摘要目的 研究常规MRI图像纹理分析对脑膜瘤术前分级的效能及临床价值.方法 回顾性连续纳入2011年1月至2016年8月行术前常规MRI检查,并经手术病理证实的脑膜瘤101例(WHOⅠ级81例、Ⅱ级19例、Ⅲ级1例),在MRI图像上勾画肿瘤最大径层面的瘤体实性部分为ROI,利用Image J软件,采用直方图和灰度共生矩阵纹理分析方法,测量各序列图像的最大值、最小值、标准差、峰度、偏度、ASM能量、对比度、逆差矩、熵、自相关等纹理参数,并与术后病理分级结果进行对照分析.采用独立样本t检验、Mann-Whitney U检验比较低级别与高级别脑膜瘤MRI图像的直方图和灰度共生矩阵参数的差异.并对有统计学意义的参数绘制ROC曲线,分析其预测脑膜瘤术前分级的效能.结果 (1)直方图参数中,低级别脑膜瘤的T2WI、FLAIR、ADC序列的标准差(SDT2WI、SDFLAIR、SDADC)分别为14.764(10.928,17.932)、9.753(7.385,13.618)、12.171(9.138, 19.691),高级别脑膜瘤分别为19.252(13.580,25.715)、13.568(8.936,17.108)、16.636(13.166, 21.498),两组间差异有统计学意义(Z值分别为-2.863、-2.250、-2.247,P值分别为0.004、0.024、0.025).低级别脑膜瘤的ADC序列和FLAIR序列的偏度值(SkeADC、SkeFLAIR)为1.377 ± 1.172、-1.327±0.930,高级别脑膜瘤为2.503±1.613、-0.827±0.834,两组间差异有统计学意义(t值分别为-2.196、-3.129,P值分别为0.002、0.030).(2)灰度共生矩阵参数中,低级别脑膜瘤的增强T1WI、T2WI、FLAIR、ADC序列的熵值Entropy(EntT1WI、EntT2WI、EntFLAIR、EntADC)分别6.881(6.174,7.305)、6.534± 0.598、6.019±0.588、6.040±0.588,高级别脑膜瘤分别为7.079(6.742,7.739)、7.014±0.514、6.370±0.703、6.576±0.450,两组间差异有统计学意义(Z=-2.007,t值分别为-3.294、-2.327、-3.245,P值分别为0.045、0.001、0.022、0.002).(3)分别绘制EntADC和SkeADC的ROC曲线,曲线下面积(AUC)分别为0.768和0.710.联合EntADC、SkeADC及EntT2WI对脑膜瘤分级效能最好,AUC达0.799.结论 纹理分析可提供更多量化信息,可在术前较为准确地区分高级别脑膜瘤和低级别脑膜瘤.

abstractsObjective To explore the efficacy and clinical value of texture analysis of conventional MRI image for the preoperative classification of meningiomas. Methods The MR images of 101 meningioma cases were retrospectively analyzed, all of them underwent routine MRI before operation, and confirmed by surgery and pathology,of whom 81 cases in WHO Ⅰ,19 cases in Ⅱand 1 case in Ⅲ.The maximum diameter of the tumor in MRI images was outlined as ROI by the Image J software.The histograms and grey-level co-occurrence matrix(GLCM)were used to measure the texture parameters,such as maximum value,minimum value,standard deviation(SD),skewness,kurtosis,angular second moment,contrast,inverse different moment, entropy, correlation and so on, and compared with postoperative pathological grading results.The independent sample t test or the Mann-Whitney U test was used to compare the difference of the histogram and the gray level co-occurrence matrix parameter of the MRI images between low-grade and high-grade meningiomas. ROC curves for statistically significant parameters were used to confirm their efficacy in predicting the preoperative grade of meningiomas.Results (1)In histogram parameters,the SDs of T2WI,FLAIR,ADC(SDT2WI,SDFLAIR,SDADC)of low grade meningioma were 14.764(10.928,17.932),9.753 (7.385,13.618) and 12.171 (9.138,19.691), the high grade meningiomas were 19.252 (13.580,25.715), 13.568 (8.936,17.108) and 16.636 (13.166,21.498), respectively. The difference between the two groups was statistically significant(Z values were-2.863,-2.250,-2.247,P respectively 0.004,0.024,0.025).The skewness values (SkeADC, SkeFLAIR) of ADC sequence and FLAIR sequence of low-grade meningiomas were 1.377 ± 1.172 and-1.327 ± 0.930, respectively, and the high-grade meningiomas were 2.503 ± 1.613 and-0.827±0.834,respectively.The differences between the two groups were statistically significant (t values were-2.196,-3.129, P values were 0.002,0.030, respectively). (2) In the GLCM parameters, entropy (EntT1WI, EntT2WI, EntFLAIR, EntADC) of the enhanced T1WI, T2WI, FLAIR and ADC sequences of low grade meningiomas were 6.881(6.174,7.305),6.534±0.598,6.019±0.588,6.040±0.588,high-grade meningiomas were 7.079 (6.742,7.739), 7.014 ± 0.514,6.370 ± 0.703,6.576 ± 0.450, respectively. And the difference between the two groups was statistically significant (Z=-2.007, t values were-3.294,-2.327,-3.245, P values were 0.045,0.001,0.022,0.002,respectively).(3)The ROC curves of EntADCand SkeADCwere plotted, and the area under the curve(AUC)was 0.768 and 0.710,respectively.Combined EntADC,SkeADCand EntT2WI were the best for the classification of meningiomas,and AUC was 0.799.Conclusion Texture analysis can provide more quantification information, which can be more accurately distinguishing high grade meningiomas and low grade meningiomas before surgery.