磁共振扩散峰度成像在第四脑室肿瘤鉴别诊断中的应用价值

摘要

目的 应用扩散峰度磁共振(MR)成像技术探定第四脑室肿瘤内部成分及细胞增殖状态,分析其各成像参数与Ki-67的相关性,同时分析扩散峰度成像各参数在鉴别四脑室区髓母细胞瘤、室管膜瘤中的应用价值.方法 收集21例四脑室区肿瘤患者,术前行常规磁共振成像(MRI)及扩散峰度成像(DKI)序列扫描.术后对标本进行S-P染色法检测Ki-67的表达,应用扩散峰度评估软件(DKE)测定肿瘤实质区平均扩散峰度(MK)、径向峰度(Kr)、轴向峰度(Ka)及平均扩散系数(MD)值、各向异性系数(FA)值.Spearman相关分析研究DKI各参数值与Ki-67的相关性,应用独立样本t检验,比较髓母细胞瘤和室管膜瘤DKI参数值的差异性,并通过ROC曲线分析MK值、FA值和MD值在鉴别诊断中的敏感性及特异性.结果 不同类型四脑室区肿瘤中髓母细胞瘤平均Ki-67值最高,MK值与Ki-67存在明显正相关性,具有统计学意义( P <0.01).MK、Kr、Ka及MD值在鉴别髓母细胞瘤和室管膜瘤中均具有显著的统计学意义( P <0.01),FA值则无统计学意义( P >0.05).在鉴别室管膜瘤和髓母细胞瘤时MK值的敏感性和特异性分别为88.89%和87.50%, ROC曲线下面积(AUC)为0.9722;MD值敏感性为77.78%,特异性87.50%,AUC为0.9028;FA值的敏感性及特异性最小,分别为66.67%和62.50%,AUC为0.6111.结论 通过扩散峰值成像(DKI)可以更好的探定第四脑室肿瘤增殖状态,尤其MK值较其他参数值可以更好的反映肿瘤Ki-67的表达水平,且在鉴别诊断不同类型四脑室区肿瘤中具有重要意义.%Objective This study aimed to explore the application values of diffusion kurtosis imaging(DKI) in detecting in-ternal components and cell proliferation of fourth ventricle tumors and to analyse the correlation of the imaging parameters with Ki-67. Meanwhile,to explore the application values in differential diagnosis of medulloblastoma and ependymoma. Methods 21 pa-tients with the four ventricle tumor were examined preoperatively with conventional magnetic resonance imaging(MRI) and DKI, respectively. S-P inmmnohistechemical staining technique was used to detect the expression of Ki-67 in postoperative. The data of DKI were analyzed with diffusion kurtosis estimator(DKE) to calculate mean kurtosis(MK),radial kurtosi(Kr),axial kurtosis (Ka),mean diffusivity(MD) and fractional anisotropy(FA). Spearman correlation was used to analyze the correlation of the pa-rameter values and Ki-67. Independent-Samples T Test was used to analysis the differences of all the values in the two groups of tumor. The sensitivity and specificity of MK value, FA and MD values in differential diagnosis of two tumors were obtained by ROC curve analysis. Results The Ki-67 values of medulloblastoma were the highest in different types of tumors in the four ven-tricle region. The expression of Ki-67 showed positive correlation with MK value,with statistical significance( P <0.01). There was a significant difference between medulloblastoma and ependymoma in the values of MK,Ka,Kr and MD( P <0.01),while the FA value was not statistically significant( P >0.05). In the identification of medulloblastoma and ependymoma,the sensitiv-ity of MK value was 88.89%, the specificity was 87.50%, the AUC was 0.9722. The sensitivity of MD value was 77.78%,specificity was 87.50%,the AUC was 0.9028. The sensitivity and specificity of the FA value were respectively 66.67% and 62.50%, AUC was 0.6111. Conclusion Diffusion kurtosis imaging(DKI) can better detect cell proliferatione in fourth ventri-cle tumors.MK value could reflect Ki-67 expression level in the tumor and also has important value in differential diagnosis of the tumors.