体素内不相干运动DWI鉴别诊断高级别胶质瘤与脑转移瘤

Intravoxel incoherent motion DWI in differential diagnosis of high-grade gliomas and metastasis

目的探讨体素内不相干运动DWI(IVIM-DWI)鉴别诊断高级别胶质瘤与脑转移瘤的价值。方法对24例高级别胶质瘤和28例脑转移瘤术前或放化疗前同时行MR平扫、增强及IVIM-DWI检查,测量肿瘤实质、瘤周1cm水肿区及对侧半卵圆中心灌注系数(D*)、扩散系数(D)、灌注分数(f)值,计算肿瘤实质、瘤周1cm水肿区各参数相对值(rD*、rD、rf值)。采用独立样本t检验比较高级别胶质瘤与脑转移上述参数的差异。对其间差异有统计学意义的参数行ROC曲线分析,评价各参数诊断高级别胶质瘤或脑转移瘤的效能。结果高级别胶质瘤肿瘤实质、瘤周1cm水肿区D*值、rD*值均高于脑转移瘤对应区域(P均<0.05);f值、rf值均低于脑转移瘤对应区域(P均<0.01);瘤周1cm水肿区D*值的AUC最大,但仅与肿瘤实质rD*的AUC差异有统计学意义(P=0.033)。结论IVIM-DWI可区分高级别胶质瘤和脑转移瘤肿瘤实质和瘤周1cm水肿区扩散和灌注差异,为鉴别诊断提供依据。

Objective To investigate the value of intravoxel incoherent motion DWI（IVIM-DWI）in differential diagnosis of high-grade gliomas and brain metastases.Methods Conventional MRI,contrast-enhanced MRI and IVIM-DWI were performed before surgery or chemoradiotherapy in 24 patients with high-grade gliomas and 28 patients with brain metastases.The diffusion constant（D）,pseudodiffusion coefficient of perfusion（D＊）and the perfusion fraction（f）in the parenchyma and peritumoral edema region within 1 cm and the normal centrum semiovale in the opposite side were measured,then the relative values of all parameters in each region（rD＊,rD,rf）were calculated.Independent sample t test was used to analyze the parameters.ROC curve analysis of the parameters statistically different between high-grade gliomas and brain metastases were performed,and the diagnostic efficacies were evaluated.Results The D＊and rD＊values of tumor parenchyma and in peritumoral edema within 1 cm of high-grade gliomas were higher than those of brain metastases（all P〈0.05）.The f and rf values of tumor parenchyma and in peritumoral edema within 1 cm of high-grade gliomas were lower than those of brain metastases（all P〈0.01）.The AUC of D＊value in peritumoral edema within 1 cm was the highest,but there was no statistically different between any two AUC except the rD＊value of peritumoral edema within 1 cm（P=0.033）.Conclusion IVIM-DWI can distinguish the differences of diffusion and perfusion information in parenchyma and edema area between high-grade gliomas and brain metastases,therefore providing the basis for differential diagnosis of them.