Malignancy assessment of brain tumours with magnetic resonance spectroscopy and dynamic susceptibility contrast MRI
Malignancy assessment of brain tumours with magnetic resonance spectroscopy and dynamic susceptibility contrast MRI
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DOI：
10.1016/j.ejrad.2008.02.039
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发表时间：
2008-09-01
影响因子：
3.3
通讯作者：
Olmos, Salvador
中科院分区：
文献类型：
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作者：
Fayed, Nicolas;Davila, Jorge;Olmos, Salvador
磁共振成像（MRI）是用于评价脑内肿瘤的最常见和完善的成像模式，但仍存在一些未完全解决的挑战，例如高级别和低级别肿瘤之间的可靠区分，肿瘤延伸的精确描绘，本研究的目的是评价两种MRI技术对非肿瘤性坏死的诊断价值。侵入性地估计脑肿瘤等级。对24例经MRI检查确诊为单发脑内肿瘤的患者进行分析。最后，进行组织病理学分析以验证肿瘤类型。10例患者表现为低级别胶质瘤，而其余患者表现为高级别肿瘤，包括胶质母细胞瘤8例，孤立转移4例和2例间变性胶质瘤。MRI检查在1.5 T扫描仪（Signa，通用电气）上进行。采集序列包括矢状位T1加权定位序列、轴位T1和T2加权成像序列、单体素磁共振波谱（MRS）序列、动态磁敏感对比（DSC）序列和增强T1加权成像序列。肿瘤级别之间差异最大的代谢物比率是胆碱/肌酸（Ch/Cr）比率，在高级别胶质瘤和转移瘤中数值升高。Ch/Cr比值等于或大于1.55预测恶性分级的敏感性为92%，特异性为80%。ROC曲线下面积为0.92（CI：95%; 0.81-1）。灌注参数方面，使用两种商业软件包从团注期间的MR信号强度时间序列估计相对脑血容量（rCBV）图。使用两个不同的感兴趣区域（ROI）来评估rCBV：病变中心和病变周围区域。将所有rCBV值标准化为对侧正常出现白色物质区域的CBV。不同肿瘤类型之间未发现统计学差异。然而，从DSC-MRI中计算的浓度-时间曲线说明了血脑屏障（BBB）损伤的存在。时间序列的聚类分析用于识别T1效应叠加到T2* 效应的造影剂外渗区域。血脑屏障损伤的浓度-时间曲线与增强后T1加权图像的增强高度相关，预测肿瘤恶性程度的敏感性为92%，特异性为90%。从聚类分析中观察到浓度-时间曲线存在较大的空间异质性，支持必须仔细选择ROI以计算血流动力学参数以提取稳健参数的假设。(C)2008爱思唯尔爱尔兰有限公司保留所有权利。
Magnetic resonance imaging (MRI) is the most common and well-established imaging modality for evaluation of intracerebral neoplasms, but there are still some incompletely solved challenges, such as reliable distinction between high- and low-grade tumours, exact delineation of tumour extension, and discrimination between recurrent tumour and radiation necrosis.The aim of this study was to evaluate the contribution of two MRI techniques to non-invasively estimate brain tumour grade. Twenty-four patients referred to MRI examination were analyzed and diagnosed with single intra-axial brain tumour. Lastly, histopathological analysis was performed to verify tumour type. Ten patients presented low-grade gliomas, while the remaining patients showed high-grade tumours, including glioblastomas in eight cases, isolated metastases in four patients and two cases with anaplastic gliomas.MRI examinations were performed on a 1.5-T scanner (Signa, General Electric). The acquisition protocol included the following sequences: saggital T1-weighted localizer, axial T1- and T2-weighted MRI, single-voxel magnetic resonance spectroscopy (MRS), dynamic susceptibility contrast (DSC) MRI and contrast-enhanced T1-weighted MRI.MRS data was analyzed with standard software provided by the scanner manufacturer. The metabolite ratio with the largest significant difference between tumour grades was the choline/creatine (Ch/Cr) ratio with elevated values in high-grade gliomas and metastases. A Ch/Cr ratio equal or larger than 1.55 predicted malignancy grade with 92% sensitivity and 80% specificity. The area under the ROC curve was 0.92 (CI: 95%; 0.81-1).Regarding to perfusion parameters, relative cerebral blood volume (rCBV) maps were estimated from the MR signal intensity time series during bolus passage with two commercial software packages. Two different regions of interest (ROI) were used to evaluate rCBV: lesion centre and perilesional region. All rCBV values were normalized to CBV in a contrallateral normal appearing white matter region. Statistical differences were not found between different tumour types. However, the presence of blood-brain barrier (BBB) damage was illustrated from concentration-time curves calculated in DSC-MRI. A cluster analysis of the time series was used to identify regions with contrast agent extravasation where T1-effects are superimposed to T2*-effects. The presence of BBB damage from concentration-time curves was highly correlated with enhancement of post-contrast T1-weighted images and predicted tumour malignancy with a 92% sensitivity and 90% specificity. A large spatial heterogeneity in concentration-time curves was observed from the cluster analysis, supporting the assumption that ROI selection to compute hemodynamic parameters must be done carefully in order to extract robust parameters. (C) 2008 Elsevier Ireland Ltd. All rights reserved.