Accurate non-invasive quantification of myelin by quantitative magnetic resonance imaging

髓鞘准确的无创成像对于监测脱髓鞘疾病（如多发性硬化症）和髓鞘再生治疗的有效性至关重要。现有的定量磁共振成像（QMRI）方法可以通过对局部环境或铁含量的影响来非侵入性地检测髓磷脂，例如扩散张量成像（DTI）；磁化转移（MT）和多分量弛豫测量。这些QMRI测量与髓磷脂染色的组织学和成像模型有不同程度的相关性。然而，QMRI和组织学的系统比较受到空间分辨率差异、大脑化学固定和“撕裂”以及切片造成的更大扭曲的影响。这些问题可以通过使用新型MRI“微线圈”对相同的薄脑切片进行QMRI和组织学成像来克服。与磁共振线圈制造商PulseTeq合作，这种线圈将被构建和优化。使用这些微线圈从脑组织中获得的数据将允许确定髓磷脂和不同QMRI测量之间的确切关系。一旦确定了不同的QMRI方法与基于组织化学的髓磷脂指数之间的关系，这些知识将被外推到将这些QMRI方法应用于更大的脑样本和全脑，使用脱髓鞘-再髓鞘（铜锌）小鼠模型作为测试平台。

Accurate non-invasive imaging of myelin is crucial for monitoring demyelinating diseases e.g., multiple sclerosis, and effectiveness of remyelination therapies. Existing quantitative magnetic resonance imaging (QMRI) methods can detect myelin non-invasively, but indirectly, via effects on the local environment or iron content, e.g. diffusion tensor imaging (DTI); magnetization transfer (MT) and multicomponent relaxometry. These QMRI measures correlate to varying degrees with myelin-stained histology and imaging models have been proposed. However, systematic comparison of QMRI and histology is confounded by spatial resolution differences, chemical fixation of the brain and 'rips and tears' and larger distortions from sectioning. Such issues can be overcome by imaging identical thin brain sections for both QMRI and histology using novel MRI 'micro-coils'. Working with PulseTeq, a manufacturer of MRI coils, such coils will be will be constructed and optimised. Data obtained from brain tissues using these microcoils will allow the exact relationship between myelin and different QMRI measures to be determined. Once the relationship between different QMRI methods with histochemical-based myelin indices has been determined, such knowledge will be extrapolated to applying these QMRI methods in larger brain samples and to the whole brain, using as a test-bed, a demyelination-remyelination (cuprizone) mouse model.