鼻咽癌放疗后局部纤维化与肿瘤复发的MRI灌注成像研究

MR perfusion of recurrent nasopharyngeal carcinoma and radiation fibrosis

目的探讨MRI灌注成像对鼻咽癌放疗后局部纤维化与肿瘤复发的诊断价值。方法将放射治疗后鼻咽癌局部纤维化(31例)及肿瘤复发病例(25例)共56例分为2组,采用FLASH序列进行动态增强及灌注成像扫描,获得动态增强时间-信号强度曲线类型,统计分析动态增强及灌注成像参数:达峰时间(TTP)、最大斜率(Slope_(max))、曲线下面积(AUC),并获取伪彩图,及进行统计学处理。结果放疗后复发组动态增强时间-信号曲线类型均呈速升型,出现明显上升期,随后转为平台期或缓升缓降期;放疗后纤维化组时间-信号曲线呈缓升型,出现缓慢上升期,随后转为平台期或缓升缓降期。2组病例MRI动态增强参数TTP、Slope_(max)、AUC的均值行组间两两比较,复发组和纤维化组的Slope_(max)、TTP均值存在统计学差异,t值分别为67.18、-21.04(P<0.05)。灌注参数伪彩图可直观的显示肿瘤或放疗后纤维化组织相应的血流灌注情况,发现AUC灌注伪彩图显示肿瘤组织较为清晰,分辨率较好。结论应用MR动态增强及灌注成像有助于鉴别鼻咽癌复发和纤维化。

Objective To investigate the value of dynamic contrast-enhanced and perfusion MRI of recurrent nasopharyngeal carcinoma （NPC） and radiation fibrosis. Methods Time-intensity curves （TIC） of 25 patients with recurrent NPC and 31 patients with radiation fibrosis were generated on the dynamic contrast-enhanced and perfusion MRI. Time to peak （TTP）, Slopemax and area under the curve （AUC） were compared. Results The TIC of recurrent NPC showed significantly more rapid rise than that of radiation fibrosis. The TTP, Slopemax and AUC between recurrent NPC and radiation fibrosis were significantly different （P〈0.05）. The pseudocolor maps of the perfusion parameters reflected the blood perfusion of tumor and fibrosis with the AUC pseudocolor maps clearly depicting the tumor. Conclusion Dynamic contrast-enhanced and perfusion MRI allows differentiation between radiation fibrosis and recurrent NPC.