钆剂对T2 WI脑肿瘤1H-MRSI代谢物波峰面积的影响

目的:探讨钆剂对T2WI脑肿瘤1H-MRSI代谢物波峰面积有无影响,为钆剂增强波谱的应用提供依据。材料和方法:在钆剂注射前后,对高级别和低级别星形细胞瘤、脑膜瘤及正常对照各4例行T2WI长TE(TE=144ms,PRESS)MRSI成像,分别记录感兴趣区内肿瘤的实性区、周围水肿区及正常表现体素的Cho、Cr及NAA代谢物波谱数据(共643个有效体素),分析增强前后代谢物波峰面积的变化。结果:钆剂注射后5-10min的长TE(TE=144ms,PRESS)MRSI显示,仅脑膜瘤组Cho峰面积下降的程度(<10%)相比正常组有显著性差异(P<0.05),余各组之间差异无显著意义。总体上Cho、Cr及NAA波峰的面积无明显变化。结论:钆剂注射后,脑膜瘤Cho波峰面积稍有下降,其影响机制可归于T2*敏感效应;总体上钆剂对T2WI长TE脑肿瘤MRSI主要代谢物波峰面积的影响甚微,可以忽略;增强波谱以Cho/Cr比值反映脑肿瘤Cho水平的变化较为可靠;应用增强后波谱完全可行。

Effects of Gd-DTPA on Metabolites Peak Areas of T2-weighted 1H-MRSI in Brain Tumors

Purpose:To determine whether Gd-DTPA has influences on the metabolites peak areas of 1H-MRSI in brain tumors.Materials and Methods:The pre-and post-administration of Gd-DTPA T2WI(TR/TE 1000/144,PRESS)CSI-MRS scans were performed in each group of patients with low-grade astrocytoma,high-grade astrocytoma,meningioma and normal subjects,each with four cases.The Cho,Cr and NAA peak areas in the solid part of tumoral,peritumoral area and normal-appearing parenchyma were recorded and analyzed(643 valid voxels in total).Results:Less than 10% decrease of Cho peak area in group of meningioma was showed on MRSI 5 to 10 minutes after Gd-DTPA administration(TE=144ms,PRESS),and significant difference was showed in comparison with normal control(P<0.05).No significant differences were found between other groups.In general,no obvious changes of the Cho,Cr and NAA peak areas were showed.Conclusion:Slightly decreased Cho peak areas was seen in meningioma after Gd-DTPA administration,and this change could be attributed to T2 susceptibility effect.In general,Gd-DTPA had minimal influences on metabolites peak areas which could be neglected.It was applicable using Gd-DTPA contrast enhanced MRSI and more reliable to adopt ratio of Cho/Cr to indicate Cho level in brain tumors.