常规MRI与^(31)P MR波谱在骨及软组织肿块中的鉴别诊断价值

The value of MRI and ^(31)P MRS in differential diagnosis of bone and soft tissue tumors

目的探讨常规MRI与^(31)PMR波谱(MRS)对骨及软组织肿块的鉴别诊断价值。方法在1.5T场强下,对16例健康志愿者及35例骨及软组织肿块患者分别行常规MRI与31PMRS检查,测定波谱中各代谢产物的峰下面积,计算各代谢产物与β-三磷酸腺苷(β-ATP)的比值,以及根据无机磷(Pi)的化学位移相对于磷酸肌酸(PCr)的改变测定细胞内pH值。结果良恶性两组肿块在大小、信号均匀性、境界及对周围结构的侵犯等方面差异无统计学意义(P值均>0.05),其MRI特征有很大重叠性。对照组的磷酸单酯/β-三磷酸腺苷(PME/β-ATP)、磷酸二酯(PDE)/β-ATP、低能磷酸盐(LEP)/β-ATP、PCr/β-ATP、细胞内pH值分别为0.33±0.21、0.64±0.27、1.62±0.67、3.12±0.78、7.08±0.16,良性肿块组的PME/β-ATP、PDE/β-ATP、LEP/β-ATP、PCr/β-ATP、pH值分别为0.55±0.31、0.81±0.31、2.03±0.87、1.65±0.65、7.18±0.23,恶性肿块组的PME/β-ATP、PDE/β-ATP、低能磷酸盐(LEP)/β-ATP、PCr/β-ATP、pH值分别为1.73±0.40、1.73±0.45、4.31±1.18、1.44±0.54、7.32±0.29。与对照组比较,恶性肿块组的PME/β-ATP(P<0.01)、PDE/β-ATP(P<0.01)、LEP/β-ATP(P<0.01)、细胞内pH值(P<0.05)升高,良性及恶性肿块组的PCr/β-ATP(P<0.01)均降低,差异均具有统计学意义。与对照组比较,良性肿块组PME/β-ATP、PDE/β-ATP、LEP/β-ATP、pH值均有所升高,但差异无统计学意义(P值均>0.05)。与良性肿块组比较,恶性肿块组的PME/β-ATP、PDE/β-ATP、LEP/β-ATP升高,差异有统计学意义(P值均<0.01);恶性肿块组的细胞内PH值较良性肿块组升高,但差异无统计学意义(P>0.05)。以良性肿块的PME/β-ATP均值的1.8倍作为鉴别良恶性肿块的标准,则对肿块潜在恶性评估的敏感性为88.89%,特异性为94.12%。结论31PMRS对骨及软组织肿块的诊断及鉴别诊断具有重要价值,是1种简单、无创、有效的补充检查手段。

Objective To explore the value of MRI and ^31p MRS in differential diagnosis of bone and soft tissue tumors. Methods MRI and ^31p MRS were performed in 35 bone and soft tissue tumor patients and 16 healthy volunteers at 1.5 T. The areas under the peak of various metabolite in spectra were measured. The spectra were analyzed by taking peak areas relative to peak area of β-ATP and by calculating the pH from the Pi shift relative to PCr. Results The differences of the size, signal intensity homogeneity, border and involvement of surround structure between benign and malignant lesions had no statistically significant differences（P 〉0. 05 ）. There was great overlap in the MR imaging characteristics of benign and malignant lesions. The mean peak area rations of PME/β-ATP. PDE/β-ATP. LEP/β-ATP. PCr/β-ATP. intracellular pH in control group were 0. 33 ± 0. 21.0. 64 ± 0. 27.1.62 ± 0. 67.3. 12 ± 0. 78.7.08 ± 0. 16. The mean peak area rations of PME/β-ATP. PDE/β-ATP. LEP/β-ATP. PCr/β-ATP. intracellular pH in benign group were 0. 55 ±0. 31.0. 81 ±0. 31.2.03 ±0. 87.1.65 ±0. 65.7. 18 ±0. 23. The mean peak area rations of PME/β-ATP. PDE/β-ATP. LEP/β-ATP. PCr/β-ATP. intracellular pH in malignant group were 1.73 ±0. 40.1.73 ±0. 45.4. 31 ± 1.18.1.44 ±0. 54.7. 32 ±0. 29. Compared with control group, the mean peak area rations of PME/β-ATP （ P 〈 0. 01 ）. PDE/β-ATP （ P 〈 0. 01 ）. LEP/β-ATP （ P 〈 0. 01 ）. intracellular pH （ P 〈 0. 05 ） in malignant group increased significantly and PCr/β-ATP（ P 〈 0. 01 ） in benign and malignant group decreased significantly. The mean peak area rations of PME/β-ATP, PDE/β-ATP, LEP/β-ATP and intracellular pH in benign group were higher than that of the normal group but did not reach statistical significance（P 〉 0. 05 ）. The mean peak area rations of PME/β-ATP,PDE/β-ATP,LEP/β-ATP in malignant group were significantly higher than that in benign group （ P 〈 0. 01 ）. Intracellular pH in malignant group was higher than that in benign group but did not reach statistical significance （P 〉 0.05 ） . If we set a standard at 1.8 time of the mean of the PME/β-ATP ration in the benign group, then the sensitivity of this discrimination for diagnosing a malignancy was 88.89% and the specificity was 94. 12%. Conclusion ^31p MRS has important value in diagnosis and differential diagnosis of bone and soft tissue tumors. It should be a simple, non-invasively, effective diagnostic method.