摘要:
Objective To investigate the value of MR intravoxel incoherent motion (IVIM)imaging and dynamic susceptibility contrast-enhanced(DSC)perfusion imaging in astrocytoma grading.Methods 22 patients with high grade astrocytoma and 28 patients with low grade astrocytoma underwent conventional MRI and IVIM,DSC scanning before operation.Parameters of IVIM included standard diffusion coefficient(ADCstandard ),slow diffusion coefficient(D),fast diffusion coefficient(D∗ ),fractional perfusion-related volume (f)values,and parameters of DSC included relative blood volume(rCBV),relative blood flow(rCBF)values of tumor solid part were measured quantitatively.The values between the two groups were compared by two samples t-test.By using ROC curve to evaluate the diagnostic efficacy of using IVIM and DSC alone or jointly.Results The ADCstandard ,D,rCBV,rCBF values of tumor solid part had significant differences between the groups(P<0.01).The D∗ and f values were no significant differences (P=0.130,P=0.379).The area under the ROC curve of the values showed that ADCstandard (0.823),D(0.854),rCBV(0.858),rCBF(0.871),D+rCBV(0.952),D+rCBF(0.953).Conclusion The D,rCBV,rCBF values are helpful to determine the grade of astrocytomas.The use of IVIM in combination with DSC may improve the diagnostic accuracy of astrocytoma grading.%目的:探讨 MR 体素内不相干运动(IVIM)成像与动态磁敏感对比增强(DSC)灌注成像在脑星形细胞瘤分级中的诊断价值。方法对手术病理证实的22例高级别及28例低级别星形细胞瘤患者术前行 MR 常规扫描及 IVIM、DSC 扫描,定量测量2组肿瘤实质区 IVIM 成像参数值,包括标准扩散系数(ADCstandard )、慢扩散系数(D)、快扩散系数(D∗)、灌注分数(f)和 DSC 灌注成像参数值,包括相对脑血容量(rCBV)、相对脑血流量(rCBF),采用两独立样本 t 检验分析各参数值在高、低级别脑星形细胞瘤中是否有统计学差异,应用受试者工作特征曲线(ROC)评价单独及联合应用 IVIM 成像和 DSC 灌注成像的诊断效能。结果肿瘤实质区ADCstandard 值、D 值、rCBV 值、rCBF 值在脑星形细胞瘤分级中有明显统计学差异(P <0.01);D∗值、f 值在脑星形细胞瘤分级中无统计学差异(P=0.130,P=0.379);各参数值对脑星形细胞瘤分级的 ROC 曲线下面积为:ADCstandard 值0.823,D 值0.854,rCBV 值0.858,rCBF值0.871,D 值与 rCBV 和 rCBF 值联合应用0.952,0.953。结论D 值及 rCBV、rCBF 值可以对脑星形细胞瘤进行分级,联合应用IVIM 成像与 DSC 灌注成像可以提高脑星形细胞瘤分级的准确性。