脑CT灌注成像在星形细胞瘤术前分级中的价值

The evaluation of CT perfusion in the histologic grading of astrocytomas

目的:评价CT灌注成像在星形细胞瘤术前分级中的应用价值。方法:对29例星形细胞瘤患者行常规CT及CT灌注成像,所有病例分为2组:低级别星形细胞瘤15例,高级别星形细胞瘤14例。灌注成像先得到TDC,并合成局部脑血容量(rCBV)图和局部脑血流量(rCBF),计算出感兴趣区的rCBF、相对rCBV(rrCBV)、相对rCBF(rrCBF)和局部血管表面通透性(rP)。比较两组间的CT灌注参数,如果差异有显著性意义,用受试者工作特征(ROC)曲线判别各参数对区分低级、高级星形细胞瘤的效果。结果:低、高级星形细胞瘤的rCBF分别为46.95±22.92 ml.min-1.100g-1,95.44±42.58 ml.min-1.100g-1;rrCBF分别为2.19±0.98,4.65±1.73;rrCBV分别为3.53±2.39,8.32±5.75;rP(中位数,四分位数间距)分别为(0.09,0.12),(0.30,0.39)。CT灌注参数诊断低、高级星形细胞瘤的效果:rCBFr、rCBFr、rCBVr、P的ROC曲线下面积分别为0.848、0.900、0.786、0.940。结论:rrCBVr、rCBF和rP均能可靠地评价星形细胞瘤的术前病理级别;在满足计算公式的前提条件下,rCBF绝对值和其它相对灌注参数一样,能可靠地评价星形细胞瘤的术前病理级别。

Objective：To evaluate CT perfusion imaging in preoperative grading of astrocytomas. Methods： Both conventional and perfusion CT were performed in 29 patients with pathologically confirmed astrocytomas. The patients were divided into two groups： low-grade astrocytomas （n=15） and high-grade astrocytomas （n=14）. The TDCs were obtained, and the ICBF maps and regional cerebral blood volume （ICBV） maps were generated. Then, the ICBF, relative ICBV （ rrCBV）, relative rCBF （ rrCBF ） and regional permeability （rP） of microvessel were calculated. The CT perfusion parameters of low-grade and high-grade astrocytomas were compared. If there was significant diference between them, the receiver operating characteristic （ROC） curve was used to assess their values on distinguishing the lowgrade and high-grade astrocytomas. Results： The rCBFs of low-grade and high-grade astrocytomas were 46.95 22.92ml·min^-1·100g^-1 and 95.44±42.58ml·min^-1·100g^-1, respectively; rrCBFs were 2.19±0.98 and 4.65±1.73, respectively; rrCBVs were 3.53±2.39 and 8.32±5.75, respectively;rPs（median, inter-quantile range）were （0.09,0.12） and （0.30,0.39）, respectively. The values of rCBF, rrCBF, rrCBV and rP of the high - grade astroeytomas were higher than ones of the low-grade astroeytomas and there were signifi- cant diferences between them. The rCBF, rrCBF, rrCBV and rP had strong association with the grade of astroeytomas. The areas under the ROC curves were 0.848,0.900,0.786,0.940.Conclusion：The rrCBF, as well as the rrCBV and rP, can apply in preoperative assessment of lfistologic grading in astroeytomas. The rCBF, if the assumption of maximal slope model can be guaranteed, is as very reliable index for preoperative estimating the histologic grading of astroeytomas as the rrCBF and rrCBV.