Personalized pathology maps to quantify diffuse and focal brain damage

Bonnier, Guillaume; Fischi-Gómez, Elda; Roche, Alexis; Hilbert, Tom; Kober, Tobias; Krueger, Gunnar; Granziera, Cristina

doi:10.1016/j.nicl.2018.11.017

Cited by 16 publications

(44 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, the average within-subject CoV was lower than the between-subject CoV, indicating that partial volume effects and registration quality affected the between-subject figure. These issues are not unique to ihMTR but affect all quantitative MRI measures 66 , 67 .…”

Section: Discussionmentioning

confidence: 99%

Silent myelin-weighted magnetic resonance imaging

et al. 2020

View full text Add to dashboard Cite

Background: Inhomogeneous Magnetization Transfer (ihMT) is an emerging, uniquely myelin-specific magnetic resonance imaging (MRI) contrast. Current ihMT acquisitions utilise fast Gradient Echo sequences which are among the most acoustically noisy MRI sequences, reducing patient comfort during acquisition. We sought to address this by modifying a near silent MRI sequence to include ihMT contrast. Methods: A Magnetization Transfer preparation module was incorporated into a radial Zero Echo-Time sequence. Repeatability of the ihMT ratio and inverse ihMT ratio were assessed in a cohort of healthy subjects. We also investigated how head orientation affects ihMT across subjects, as a previous study in a single subject suggests this as a potential confound. Results: We demonstrated that ihMT ratios comparable to existing, acoustically loud, implementations could be obtained with the silent sequence. We observed a small but significant effect of head orientation on inverse ihMTR. Conclusions: Silent ihMT imaging is a comparable alternative to conventional, noisy, alternatives. For all future ihMT studies we recommend careful positioning of the subject within the scanner.

show abstract

Section: Discussionmentioning

confidence: 99%

Silent myelin-weighted magnetic resonance imaging

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Development of a normative myelin imaging atlas, to which individual patients can be compared, can address these challenges. Atlas‐based approaches for magnetic resonance (MR) methods influenced by myelin have been implemented for a number of different quantitative imaging techniques, including diffusion, T 1 , T 2 , MT, and mcDESPOT‐derived myelin water assessment …”

Section: Introductionmentioning

confidence: 99%

Myelin Water Atlas: A Template for Myelin Distribution in the Brain

Liu

Rubino

Dvorak

et al. 2019

Journal of Neuroimaging

View full text Add to dashboard Cite

BACKGROUND AND PURPOSE: Myelin water imaging (MWI) is a magnetic resonance imaging technique that quantifies myelin in-vivo. Although MWI has been extensively applied to study myelin-related diseases in groups, clinical use in individual patients is challenging mainly due to population heterogeneity. The purpose of this study was twofold: (1) create a normative brain myelin water atlas depicting the population mean and regional variability of myelin content; and (2) apply the myelin atlas to assess the degree of demyelination in individuals with multiple sclerosis (MS). METHODS: 3T MWI was performed on 50 healthy adults (25 M/25 F, mean age 25 years [range 17-42 years]). The myelin water atlas was created by averaging coregistered myelin water fraction (MWF) maps from all healthy individuals. To illustrate the preliminary utility of the atlas, white matter (WM) regional MWF variations were evaluated and voxel-wise z-score maps (z < −1.96) from the MWI of three MS participants were produced to assess individually the degree of demyelination. RESULTS: The myelin water atlas demonstrated significant MWF variation across control WM. No significant MWF differences were found between male and female healthy participants. MS z-score maps revealed diffuse regions of demyelination in the two participants with Expanded Disability Status Scale (EDSS) = 2.0 but not in the participant with EDSS = 0. CONCLUSIONS:The myelin water atlas can be used as a reference (URL: https://sourceforge.net/projects/myelin-wateratlas/) to demonstrate areas of demyelination in individual MS participants. Future studies will expand the atlas age range, account for education, and other variables that may affect myelination.

show abstract

“…Previously established norms for brain relaxation times pooled values from different brain regions, missing the spatial specificity of a voxel‐by‐voxel atlases as established here, or were not further explored for single‐subject comparisons . Moreover, in previously reported single‐subject comparison studies based on relaxometry data, reference values were derived by averaging the respective tissue property across the entire HC, as well as in other imaging studies based on diffusion or myelin water imaging data. Conversely, our proposed method allows including confounding factors in the normative atlases such as sex and age of the subjects.…”

Section: Discussionmentioning

confidence: 99%

“…Although quantitative maps are better comparable across scanners and sites, they only have limited direct clinical value. To fully exploit the information provided by T 1 and T 2 maps, normative values for relaxometry in healthy tissue are required, enabling the comparison of tissue properties from a single patient to normal values . Furthermore, the quantification of changes in T 1 and T 2 with respect to norm values promotes the definition of imaging biomarkers for characterization of pathologies, potentially improving diagnosis and follow‐up assessments by correlating T 1 and T 2 variations with the undergoing microstructural changes.…”

Section: Introductionmentioning

confidence: 99%

Quantitative brain relaxation atlases for personalized detection and characterization of brain pathology

Piredda

Hilbert

Granziera

et al. 2019

Magnetic Resonance in Med

View full text Add to dashboard Cite

Purpose To exploit the improved comparability and hardware independency of quantitative MRI, databases of MR physical parameters in healthy tissue are required, to which tissue properties of patients can be compared. In this work, normative values for longitudinal and transverse relaxation times in the brain were established and tested in single‐subject comparisons for detection of abnormal relaxation times. Methods Relaxometry maps of the brain were acquired from 52 healthy volunteers. After spatially normalizing the volumes into a common space, T1 and T2 inter‐subject variability within the healthy cohort was modeled voxel‐wise. A method for a single‐subject comparison against the atlases was developed by computing z‐scores with respect to the established healthy norms. The comparison was applied to two multiple sclerosis and one clinically isolated syndrome cases for a proof of concept. Results The established atlases exhibit a low variation in white matter structures (median RMSE of models equal to 32 ms for T1 and 4 ms for T2), indicating that relaxation times are in a narrow range for normal tissues. The proposed method for single‐subject comparison detected relaxation time deviations from healthy norms in the example patient data sets. Relaxation times were found to be increased in brain lesions (mean z‐scores >5). Moreover, subtle and confluent differences (z‐scores ~2–4) were observed in clinically plausible regions (between lesions, corpus callosum). Conclusions Brain T1 and T2 quantitative norms were derived voxel‐wise with low variability in healthy tissue. Example patient deviation maps demonstrated good sensitivity of the atlases for detecting relaxation time alterations.

show abstract

Personalized pathology maps to quantify diffuse and focal brain damage

Cited by 16 publications

References 57 publications

Silent myelin-weighted magnetic resonance imaging

Silent myelin-weighted magnetic resonance imaging

Myelin Water Atlas: A Template for Myelin Distribution in the Brain

Quantitative brain relaxation atlases for personalized detection and characterization of brain pathology

Contact Info

Product

Resources

About