Nerve Hypertrophy and Altered Diffusion in Anti-Myelin-Associated Glycoprotein Neuropathy Detected by Brachial Plexus Magnetic Resonance Neurography

2021 ◽  
pp. 1-9
Author(s):  
Kyosuke Koide ◽  
Atsuhiko Sugiyama ◽  
Hajime Yokota ◽  
Hiroki Mukai ◽  
Jiaqi Wang ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Brachial Plexus ◽  
Diffusion Tensor ◽  
Morphological Changes ◽  
Mean Diffusivity ◽  
Nerve Roots ◽  
Magnetic Resonance Neurography ◽  
Cross Sectional ◽  
3 Dimensional ◽  
Myelin Associated Glycoprotein

<b><i>Introduction:</i></b> This study assessed the morphological changes and diffusion tensor imaging (DTI)-derived parameters of the brachial plexus using magnetic resonance neurography (MRN) in patients with anti-myelin-associated glycoprotein (anti-MAG) neuropathy. <b><i>Methods:</i></b> Eight patients with anti-MAG neuropathy underwent MRN of the brachial plexus with 3-dimensional (3D) short tau inversion recovery (STIR) and DTI sequences. Two neuroradiologists and a neurologist qualitatively assessed nerve hypertrophy on 3D STIR MRN. The cross-sectional area (CSA) of the nerve roots was measured. Quantitative analyses of fractional anisotropy (FA) and axial, radial, and mean diffusivity (AD, RD, and MD) were obtained after postprocessing on DTI and manual segmentation. <b><i>Results:</i></b> There was nerve hypertrophy in 37.5% of the patients with anti-MAG neuropathy. All patients with anti-MAG neuropathy with nerve hypertrophy were refractory to rituximab therapy. The CSA of the nerve roots was inversely correlated with FA and positively correlated with MD and RD. FA decreased in the nerve roots and inversely correlated with disease duration. <b><i>Conclusions:</i></b> Nerve hypertrophy appears in the proximal portion of peripheral nerves, such as the brachial plexus, in patients with anti-MAG neuropathy. Altered diffusion in the nerve roots might be associated with the loss of myelin integrity due to the demyelination process in anti-MAG neuropathy.

scholarly journals Magnetic Resonance Neurography: Improved Diagnosis of Peripheral Neuropathies

2021 ◽  
Author(s):  
Jennifer Kollmer ◽  
Martin Bendszus
Keyword(s):  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Correct Diagnosis ◽  
Imaging Biomarkers ◽  
Peripheral Neuropathies ◽  
Contrast Imaging ◽  
Magnetic Resonance Neurography ◽  
Cross Sectional ◽  
Nerve Lesions ◽  
Technical Requirements

AbstractPeripheral neuropathies account for the most frequent disorders seen by neurologists, and causes are manifold. The traditional diagnostic gold-standard consists of clinical neurologic examinations supplemented by nerve conduction studies. Due to well-known limitations of standard diagnostics and atypical clinical presentations, establishing the correct diagnosis can be challenging but is critical for appropriate therapies. Magnetic resonance neurography (MRN) is a relatively novel technique that was developed for the high-resolution imaging of the peripheral nervous system. In focal neuropathies, whether traumatic or due to nerve entrapment, MRN has improved the diagnostic accuracy by directly visualizing underlying nerve lesions and providing information on the exact lesion localization, extension, and spatial distribution, thereby assisting surgical planning. Notably, the differentiation between distally located, complete cross-sectional nerve lesions, and more proximally located lesions involving only certain fascicles within a nerve can hold difficulties that MRN can overcome, when basic technical requirements to achieve sufficient spatial resolution are implemented. Typical MRN-specific pitfalls are essential to understand in order to prevent overdiagnosing neuropathies. Heavily T2-weighted sequences with fat saturation are the most established sequences for MRN. Newer techniques, such as T2-relaxometry, magnetization transfer contrast imaging, and diffusion tensor imaging, allow the quantification of nerve lesions and have become increasingly important, especially when evaluating diffuse, non-focal neuropathies. Innovative studies in hereditary, metabolic or inflammatory polyneuropathies, and motor neuron diseases have contributed to a better understanding of the underlying pathomechanism. New imaging biomarkers might be used for an earlier diagnosis and monitoring of structural nerve injury under causative treatments in the future.

