大鼠肝脏纤维化模型^(13)N-NH_3·H_2O PET/CT与多b值DWI对比研究

Quantitative comparison of ^(13)N-NH_3·H_2O PET/CT and multi-b DWI in rat liver fibrosis model

目的对大鼠肝脏纤维化模型行13N-NH3·H2O PET/CT和多b值DWI对比研究,探讨不同b值DWI对肝脏纤维化早期诊断及分期的价值。方法 15只大鼠,对照组3只,肝脏纤维化模型12只(S1期、S2期和S3期分别是6只、5只和1只)。15只大鼠均先做13N-NH3·H2O PET/CT扫描,然后进行常规MR和多b值扫描。扫描结束后取出肝脏标本进行常规病理和水通道蛋白1(AQP1)免疫组化分析。获得13N-NH3·H2O PET/CT 20 s、90 s、5 min、10 min和15 min肝脏标准摄取值(SUV),及单指数模型、多指数模型ADC的平均值,然后计算不同时相SUV和ADC值之间的相关系数。结果 13N-NH3·H2O PET/CT 90 s时对照组和S1组、5 min时对照组和S2 + S3组,及多指数模型对照组和S2 + S3组的中b值和高b值ADC值差异有统计学意义,其余各组之间差异均无统计学意义。单指数模型ADC值与13N-NH3·H2O PET/CT肝脏在90 s的SUV相关性最高,多指数模型小b值、中b值和高b值ADC值分别与13N-NH3·H2O PET/CT肝脏在20 s、5 min和15 min的SUV相关性最高。结论 13N-NH3·H2O PET/CT肝脏SUV和ADC值并不能区分对照组和S1组、S1和S2 + S3分期。ADC值与13N-NH3·H2O PET SUV的相关性表明,单指数模型ADC值与水分子扩散密切相关,多指数模型小b值、中b值分别与组织血流灌注、细胞间隙和细胞内水分子扩散高度相关,而高b值与水分子通过细胞膜转运相关。

Objective To compare the ^13N-NH3·H2O PET/CT and multi-b DWI images of rat liver fibrosis model and to explore the value of different b values in DWI in the early diagnosis and staging of liver fibrosis. Methods ^13N-NH3·H2O PET/CT and multi-b DWI scan were performed on 15 rats, including a control group （n = 3）, and a group of rat with liver fibrosis of various stages （n = 12 including 6 at S1, 5 at S2 and 1 at S3）. After that routine pathologic analysis was performed on liver specimens and the aquaporinl （AQP1） immunohistochemical information was obtained. Liver standardized uptake value （SUV） were obtained from ^13N-NH3·H2O PET/CT in 20 seconds, 90 seconds, 5 minutes, 10 minutes and 15 minutesrespectively; and ADC from single index model and multi-exponential model were averaged. The correlation between the SUV values and ADC were calculated. Results There are not significant difference among control, S 1 and S2 ＋ S3 group excluding ^13N-NH3·H2O PET/CT between control and S1 group at 90 s, between control and S2 ＋ S3 group at 5min, multi-index model ADC of middle b and high b value between control and S2 ＋ S3 group respectively.ADC from single index model and the SUV from ^13N-NH3·H2O PET/CT of the liver in 90 s shows the highest correlation, ADC values from multi-index model of low b, middle b; high b values correlated with SUV from ^13N-NH3·H2O PET/CT in 20 s, 15 min and 5 min the best. Conclusion 13N-NH3·H2O PET/CT liver SUV and ADC do not distinguish between control and S1 group, between S1 and S2 ＋ S3 group. Our results showed that ADC values from single index model is closely related to the diffusion of water molecules; ADC values from multiindex of low b, middle b and high b value correlated with in tissue perfusion, molecular diffusion in cell and tissue waters respectively; and high b values associated with the water molecules through the membrane transport.