定量动态增强MRI对骨肿瘤良恶性的鉴别诊断价值

Evaluation of Quantitative Dynamic Contrast Enhanced MRI in Differential Diagnosis of Benign and Malignant Bone Tumors

目的探讨定量动态增强(DCE)MRI对骨肿瘤良恶性的鉴别诊断价值。方法选取2014年7月至2016年2月河南省肿瘤医院骨肿瘤患者61例(其中良性组21例,恶性组40例)并行DCE-MRI检查,分别计算两组患者的相关参数:容量转运常数(K^(trans))、速率常数(K_(ep))、血管外细胞外间隙容积分数(V_e)及1分钟内初始曲线下面积(iAUC),并进行独立样本t检验分析,随后应用受试者工作特征曲线(ROC)找出两组的鉴别切点,并计算有统计学差异的各指标诊断恶性骨肿瘤的敏感度、特异度、准确率、阳性预测值、阴性预测值。结果 K^(trans)、K_(ep)、iAUC在良、恶性组间差异有统计学意义(P<0.05),ROC曲线下面积(AUC)分别为0.802、0.802、0.693,K^(trans)、K_(ep)、iAUC的最佳诊断切点值分别为0.570(min^(-1))、2.467(min^(-1))、14.13,定量参数中K^(trans)>0.570(min^(-1)),K_(ep)>2.467(min^(-1)),iAUC>14.13作为恶性骨肿瘤的诊断标准,敏感度为92.5%、75.0%、80.0%,特异度为57.1%、71.4%、52.3%,准确率80.3%、73.4%、70.5%,阳性预测值80.4%、83.3%、76.2%,阴性预测值80.0%、60.0%、57.9%。V_e在良性组、恶性组间差异无统计学意义(P>0.05)。结论定量DCE-MRI可以用于骨肿瘤良恶性的鉴别诊断,其中K^(trans)、K_(ep)、iAUC为有鉴别价值的参数。

Objective To evaluate the value of quantitative dynamic contrast enhanced（ DCE） MRI in differential diagnosis of benign and malignant bone tumors. Methods Between July 2014 and February 2016,61 patients with bone tumors were chosen as the subjects of this study and had underwent DCE-MRI examination. Patients for the study did not undergo biopsy,chemotherapy or radiotherapy before MRI examination. Quantitative pharmacokinetic parameters were measured including volume transfer constant（ Ktrans）,exchange rate constant（ Kep）,extravascular extracellular volume fraction（ Ve） and the initial area under the gadolinium curve over 60 seconds after the arrival of contrast agent（ iAUC）. Consistency check was done for the data from the two radiologists. ICC（ intraclass correlation coefficient） was used for quantitative data. After the consistency test,data from one radiologist was used for analysis. The subjects were divided into benign group（ 21 cases） and malignant group（ 40 cases） based on the pathological results. Independent-samples t-test and Receiver operating characteristic curve（ ROC） analyses were used for comparing the differences between benign and malignant groups.The cut off values were determined when the Youden＇s index was at the largest. The area of ROC was calculated. The sensitivity,specificity,accuracy,positive predictive value and negative predictive value of the different significant indicators in diagnosing diagnosing malignant bone tumors were calculated respectively according to the gold standard of pathological diagnosis. Results Ktrans,Kep and iAUC showed a significant difference between the benign and malignant groups（ P〈0. 05）,however,Veshowed no significant differences between the benign and malignant groups（ P〈0. 05）. The sensitivities of the indicators with Ktrans 0. 570（ min^-1）,Kep 2. 467（ min^-1）,iAUC 14. 13 in diagnosing malignant bone tumors were 92. 5%,75. 0%,80. 0%,the specificities were 57. 1%,71. 4%,52. 3%,the accuracies were 80. 3%,73. 4%,70. 5%,the positive predictive value were 80. 4%,83. 3%,76. 2%,and the negative predictive value were 80. 0%,60. 0%,57. 9%,respectively. Conclusion Quantitative DCE-MRI is a useful method for differentiating the benign and malignant bone tumors and Ktrans,Kepand iAUC are the valuable parameters.