Arterial Stiffness Is Associated with White Matter Disruption and Cognitive Impairment: A Community-Based Cohort Study

2021 ◽  
Vol 80 (2) ◽  
pp. 567-576
Author(s):  
Fei Han ◽  
Fei-Fei Zhai ◽  
Ming-Li Li ◽  
Li-Xin Zhou ◽  
Jun Ni ◽  
...  
Keyword(s):  
Cognitive Function ◽  
White Matter ◽  
Arterial Stiffness ◽  
Cognitive Decline ◽  
Sex Education ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
White Matter Injury ◽  
White Matter Integrity ◽  
Cross Sectional

Background: Mechanisms through which arterial stiffness impacts cognitive function are crucial for devising better strategies to prevent cognitive decline. Objective: To examine the associations of arterial stiffness with white matter integrity and cognition in community dwellings, and to investigate whether white matter injury was the intermediate of the associations between arterial stiffness and cognition. Methods: This study was a cross-sectional analysis on 952 subjects (aged 55.5±9.1 years) who underwent diffusion tensor imaging and measurement of brachial-ankle pulse wave velocity (baPWV). Both linear regression and tract-based spatial statistics were used to investigate the association between baPWV and white matter integrity. The association between baPWV and global cognitive function, measured as the mini-mental state examination (MMSE) was evaluated. Mediation analysis was performed to assess the influence of white matter integrity on the association of baPWV with MMSE. Results: Increased baPWV was significantly associated with lower mean global fractional anisotropy (β= –0.118, p < 0.001), higher mean diffusivity (β= 0.161, p < 0.001), axial diffusivity (β= 0.160, p < 0.001), and radial diffusivity (β= 0.147, p < 0.001) after adjustment of age, sex, and hypertension, which were measures having a direct effect on arterial stiffness and white matter integrity. After adjustment of age, sex, education, apolipoprotein E ɛ4, cardiovascular risk factors, and brain atrophy, we found an association of increased baPWV with worse performance on MMSE (β= –0.093, p = 0.011). White matter disruption partially mediated the effect of baPWV on MMSE. Conclusion: Arterial stiffness is associated with white matter disruption and cognitive decline. Reduced white matter integrity partially explained the effect of arterial stiffness on cognition.

scholarly journals Demyelination and remyelination detected in an alternative cuprizone mouse model of multiple sclerosis with 7.0 T multiparameter magnetic resonance imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuang Ding ◽  
Yu Guo ◽  
Xiaoya Chen ◽  
Silin Du ◽  
Yongliang Han ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Multiple Sclerosis ◽  
Magnetic Resonance ◽  
Mouse Model ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Blue Staining ◽  
Resonance Imaging ◽  
The Mean ◽  
Underlying Mechanisms

AbstractThe aim of this study was to investigate the mechanisms underlying demyelination and remyelination with 7.0 T multiparameter magnetic resonance imaging (MRI) in an alternative cuprizone (CPZ) mouse model of multiple sclerosis (MS). Sixty mice were divided into six groups (n = 10, each), and these groups were imaged with 7.0 T multiparameter MRI and treated with an alternative CPZ administration schedule. T2-weighted imaging (T2WI), susceptibility-weighted imaging (SWI), and diffusion tensor imaging (DTI) were used to compare the splenium of the corpus callosum (sCC) among the groups. Prussian blue and Luxol fast blue staining were performed to assess pathology. The correlations of the mean grayscale value (mGSV) of the pathology results and the MRI metrics were analyzed to evaluate the multiparameter MRI results. One-way ANOVA and post hoc comparison showed that the normalized T2WI (T2-nor), fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) values were significantly different among the six groups, while the mean phase (Φ) value of SWI was not significantly different among the groups. Correlation analysis showed that the correlation between the T2-nor and mGSV was higher than that among the other values. The correlations among the FA, RD, MD, and mGSV remained instructive. In conclusion, ultrahigh-field multiparameter MRI can reflect the pathological changes associated with and the underlying mechanisms of demyelination and remyelination in MS after the successful establishment of an acute CPZ-induced model.

Application of magnetic resonance neurography in the evaluation of patients with peripheral nerve pathology

1996 ◽  
Vol 85 (2) ◽  
pp. 299-309 ◽  
Author(s):  
Aaron G. Filler ◽  
Michel Kliot ◽  
Franklyn A. Howe ◽  
Cecil E. Hayes ◽  
Dawn E. Saunders ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Time Course ◽  
Spin Echo ◽  
Fast Spin Echo ◽  
Mr Neurography ◽  
Magnetic Resonance Neurography ◽  
Cross Sectional ◽  
Content Type ◽  
Direct Nerve ◽  
Fine Print

