磁共振血氧水平依赖成像在鼻咽癌化放疗近期疗效评估中的价值

Value of BOLD-MRI for the evaluation of short-term chemoradiotherapy efficacy in nasopharyngeal carcinoma

目的探讨磁共振血氧水平依赖成像(blood oxygenation level-dependent MRI,BOLD-MRI)预测鼻咽癌化放疗近期疗效的可行性。材料与方法收集我院经病理证实的鼻咽癌患者41例,所有患者接受诱导化疗(induction chemotherapy,IC)、同步放化疗(concurrent chemoradiotherapy,CCRT)和辅助化疗(adjuvant chemotherapy,AC)三个阶段治疗。分别利用IC前和CCRT+AC后的MRI常规成像测量原发肿瘤长径、病理淋巴结短径和转移灶长径,计算病灶的退缩率;利用IC前、后的BOLD成像测量肿瘤的T2*值(T2*_(baseline)和T2*IC)。参照实体瘤疗效评价标准1.1,将患者分为完全缓解组(complete response,CR组)及非完全缓解组(non-CR组)。采用卡方检验或两独立样本t检验比较CR组和non-CR组的T分期、T2*_(baseline)和T2*IC。将T分期、T2*_(baseline)和T2*IC分别与退缩率进行相关性分析。采用ROC曲线分析T分期、T2*_(baseline)和T2*IC预测鼻咽癌化放疗近期完全缓解的诊断价值。结果 T分期、T2*_(baseline)和T2*IC在CR组与non-CR组间存在差异(P均<0.05)。T分期、T2*_(baseline)和T2*IC分别与退缩率呈不同程度相关(r分别依次为-0.481、0.748和0.617,P均<0.05)。T分期、T2*_(baseline)和T2*IC预测鼻咽癌CR的受试者特征曲线下面积分别依次为0.778、0.903和0.763,其中T2*_(baseline)的受试者特征曲线下面积最大(P<0.05),T2*_(baseline)诊断肿瘤完全缓解的最佳阈值为37.5 ms。结论鼻咽癌治疗前BOLD的定量参数T2*_(baseline)值能够预测鼻咽癌化放疗的早期疗效,可作为传统T分期疗效预测的有益补充。

Objective:To investigate the feasibility of blood oxygenation level-dependent MRI(BOLD-MRI)for evaluating short-term therapeutic effect of chemoradiotherapy in nasopharyngeal carcinoma(NPC).Materials and Methods:Forty-one cases with NPC confirmed by pathological biopsy exposed to the chemoradiotherapy being the induction chemotherapy(IC)followed by the concurrent chemoradiotherapy(CCRT)and adjuvant chemotherapy(AC)therapy.The conventional MRI was performed pre-IC and after CCRT+AC.They were used to measure the maximal length of the primary and metastatic tumors,and the diameter of the pathological lymph node,and then the regression rate of lesions was calculated for each patient.BOLD was performed pre-and post-IC,then the corresponding T2*value of tumor was measured(T2*baseline and T2^*IC),respectively.According to the response evaluation criteria in solid tumors(Version 1.1),the patients were divided into the complete response(CR group)and not(non-CR)groups.The T stage,T2*baseline,and T2^*IC were compared between the CR and non-CR groups.The correlation of the regression rate of tumor with the T stage,T2^*baseline,and T2^*IC was tested,respectively.The receiver operating characteristic curve(ROC)was used to compare the capacity of T stage,T2^*baseline,and T2^*IC in predicting complete response to the chemoradiotherapy for the cases with NPC.Results:T stage,T2^*baseline,and T2^*IC were statistically different between CR and non-CR groups(P<0.05),and they showed a linear correlation with the regression rate of tumor(r=-0.481,0.748,and 0.617,all P<0.05).For predicting the complete response of the cases with NPC post-chemoradiotherapy,the area under ROC was 0.778,0.903,and 0.763 for T stage,T2^*baseline,and T2^*IC,respectively(all P<0.05).T2^*baseline was the best one that can predict the complete response for the cases with NPC while it is larger than 37.5 ms(P<0.05).Conclusions:The BOLDbased T2^*baseline can predict the short-term chemoradiotherapy efficacy in NPC and can be used as a useful supplement to the conventional T stage.