磁共振弥散加权成像对脊柱转移瘤放疗疗效的评估

[目的]探讨磁共振弥散加权成像（DWI）对脊柱转移瘤放疗疗效的评估价值。[方法]收集30例脊柱转移瘤患者放疗前、后2个月的磁共振图像，所有患者均进行常规MRI及DWI序列。比较常规MRI序列与DWI序列对病灶的检出率。同时对照分析30例患者放疗前、后的DWI信号、ADC值。[结果]放疗前常规MRI扫描共发现病灶48个，累及42个椎体。DWI序列发现病灶56个，累及48个椎体。放疗结束后2个月复查MRI，SET1WI上脊柱转移瘤信号不变或略有下降。FSET2WI上20例信号轻度下降，10例不变。而在临床症状有改善的26例病例中，相对于放疗前，转移瘤DWI信号明显降低。在b=650s／mm2的DWI中，脊柱转移瘤放疗前表观扩散系数（ADC）值为（0．72±0．21）×10-3mm2／s，放疗后ADC值升高到（1．32±0．22）×10-3mm2／s；相邻正常椎体骨髓的ADC值较转移瘤低，且放疗前后没有变化。f结论]DWI序列既可以提高MRI对脊柱转移瘤的检出率，也可以用于监测和评估脊柱转移瘤的放疗疗效。

Evaluation of Diffusion Weighted Imaging on Radiotherapeutic Effect of Spinal Metastatic Tumors

[Purpose] To study the effect of diffusion weighted imaging on the radiotherapy for spinal metastatic tumors. [Methods] The MR imaging in 30 patients with spinal metastatic tumor were enrolled. Before and two months after radiotherapy, all cases were scanned by conven- tional sequences and DWI.The detection rate of conventional sequences and DWI was analyzed. The DWI signals and ADC value before and after radiotherapy were compared. [Results] Forty-eight lesions involved 42 centrums were detected by conventional sequences ;Fifty-six le- sions involoved 48 centrums were detected by DWI. Two months after radiotherapy,the signals of spinal metastatic tumors demonstrated unchange or slight decrease on SE-T1WI;20 cases demonstrated slight decrease and 10 cases demonstrated unchange on FSE-T2WI.In 26 patients with clinical symptom improved,the metastatic tumors demonstrated decrease obviously on DWI. The ADC values of spinal metastatic tumors were （0.72＋0.21）x10-3mm2/s on the images of pre-radiotherapeutic DWI（b=650s/mmZ）. Two months after radiotherapy,the ADC values were （1.32±0.22） ×10-3mm2/s. The ADC value of normal centrums was lower than that of metastatic tumors and unchanged before and after radiation. [Conclusion] DWI sequence is not only able to improve the detection rate of spinal metastases, but also be used for monitoring and evaluating radiotherapeutic effect for spinal metastatic tumor.