探讨DCE-MRI早期预测鼻咽癌新辅助化疗和调强放疗疗效的价值

摘要

目的 探讨DCE-MRI早期预测鼻咽癌放化疗(chemoradiotherapy,CRT)疗效的应用价值.材料与方法 前瞻性入组87例局部中晚期鼻咽癌患者,在新辅助化疗(nasopharyngeal carcinoma,NAC)前和调强放疗(intensity-modulated radiotherapy,IMRT)1周后(即分割照射5次)分别进行动态增强MRI(dynamic contrast-enhanced magnetic resonance imaging,DCE-MRI)扫描.获得各时间点原发肿瘤的DCE-MRI参数值(Ktrans、Kep、Ve和Vp).比较放疗早期和放疗后的不同疗效组之间DCE-MRI参数在治疗前后变化的差异.结果 在放疗早期和放疗后,有效组的Ktrans和Kep参数在放疗早期发生了明显下降.调强放疗结束后,治愈组的治疗前Ktrans以及与放疗后早期的数学差值(△Ktrans和△Kep)和变化百分比(Ktrans(Perc)和Kep(Perc))、放疗早期的肿瘤退缩率均显著大于残留组(P<0.05),上述各DCE-MRI参数早期预测IMRT的诊断效用介于0.655~0.829,联合肿瘤退缩率后的诊断效用最高,高达0.832.结论 DCE-MRI具有潜在早期预测局部中晚期鼻咽癌CRT近期疗效的价值.%Objective:To investigate the utility of dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) in assessing short-term control of chemoradiotherapy (CRT) in nasopharyngeal carcinoma (NPC).Materials and Methods:MRI and clinical materials of local advanced NPC patients (n=87) who were scheduled for neoadjuvant chemotherapy (NAC) following by aggressive intensity-modulated radiation therapy (IMRT) were studied. DCE MRI was performed [before NAC and five fractions after IMRT (one week) treatment] and four kinetic parameters (Ktrans, Kep, Ve and Vp) based on extended Tofts model were measured. Comparisons were made between different clinical response groups during and after IMRT using independent-samplest test or Mann-Whitney U test.Results:Reductions of both Ktrans and Kep values early after one week IMRT were observed in patients who achieved well clinical response after NAC and IMRT treatment. Compared to residual disease (partial response, PR) patients after radical CRT, the pretreatment Ktrans value, percentage change and difference values of Ktrans and Kep parameters between pretreatment and after one week IMRT, and tumorregression ratio after one week IMRT were all significantly larger in complete response (CR) patients (P<0.05). According to receiver operating characteristic analyses, diagnosis efficacies of single Ktrans,△Ktrans,△Kep, Ktrans(Perc), and Kep(Perc) values ranged from 0.655—0.829, while combined tumor regression ratio with above kinetic parameters yielded the highest diagnosis efficacy, sensitivity, and equivalent specificity (0.832, 84.0%, 64.5%, respectively).Conclusions:DCE MRI has the potential to predict short-term control of local advanced toward chemoradiotherapy.