumab. Methods: A total of 42 relapsing–remitting alemtuzumab-treated MS subjects were scanned for 2 years at 3 T. T1 relaxation, T2 relaxation, diffusion tensor, MR spectroscopy and volumetric sequences were performed. Mean T1 and myelin water fraction (MWF) were determined for stable lesions, new lesions and NAWM. Fractional anisotropy was calculated for the corpus callosum (CC) and N-acetylaspartate (NAA) concentration was determined from a large NAWM voxel. Brain parenchymal fraction (BPF), cortical thickness and CC area were also calculated. Results: No change in any MR measurement was found in lesions or NAWM over 24 months. BPF, cortical thickness and CC area all showed decreases in the first year followed by stability in the second year. Conclusion: Advanced MR biomarkers of myelin (MWF) and neuron/axons (NAA) show no change in NAWM over 24 months in alemtuzumab-treated MS participants.

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Heterogeneity of acute multiple sclerosis lesions on sodium (23Na) MRI

Multiple Sclerosis Journal ◽

10.1177/1352458515609430 ◽

2015 ◽

Vol 22 (8) ◽

pp. 1040-1047 ◽

Cited By ~ 15

Author(s):

Philipp Eisele ◽

Simon Konstandin ◽

Martin Griebe ◽

Kristina Szabo ◽

Marc E Wolf ◽

...

Keyword(s):

Multiple Sclerosis ◽

Sodium Concentration ◽

Sodium Mri ◽

Highly Sensitive ◽

Apparent Diffusion ◽

Magnetic Resonance Imaging Mri ◽

Tissue Abnormalities ◽

23Na Mri ◽

Sensitive Marker ◽

Total Sodium

Background: Advanced magnetic resonance imaging (MRI) techniques provide a window into pathological processes in multiple sclerosis (MS). Nevertheless, to date only few studies have performed sodium MRI in MS. Objectives: We analysed total sodium concentration (TSC) in hyperacute, acute and chronic lesions in MS with 23Na MRI. Methods: 23Na MRI and 1H MRI were performed in 65 MS patients and 10 healthy controls (HC). Mean TSC was quantified in all MS lesions with a diameter of >5 mm and in the normal appearing white and grey matter (NAWM, NAGM). Results: TSC in the NAWM and the NAGM of MS patients was significantly higher compared to HC (WM: 37.51 ± 2.65 mM versus 35.17 ± 3.40 mM; GM: 43.64 ± 2.75 mM versus 40.09 ± 4.64 mM). Acute and chronic MS lesions showed elevated TSC levels of different extent (contrast-enhancing lesions (49.07 ± 6.99 mM), T1 hypointense lesions (45.06 ± 6.26 mM) and remaining T1 isointense lesions (39.88 ± 5.54 mM)). However, non-enhancing hyperacute lesions with a reduced apparent diffusion coefficient showed a TSC comparable to the NAWM (37.22 ± 4.62 mM). Conclusions: TSC is not only a sensitive marker of the severity of chronic tissue abnormalities in MS but is also highly sensitive to opening of the blood–brain barrier and vasogenic tissue oedema in contrast-enhancing lesions.

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Global loss of myelin water over 5 years in multiple sclerosis normal-appearing white matter

Multiple Sclerosis Journal ◽

10.1177/1352458517723717 ◽

2017 ◽

Vol 24 (12) ◽

pp. 1557-1568 ◽

Cited By ~ 17

Author(s):

Irene M Vavasour ◽

Sophie C Huijskens ◽

David KB Li ◽

Anthony L Traboulsee ◽

Burkhard Mädler ◽

...

