对比分析磁共振化学位移成像与扩散加权成像对良恶性椎体骨折的鉴别诊断价值

Comparison of Qualitative and Quantitative Evaluation of Chemical-Shift Imaging and Diffusion-Weighted MRI in the Differentiation of Benign and Malignant Vertebral Body Fractures

目的回顾性对比分析磁共振化学位移成像（CSI）与回波平面序列扩散加权成像（DWI-EPI）对急性良恶性椎体骨折的鉴别诊断价值。方法搜集14例骨质疏松性椎体骨折（9例女性,5例男性;年龄25~82岁,平均63岁）和13例恶性椎体骨折病例（6例女性,7例男性;年龄41~83岁,平均60岁）。1.5 T磁共振常规采集T1WI、STIR和T2WI,对DWI-EPI进行定性和定量（测量表观扩散系数）分析,对反相位图像病变的信号强度进行定性评价,对同相位、反相位之间的信号丢失（信号强度比）进行定量分析。采用双尾Fisher精确检验、t检验和ROC曲线进行统计检验分析,记录其敏感性、特异性和准确性。结果 CSI定量分析对良恶性骨折的鉴别显示了较好的诊断效能（P=0.03）,而DWI-EPI定量分析未显示统计学意义（P=0.31）。CSI反相位定性分析评价良恶性椎体骨折诊断能力的敏感性、特异性和准确性分别为92.4%、50.0%和70.4%（P=0.03）;而DWI-EPI定性分析（b=400 s/mm2）的敏感性、特异性和准确性分别为84.6%、57.1%和70.4%（P=0.05）。结论 CSI定量分析对鉴别良恶性椎体骨折有一定价值,而CSI定性分析和DWI-EPI定性分析对良恶性椎体骨折诊断效能较低,DWI-EPI定量分析不适合鉴别良恶性椎体骨折。

Objective To compare the diagnostic value of chemical-shift imaging（ CSI） and diffusion-weighted echoplanar imaging（ DW-EPI） in a single prospective cohort of patients with acute osteoporotic and malignant vertebral fractures. Methods The study group was composed of patients with 14 osteoporotic vertebral fractures（ 9 Women,5 men;mean age： 63 years; age range： 25 to 82 years） and 13 malignant vertebral fractures（ 6 Women,7 men; mean age ： 60years; age range： 41 to 83 years）. T1-weighted,T2- weighted,and STIR were acquired at 1. 5 T. A DW echo-planar imaging（ EPI） sequence was evaluated qualitatively and quantitatively using the apparent diffusion coefficient. Opposed-phase sequences were used to assess signal intensity qualitatively. The signal loss between in- and opposed-phase images was determined quantitatively. Two-tailed fisher exact test,Mann-Whitney test and receiver operating characteristic analysis were perfomed. Sensitivities,specificities,and accuracies were determined. Results Quantitative chemical-shift imaging（ P= 0. 03） showed significant differences between benign and malignant fractures,and quantitative DW-EPI did not indicate significant differences（ P = 0. 31）. Qualitative opposed-phase imaging（ P = 0. 03） and DW-EPI using a b value of 400 s /mm2（ P = 0. 05） did not exhibit significant differences between benign and malignant vertebral fractures because of a large overlap. Conclusion Quantitative chemical-shift imaging had some accuracy in differentiating benign from malignant vertebral fractures,and qualitative assessment of opposed-phased imaging,DW-EPI had a lower accuracy. Quantitative assessment of the DW-EPI sequence were not suitable for distinguishing between benign and malignant vertebral fractures.