MR灌注成像在评价神经胶质瘤肿瘤血管中的价值

The potential of MR perfusion imaging in evaluation of tumor vessels of cerebral gliomas

目的 运用磁共振灌注成像 (PWI) ,探讨肿瘤血流容积在术前评估胶质瘤组织学分级中的价值。并与微血管密度 (MVD)对照 ,评估二者的相关性。方法 共搜集了 3 2例神经胶质瘤 ,均系常规MR扫描后 ,在首过期间行PWI ,通过非弥散示踪模式 ,获得局部相对脑血流容积 (rCBV)彩图 ,并计算肿瘤局部血容量。用免疫组织化学检测技术测量MVD ,以判断血管形成活性。将rCBV、rCBV比值与术后病理分级 ,以及rCBV与MVD进行统计学分析。结果 分级高的胶质瘤 ( 18例 )rCBV比值在 5 3 0～ 14 80之间 ,均值为 8 3 2± 1 68。分级低的胶质瘤 ( 14例 )rCBV比值在 0 89～ 5 40之间 ,均值为 2 93± 1 19。经组间t检验 ,两组rCBV比值均数差异有非常显著性意义 (t=9 618,P =0 0 0 0 )。分级高的胶质瘤rCBV值在 43 55～ 2 90 54之间 ,中位数为 113 60。分级低的肿瘤rCBV值在 9 66～168 76之间 ,中位数 2 8 84。经组间Wilcoxon检验 ,两组rCBV值差异有非常显著性意义 ( |Z| =4 0 2 7,P =0 0 0 0 )。rCBV和MVD的关系用线性回归分析 ,二者密切相关 (r =0 87,P <0 0 0 1)。结论 胶质瘤MR灌注成像与病理分级和MVD有良好的相关性 ,和常规MR联合应用 ,可显著提高胶质瘤术前分级的准确性 ,有效指导治疗方案的选择 。

Objective To evaluate the potential of rCBV in preoperative assessment of histologic grading and vascularity of gliomas Methods MR imaging was performed in 32 patients by using a first-pass gadopentetate dimeglumine T  2-weighted echo-planar perfusion sequence followed by conventional imaging The perfusion data were deconvoluted to obtain a color map of relative regional CBV, and rCBV, rCBV ratio values were calculated with a nondiffusible tracer model The rCBV ratio of lesions was expressed as a percentage of the relative CBV of normal white matter The maximal rCBV ratio, rCBV of each lesion was correlated with the histopathologic grading of gliomas and microvessel density (MVD) obtained from samples of volumetric resection Results The maximal rCBV ratio in high-grade gliomas ( n = 18) varied from 5 30 to 14 80, with a mean of 8 32 ±1 68, and in the low-grade cohort ( n = 14), the maximal rCBV ratio varied from 0 89 to 5 40, with a mean of 2 93±1 19 The difference in rCBV ratio was statistically significant ( P <0 001; Student t test) The maximal rCBV in high-grade gliomas varied from 43 55 to 290 54, with a median of 113 60, and in the low-grade cohort, it varied from 9 66 to 168 76, with a median of 28 84 This difference in relative rCBV was statistically significant ( P =0 000, ∣ Z ∣=4 027, Wilcoxon test) The correlation between rCBV and MVD was obtained from linear regression analysis of rCBV and corresponding MVD Significant correlation was observed between them( r =0 87, P <0 001). Conclusions Echo-planar perfusion imaging appears to have great potential to improve preoperative evaluation of gliomas because there is good correlation between rCBV and MVD, and between perfusion and histologic grading A combination of PWI with conventional MR images can greatly improve the diagnostic accuracy before surgery