Myelin Measurement Using Quantitative Magnetic Resonance Imaging: A Correlation Study Comparing Various Imaging Techniques in Patients with Multiple Sclerosis

Abstract

Evaluation of myelin by magnetic resonance imaging (MRI) is a difficult challenge, but holds promise in demyelinating diseases, such as multiple sclerosis (MS). Although multiple techniques have been developed, no gold standard has been established. This study aims to evaluate the correlation between synthetic MRI myelin volume fraction (SyMRIMVF) and myelin fraction estimated by other techniques, i.e., magnetization transfer saturation (MTsat), T1-weighted images divided by T2-weighted images (T1w/T2w), and radial diffusivity (RD) in patients with MS. We also compared the sensitivities of these techniques for detecting MS-related myelin damage. SyMRIMVF, MTsat, T1w/T2w, and RD were averaged on plaque, periplaque white matter, and normal-appearing white matter (NAWM). Pairwise correlation was calculated using Spearman’s correlation analysis. For all segmented regions, strong correlations were found between SyMRIMVF and T1w/T2w (Rho = 0.89), MTsat (Rho = 0.82), or RD (Rho = −0.75). For each technique, the average estimated myelin differed significantly among regions, but the percentage change of NAWM from both periplaque white matter and plaque were highest in SyMRIMVF. SyMRIMVF might be suitable for myelin evaluation in MS patients, with relevant results as compared to other well-studied techniques. Moreover, it presented better sensitivity for the detection of the difference between plaque or periplaque white matter and NAWM.

Age-Related Changes in Relaxation Times, Proton Density, Myelin, and Tissue Volumes in Adult Brain Analyzed by 2-Dimensional Quantitative Synthetic Magnetic Resonance Imaging

“… 1 Quantitative synthetic MRI is typically performed through a commercial 2-dimensional (2D) multidynamic multiecho (MDME) sequence, providing simultaneous quantification of T1, T2, and PD, with a scan time of about 5 to 6 minutes for full head coverage. 16 Quantitative synthetic MRI has enabled objective evaluation of diseases such as Alzheimer disease, 19 multiple sclerosis, 20 – 22 brain infarction, 23 brain tumor, 24 , 25 and Sturge-Weber syndrome. 26 Using dedicated software, we can also automatically obtain brain parenchymal volume (BPV), white matter volume (WMV), and gray matter volume (GMV), based on these quantitative values.…”

“… 28 Myelin volume fraction derived from quantitative synthetic MRI has been validated by postmortem imaging 29 , 30 and comparison with other myelin imaging techniques. 22 , 31 …”

Myelin and Axonal Damage in Normal-Appearing White Matter in Patients with Moyamoya Disease

“…Because many myelin-specific imaging techniques are available, it is possible that different types of myelin-sensitive imaging might show different results. [33][34][35][36] Given the complicated postprocessing, myelin imaging may not be practical for routine application in clinical settings compared with conventional diffusion parameters (On-line Table 2). Despite these limitations, this study is the first to directly investigate myelin damage using a myelin-sensitive MR imaging technique in adult patients with MMD and its relationship with cognitive function.…”

6-month aerobic walking training increases T1w/T2w signal in the white matter of healthy older adults

“…Indeed, previous studies using the T1w/T2w showed a strong correlation with myelin volume fraction in human WM (Saccenti et al, 2020), oligodendrocyte-specific gene expression in humans (Patel et al, 2020), and with cortical myelin as compared to histological myeloarchitectural studies in both humans and non-human primates (Glasser & van Essen, 2011). However, others have found that the T1w/T2w correlated with MRI estimates of axonal diameter (Arshad et al, 2017), axonal density (Fukutomi et al, 2018), and iron content in healthy adults (Shams et al, 2019).…”