✓ Currently, diagnosis and management of disorders involving nerves are generally undertaken without images of the nerves themselves. The authors evaluated whether direct nerve images obtained using the new technique of magnetic resonance (MR) neurography could be used to make clinically important diagnostic distinctions that cannot be readily accomplished using existing methods. The authors obtained T2-weighted fast spin—echo fat-suppressed (chemical shift selection or inversion recovery) and T1-weighted images with planes parallel or transverse to the long axis of nerves using standard or phased-array coils in healthy volunteers and referred patients in 242 sessions. Longitudinal and cross-sectional fascicular images readily distinguished perineural from intraneural masses, thus predicting both resectability and requirement for intraoperative electrophysiological monitoring. Fascicle pattern and longitudinal anatomy firmly identified nerves and thus improved the safety of image-guided procedures. In severe trauma, MR neurography identified nerve discontinuity at the fascicular level preoperatively, thus verifying the need for surgical repair. Direct images readily demonstrated increased diameter in injured nerves and showed the linear extent and time course of image hyperintensity associated with nerve injury. These findings confirm and precisely localize focal nerve compressions, thus avoiding some exploratory surgery and allowing for smaller targeted exposures when surgery is indicated. Direct nerve imaging can demonstrate nerve continuity, distinguish intraneural from perineural masses, and localize nerve compressions prior to surgical exploration. Magnetic resonance neurography can add clinically useful diagnostic information in many situations in which physical examinations, electrodiagnostic tests, and existing image techniques are inconclusive.

scholarly journals Verbal memory and hippocampal volume predict subsequent fornix microstructure in those at risk for Alzheimer’s disease

2019 ◽  
Vol 14 (6) ◽  
pp. 2311-2322 ◽  
Author(s):  
Junhong Yu ◽  
◽  
Tatia M. C. Lee
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Verbal Memory ◽  
Structural Equation ◽  
Structural Equation Models ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Hippocampal Atrophy ◽  
Cross Sectional ◽  
Mci Due To Ad

Abstract While strong cross-sectional evidence supported the use of fornix microstructure as a marker for detecting Alzheimer’s disease (AD), longitudinal data remains inconclusive on the sequential nature of fornix microstructure abnormalities and AD progression. An unequivocal longitudinal relationship between fornix microstructure and markers of AD progression –memory impairment and hippocampal atrophy, must be established to validate fornix microstructure as a marker of AD progression. We included 115 participants from the Alzheimer’s Disease Neuroimaging Initiative across the non-demented AD spectrum— defined as those who had at least one AD risk marker at baseline (e.g., mild cognitive impairment (MCI) due to AD diagnosis, amyloid or ApoE4 positivity) and/or ‘cognitively normal individuals who converted to MCI due to AD or AD, with structural and diffusion tensor imaging scans at baseline and two years follow-up. Hippocampal volumes (HV), fractional anisotropy (FA) and mean diffusivity (MD) in the fornix were extracted. Memory was indexed via composite scores of verbal memory tests. Structural equation models tested the bidirectional cross-lagged effects of fornix microstructure, memory, and HV. Impaired memory and smaller HV at baseline significantly predicted worse fornix microstructure (decreased FA and increased MD) two years later. Baseline fornix microstructure was not associated with subsequent changes in memory and HV. Fornix microstructure is compromised likely at a later stage, where significant decline in memory and hippocampal atrophy have occurred. This limits the utility of fornix microstructure in the early detection of AD. Our findings inform the possible pathophysiology and refined the use of AD neural markers.

scholarly journals Troponin T Parallels Structural Nerve Damage in Type 2 Diabetes: A Cross-sectional Study Using Magnetic Resonance Neurography

Diabetes ◽  
2020 ◽  
Vol 69 (4) ◽  
pp. 713-723 ◽  
Author(s):  
Johann M.E. Jende ◽  
Jan B. Groener ◽  
Zoltan Kender ◽  
Artur Hahn ◽  
Jakob Morgenstern ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Magnetic Resonance ◽  
Troponin T ◽  
Cross Sectional Study ◽  
Nerve Damage ◽  
Sectional Study ◽  
Magnetic Resonance Neurography ◽  
Cross Sectional

scholarly journals Magnetic resonance diffusion tensor imaging in psychiatry: a narrative review of its potential role in diagnosis

2020 ◽  
Author(s):  
Piotr Podwalski ◽  
Krzysztof Szczygieł ◽  
Ernest Tyburski ◽  
Leszek Sagan ◽  
Błażej Misiak ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Magnetic Resonance ◽  
Potential Role ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Water Molecules ◽  
Mental Diseases ◽  
The Brain ◽  
Diffusion Tensor Imaging Dti

