Ding Xun, Xu Haibo, Zhou Jun, Xu Jia, Mei Hao, Long Qingyun, Wang Yaxun
Department of Medical Imaging, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, PR China.
Medicine (Baltimore). 2019 Apr;98(14):e15104. doi: 10.1097/MD.0000000000015104.
To prospectively compare the reproducibility of normal pancreas-normalized apparent diffusion coefficient (ADC) measurements for the normal pancreas and mean normalized ADCs at different pancreas anatomic locations.In total, 22 healthy volunteers underwent pancreatic 3.0-T magnetic resonance (MR) imaging, including axial diffusion-weighted (DW) imaging with 3 b values used (0, 400, and 800 s/mm) and with the respiratory-triggered (RT) technique. The mean ADCs from 3 regions of interest (ROIs) in 5 anatomic locations (head [H], body [B], and tail [T] of pancreas and spleen [S] and erector spinae muscles [M]) were calculated. The pancreas-normalized ADC was defined as the ratio of the ADC for the pancreas to the ADC for the spleen or erector spinae muscle. Reproducibility of ADCs and normalized ADCs was assessed by the Bland-Altman method. The ADC and normalized ADC data were analyzed by repeated-measures ANOVA.Mean ADC and normalized ADC values did not differ (P >.05) with repeated measurements at the different pancreas anatomic locations. Reproducibility of pancreas-normalized ADC measurements in each of the 3 pancreatic anatomic locations was better with the erector spinae muscle rather than the spleen used as a reference. Mean ADC and normalized ADC values significantly differed between the 3 pancreatic segments (H: 1.36 × 10 mm/s, B: 1.38 × 10 mm/s, T: 1.25 × 10 mm/s, P = .022; H/S: 1.75, B/S: 1.78, T/S: 1.59, P = .009; H/M: 0.91, B/M: 0.95, T/M: 0.85, P = .008). Mean ADC values and normalized ADC values showed a trend to decrease from the pancreatic head to tail.Our preliminary results suggest that normalized ADC measurements for the pancreas show good intra- and interobserver reproducibility, the erector spinae muscle is a better choice than the spleen for calculating normalized ADC values for the pancreas, and the normalized ADC values are lower for the pancreatic tail than other pancreatic segments.
前瞻性比较正常胰腺归一化表观扩散系数（ADC）测量值在正常胰腺中的可重复性以及不同胰腺解剖位置的平均归一化ADC值。总共22名健康志愿者接受了胰腺3.0-T磁共振（MR）成像，包括使用3个b值（0、400和800 s/mm²）并采用呼吸触发（RT）技术的轴向扩散加权（DW）成像。计算了5个解剖位置（胰腺头部[H]、体部[B]、尾部[T]、脾脏[S]和竖脊肌[M]）中3个感兴趣区域（ROI）的平均ADC值。胰腺归一化ADC定义为胰腺的ADC与脾脏或竖脊肌的ADC之比。采用Bland-Altman方法评估ADC值和归一化ADC值的可重复性。通过重复测量方差分析对ADC和归一化ADC数据进行分析。在不同胰腺解剖位置重复测量时，平均ADC值和归一化ADC值无差异（P＞0.05）。以竖脊肌而非脾脏作为参考时，胰腺3个解剖位置各自的胰腺归一化ADC测量的可重复性更好。胰腺3个节段之间的平均ADC值和归一化ADC值存在显著差异（H：1.36×10⁻³mm²/s，B：1.38×10⁻³mm²/s，T：1.25×10⁻³mm²/s，P = 0.022；H/S：1.75，B/S：1.78，T/S：1.59，P = 0.009；H/M：0.91，B/M：0.95，T/M：0.85，P = 0.008）。平均ADC值和归一化ADC值显示出从胰头到胰尾逐渐降低的趋势。我们的初步结果表明，胰腺归一化ADC测量显示出良好的观察者内和观察者间可重复性，对于计算胰腺归一化ADC值，竖脊肌是比脾脏更好的选择，并且胰腺尾部的归一化ADC值低于其他胰腺节段。
