CNRS, CEMHTI UPR3079, Université d'Orléans, F-45071, Orléans, France.
Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Str. 6, Dresden, Germany.
Sci Rep. 2017 Aug 15;7(1):8224. doi: 10.1038/s41598-017-08458-0.
In this work, we show that it is possible to overcome the limitations of solid-state MRI for rigid tissues due to large line broadening and short dephasing times by combining Magic Angle Spinning (MAS) with rotating pulsed field gradients. This allows recording ex vivo P 3D and 2D slice-selected images of rigid tissues and related biomaterials at very high magnetic field, with greatly improved signal to noise ratio and spatial resolution when compared to static conditions. Cross-polarization is employed to enhance contrast and to further depict spatially localized chemical variations in reduced experimental time. In these materials, very high magnetic field and moderate MAS spinning rate directly provide high spectral resolution and enable the use of frequency selective excitation schemes for chemically selective imaging. These new possibilities are exemplified with experiments probing selectively the 3D spatial distribution of apatitic hydroxyl protons inside a mouse tooth with attached jaw bone with a nominal isotropic resolution nearing 100 µm.
在这项工作中，我们展示了通过将魔角旋转（MAS）与旋转脉冲磁场梯度相结合，克服固态 MRI 在刚性组织中由于线宽较大和弛豫时间短而带来的局限性。这使得在非常高的磁场下对刚性组织和相关生物材料进行体外 P3D 和 2D 切片选择成像成为可能，与静态条件相比，其信噪比和空间分辨率大大提高。交叉极化被用来增强对比度，并在更短的实验时间内进一步描绘空间局部的化学变化。在这些材料中，非常高的磁场和中等的 MAS 旋转速度直接提供了高的光谱分辨率，并能够为化学选择性成像使用频率选择激发方案。这些新的可能性通过实验得到了例证，实验选择性地探测了带有颌骨的小鼠牙齿内部磷灰石羟基质子的 3D 空间分布，其标称各向同性分辨率接近 100μm。
