磁共振3D-ASL技术在高级别胶质瘤靶区勾画术后残留病灶识别中的应用

Clinical evaluation of postoperative residual tumor by 3D-ASL magnetic resonance imaging in high-grade glioma patients

背景与目的:高级别胶质瘤呈浸润性生长,手术通常难以完全切除,术后联合放化疗能改善患者的预后。探讨三维动脉自旋标记(three-dimensional arterial spin labeling,3D-ASL)技术联合对比增强扫描在诊断胶质瘤患者术后残留中的价值,为放疗靶区勾画提供准确定位。方法:对贵州省人民医院2015年3月-2017年5月经手术后病理学检查证实的30例术后高级别胶质瘤患者(其中Ⅲ级12例,Ⅳ级18例)行常规MRI、3D-ASL扫描。通过联合常规MRI及3D-ASL序列进行分析,计算感兴趣区肿瘤血流灌注值(tumor blood flow,TBF)、对侧正常白质的区域血流灌注值(contralateral white matter blood flow,CBFwm)及标准化肿瘤血流量(normalized tumor blood flow,nTBF),nTBF=TBF/CBFwm。进行t检验统计学处理。结果:GE 3D-ASL灌注图显示,胶质瘤术后残留组(20例)呈高血流灌注,术后残腔组(10例)呈低血流灌注。术后残留组TBF与nTBF均高于术后残腔组,术后残留组TBF:(85.97±17.54)mL/min,nTBF:4.19±1.58,术后残腔组TBF:(26.51±8.93)mL/min,nTBF:0.91±0.44,差异有统计学意义(P<0.01);但CBFwm差异无统计学意义(P>0.05)。结论:磁共振3D-ASL技术联合对比增强扫描可以半定量测定高级别胶质瘤灌注情况,对于高级别胶质瘤患者的术后残留病灶有定位及定性诊断的价值,对于精确勾画放疗靶区具有实用价值。

Background and purpose: It is difficult to eradicate high-grade gliomas(HGG) due to their invasive growth. Postoperative radiochemotherapy can improve the prognosis of the patients. Three-dimensional arterial spin labeling(3 D-ASL) technique has been successfully used as a significant non-invasive method for preoperative diagnosis in HGG. This study explored its usefulness to assess residual tumor burden after resection of glioma before postoperative radiotherapy. Methods: From March 2015 to May 2017, 30 patients with pathologically confirmed HGG(12 of grade Ⅲ and 18 of grade Ⅳ) in Guizhou Provincial People’s Hospital were examined after tumor resection by conventional MRI and 3 D-ASL scan. The data of 3 D-ASL scan signals at the regions of interest in these patients were analyzed to investigate the evolution of the tumor blood flow(TBF), normalized TBF(nTBF) and contralateral white matter blood flow(CBFwm). Results: The 3 D-ASL data of the 30 patients were divided into two groups according to clinical diagnosis. The results showed that the residual tumor positive group(20 patients) displayed high ASL perfusion whereas the residual cavity group(10 patients) displayed low ASL perfusion. The TBF was(85.97±17.54) mL/min in the residual tumor positive group, and(26.51±8.93) mL/min in the residual cavity group. The nTBF was 4.19±1.58 in the residual tumor positive group, and 0.91±0.44 in the residual cavity group. The differences between the two groups were statistically significant(P<0.01). However CBFwm showed no statistically significant difference(P>0.05). Conclusion: The significantly higher perfusion index of TBF and nTBF in residual tumor group of HGG patients indicates existence of residual tumors and rich microvascular angiogenesis in these patients. Therefore, 3 D ASL technique is recommended in HGG patients after tumor resection, so as to facilitate clinical decision making for postoperative chemotherapy and radiotherapy.