Abstract Diffusion tensor imaging (DTI) is an imaging technique that uses magnetic resonance. It measures the diffusion of water molecules in tissues, which can occur either without restriction (i.e., in an isotropic manner) or limited by some obstacles, such as cell membranes (i.e., in an anisotropic manner). Diffusion is most often measured in terms of, inter alia, fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD). DTI allows us to reconstruct, visualize, and evaluate certain qualities of white matter. To date, many studies have sought to associate various changes in the distribution of diffusion within the brain with mental diseases and disorders. A better understanding of white matter integrity disorders can help us recognize the causes of diseases, as well as help create objective methods of psychiatric diagnosis, identify biomarkers of mental illness, and improve pharmacotherapy. The aim of this work is to present the characteristics of DTI as well as current research on its use in schizophrenia, affective disorders, and other mental disorders.

scholarly journals The comparison of MRN, electrophysiology and progression among typical CIDP and atypical CIDP subtypes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuan Feng ◽  
Yu Zhang ◽  
Xiaoyun Su ◽  
Chuansheng Zheng ◽  
Zuneng Lu
Keyword(s):  
Medical Records ◽  
The Other ◽  
Nerve Roots ◽  
Magnetic Resonance Neurography ◽  
Cross Sectional ◽  
Motor Action ◽  
Compound Motor Action Potential ◽  
Sum Score ◽  
Rate Of Progression ◽  
Pure Motor

Abstract We aimed to compare the electrophysiology and magnetic resonance neurography (MRN) results of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) subtypes and to explore the progression from atypical CIDP to typical CIDP. We collected the medical records of 45 CIDP patients to analyse the rate of progression from atypical CIDP to typical CIDP subtypes. The cerebrospinal fluid (CSF) protein (p = 0.024) and overall disability sum score (ODSS) (p = 0.000) differed among patients with typical CIDP, distal acquired demyelinating symmetric neuropathy (DADS) and Lewis-Sumner syndrome (LSS). The compound motor action potential (CMAP) of typical CIDP was lower than that of the other subtypes (p = 0.016, p = 0.022 and p = 0.012). The cross-sectional area (CSA) of nerve roots in typical CIDP was significantly thicker than that of nerve roots in DADS and LSS. There were fewer DADS and LSS patients who progressed to typical CIDP than those who progressed to pure motor and pure sensory CIDP (p = 0.000), and the progression from pure motor to typical CIDP required a significantly longer time than the progression from pure sensory to typical CIDP (p = 0.007). Typical CIDP was more severe than the other subtypes not only in terms of clinical and electrophysiology factors but also in terms of MRN factors.

scholarly journals Diffusion tensor imaging of the roots of the brachial plexus: a systematic review and meta-analysis of normative values

2020 ◽  
Vol 8 (6) ◽  
pp. 419-431 ◽  
Author(s):  
Ryckie G. Wade ◽  
Alexander Whittam ◽  
Irvin Teh ◽  
Gustav Andersson ◽  
Fang-Cheng Yeh ◽  
...  
Keyword(s):  
Brachial Plexus ◽  
Diffusion Tensor ◽  
Meta Analysis ◽  
Mean Diffusivity ◽  
Normative Values ◽  
Spinal Root ◽  
Experimental Conditions ◽  
Tissue Microstructure ◽  
The Mean ◽  
Generalised Linear Modelling

Abstract Purpose Diffusion tensor magnetic resonance imaging (DTI) characterises tissue microstructure and provides proxy measures of myelination, axon diameter, fibre density and organisation. This may be valuable in the assessment of the roots of the brachial plexus in health and disease. Therefore, there is a need to define the normal DTI values. Methods The literature was systematically searched for studies of asymptomatic adults who underwent DTI of the brachial plexus. Participant characteristics, scanning protocols, and measurements of the fractional anisotropy (FA) and mean diffusivity (MD) of each spinal root were extracted by two independent review authors. Generalised linear modelling was used to estimate the effect of experimental conditions on the FA and MD. Meta-analysis of root-level estimates was performed using Cohen’s method with random effects. Results Nine articles, describing 316 adults (1:1 male:female) of mean age 35 years (SD 6) were included. Increments of ten diffusion sensitising gradient directions reduced the mean FA by 0.01 (95% CI 0.01, 0.03). Each year of life reduced the mean MD by 0.03 × 10–3 mm2/s (95% CI 0.01, 0.04). At 3-T, the pooled mean FA of the roots was 0.36 (95% CI 0.34, 0.38; I2 98%). The pooled mean MD of the roots was 1.51 × 10–3 mm2/s (95% CI 1.45, 1.56; I2 99%). Conclusions The FA and MD of the roots of the brachial plexus vary according to experimental conditions and participant factors. We provide summary estimates of the normative values in different conditions which may be valuable to researchers and clinicians alike.

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