扩散峰度成像早期评估化学治疗鼻咽癌颈部淋巴结转移效果

Diffusion kurtosis imaging in early assessment on response of neoadjuvant chemotherapy for metastatic neck lymph nodes from nasopharyngeal carcinoma

目的观察以扩散峰度成像(DKI)早期评估新辅助化学治疗(NAC)鼻咽癌(NPC)颈部淋巴结转移效果的可行性。方法对38例NPC患者分别于NAC前(DayPre)及治疗第4天(Day4)、第1周期末(Day21)和第2周期末(Day42)行MR检查,测量咽后和颈部转移淋巴结短直径、DKI[平均扩散系数(MD)及平均峰度系数(MK)]和DWI(ADC)参数值,计算淋巴结退缩率。将淋巴结分为有效组(RG组)和无效组(NRG组),分析2组淋巴结退缩率、DKI及DWI参数值的差异。绘制DKI及DWI参数的ROC曲线,计算AUC值,比较DKI及DWI参数的诊断效能。结果共29例NPC、38枚转移淋巴结纳入研究,RG 23枚,NRG 15枚。RG组Day21和Day42淋巴结短直径及退缩率与NRG组差异均有统计学意义(P<0.05);2组间MD4值、MD21值及相的ΔMD差异均有统计学意义(P均<0.05),NRG的ADC4值低于RG(P=0.02)。绘制MD4和ADC4的ROC曲线,相应AUC值分别为0.75和0.73,诊断特异度为86.7%时,MD4(56.5%)诊断敏感度大于ADC4(47.8%)。结论 DKI可用于早期预测NAC对NPC颈部淋巴结转移的疗效,有望为临床个体化治疗NPC提供新的参考依据;MD是预测NAC早期疗效的良好指标。

Objective To explore the feasibility of diffusion kurtosis imaging(DKI) in early assessing treatment response of metastatic neck lymph nodes of nasopharyngeal carcinoma(NPC) after neoadjuvant chemotherapy(NAC). Methods Totally 38 patients with NPC were enrolled. MRI was obtained in all patients before NAC(DayPre) and on the 4 th(Day4), 21 st(Day21) and 42 nd(Day42) days after NAC, while the short diameter, DKI(mean diffusion [MD] and mean kurtosis [MK]) and diffusion weighted imaging(DWI)(apparent diffusion coefficient [ADC]) parameters of metastatic lymph nodes of neck were respectively measured, and the lymph node regression rate was calculated. The lymph nodes were then classified into non-responder group(NRG) and responder group(RG) according to the response of NAC. The differences of lymph node withdrawal rate, also of DKI and DWI parameter values were analyzed between 2 groups. Finally ROC curves of DKI and DWI parameters were drawn, and AUC values were calculated to compare the diagnostic efficacy of DKI and DWI. Results A total of 29 NPC patients and 38 metastatic lymph nodes were enrolled, including 23 in RG group and 15 in NRG group. There were statistical differences of short diameter and withdrawal rate of lymph nodes between 2 groups on Day21 and Day42(P<0.05), also of MD4, MD21 and the corresponding ΔMD between 2 groups(all P<0.05). ADC4 of NRG group was lower than that of RG group(P=0.02). ROC curves of MD4 and ADC4 were drawn, and the corresponding AUC values were 0.75 and 0.73, respectively. When the diagnostic specificity was 86.7%, the diagnostic sensitivity of MD4(56.5%) was higher than that of ADC4(47.8%). Conclusion DKI can be used to early evaluate the response of NAC for metastatic neck lymph nodes from NPC, is expected to provide new foundation for clinical individualized treatment of NPC. MD is a good indicator to predict early efficacy of NAC.