We used ultra-high field MRI to visualize cortical lesion types described by neuropathology in 16 patients with multiple sclerosis (MS) compared with 8 age-matched controls; to characterize the ...contrast properties of cortical lesions including T2*, T2, T1, and phase images; and to investigate the relationship between cortical lesion types and clinical data.
We collected, on a 7-T scanner, 2-dimensional fast low-angle shot (FLASH)-T2*-weighted spoiled gradient-echo, T2-weighted turbo spin-echo (TSE) images (0.33 x 033 x 1 mm(3)), and a 3-dimensional magnetization-prepared rapid gradient echo.
Overall, 199 cortical lesions were detected in patients on both FLASH-T2* and T2-TSE scans. Seven-tesla MRI allowed for characterization of cortical plaques into type I (leukocortical), type II (intracortical), and type III/IV (subpial extending partly or completely through the cortical width) lesions as described histopathologically. Types III and IV were the most frequent type of cortical plaques (50.2%), followed by type I (36.2%) and type II (13.6%) lesions. Each lesion type was more frequent in secondary progressive than in relapsing-remitting MS. This difference, however, was significant only for type III/IV lesions. T2*-weighted images showed the highest, while phase images showed the lowest, contrast-to-noise ratio for all cortical lesion types. In patients, the number of type III/IV lesions was associated with greater disability (p < 0.02 by Spearman test) and older age (p < 0.04 by Spearman test).
Seven-tesla MRI detected different histologic cortical lesion types in our small multiple sclerosis (MS) sample, suggesting, if validated in a larger population, that it may prove a valuable tool to assess the contribution of cortical MS pathology to clinical disability.
Objective
Magnetic resonance imaging (MRI) is essential for multiple sclerosis diagnostics but is conventionally not specific to demyelination. Myelin imaging is often hampered by long scanning ...times, complex postprocessing, or lack of clinical approval. This study aimed to assess the specificity, robustness, and clinical value of Rapid Estimation of Myelin for Diagnostic Imaging, a new myelin imaging technique based on time‐efficient simultaneous T1/T2 relaxometry and proton density mapping in multiple sclerosis.
Methods
Rapid myelin imaging was applied using 3T MRI ex vivo in 3 multiple sclerosis brain samples and in vivo in a prospective cohort of 71 multiple sclerosis patients and 21 age/sex‐matched healthy controls, with scan–rescan repeatability in a subcohort. Disability in patients was assessed by the Expanded Disability Status Scale and the Symbol Digit Modalities Test at baseline and 2‐year follow‐up.
Results
Rapid myelin imaging correlated with myelin‐related stains (proteolipid protein immunostaining and Luxol fast blue) and demonstrated good precision. Multiple sclerosis patients had, relative to controls, lower normalized whole‐brain and normal‐appearing white matter myelin fractions, which correlated with baseline cognitive and physical disability. Longitudinally, these myelin fractions correlated with follow‐up physical disability, even with correction for baseline disability.
Interpretation
Rapid Estimation of Myelin for Diagnostic Imaging provides robust myelin quantification that detects diffuse demyelination in normal‐appearing tissue in multiple sclerosis, which is associated with both cognitive and clinical disability. Because the technique is fast, with automatic postprocessing and US Food and Drug Administration/CE clinical approval, it can be a clinically feasible biomarker that may be suitable to monitor myelin dynamics and evaluate treatments aiming at remyelination. ANN NEUROL 2020;87:710–724
Introduction
Cognitive complaints and psychological distress are common in oncologic patients, in particular many studies have focused on women with breast cancer.Patients presenting the phenomenon ...of “chemofog” show changes after chemotherapy with regard to memory and emotional regulaiton.
Objectives
To explore brain connectivity prior to chemotherapy that nevertheless,is understudied.