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Geometric Mean ◽

Peak Height ◽

Cross Sectional ◽

Longitudinal Changes ◽

Water Fraction ◽

Normal Appearing White Matter ◽

Long Term Follow Up ◽

Long Time

Background: Reduced myelin water fraction (MWF, a marker for myelin), increased geometric mean T2 (ieGMT2, reflecting intra/extracellular water properties), and increased T1 (related to total water content) have been observed in cross-sectional studies of multiple sclerosis (MS) normal-appearing white matter (NAWM). Objective: To assess longitudinal changes of magnetic resonance (MR) measures in relapsing-remitting MS (RRMS) brain NAWM. Methods: A total of 11 subjects with RRMS and 4 controls were scanned on a 3T MRI at baseline and long-term follow-up (LTFU; 3.2–5.8 years) with a 32-echo T2 relaxation and an inversion recovery T1 sequence. For every voxel, MWF, ieGMT2, and T1 were obtained. Mean, peak height, and peak location from NAWM mask-based histograms were determined. Results: In MS subjects, NAWM MWF mean decreased by 8% ( p = 0.0016). No longitudinal changes were measured in T1 or ieGMT2. There was no relationship between change in any MR metric and change in EDSS. Control white matter showed no differences over time in any metric. Conclusion: The decreases we observed in MWF suggest that changes in myelin integrity and loss of myelin may be occurring diffusely and over long time periods in the MS brain. The timescale of these changes indicates that chronic, progressive myelin damage is an evolving process occurring over many years.

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Non-lesional white matter changes in pediatric multiple sclerosis and monophasic demyelinating disorders

Multiple Sclerosis Journal ◽

10.1177/1352458512447527 ◽

2012 ◽

Vol 18 (12) ◽

pp. 1754-1759 ◽

Cited By ~ 17

Author(s):

JM Tillema ◽

J Leach ◽

I Pirko

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Demyelinating Disease ◽

Diffusion Tensor ◽

Internal Capsule ◽

Acute Disseminated Encephalomyelitis ◽

Childhood Onset ◽

Normal Appearing White Matter ◽

Automated Method ◽

Demyelinating Disorders

Objective: To analyze diffusion tensor imaging (DTI) derived metrics between patients with childhood onset multiple sclerosis (MS), monophasic demyelinating illnesses, and healthy controls. Background: Monophasic demyelinating illnesses can be indistinguishable clinically and radiologically, utilizing standard MRI studies. DTI studies in adults implicate the involvement of normal-appearing white matter (NAWM) in MS. Methods: Subjects with DTI studies (15 directions, 1.5 Tesla (GE), 3x3x3 mm, interpolated to 1.5x1.5x3 mm) were retrospectively identified. We studied three groups: childhood onset MS ( n=18), monophasic illness (eight with acute disseminated encephalomyelitis (ADEM), seven with clinically isolated syndrome (CIS)) and age-matched controls. DTI had been obtained within one month of symptom onset for patients with ADEM and within a median of 20 months for the MS group. DTI measures were determined using a semi-automated method from standardized regions of interest (ROI) containing central fibers of the corpus callosum genu and internal capsule. Results: The MS group had significantly lower fractional anisotropy (FA) values compared to controls ( p<0.001), with increased radial diffusivity (RD) and decreased axial diffusivity (AD). In the monophasic group FA was smaller than the controls ( p=0.01) with increased RD and no difference in AD. Conclusions: This retrospective analysis provides evidence that NAWM is affected in pediatric MS and monophasic demyelinating disease, with a potentially novel pattern demonstrating reduced AD in pediatric MS. Further larger scale confirmatory studies are needed to address whether the demonstrated DTI changes could be used as a biomarker in pediatric patients presenting with an initial demyelinating event.

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

Multiple Sclerosis Journal ◽

10.1177/1352458518765671 ◽

2018 ◽

Vol 25 (5) ◽

pp. 687-698 ◽

Cited By ~ 2

Author(s):

Piotr Sowa ◽

Hanne F Harbo ◽

Nathan S White ◽

Elisabeth G Celius ◽

Hauke Bartsch ◽

...

