Myelin Mapping Techniques in Neuroimaging

Myelin mapping techniques have transformed our ability to probe the organisation and integrity of white matter non-invasively. By exploiting magnetic resonance imaging contrasts sensitive to the lipid‐rich sheath surrounding axons, researchers can infer local myelin content across the cortex and subcortical regions. Quantitative approaches such as relaxometry (measuring T1 and T2 relaxation times), ratio-based methods (for example T1-weighted/T2-weighted images), magnetisation transfer imaging and susceptibility mapping each provide complementary insights into myelin distribution. Ultra-high field systems enhance spatial resolution and contrast, enabling layer-specific analyses of cortical laminae and the fine-grained parcellation of brain regions. Advanced pulse sequences, including MP2RAGE and prototype rapid T2 mapping, facilitate standardised, reproducible maps of myelin proxies in clinically acceptable times. These methods support investigations of normal development, ageing, psychiatric and neurodegenerative disorders, and environmental influences on brain health. By integrating multiple quantitative contrasts and biophysical modelling, current research aims to increase specificity for myelin detection, improve across-subject normalisation and establish robust biomarkers for precision medicine.

Research from Nature Portfolio

Recent studies have leveraged the ratio of T1-weighted to T2-weighted signal intensities to chart cortical microstructure in relation to social and environmental factors. Analyses across cortical depths revealed region-specific variations in the T1w/T2w ratio, linking lower values in sensorimotor areas with adversity and higher values in limbic regions with dietary metrics. Body mass index emerged as a partial mediator between environmental disadvantage and myelin-related signal changes, emphasising the interplay between physiology, lifestyle and cortical myelination. Earlier foundational work applied quantitative R1 mapping in mood disorders, demonstrating globally reduced myelin proxies in key affective circuitry, such as the nucleus accumbens and prefrontal cortices. These findings firmly establish quantitative relaxometry as a sensitive tool for detecting subtle myelin alterations in both health and disease.

Myelin Mapping Techniques in Neuroimaging publication trend

The graph below shows the total number of articles in myelin mapping techniques in neuroimaging across all publications each year (not limited to Nature Index journals).

Technical terms

Myelin: A lipid-rich sheath around axons that increases conduction speed and supports neural circuit efficiency.

Quantitative MRI (qMRI): A family of techniques that measure physical tissue properties (such as T1 or T2 relaxation times) to derive absolute maps, rather than relative intensity images.

T1 relaxation time: The time constant governing recovery of longitudinal magnetisation, inversely related to myelin content in white matter.

MP2RAGE: A magnetisation-prepared sequence that yields uniform T1 maps and high-contrast structural images independent of transmit field inhomogeneity.

T1w/T2w ratio: A simple ratio of T1-weighted to T2-weighted image intensities used as a proxy measure of cortical myelin distribution.

References

1. Whole brain myelin mapping using T1- and T2-weighted MR imaging data. Frontiers in Human Neuroscience (2014).
2. Waves of Maturation and Senescence in Micro-structural MRI Markers of Human Cortical Myelination over the Lifespan. Cerebral Cortex (2018).
3. Normative volumes and relaxation times at 3T during brain development. Scientific Data (2024).
4. Mediation of the association between disadvantaged neighborhoods and cortical microstructure by body mass index. Communications Medicine (2023).
5. In-vivo magnetic resonance imaging (MRI) of laminae in the human cortex. NeuroImage (2017).
6. Microstructural Parcellation of the Human Cerebral Cortex – From Brodmann's Post-Mortem Map to in vivo Mapping with High-Field Magnetic Resonance Imaging. Frontiers in Human Neuroscience (2011).
7. New Developments and Applications of the MP2RAGE Sequence - Focusing the Contrast and High Spatial Resolution R1 Mapping. PLOS ONE (2013).
8. Myelination of the brain in Major Depressive Disorder: An in vivo quantitative magnetic resonance imaging study. Scientific Reports (2017).