慢性乙型病毒性肝炎患者不同场强下磁共振扩散加权成像定量对比分析

Quantitative comparison of diffusion weighted image in liver at two field strengths for chronic hepatitis B

目的 评价不同场强下慢性乙型病毒性肝炎患者扩散加权成像（DWI）测得的表观扩散系数（ADC）值间是否存在差异。方法 2016年1至11月招募解放军第三〇二医院40例慢性乙型病毒性肝炎患者，在肝穿前1周内随机先后接受了同一厂家1.5和3.0 T磁共振的DWI序列扫描，两次扫描间隔15 min之内，扫描方案为呼吸触发DWI（RT-DWI），利用感兴趣区域（ROI）方法测量两个场强下肝脏的穿刺部位附近的ADC值，使用Bland-Altman检验和配对t检验比较不同场强下的ADC值。结果 轻度炎症组1.5 T不同b值下的ADC值为[1.22-1.48（1.35±0.08）×10^-3 mm^2/s], 3.0 T不同b值下的ADC值为[1.18-1.45（1.30±0.08）×10^-3 mm^2/s]；中重度炎症组1.5 T不同b值下的ADC值为[1.11-1.37（1.25±0.06）×10^-3 mm^2/s]，3.0 T不同b值下的ADC值为[1.08-1.31（1.20±0.06）×10^-3 mm^2/s]；慢性乙型病毒性肝炎患者1.5和3.0 T磁共振不同b值下的ADC值差异有统计学意义（P〈0.01）。结论 磁共振场强对慢性乙型病毒性肝炎患者肝脏ADC值有影响，同一受试对象3.0 T场强下肝脏ADC值〈1.5 T场强下肝脏ADC值。

Objective To evaluate whether there were differences between apparent diffusion coefficient （ADC） values derived from 3.0 T and 1.5 T MR diffusion-weighted imaging （DWI） in liver of patients with chronic hepatitis B. Methods From January 2016 to November 2016, a total of 40 chronic hepatitis B prospectively underwent both 1.5 T and 3.0 T DWI before liver biopsy, the interval between two scans was within 15 minutes, the protocol was respiratory-triggered DWI （RT-DWI）. The ADC values were measured at both fieht strengths using ROI method. Bland-Altman tests and paired t-tests were used to compare ADC values obtained at 1.5 T and 3.0 T. Results The ADC values of different b values for patients with mild inflammation at 1.5 T were（ 1.22 - 1.48 （1.35 ± 0. 08 ） ×10^-3 mm^2/s） , the ADC values of different b values for patients with mild inflammation at 3.0 T were（ 1. 18 - 1.45（ 1.30 ±0. 08） ×10^-3 mm^2/s） ; the ADC values of different b values for patients with moderate to severe inflammation at 1.5 T were（ 1.11 -1.37（ 1.25 ± 0. 06 ） ×10^-3 mm^2/s） , the ADC values of different b values for patients with moderate to severe inflammation at 3.0 T were（ 1.08 - 1.31 （ 1.20 ± 0. 06） ×10^-3 mm^2/s）. There were significantly differences between the ADC values of different b values for patients with chronic hepatitis B obtained at two field strengths （ P 〈 0. 01 ）. Conclusions Different field strengths have influence on ADC values in liver, the ADC values derived from 3.0 T are lower than the ADC values derived from 1.5 T.