IDEAL-IQ定量评价兔糖尿病模型椎体骨髓脂肪含量的可行性研究

The feasibility of IDEAL-IQ quantitative evaluation of vertebral fat fraction content in rabbit models of diabetes mellitus

目的探索定量非对称回波的最小二乘估算法迭代水脂分离序列（iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation sequence,IDEAL-IQ）定量评估兔糖尿病模型椎体骨髓脂肪含量的可行性。材料与方法12只3月龄新西兰雄性大白兔随机分为糖尿病组（n=6）和对照组（n=6）。用四氧嘧啶对糖尿病组造模,在造模成功后各时间点（0、4、8、12、16周）,对糖尿病组及对照组行腰椎矢状位T1WI、T2WI、IDEAL-IQ检查。在IDEAL-IQ脂肪分数图像测量兴趣区内脂肪含量比值;在16周处死糖尿病组和对照组的大白兔,取腰3~7椎体做HE染色脂肪细胞计数;对实验组和对照组兔各时间点的脂肪含量比值采用重复测量的方差分析;对16周实验组和对照组IDEAL-IQ测量腰椎体脂肪比参数与HE切片镜下脂肪细胞计数行Pearson相关分析。结果16周实验组兔腰椎常规矢状位T1WI和T2WI显示诸腰椎椎体信号轻度增高。常规HE染色显示,16周糖尿病组兔椎体终板下骨髓腔脂肪含量较对照组明显增多,骨髓细胞明显减少。糖尿病组各时间节点椎体骨髓的脂肪含量比值差异存在统计学意义（F=50.387,P〈0.01）,对照组各时间点脂肪含量比值差异不存在统计学意义（F=1.477,P〉0.05）;16周实验组与对照组的椎体骨髓脂肪含量比值（FF%）差异有统计学意义（t=-10.726,P〈0.01）;IDEAL-IQ测量椎体脂肪含量比与脂肪细胞计数高度正相关关系（r=0.925,P〈0.05）。结论 IDEALIQ定量评估兔糖尿病模型椎体骨髓脂肪含量是可行的。.

Abrtract Objective： To use the IDEAL-IQ technique to estimate vertebral fat fraction（FF） in alloxan-induced diabetic rabbits. Materials and Methods： Twelve young New Zealand white rabbits were randomly assigned to alloxan-induced diabetic group（n=6） and control group（n=6）. The rabbits in alloxan-induced diabetic group were injected with a total amount of 100 mg/kg of alloxan. Both of the rabbits in alloxaninduced diabetic and control group underwent magnetic resonance imaging（TIWI, T2 WI, IDEAL-IQ） at each time point（0, 4, 8, 12, 16 weeks）. Each vertebral fat fraction was measured at a standard workstation（AW 4.6; GE Medical Systems）. Region of interest（ROI） had a shape of rectangle and they were drawn manually. HE staining was performed. Results： Slight increase of the signal of the lumbar vertebral bodies was found at the T1 WI and T2 WI in the alloxan-induced diabetic group at the week of 16. Compared to the control group, the alloxan-induced diabetic group showed thereduce of bone cells and increase of the fat cells. The alloxan-induced diabetic group has statistically differences in vertebral fat fraction at each time point（F=50.387,P〈0.01）. The control group has no statistical differences in vertebral fat fraction at each time point（F=1.477,P〉0.05）. There is statistical difference in vertebral fat fraction between alloxan-induced diabetic and control group at the week of 16（t=-10.726, P〈0.05）. A signifi cant positive correlation is found between vertebral fat fraction and fat cell count（r=0.925, P〈0.05）. Conclusion： IDEAL-IQ technique can quantify the vertebral fat fraction in alloxan-induced diabetic rabbits.