脑胶质瘤MR灌注成像和病理分级对照研究

目的:本研究旨在评价相对脑血流容积(rCBV)和相对脑血流量(rCBF)在评估脑胶质瘤组织病理学分级中的价值。方法:对病理证实为脑胶质瘤的患者(低级别胶质瘤13例,高级别胶质瘤23例)行MR灌注成像及常规MRI检查。由灌注数据获取脑血流容积(CBV)图和脑血流量(CBF)图,计算出最大rCBV值和最大rCBF值。结果:高级别胶质瘤最大rCBV值及最大rCBF值分别为6.55±4.23和3.34±1.85,低级别胶质瘤分别为1.70±0.49和1.18±0.36,两组间最大rCBV值和rCBF值均有显著性差异(t检验,P<0.01);非参数相关性分析表明最大rCBV值和最大rCBF值间存在显著的相关性(r=0.812,P<0.05)。对于脑胶质瘤的定性评价,MR灌注成像结果与常规T1增强图像结果有时不吻合,不吻合率达30%。结论:MR灌注成像能有效地在术前评价脑胶质瘤的病理级别,最大rCBV值结合最大rCBF值可以更好地评估脑胶质瘤组织病理学分级。

Correlative study of MR perfusion weighted imaging with histopathologic grade in glioma

Objective: Relative cerebral blood volume(rCBV) is a commonly used perfusion MRI technique for the evaluation of glioma grade. Relative cerebral blood flow(rCBF) has less been studied. The goal of our study is to determine the usefulness of two parameters in evaluating the histopathologic grade of glioma. Methods: This study involved 36 patients(23 high-grade and 13 low-grade) who were identified as having histopathologically proven gliomas. MR perfusion imaging and MR conventional imaging were performed preoperatively in them. The perfusion data were deconvoluted to get a color map of CBV and CBF. The maximal rCBV and rCBF ratios of each lesion were calculated and were correlated with histopathologic grading of gliomas. Results: The maximal rCBV and rCBF ratios of high-grade gliomas were statistically different from those of low-grade gliomas(P<0.01). There was a strong correlation between the maximal rCBV and rCBF ratios(r=0.812, P<0.05). There was frequent mismatch(30%) between the qualitative assessment of the contrast-enhanced T1 weighted MR imaging and the perfusion maps. Conclusion: MR perfusion imaging is useful in the preoperative assessment of the histopathologic grade of gliomas. The maximal rCBF ratio in addition to the maximal rCBV ratio can be incorporated in MR perfusion analysis for the evaluation of cerebral gliomas.