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Fractional Anisotropy ◽

Free Water ◽

White Matter Lesions ◽

Neurological Disability ◽

Water Fraction ◽

Neurite Density ◽

Normal Appearing White Matter ◽

Spectrum Imaging

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

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Deep brain stimulation of the posterior limb of the internal capsule in the treatment of central poststroke neuropathic pain of the lower limb: case series with long-term follow-up and literature review

Journal of Neurosurgery ◽

10.3171/2019.5.jns19227 ◽

2020 ◽

Vol 133 (3) ◽

pp. 830-838 ◽

Cited By ~ 1

Author(s):

Andrea Franzini ◽

Giuseppe Messina ◽

Vincenzo Levi ◽

Antonio D’Ammando ◽

Roberto Cordella ◽

...

Keyword(s):

Neuropathic Pain ◽

Lower Limb ◽

Internal Capsule ◽

Posterior Limb ◽

Vas Score ◽

The Mean ◽

Deep Brain ◽

Stimulation Of

OBJECTIVECentral poststroke neuropathic pain is a debilitating syndrome that is often resistant to medical therapies. Surgical measures include motor cortex stimulation and deep brain stimulation (DBS), which have been used to relieve pain. The aim of this study was to retrospectively assess the safety and long-term efficacy of DBS of the posterior limb of the internal capsule for relieving central poststroke neuropathic pain and associated spasticity affecting the lower limb.METHODSClinical and surgical data were retrospectively collected and analyzed in all patients who had undergone DBS of the posterior limb of the internal capsule to address central poststroke neuropathic pain refractory to conservative measures. In addition, long-term pain intensity and level of satisfaction gained from stimulation were assessed. Pain was evaluated using the visual analog scale (VAS). Information on gait improvement was obtained from medical records, neurological examination, and interview.RESULTSFour patients have undergone the procedure since 2001. No mortality or morbidity related to the surgery was recorded. In three patients, stimulation of the posterior limb of the internal capsule resulted in long-term pain relief; in a fourth patient, the procedure failed to produce any long-lasting positive effect. Two patients obtained a reduction in spasticity and improved motor capability. Before surgery, the mean VAS score was 9 (range 8–10). In the immediate postoperative period and within 1 week after the DBS system had been turned on, the mean VAS score was significantly lower at a mean of 3 (range 0–6). After a mean follow-up of 5.88 years, the mean VAS score was still reduced at 5.5 (range 3–8). The mean percentage of long-term pain reduction was 38.13%.CONCLUSIONSThis series suggests that stimulation of the posterior limb of the internal capsule is safe and effective in treating patients with chronic neuropathic pain affecting the lower limb. The procedure may be a more targeted treatment method than motor cortex stimulation or other neuromodulation techniques in the subset of patients whose pain and spasticity are referred to the lower limbs.

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A Case of Anterior Choroidal Artery Occlusion and Stroke Secondary to External Compression

Case Reports in Neurology ◽

10.1159/000515574 ◽

2021 ◽

pp. 369-374

Author(s):

Satya Narayana Patro ◽

Khawaja Hassan Haroon ◽

Khansabegum Tamboli ◽

Abdulaziz Zafar ◽

Suhail Hussain ◽

...

Keyword(s):

Medial Temporal Lobe ◽

Optic Tract ◽

Internal Capsule ◽

Cerebral Peduncle ◽

Anterior Choroidal Artery ◽

Vessel Occlusion ◽

External Compression ◽

Posterior Limb ◽

Anterior Choroidal ◽

Choroidal Artery

The anterior choroidal artery (AChA) is a small artery commonly arising from the supraclinoid segment of the internal carotid artery (ICA). The significance of the AChA is related to its strategic supply to various important structures of the brain, such as the optic tract, the posterior limb of the internal capsule, the cerebral peduncle, the lateral geniculate body, medial temporal lobe, medial area of pallidum, and the choroid plexus [J Neurol. 1988;235:387–91]. The AChA syndrome in its complete form consists of the triad of hemiplegia, hemisensory loss, and hemianopia. However, incomplete forms are more frequent in clinical practice [Stroke. 1994;25:837–42]. Isolated infarction in the AChA territory is relatively rare. The presumed pathogenic mechanisms of AChA infarction are cardiac emboli, large-vessel atherosclerosis, dissection of the ICA, small-vessel occlusion, or other determined or undetermined causes [Stroke. 1994;25:837–42 and J Neurol Sci. 2009;281:80–4].

