多参数磁共振成像在脑胶质母细胞瘤与单发脑转移性肿瘤鉴别诊断中的应用价值

Differentiation of Glioblastomas and Brain Metastases:Comparisons of Diagnostic Performance of the Parameters Derived from Preoperative DSC-MRI and DCE-MRI

目的探讨基于动态磁敏感对比增强MRI（DSC-MRI）和动态对比增强MRI（DCE-MRI）扫描所获得的多参数在脑胶质母细胞瘤及单发脑转移性肿瘤术前鉴别诊断中的应用价值。方法选择2012年1月到2017年8月接受手术治疗并确定病理类型的胶质母细胞瘤患者12例及脑转移性肿瘤患者12例,术前均行DSC-MRI及DCE-MRI扫描,通过颅内肿瘤实质区域（TP）及瘤周区域（PT）DSC-MRI扫描所得的时间信号回复百分比（PSR）及DCE-MRI扫描所得的对比剂容积转运常数（Ktrans）、时间-信号曲线下面积（i AUC）的比较,利用独立样本t检验、Pearson相关分析评价两种肿瘤之间各参数差异,受试者工作特性曲线（ROC）获取诊断阈值（cutoff值）,对病理结果未知、常规影像学无法区分的脑胶质母细胞瘤及单发脑转移性肿瘤94例进行鉴别。结果脑胶质母细胞瘤肿瘤实质区域的PSR平均值及最小值明显高于单发脑转移性肿瘤（P〈0.05）,其ROC曲线下面积分别为0.924和0.785,诊断阈值分别为0.613和0.376。脑胶质母细胞瘤肿瘤瘤周区域的iAUC平均值明显高于单发脑转移性肿瘤（P〈0.05）,其ROC曲线下面积为1.000,诊断阈值为0.025。此外,肿瘤实质区域的PSR平均值与瘤周区域的iAUC值具有中度相关性（r=0.591,P=0.003）。通过以上获取的诊断阈值对病理结果未知的两种肿瘤行鉴别诊断,肿瘤瘤周区域i AUC平均值的敏感性及特异性最高,分别为87.50%和76.47%。结论结合DSC-MRI及DCE-MRI两种灌注功能磁共振的术前扫描,肿瘤实质区域的PSR平均值及最小值、肿瘤瘤周区域的i AUC平均值可以区分胶质母细胞瘤和单发脑转移性肿瘤,这对于术前无创性评价颅内肿瘤类型采用的磁共振参数具有临床指导价值。

Objective To compare the diagnostic performance of parameters derived from preoperative dynamic susceptibility contrast-enhanced（ DSC）-MRI and dynamic contrast-enhanced（ DCE）-MRI in differentiating glioblastomas and solitary brain metastases. Methods 12 cases with glioblastoma and 12 cases with brain metastasis from January,2012 to August,2017 were retrospectively reviewed. They received preoperative DSC-MRI and DCE-MRI. The percentage of signal intensity recovery（ PSR） derived from DSC-MRI and transfer constant（ Ktrans） and the area under the signal intensity time curve（ i AUC） derived from DCE-MRI between these two entities were compared by independent 2-sample t tests. The cutoff values obtained from receiver operating characteristic（ ROC） analysis were used as diagnostic predictors to differentiate the other 94 cases with unknown pathological results and unclear conventional imaging features. Results The mean and minimal PSR in the tumor parenchyma（ TP） area of glioblastoma were significantly higher than those of brain metastasis（ P〈0. 05）. The AUC were 0. 924 and 0. 785,and the cutoff values were 0. 613 and 0. 376,respectively. In the tumor peritumoral（ PT） area,the mean i AUC were significantly higher than that of brain metastasis（ P〈0. 05）. The AUC was1. 000 and the cutoff value was 0. 025,respectively. There were moderate correlations between PSR mean values in TP and i AUC mean values in the PT area（ r = 0. 591,P = 0. 003）. Moreover,the cutoff value of i AUC demonstrated the highest diagnostic power with 87. 50% sensitivity and 76. 47% specificity,respectively. Conclusion Combining preoperative DCE-MRI and DSC-MRI,glioblastoma can be differentiated from brain metastasis using mean and min PSR values in the TP area and mean i AUC values in the PT area. This has an important clinical guiding significance for the application of MR parameters in preoperative noninvasive evaluation of intracranial tumor types.