采用扩散峰度成像评估肝癌及其周围肝实质肿瘤浸润的价值

Diffusional kurtosis imaging value for assessment of liver cancer and tumoral cell invasion of peritumoral zone

目的 探讨采用扩散峰度成像（DKI）评估肝癌及其周围肝实质肿瘤浸润的价值.方法 前瞻性收集经临床和影像检查综合诊断为肝癌的24例患者（肝癌组）和10名健康志愿者（对照组）.肝癌组行肝脏常规MRI平扫、对比增强扫描和DKI扫描;对照组行常规MRI平扫和DKI扫描.观察常规MRI及DKI图像上肝实质及肝癌信号表现.测量记录对照组正常肝实质和肝癌组癌周肝实质、远癌肝实质和肝癌组织的各向异性分数（FA）、平均扩散系数（MD）、轴向扩散系数（Da）、径向扩散系数（Dr）、扩散峰度各向异性分数（FAk）、平均扩散峰度（MK）、轴向扩散峰度（Ka）和径向扩散峰度（Kr）值,并采用单因素方差分析进行比较.结果 肝癌组平扫肿瘤表现为稍长T1、稍长T2信号,增强MRI肿瘤实质为＂快进快出＂的增强表现,DKI图像上肝癌病灶信号随着b值的增高,信号不衰减.正常肝实质、远癌肝实质、癌周肝实质和肝癌组织间,除MK及Kr值差异无统计学意义外（P均〉0.05）,其他参数（FA、MD、Da、Dr、FAk和Ka）差异均有统计学意义（P均〈0.05）.其中正常肝实质MD、Da、Dr值高于周围肝实质及肝癌组织;正常肝实质Ka值低于肝癌周围肝实质及肝癌组织.除远癌肝实质与癌周肝实质间的MD、Da、Dr和Ka差异无统计学意义（P均〉0.05）外,其余各组间的差异均有统计学意义（P均〈0.05）.结论 DKI定量参数可反映不同组织水分子扩散运动的差异,为评价肝癌及癌细胞周围浸润提供依据.

Objective Study the apply of diffusional kurtosis imaging（DKI） value to assess liver cancer and tumoral cell invasion of peritumoral liver zone. Methods This research belonging to prospective study which included 24 patients with liver cancer and confirmed by clinical history and imaging features（liver cancer group）, 10 healthy volunteers as control group. The liver cancer group underwent MRI plain and contrast enhanced scan, and DKI examination, while control group underwent MRI plain scan and DKI scan. The signal features of liver parenchyma and liver cancer lesion could be observed from the routine MRI and DKI. Fractional anisotropy （FA）, mean diffusion （MD）, axial diffusivity （Da）, radial diffusivity （Dr）, fractional anisotropy kurtosis （Fak）, mean kurtosis （MK）, kurtosis anisotropy （Ka） and radial kurtosis （Kr） value of four groups, the distant liver parenchyma（far away from the tumor〉2 cm）, peritumoral liver parenchyma（the distance≤2 cm around the tumor） and liver cancer were recorded. The differences of DKI parameters were evaluated using one-way analysis of variance （ANOVA）. Results The signal of liver cancer in MR plain scan showed mild long T1 and mild long T2 signal, fast in and fast out enhanced feature of the neoplasms could be observed from the enhanced MRI and signal of liver cancer would not lower in DKI with b value up to top. The difference of DKI parameters including FA, MD, Da, Dr and Ka value had statistical significance in these four groups excepted for MK and Kr value. MD, Da and Dr value of normal parenchyma were higher than that of peritumoral parenchyma and liver cancer,while the Ka value was reverse. The differences of MD, Da, Dr and Ka value only had no statistical significance between the distant liver parenchyma and peritumoral liver parenchyma（P〉0.05）,and the differences of them had statistical significance among the rest group（P〈0.05）. Conclusion The DKI quantitative parameters can reflect the differences of different tissue, meaning that they can provide molecular imaging information for evaluating liver cancer and peritumoral zone.