Chen Shiyue, Liu Ri, Ma Chao, Bian Yun, Li Jing, Yang Panpan, Wang Minjie, Lu Jianping
Radiology, Changhai Hospital of Shanghai, Shanghai, CHN.
Cureus. 2021 Jun 18;13(6):e15734. doi: 10.7759/cureus.15734. eCollection 2021 Jun.
To evaluate the apparent diffusion coefficient (ADC) test-retest repeatability of the normal pancreas based on diffusion-weighted imaging (DWI).
Twenty-six healthy volunteers (mean 47.6 years; 13 men) were included and scanned twice with reposition for a DWI sequence at 3.0-T. Two readers measured the ADCs of pancreatic head, body and tail for two DWIs, independently. The mean ADCs of the pancreatic head, body and tail were calculated as the global pancreatic ADC. Test-retest repeatability and agreement of ADC measurement were evaluated by the Bland-Altman analysis, intra-class correlation coefficient (ICC) and coefficient of variation (CV).
The global pancreatic ADC showed the best test-retest repeatability (mean difference ± limits of agreement were 0.05 ± 0.25×10 mm/s; ICC, 0.79; CV, 6%). Test-retest repeatabilities for ADC of pancreatic head, body or tail were scattered, with mean difference ± limits of agreement between two tests were 0.03 ± 0.47, 0.05 ± 0.42 and 0.06 ± 0.31 (×10 mm/s) (ICCs, 0.81, 0.52 and 0.68; CVs, 9%, 8% and 8%), respectively. Both intra-observer repeatability and inter-observer reproducibility were acceptable for global pancreatic ADC between measurements of the two DWIs.
The best test-retest repeatability of ADC in the normal pancreas was only for the whole pancreas with a CV of 6%. Cautions should be taken in interpreting longitudinal clinical changes in ADC values of the normal pancreas for the measurements do have an inherent variability by locations.
基于扩散加权成像（DWI）评估正常胰腺的表观扩散系数（ADC）的重测重复性。
纳入26名健康志愿者（平均年龄47.6岁；13名男性），在3.0-T磁共振成像仪上对DWI序列进行两次重新定位扫描。两名阅片者分别独立测量两次DWI图像上胰头、胰体和胰尾的ADC值。计算胰头、胰体和胰尾的平均ADC值作为整体胰腺ADC值。采用Bland-Altman分析、组内相关系数（ICC）和变异系数（CV）评估ADC测量的重测重复性和一致性。
整体胰腺ADC显示出最佳的重测重复性（平均差值±一致性界限为0.05±0.25×10⁻³mm²/s；ICC为0.79；CV为6%）。胰头、胰体和胰尾ADC的重测重复性存在差异，两次测量之间的平均差值±一致性界限分别为0.03±0.47、0.05±0.42和0.06±0.31（×10⁻³mm²/s）（ICC分别为0.81、0.52和0.68；CV分别为9%、8%和8%）。两次DWI测量之间，整体胰腺ADC的观察者内重复性和观察者间再现性均可接受。
正常胰腺ADC的最佳重测重复性仅体现在整个胰腺上，CV为6%。在解释正常胰腺ADC值的纵向临床变化时应谨慎，因为不同部位的测量存在固有变异性。
