胰腺不同部位表观扩散系数正常值初探

Normal apparent diffusion coefficient values of different regions of pancreas

目的分析表观扩散系数（ADC）随胰腺形态学变化的特征。方法对393例胰腺正常的志愿者行上腹部横断面单次激发平面回波扩散加权成像（SSEP—DWI，扩散敏感因子值为0，500s／mm2）。依据DWI计算出相应的ADC图，测量胰腺头、颈、体及尾部ADC。Kruskal—Wallis秩和检验和Wilcoxon配对符号秩和检验进行统计学分析。结果393例正常胰腺头、颈、体及尾部ADC平均值分别为（1．52．4±0．29）×10—0、（1．644±0．34）×10-3、（1．67±0．35）×10-3、（1．58±0．31）×10-3mm2／s。Kruskal-Wallis检验结果表明，胰腺不同部位ADC差异具有统计学意义（X2=44．8748，P〈0．0001）；Wilcoxon配对符号秩和检验结果显示，胰腺头与颈部、头与体部、头与尾部、颈与尾部和体与尾部的ADC之间差异均具有统计学意义（P值分别为〈0．0001、〈0．0001、0．0008、0．0062、〈0．0001），而颈与体部ADC差异无统计学意义（P=0．1181）。结论正常胰腺ADC随胰腺形态结构不同其差异具有统计学意义，这一特征可为DWI及ADC在胰腺疾病的临床应用及研究提供参考。

Objective To investigate and determine the apparent diffusion coefficient （ADC） values in different anatomical regions of normal pancreas. Methods A total of 383 volunteers with normal pancreas were included in this study. Single-shot echo planar imaging diffusion weighted imaging （SSEP-DWI; b value = O, 500 s/ram2） was employed to determine the ADCs in the head, neck, body and tail parts of the pancreas. Statistical analysis was performed by using Kruskal-Wallis and Wilcoxon signed rank tests. Results The ADCs in the head, neck, body and tail parts of the pancreas was （1.52 ±0.29）×10-3, （1.64 ±0.34） ×10-3, （1.67 ±0.35） × 10-3, （1.58±0.31） × 10-3 mm2/s, the Kruskal-Wallis test results showed a significant difference of mean ADCs among the different anatomical regions （chi square =44. 8748, P 〈O.O0O1 ）. Wilcoxon signed rank test results showed the mean ADCs differed remarkably between the head and neck （P〈O. 0001）, head and body （P〈O. 0001）, head and tail （P =0.0008）, neck and tail （P =0.0062）, body and tail （P 〈 O. 0001 ） , respectively. The mean ADCs between the neck and body was not significantly different （P = O. 1181 ）. Conclusions The mean ADC values of normal pancreas vary significantly within different anatomical regions, which can serve as a guide for DWI and ADC in clinical application and research of pancreatic diseases.