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

髓鞘的精确非侵入性成像对于监测脱髓鞘疾病是至关重要的，多发性硬化症和髓鞘再生治疗的有效性。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非侵入性但间接地检测髓鞘，例如扩散张量成像（DTI）;磁化转移（MT）和多组分弛豫法。这些QMRI测量在不同程度上与髓鞘染色的组织学和成像模型相关。然而，QMRI和组织学的系统比较被空间分辨率差异、大脑的化学固定和“撕裂和撕裂”以及切片的较大失真所混淆。这些问题可以通过使用新型MRI“微线圈”对QMRI和组织学的相同薄脑切片进行成像来克服。与MRI线圈制造商PulseTeq合作，将构建和优化此类线圈。使用这些微线圈从脑组织获得的数据将允许确定髓鞘和不同QMRI测量之间的确切关系。一旦确定了不同QMRI方法与基于组织化学的髓鞘指数之间的关系，这些知识将被外推到将这些QMRI方法应用于更大的脑样品和整个脑，使用脱髓鞘-髓鞘再生（cuprizone）小鼠模型作为试验床。

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.