Methods
We used fMRI to investigate the resting state connectivity in 24 patients before chemotherapy and 15 controls.Patients were assessed with self-administered questionnaires,such as the Patient’s Assessment of Own Functioning Inventory (PAOFI) that quantifies the decrease in perceived functioning in memory, language and problem solving (Image 1).We used a preliminary structural analysis in order to choose which neuropsychological test was affected in correlation with a significant anatomical volume alteration,as showed in the p-value table.Therefore, patients were ranked and divided into two group of “Impaired vs Preserved”, measured using the median of the questionnaire results.Higher scores indicate a poor cognitive self-perceived performance.
Results
Connectivity was altered in amygdala and hippocampus, in the subgroup of patients with higher subjective cognitive complaints i.e with a high PAOFI Memory score.More specifically, we found an association between memory impairment and the increase of the resting state connectivity of both right structures, as opposed to a reduction in left amygdala (Image 3).
Conclusions
These findings may suggest a potential effect on brain functional connectivity of the psychological awareness and stress of cancer itself. We found connectivity alterations for both amygdala and hippocampus, two structures belonging to the limbic system, that is involved in the interplay between cognition and emotions, such as anxiety and fear.
Recently, T2* imaging at 7Tesla (T) MRI was shown to reveal microstructural features of the cortical myeloarchitecture thanks to an increase in contrast-to-noise ratio. However, several confounds ...hamper the specificity of T2* measures (iron content, blood vessels, tissues orientation). Another metric, magnetization transfer ratio (MTR), is known to also be sensitive to myelin content and thus would be an excellent complementary measure because its underlying contrast mechanisms are different than that from T2*. The goal of this study was thus to combine MTR and T2* using multivariate statistics in order to gain insights into cortical myelin content.
Seven healthy subjects were scanned at 7T and 3T to obtain T2* and MTR data, respectively. A multivariate myelin estimation model (MMEM) was developed, and consists in (i) normalizing T2* and MTR values and (ii) extracting their shared information using independent component analysis (ICA). B0 orientation dependence and cortical thickness were also computed and included in the model.
Results showed high correlation between MTR and T2* in the whole cortex (r=0.76, p<10−16), suggesting that both metrics are partly driven by a common source of contrast, here assumed to be the myelin. Average MTR and T2* were respectively 31.0+/−0.3% and 32.1+/−1.4ms. Results of the MMEM spatial distribution showed similar trends to that from histological work stained for myelin (r=0.77, p<0.01). Significant right-left differences were detected in the primary motor cortex (p<0.05), the posterior cingulate cortex (p<0.05) and the visual cortex (p<0.05).
This study demonstrates that MTR and T2* are highly correlated in the cortex. The combination of MTR, T2*, CT and B0 orientation may be a useful means to study cortical myeloarchitecture with more specificity than using any of the individual methods. The MMEM framework is extendable to other contrasts such as T1 and diffusion MRI.
Ultra-high-field MR imaging in multiple sclerosis Filippi, Massimo; Evangelou, Nikos; Kangarlu, Alayar ...
Journal of neurology, neurosurgery and psychiatry,
01/2014, Letnik:
85, Številka:
1
Journal Article
Recenzirano
In multiple sclerosis (MS), MRI is the most important paraclinical tool used to inform diagnosis and for monitoring disease evolution, either natural or modified by treatment. The increased ...availability of ultra-high-field magnets (7 Tesla or higher) gives rise to questions about the main benefits of and challenges for their use in patients with MS. The main advantages of ultra-high-field MRI are the improved signal-to-noise ratio, greater chemical shift dispersion, and improved contrast due to magnetic susceptibility variations, which lead to increased sensitivity to the heterogeneous pathological substrates of the disease. At present, ultra-high-field MRI is mainly used to improve our understanding of MS pathogenesis. This review discusses the main achievements that have so far come from the use of these scanners, which are: better visualisation of white matter lesions and their morphological characteristics; an improvement in the ability to visualise grey matter lesions and their exact location; the quantification of 'novel' metabolites which may have a role in axonal degeneration; and greater sensitivity to iron accumulation. The application of ultra-high-field systems in standard clinical practice is still some way off since their role in the diagnostic work-up of patients at presentation with clinically isolated syndromes, or in monitoring disease progression or treatment response in patients with definite MS, needs to be established. Additional challenges remain in the development of morphological, quantitative and functional imaging methods at these field strengths, techniques which may ultimately lead to novel biomarkers for monitoring disease evolution and treatment response.
