生物组织脂类材料探测和分析方法研究

脂肪是一种生物组织脂类材料，在人体代谢活动中发挥重要作用，与骨质疏松等多种代谢疾病密切相关。脂肪定量是脂类材料研究的重要部分，磁共振成像是脂肪定量的主要途径之一，其中Z谱成像（Z-spectral imaging，ZSI）技术可基于饱和效应获取大分子的频谱分布信息，为脂肪定量研究提供新途径。

本文以3.0 T磁共振成像系统和9.4 T磁共振波谱仪为研究平台，基于纯油仿体和脂肪含量介于0~40%的水脂仿体，对ZSI序列中重复时间和饱和能量进行优化；发展高斯洛伦兹模型，拟合化学位移为-3.8、-3.4、-2.7、-2.0、-0.5、0.6 ppm的6个脂肪峰；招募了15名健康志愿者（男性7名，女性8名，平均年龄为27.5±6岁）和14名骨质疏松患者（男性4名，女性10名，平均年龄为62.5±11.5岁），使用发展的ZSI技术扫描其第四腰椎进行骨髓脂肪定量。结果显示，在纯油仿体中，重复时间为1.6 s，饱和能量为0.25 μT时，ZSI方法所得的6个脂肪峰幅值与核磁波谱结果呈现高度一致（R²=0.951，P<0.001）。在6个脂肪含量不同的水脂仿体中，由ZSI所得水脂分数与仿体实际脂肪含量高度相关（R²=0.982，P<0.001）。人体实验研究中，健康组6个归一化后的脂肪峰幅值显著低于患者组（P=0.004；P<0.001；P<0.001；P=0.001；P=0.004；P=0.002）。此外，健康组的水脂分数（36.3%±8.7%）显著低于患者组（55.3%±6.0%，P<0.001），而不饱和脂肪分数（17.0%±3.5%）则显著高于患者组（12.8%±2.1%，P=0.004）。

本文优化了可用于脂肪定量的ZSI技术，并在脂肪波谱成像中展示了其有效性。在健康志愿者与骨质疏松患者的人体实验中，其第四腰椎骨髓中归一化后的6个脂肪峰幅值以及水脂分数和不饱和脂肪分数均存在显著差异，为了解脂肪相关病变提供补充信息。ZSI技术兼备优异的空间分辨率和频谱分辨率等特点，可以成为人体脊柱骨髓脂肪定量新方法，为生物组织脂肪材料定量成像提供便利。

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