DCE-MRI减影技术及DWI序列在原发性肝癌局部介入术后评估的应用研究

目的探讨磁共振动态增强减影技术及DWI序列在原发性肝癌经局部介入治疗术后疗效评估中的应用价值。方法收集56例经临床或病理证实为原发性肝癌的患者,同时满足1)接受过射频消融、微波消融、动脉内碘油栓塞等局部介入治疗术后≥6个月;2)治疗后病灶MRI表现为平扫T1高信号,且病灶直径≥1cm。共纳入符合标准的74个病灶,根据mRECIST标准,将所有病灶分为完全坏死组(42个病灶)和复发残留组(32个病灶)。由两位腹部影像诊断医师对MRI常规动态增强、动态增强减影及DWI(联合ADC)图像分别进行肉眼分析并对疗效判断的信心度进行评分,采用方差分析比较三种技术医师信心度水平差异;分别计算病灶在MRI常规动态增强与增强减影后动脉期、静脉期图像上的对比信噪比(CNR),采用t检验比较减影前后差异;测量所有病灶ADC值并对比完全坏死组与复发残留组之间差异。P<0.05为差异有统计学意义。结果完全坏死组1)诊断医师对常规动态增强、动态增强减影、DWI(联合ADC)三种技术肉眼判断肿瘤完全性坏死的信心度评分无显著差异;2)MRI动态增强动脉期减影前、后病灶CNR值无显著差异;静脉期减影后病灶CNR值明显大于减影前。复发残留组1)三种技术判断病灶内仍有活性肿瘤组织残留或复发的医师信心度评分由高到低为动态增强减影>常规动态增强>DWI(联合ADC);2)MRI动态增强动脉期、静脉期减影后病灶CNR值均显著大于减影前。复发残留组病灶平均ADC值明显低于完全性坏死组。结论与常规动态增强相比,减影技术结合DWI及ADC图像的定量分析,可以更加准确评估原发性肝癌局部治疗疗效。

Value of dynamic contrast-enhanced MRI subtraction and DWI in assessing treatment response for primary liver cancer after loco-regional therapies

Objective To explore the value of magnetic resonance imaging(MRI)dynamic contrast-enhanced subtraction and diffusion-weighted imaging(DWI)in assessing treatment response after loco-regional therapies for primary liver cancer.MethodsFifty-six patients with primary liver cancer confirmed clinically or pathologically were included in this study.Six months after patients received loco-regional therapies such as Radiofrequency ablation(RFA),microwave ablation,or transarterial chemoembolization(TACE),all lesions showed hyperintensity on non-enhanced T1WI.According to the modified response evaluation criteria in solid tumors(RECIST),74 leisions that complied with the standards were divided into complete necrosis group(42 leisions)and residual disease group(32 leisions).Two abdominal imaging diagnostic physicians performed visual analysis on conventional dynamic contrast-enhanced MRI,dynamic contrast-enhanced MRI subtraction and DWI(combined ADC)images,and the physicians’confidence scores of the three techniques in evaluating treatment efficacy were compared by Analysis of Variance.The contrast-noise ratio(CNR)values of the lesions in arterial and portal phase were calculated pre-and post-subtraction,respectively.A t test was used to compare the difference of the CNR values between pre-and post-subtraction.The ADC values of all lesions were measured,and the mean ADC values of the complete necrosis group and residual disease group were compared.A P value of≤0.05 was considered significant.Results For the complete necrosis group 1)the confidence scores determined by the physicians according to the conventional MRI dynamic enhancement,dynamic enhancement subtraction,and DWI(combined ADC)images were not significantly different;2)the CNR values of the lesions that pre-and post-subtraction in arterial phase were not significantly different;but the CNR value of post-subtraction in portal phase was significantly greater than that of pre-subtrac-tion.For the residual disease group 1)the confidence score that determining the presence of active tissue in the leision from high to low was dynamic enhancement subtraction>conventional MRI dynamic enhancement>DWI(combined ADC);2)the CNR values of the lesions post-subtraction were significantly greater than pre-subtraction in both arterial phase and portal phase.The mean ADC value of the complete necrosis group was significantly greater than the residual disease group.Conclusion Compared with conventional dynamic enhancement,the subtraction technique with DWI and quantitative analysis of ADC images can significantly improve the diagnostic accuracy in assessing the efficacy of loco-regional therapies for primary liver cancer.