1H MＲS对脑转移瘤的诊断价值

The value of ^1 H MRS in the diagnosis of brain metastasis

目的:探讨氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H MRS)对脑转移瘤的诊断价值。方法:收集术后病理或临床证实脑转移瘤32例。所有患者MRS前均行MR平扫及增强扫描。3.0T MR多体素波谱(TE 144ms)扫描,分别于肿瘤实质、瘤周水肿及正常脑实质取感兴趣区(VOI),测量代谢物浓度,计算Cho/Cr、NAA/Cr、Cho/NAA值,比较肿瘤实质与正常脑实质、瘤周水肿与正常脑实质代谢物比值的差异,采用配对t检验。观察肿瘤实质是否出现1.3ppm脂峰(Lip)及可流动脂质。结果:肿瘤实质与正常脑实质代谢物比较,Cho/Cr增高、NAA/Cr降低、Cho/NAA增高,差异有统计学意义(P均<0.05)。瘤周水肿与正常脑实质代谢物比较,Cho/Cr略有增高,NAA/Cr略有降低,差异无统计学意义(P均>0.05);Cho/NAA增高,差异有统计学意义(P<0.05)。32例中24例出现Lip,出现率75%,15例出现可流动脂质,出现率46.9%。结论:脑转移瘤的MRS具有一定特征,脂峰及可流动脂质的出现有助于脑转移瘤的诊断。

Objective：To evaluate the diagnostic value of ^1 H MRS in brain metastasis.Methods：Thirty-two pa-tients with brain metastases were enrolled in this study.All patients,whose final dignosis were confirmed by his-topathological or clinical comprehensions,performed conventional and contrast enhanced MRI scans before MRS.All cases underwent multi-voxel ^1 H MRS（TE 144ms）on a 3.0 T MR scanner.The volume of interesting（VOI）was placed in tumor parenchyma,peritumoral edematous area and normal brain parenchyma ,respectively .The ratio val-ue of Cho/Cr ,NAA/Cr ,Cho/NAA were measured .We used paired t test to compare the differences of the rati-os between the parenchyma of tumor ,peritumoral edema and the normal brain area separately .The presence of Lip peak at 1.3ppm and mobile lipids were evaluated.Results：In contrast with normal brain area,we found signifi-cant increase of Cho/Cr,Cho/NAA ratio and decrease of NAA/Cr ratio in tumor parenchyma（P〈0.05）.The slightly increase of Cho/Cr,and reduce of NAA/Cr between tumor edema and normal brain area did not reach significance（P〉0.05）,except Cho/NAA,which were significantly increased in tumor edematous areas（P〈0.05）.The incidence of Lip was 75%.The incidence of mobile lipids was 46.9%.Conclusion：The feature of MRS in brain metastasis is distinguished.The combination of the lipid peak and the mobile lipids can improve the diagnosis accuracy for brain metastasis.