The Combined Quantification and Interpretation of Multiple Quantitative Magnetic Resonance Imaging Metrics Enlightens Longitudinal Changes Compatible with Brain Repair in Relapsing-Remitting Multiple Sclerosis Patients

Bonnier, Guillaume; Maréchal, Bénédicte; Fartaria, Mário João; Falkowskiy, Pavel; Marques, José P.; Simioni, Samanta; Schluep, Myriam; Pasquier, Renaud Du; Thiran, Jean‐Philippe; Krueger, Gunnar; Granziera, Cristina

doi:10.3389/fneur.2017.00506

Cited by 30 publications

(72 citation statements)

References 48 publications

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“…In consequence, this would prolong the scan time far beyond what is clinically acceptable, compromising the applicability of our approach. In addition, the proposed T 2 mapping strategy has been proved to deliver maps in agreement with conventional techniques and with excellent reproducibility, as well as good sensitivity toward T 2 alterations caused by pathologies . Lastly, it should be noted that fitting errors leading to an inaccurate estimation of T 1 and T 2 values were not discussed here, because these can be found in the original publications …”

Section: Discussionmentioning

confidence: 96%

“…In addition, the proposed T 2 mapping strategy has been proved to deliver maps in agreement with conventional techniques and with excellent reproducibility, 16 as well as good sensitivity toward T 2 alterations caused by pathologies. 4,6,46,47 Lastly, it should be noted that fitting errors leading to an inaccurate estimation of T 1 and T 2 values were not discussed here, because these can be found in the original publications. 14,16 The main limitation of our current HC is the narrow age range of healthy subjects included in the study and restricts the use of the method to patients whose ages fall into this very range.…”

Section: Discussionmentioning

confidence: 99%

“…Conversely, quantitative MRI (qMRI) techniques allow moving from such relative contrast information to a single, absolute measure of one or more separate tissue properties, hence providing the means for tissue characterization and the potential to gain further insight into microstructural changes caused by diseases . Moreover, the quantitative nature of the images may potentially overcome problems related to image reproducibility and interpretation, facilitating comparison in longitudinal and multi‐centric studies …”

Section: Introductionmentioning

confidence: 99%

“…3 Moreover, the quantitative nature of the images may potentially overcome problems related to image reproducibility and interpretation, facilitating comparison in longitudinal and multi-centric studies. 4,5 Brain relaxometry measures proved to be of value in several neurological diseases because alterations of T 1 and T 2 were related to neuronal cell death, axonal loss, and demyelination processes. [6][7][8] One target pathology for these techniques is multiple sclerosis (MS), a neurodegenerative and inflammatory disease of the central nervous system characterized by white matter (WM) and gray matter (GM) lesions, as well as inflammation of normal-appearing white matter (NAWM).…”

Section: Introductionmentioning

confidence: 99%

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

Piredda

Hilbert

Granziera

et al. 2019

Magnetic Resonance in Med

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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.

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Piredda

Hilbert

Granziera

et al. 2019

Magnetic Resonance in Med

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“…One possible explanation for non-enhancing MS lesions having relaxation and PD values that overlap with enhancing lesions is remyelination, which occurs in some lesions. [97][98][99] The number of enhancing MS lesions was rather small in this study, which is a limitation. Even though care was taken during manual ROI delineation of lesions not to include other structures to avoid partial volume, images were only available in the axial plane.…”

