磁共振弥散加权成像在评估鼻咽癌调强放疗疗效的价值研究

目的:探讨磁共振弥散加权成像(diffusion weighted imaging,DWI)在鼻咽癌调强放疗、放疗后随访的临床价值。方法:分析经病理证实的32例鼻咽癌患者在放疗前、放疗剂量40 Gy时和放疗结束后均行MRI常规扫描、增强扫描及DWI检查,分析病变体积及弥散表观系数(apparent diffusion coefficient,ADC)值动态变化情况,并探讨两者的相关性。结果:随着调强放疗时间的延长,肿瘤体积不同程度缩小,且不同放疗时间段各组间差异具有统计学意义(P<0.05);ADC值逐渐增高,放疗晚期ADC的增高程度大于放疗早期的增高程度,且不同放疗时间段各组间差异具有统计学意义(P<0.05);肿瘤体积与ADC值呈负相关(r=-0.667,P=0.000)。结论:MRI及DWI-MRI成像可较准确的显示鼻咽癌调强放疗后形态学、组织学变化,能较好的监测NPC放射治疗后肿瘤的消退情况和治疗的敏感性。

Evaluation of therapy effect of intensity modulated radiation therapy for nasopharyngeal carcinoma using diffusion weighted MR

Objective:To explore the value of diffusion-weighted imaging magnetic resonance imaging (DWI-MRI)in intensity modulated radiotherapy (IMRT)for nasopharyngeal carcinoma(NPC)and on the follow-up of NPC after radiotherapy.Methods:32 pa-tients histopathologically confirmed NPC underwent conventional,enhanced and DWI MRI.MRI and DWI-MRI were carried out at pre-radiotherapy and during IMRT at accumulative dose of 40 Gy,and immediately after radiotherapy.MRI and DWI imaging were analyzed in details,and the apparent diffusion coefficient (ADC)of nasopharyngeal mass and the volume of the tumor were be determined;the volume was then correlated to the ADC.Results:During the process of the intensity modulated radiation therapy,the tumor volume was reduced in different degrees,and there were significant differences between each group in different time period after IMRT (all P <0.05 );ADC value is gradually increased,the degree of advanced radiotherapy ADC is increased greater than the early radiotherapy, there were significant differences between each group of different time after IMRT (all P <0.05);tumor volume was negatively correla-ted with ADC value (r =-0.667,P =0.000).Conclusion:MR and DWI-MR can provide morphological and histology changes of NPC after IMRT,and were helpful in the evaluation of the NPC primary tumor regression and the sensitivity of IMRT.