小肝癌与肝硬化结节MRI表观扩散系数值与R2^*值差异分析

Analysis of the difference between MRI apparent diffusion coefficient and R2^* value of small hepatocellular carcinoma and cirrhosis nodule

目的探讨微小肝细胞癌与肝硬化结节磁共振成像(MRI)表观扩散系数值与横向弛豫率(R2^*)值差异。方法回顾分析68例微小肝细胞癌(病灶76枚)和45例肝硬化结节(病灶48枚)患者的临床资料,均行扩散加权成像和R2^*成像。比较微小肝细胞癌与肝硬化结节患者病灶表观扩散系数值与R2^*值的差异。通过绘制受试者工作特征(ROC)曲线评价表观扩散系数值与R2^*值对微小肝细胞癌的诊断效能。结果相比肝硬化结节者,微小肝细胞癌者平均表观扩散系数值与R2^*值均明显下降(P<0.05)。经ROC曲线分析显示,表观扩散系数值的诊断阈值为1.35×10-3 mm^2/s时,诊断微小肝细胞癌的灵敏度为80.88%,特异度为91.11%,此时对应的ROC曲线下面积为0.88;R2^*值的诊断阈值为53.96 Hz时,诊断微小肝细胞癌的灵敏度为91.18%,特异度为77.78%,此时对应的ROC曲线下面积为0.84。结论MRI表观扩散系数值与R2^*值均可用于鉴别和诊断微小肝细胞癌与肝硬化结节,其中肝硬化结节病灶表观扩散系数值低于1.35×10-3mm^2/s、R2^*值低于53.96 Hz可能预示结节癌变的发生。

Objective To analyze the difference of apparent diffusion coefficient and transverse relaxation rate(R2^*)between small hepatocellular carcinoma and cirrhosis nodule on magnetic resonance imaging(MRI).Methods The clinical data of 68 patients with micro hepatocellular carcinoma(76 lesions)and 45 patients with cirrhosis nodules(48 lesions)were analyzed retrospectively.We compared the difference of apparent diffusion coefficient and R2^*value between patients with microcellular carcinoma and cirrhosis nodule.The diagnostic efficacy of apparent diffusion coefficient and R2^*was evaluated by drawing receiver operating characteristic(ROC)curve.Results Compared with the patients with cirrhosis nodule,the mean value of apparent diffusion coefficient and R2^*of patients with microcellular carcinoma decreased significantly(P<0.05).According to ROC curve analysis,when the diagnostic threshold of apparent diffusion coefficient was 1.35×10-3 mm^2/s,the sensitivity and specificity of diagnosis of micro HCC were 80.88%and 91.11%respectively,and the area under ROC curve was 0.88;the diagnostic threshold of R2^*value was 53.96 At Hz,the sensitivity and specificity of diagnosis were 91.18%and 77.78%,respectively.At this time,the area under ROC curve was 0.84.Conclusion MRI apparent diffusion coefficient and R2^*value can be used to differentiate and diagnose microcellular carcinoma and cirrhotic nodule,in which the apparent diffusion coefficient of cirrhotic nodule is lower than 1.35×10-3 mm^2/s and R2^*value is lower than 53.96 Hz,which may indicate the occurrence of nodule canceration.