Section: Paper IImentioning

confidence: 89%

Clinical Applications of Synthetic MRI of the Brain

Blystad¹

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Magnetic Resonance Imaging (MRI) has a high soft-tissue contrast with a high sensitivity for detecting pathological changes in the brain. Conventional MRI is a time-consuming method with multiple scans that relies on the visual assessment of the neuroradiologist. Synthetic MRI uses one scan to produce conventional images, but also quantitative maps based on relaxometry, that can be used to quantitatively analyse tissue properties and pathological changes. The studies presented here apply the use of synthetic MRI of the brain in different clinical settings. In the first study, synthetic MR images were compared to conventional MR images in 22 patients. The contrast, the contrast-to-noise ratio, and the diagnostic quality were assessed. Image quality was perceived to be inferior in the synthetic images, but synthetic images agreed with the clinical diagnoses to the same extent as the conventional images. Patients with early multiple sclerosis were analysed in the second study. In patients with multiple sclerosis, contrast-enhancing white matter lesions are a sign of active disease and can indicate a need for a change in therapy. Gadolinium-based contrast agents are used to detect active lesions, but concern has been raised regarding the long-term effects of repeated use of gadolinium. In this study, relaxometry was used to evaluate whether pre-contrast injection tissue-relaxation rates and proton density can identify active lesions without gadolinium. The findings suggest that active lesions often have relaxation times and proton density that differ from non-enhancing lesions, but with some overlap. This makes it difficult to replace gadolinium-based contrast agent injection with synthetic MRI in the monitoring of MS patients. Malignant gliomas are primary brain tumours with contrast enhancement due to a defective blood-brain barrier. However, they also grow in an infiltrative, diffuse manner, making it difficult to clearly delineate them from surrounding normal brain tissue in the diagnostic workup, at surgery, and during follow-up. The contrast-enhancing part of the tumour is easily visualised, but not the diffuse infiltration. In studies three and four, synthetic MRI was used to analyse the peritumoral area of malignant gliomas, and revealed quantitative findings regarding peritumoral relaxation changes and non-visible contrast enhancement suggestive of non-visible infiltrative tumour growth. In conclusion, synthetic MRI provides quantitative information about the brain tissue and this could improve the diagnosis and treatment for patients

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Advanced MRI Measures of Myelin and Axon Volume Identify Repair in Multiple Sclerosis

Sanabria‐Diaz,

Cagol,

et al. 2024

Annals of Neurology

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ObjectivePathological studies suggest that multiple sclerosis (MS) lesions endure multiple waves of damage and repair; however, the dynamics and characteristics of these processes are poorly understood in patients living with MS.MethodsWe studied 128 MS patients (75 relapsing–remitting, 53 progressive) and 72 healthy controls who underwent advanced magnetic resonance imaging and clinical examination at baseline and 2 years later. Magnetization transfer saturation and multi‐shell diffusion imaging were used to quantify longitudinal changes in myelin and axon volumes within MS lesions. Lesions were grouped into 4 classes (repair, damage, mixed repair damage, and stable). The frequency of each class was correlated to clinical measures, demographic characteristics, and levels of serum neurofilament light chain (sNfL).ResultsStable lesions were the most frequent (n = 2,276; 44%), followed by lesions with patterns of “repair” (n = 1,352; 26.2%) and damage (n = 1,214; 23.5%). The frequency of “repair” lesion was negatively associated with disability (β = −0.04; p < 0.001) and sNfL (β = −0.16; p < 0.001) at follow‐up. The frequency of the “damage” class was higher in progressive than relapsing–remitting patients (p < 0.05) and was related to disability (baseline: β = −0.078; follow‐up: β = −0.076; p < 0.001) and age (baseline: β = −0.078; p < 0.001). Stable lesions were more frequent in relapsing–remitting than in progressive patients (p < 0.05), and in younger patients versus older (β = −0.07; p < 0.001) at baseline. Further, “mixed” lesions were most frequent in older patients (β = 0.004; p < 0.001) at baseline.InterpretationThese findings show that repair and damage processes within MS lesions occur across the entire disease spectrum and that their frequency correlates with patients disability, age, disease duration, and extent of neuroaxonal damage. ANN NEUROL 2024

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The Combined Quantification and Interpretation of Multiple Quantitative Magnetic Resonance Imaging Metrics Enlightens Longitudinal Changes Compatible with Brain Repair in Relapsing-Remitting Multiple Sclerosis Patients

Cited by 30 publications

References 48 publications

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

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

Clinical Applications of Synthetic MRI of the Brain

Advanced MRI Measures of Myelin and Axon Volume Identify Repair in Multiple Sclerosis

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