ABSTRACT
BACKGROUND AND PURPOSE
Hereditary diffuse leukoencephalopathy with spheroids (HDLS) and multiple sclerosis (MS) are demyelinating and neurodegenerative disorders that can be hard to ...distinguish clinically and radiologically. HDLS is a rare disorder compared to MS, which has led to occurrent misdiagnosis of HDLS as MS. That is problematic since their prognosis and treatment differ. Both disorders are investigated by MRI, which could help to identify patients with high probability of having HDLS, which could guide targeted genetic testing to confirm the HDLS diagnosis.
METHODS
Here, we present a machine learning method based on quantitative MRI that can achieve a robust classification of HDLS versus MS. Four HDLS and 14 age‐matched MS patients underwent a quantitative brain MRI protocol (synthetic MRI) at 3 Tesla (T) (scan time <7 minutes). We also performed a repeatability analysis of the predicting features to assess their generalizability by scanning a healthy control with five scan‐rescans at 3T and 1.5T.
RESULTS
Our predicting features were measured with an average confidence interval of 1.7% (P = .01), at 3T and 2.3% (P = .01) at 1.5T. The model gave a 100% correct classification of the cross‐validation data when using 5‐11 predicting features. When the maximum measurement noise was inserted in the model, the true positive rate of HDLS was 97.2%, while the true positive rate of MS was 99.6%.
CONCLUSIONS
This study suggests that computer‐assistance in combination with quantitative MRI may be helpful in aiding the challenging differential diagnosis of HDLS versus MS.
Cortical subpial demyelination is frequent in multiple sclerosis (MS) and is closely associated with disease progression and poor neurological outcome. Although cortical lesions have been difficult ...to detect using conventional MRI, preliminary data using T2*-weighted imaging at ultra-high field 7T MRI showed improved sensitivity for detecting and categorizing different histological types of cortical MS lesions. In this study we combined high-resolution 7T MRI with a surface-based analysis technique to quantify and map subpial T2*-weighted signal changes in seventeen patients with MS. We applied a robust method to register 7T data with the reconstructed cortical surface of each individual and used a general linear model to assess in vivo an increase in subpial T2*-weighted signal in patients versus age-matched controls, and to investigate the spatial distribution of cortical subpial changes across the cortical ribbon. We also assessed the relationship between subpial T2* signal changes at 7T, Expanded Disability Status Scale (EDSS) score and white matter lesion load (WMLL). Patients with MS showed significant T2*-weighted signal increase in the frontal lobes (parsopercularis, precentral gyrus, middle and superior frontal gyrus, orbitofrontal cortex), anterior cingulate, temporal (superior, middle and inferior temporal gyri), and parietal cortices (superior and inferior parietal cortex, precuneus), but also in occipital regions of the left hemisphere. We found significant correlations between subpial T2*-weighted signal and EDSS score in the precentral gyrus (ρ=0.56, P=0.02) and between T2*-weighted signal and WMLL in the lateral orbitofrontal, superior parietal, cuneus, precentral and superior frontal regions. Our data support the presence of disseminated subpial increases in T2* signal in subjects with MS, which may reflect the diffuse subpial pathology described in neuropathology.
Background: Sex related differences in the course and severity of multiple sclerosis (MS) could be mediated by the sex hormones. Objective: To investigate the relation between serum sex hormone ...concentrations and characteristics of tissue damage on conventional magnetic resonance imaging (MRI) in men and women suffering from relapsing-remitting MS. Results: Serum testosterone was significantly lower in women with MS than in controls. The lowest levels were found in women with a greater number of gadolinium enhancing lesions. A positive correlation was observed between testosterone concentrations and both tissue damage on MRI and clinical disability. In men, there was a positive correlation between oestradiol concentrations and brain damage. Conclusions: The hormone related modulation of pathological changes supports the hypothesis that sex hormones play a role in the inflammation, damage, and repair mechanisms typical of MS.
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