感兴趣区设置方法的不同对肝癌 ADC 值测量及观察者间变异的影响

摘要

目的：评估感兴趣区（ROI）不同设置方法对肝癌（HCC）患者 TACE术治疗前后ADC值测量及观察者之间变异的影响。方法36例经病理证实中晚期肝癌患者于肝动脉栓塞化疗（TACE）术前、术后1个月行扩散加权成像检查（ b ＝1000）。两位有经验的放射科医生通过三种不同 ROI 设置方法对肝癌病灶行 ADC 值测量，这三种方法分别为：整体容积法、最大层面法、多个小样本法，最后对不同 ROI 设置方法测量的平均 ADC ± SD 值及观察者之间变异的差异用组内相关系数（ICC）进行对比分析。结果三种 ROI 设置方法在不同观察者间均存在较好的一致性（ P ＞0．05，ICC ＝0.99）。整体容积法 ROI 的 ICC 在 TACE 术前非常好（0．91），在 TACE 术后良好（0．79），单层最大层面法在 TACE 术前、后的 ICC 分别为 0．77 和 0．63，多个小样本法的 ICC 分别为 0．76 和 0．37。多个小样本法 TACE 术前 ADC 值低于整体容积法或最大层面法。 TACE 术后的 ADC 值在整体容积、最大层面或多个小样本 ROI 间差异无统计学意义。整体容积和最大层面 ROI 的 SD 显著大于多个小样本 ROI 。结论 ROI 设置大小和位置对肿瘤的 ADC 值测量和观察者间变异有相当大的影响。 TACE 术后观察者间变异性更大。整体容积法获得的肿瘤 ADC 值最具可重复性的结果。%Objective To assess the influence of region of interest (ROI) size and positioning on tumour ADC measure‐ments and interobserver variability in patients with liver tumors before and after Transcatheter arterial chemoembolization (TACE) .Methods Thirty‐six cases confirmed by pathology terminal‐stage liver cancer patients were included .Patients underwent MRI including DWI ( b = 0 ,600 ,1000) before and one months after TACE .Two readers measured mean tumour ADCs (pre‐ and post‐TACE) according to three ROI protocols :whole‐volume ,single‐slice or small solid samples . The three protocols were compared for differences in ADC ,SD and interobserver variability (measured as the intraclass correlation coefficient ;ICC) .Results Three methods of ROI set there were good consistency between different observers ( P > 0.05 ,ICC = 0 .99) .ICC for the whole‐volume ROIs was excellent (0 .91) pre‐CRT versus good (0 .79) post‐CRT . ICCs were 0 .77 and 0 .63 for the single‐slice ROIs versus 0 .76 and 0 .37 for the sample ROIs .Pre‐CRT ADCs for the sample ROIs were significantly lower than for the whole‐volume or single‐slice ROIs .Post‐CRT there were no significant differences between the whole‐volume ROIs and the single‐slice or sample ROIs ,respectively .The SDs for the whole‐vol‐ume and single‐slice ROIs were significantly larger than for the sample ROIs .Conclusion ROI size and positioning have a considerable influence on tumour ADC values and interobserver variability .Interobserver variability is worse after TACE . ADCs obtained from the whole tumour volume provide the most reproducible results .