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Characterization of multiple sclerosis neuroinflammation and neurodegeneration with relaxation and diffusion basis spectrum imaging

Multiple Sclerosis Journal ◽

10.1177/13524585211023345 ◽

2021 ◽

pp. 135245852110233

Author(s):

Irene M Vavasour ◽

Peng Sun ◽

Carina Graf ◽

Jackie T Yik ◽

Shannon H Kolind ◽

...

Keyword(s):

Multiple Sclerosis ◽

Specific Information ◽

Axonal Loss ◽

Normal Appearing White Matter ◽

Relapsing Remitting ◽

Tissue Changes ◽

Spectrum Imaging ◽

Magnetic Resonance Imaging Mri ◽

And Diffusion

Background: Advanced magnetic resonance imaging (MRI) methods can provide more specific information about various microstructural tissue changes in multiple sclerosis (MS) brain. Quantitative measurement of T1 and T2 relaxation, and diffusion basis spectrum imaging (DBSI) yield metrics related to the pathology of neuroinflammation and neurodegeneration that occurs across the spectrum of MS. Objective: To use relaxation and DBSI MRI metrics to describe measures of neuroinflammation, myelin and axons in different MS subtypes. Methods: 103 participants (20 clinically isolated syndrome (CIS), 33 relapsing-remitting MS (RRMS), 30 secondary progressive MS and 20 primary progressive MS) underwent quantitative T1, T2, DBSI and conventional 3T MRI. Whole brain, normal-appearing white matter, lesion and corpus callosum MRI metrics were compared across MS subtypes. Results: A gradation of MRI metric values was seen from CIS to RRMS to progressive MS. RRMS demonstrated large oedema-related differences, while progressive MS had the most extensive abnormalities in myelin and axonal measures. Conclusion: Relaxation and DBSI-derived MRI measures show differences between MS subtypes related to the severity and composition of underlying tissue damage. RRMS showed oedema, demyelination and axonal loss compared with CIS. Progressive MS had even more evidence of increased oedema, demyelination and axonal loss compared with CIS and RRMS.

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Sodium Radiofrequency Coils for Magnetic Resonance: From Design to Applications

Electronics ◽

10.3390/electronics10151788 ◽

2021 ◽

Vol 10 (15) ◽

pp. 1788

Author(s):

Giulio Giovannetti ◽

Alessandra Flori ◽

Nicola Martini ◽

Roberto Francischello ◽

Giovanni Donato Aquaro ◽

...

Keyword(s):

Magnetic Resonance ◽

Sodium Concentration ◽

Resonance Spectroscopy ◽

Sodium Mri ◽

Human Organs ◽

Low Sodium ◽

Radiofrequency Coils ◽

Anatomical Imaging ◽

Strong Gradient

Sodium (23Na) is the most abundant cation present in the human body and is involved in a large number of vital body functions. In the last few years, the interest in Sodium Magnetic Resonance Imaging (23Na MRI) has considerably increased for its relevance in physiological and physiopathological aspects. Indeed, sodium MRI offers the possibility to extend the anatomical imaging information by providing additional and complementary information on physiology and cellular metabolism with the heteronuclear Magnetic Resonance Spectroscopy (MRS). Constraints are the rapidly decaying of sodium signal, the sensitivity lack due to the low sodium concentration versus 1H-MRI induce scan times not clinically acceptable and it also constitutes a challenge for sodium MRI. With the available magnetic fields for clinical MRI scanners (1.5 T, 3 T, 7 T), and the hardware capabilities such as strong gradient strengths with high slew rates and new dedicated radiofrequency (RF) sodium coils, it is possible to reach reasonable measurement times (~10–15 min) with a resolution of a few millimeters, where it has already been applied in vivo in many human organs such as the brain, cartilage, kidneys, heart, as well as in muscle and the breast. In this work, we review the different geometries and setup of sodium coils described in the available literature for different in vivo applications in human organs with clinical MR scanners, by providing details of the design, modeling and construction of the coils.

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