钆剂对T_2WI脑肿瘤~1H-MRSI代谢物波峰面积的影响

Effects of Gd-DTPA on Metabolites Peak Areas of T_2-weighted ~1H-MRSI in Brain Tumors

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。

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, peritumorai 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.