扩散峰度成像和3D动脉自旋标记成像对脑胶质瘤术前分级的诊断价值及相关性研究

Value of diffusion kurtosis imaging and 3D arterial spin-labeling imaging in the preoperative grading of brain gliomas and its correlation analysis

目的:探讨扩散峰度成像(DKI)和3D动脉自旋标记成像(3D ASL)对脑胶质瘤术前分级的诊断价值及相关性。方法:收集36例经病理证实的脑胶质瘤患者,分别行常规MRI平扫、DKI、3D ASL及增强扫描,经后处理得到DKI、3D ASL相关参量图,选择肿瘤实性部分和对侧正常脑白质,分别测量平均扩散峰度(MK)、径向扩散峰度(Kr)、轴向扩散峰度(Ka)和部分各向异性(FA)、平均扩散系数(MD)、脑血流量(CBF),并计算各相对参数值rMK、rKr、rKa、rFA、rMD和rCBF。采用两样本t检验,比较分析不同级别脑胶质瘤的各参数值及相对参数值。采用Spearman相关分析rMK值、rCBF值及病理级别三者间的相关性。绘制rMK值与rCBF值诊断高级别脑胶质瘤的ROC曲线,计算AUC,寻找最佳诊断界值,两者AUC比较行Z检验。结果:经检验分析,MK、Kr、Ka值在不同病理级别胶质瘤中差异均有统计学意义(均P<0.05),FA、MD值在不同病理级别胶质瘤中差异无统计学意义(均P>0.05)。不同病理级别胶质瘤的rMK、rKr、rKa、rFA、rMD值及rCBF值差异均有统计学意义(均P<0.05)。Spearman相关分析显示,rMK值、rCBF值均与病理级别呈正相关,rMK值与rCBF值呈正相关。应用ROC曲线比较rMK值与rCBF值诊断高级别胶质瘤的效能,AUC分别为0.841、0.818,两者差异无统计学意义(P>0.05)。rMK值取诊断界值为0.56,诊断高级别胶质瘤的敏感度为92.9%,特异度为63.6%。rCBF值取诊断界值为3.25,诊断高级别胶质瘤的敏感度为92.9%,特异度为54.5%。结论:DKI参数MK、Kr、Ka和相对参数rMK、rKr、rKa、rFA、rMD、rCBF均可用于胶质瘤术前分级。rMK值、rCBF值、胶质瘤病理级别三者间均呈正相关。rMK和rCBF诊断高级别胶质瘤的敏感度均较高。

Objective:To investigate the value and the relevance of diffusion kurtosis imaging(DKI)and 3D arterial spin-labeling(ASL)in the preoperative grading of brain gliomas.Methods:Thirty-six patients with pathologically confirmed brain gliomas were included in the study,and routine MRI scans,DKI,3D ASL,contrast-enhanced scan were performed.The raw data of DKI and 3D ASL were post processed.The solid part of the tumor and the contralateral normal brain white matter were selected,and the corresponding MK,Kr,Ka,FA,MD,CBF values were measured and the corresponding rMK,rKr,rKa,rFA,rMD,rCBF were calculated.The parameters were compared with pathological grades separately using a two-sample t test.And the correlation of rMK,rCBF value and pathological grades was analyzed by Spearman correlation analysis.ROC curve was used to assess the diagnostic value of rCBF and rMK to high-grade gliomas.The AUC was calculated to find the optimal diagnostic critical point.And the AUC of rCBF value was analyzed by Z test compared with that of rMK value.Results:After analysis,MK,Kr,Ka values had significant differences in different grades of gliomas,while FA,MD values had no significant differences.And rMK,rKr,rKa,rFA,rMD,rCBF values had significant differences in different grades of glioma.Spearman correlation analysis showed a positive correlation between rMK and and pathological grade,between rCBF value and pathological grade,and between rMK and rCBF.ROC curve showed that rMK and rCBV had a high diagnostic accuracy for brain gliomas,with AUC of 0.841 and 0.818,respectively(P>0.05).The rMK value was taken at a diagnostic critical point of 0.56,with the sensitivity of 92.9%and the specificity of 63.6%;and the rCBF value was taken a diagnostic critical point of 3.25,with the sensitivity of 92.9%and specificity of 54.5%.Conclusions:The DKI parameters(MK,Kr,Ka)and the corresponding parameters(rMK,rKr,rKa,rFA,rMD,rCBF)can be used in preoperative grading of brain gliomas.The rMK,rCBF value and pathological grades are all positive correlated.The rMK and rCBF values have a high sensitivity in the diagnosis of high-grade gliomas.