目的评价化学位移成像（chemical shift imaging，CSI）和MRS两种方法在脂肪研究中的作用，为进一步活体实验提供定量标准。方法在7．0TMR成像仪上运用CSI和MRS方法对体外水脂模型进行水脂定量分析。体外水脂模型的脂肪含量从0～100％平均分成11个组，各组间浓度相差10％，分别应用水、脂肪选择性CSI和1H—MRS对体外水脂模型进行图像和波谱数据采集，对2种方法所得结果分别与实际水脂含量进行单样本t检验及相关分析并比较两种方法间的相关性。MRS计算100％油模型饱和脂肪酸（fraction of saturatedfattyacids，FS）、不饱和脂肪酸（fraction of unsaturatedfattyacids，FU）的相对含量及多聚不饱和程度（polyunsaturation degree，PUD）。结果CSI法测定实际脂肪含量为50％-100％的测量值分别为（48．0±1．0）％、（57．0±0．5）％、（67．3±0．6）％、（77．3±0．6）％、（83．3±0．6）％和（91．0±1．0）％；MRS测定实际脂肪含量为10％-60％的测量值分别为（8．3±0．6）％、（16．3±0．7）％、（27．7±0．6）％、（36．0±1．0）％、（43．5±0．6）％和（56．5±1．0）％，均轻度低估了脂肪含量，差异均有统计学意义（P值均〈0．05）。CSI与MRS计算的脂肪含量与实际脂肪含量间均呈线性相关（CSI：r=0．998，MRS：r=0．996；P值均〈0．01）；两种方法间也呈线性相关（r=0．992，P〈0．01），两种方法定量脂肪含量差异无统计学意义（t=-0．125，P=0．903）。MRS计算橄榄油的FS和FU相对含量分别为0．15和0．85，PUD为0．0325，与实际含量一致。结论在7．0TMR成像仪上，体外水脂模型证实CSI和MRS定量脂肪的准确性及在脂肪研究上的可行性。
Lipodystrophies are clinically heterogeneous acquired or inherited disorders characterized by selective loss of the adipose tissue. Non-invasive in vivo phenotyping of adipose tissue deposits in small animal models of the disease is studied using 7T magnetic resonance imaging （MRI）. Pseudo image and multi-weight MRI methods show that the fat of seipin mice is virtually absent compared with WT mice. The three-dimensional （3-D） small animal visualization system for 7T MRI developed in this project facilitates to obtain the interested feature with stroke-based classification method. Student＇s t-test statistic result confirms that total fat and subcutaneous fat are less in seipin mice than those in WT mice. However, the visceral fat difference is not found in the experiment. Based on 7T MIRI, the study gives more reliable information on location and lipid contents of the tissue about seipin mice, thus it is important to explore the pathophysiological characteristics of the disease.
