磁共振扩散成像在诊断家兔肝纤维化中的应用

A pilot study of hepatic fibrosis with magnetic resonance diffusion-weighted imaging in a rabbit model

目的评价磁共振扩散成像在诊断家兔肝纤维化中的作用。方法选用普通级家兔58只，随机分为对照组和实验组。实验组腹腔注射四氯化碳建立家兔肝纤维化模型，然后行磁共振扩散成像。磁共振扩散成像采用自旋回波平面成像序列，分别取扩散敏感梯度（b值）为300、500进行扫描，通过软件处理获得表观扩散系数（ADC）值以及指数表观扩散系数（EADC）值，磁共振检查后取家兔肝脏行病理检查，并按病理学分期分组，用SPSS11．0统计软件分析。结果在磁共振扩散成像结果中，b值为300时，对照组（SO）ADC值为（2．460±0．424）×10^-3，实验组（S1～S4）ADC值分别为（2．170±0．311）×10^-3，（1．950±0．248）×10^-3，（1．635±0．296）×10^-3，（1．566±0．353）×10^-3，对照组EADC值为0．102±0．044，实验组（S1～S4）EADC值分别为0．167±0．047，0．183±0．042，0．216±0．054，0．219±0．048。对照组和实验组ADC值以及EADC值差异有统计学意义（F=12．13，P=0．0006；F=10．06，P=0．004）。b值为500时，对照组ADC值为（2．044±0．215）×10^-3，实验组（S1～S4）ADC值分别为（1．907±0．223）×10^-3，（1．785±0．232）×10^-3，（1．542±0．268）×10^-3，（1．312±0．212）×10^-3。对照组EADC值为0．1106±0．069，实验组（S1～S4）EADC值分别为0．1764±0．073，0．1889±0．056，0．2421±0．079，0．2657±0．037。对照组和实验组ADC值以及EADC值差异有统计学意义（F=14．57，P=0．0002;F=10．42，P=0．003）。同时，b值为300、500时，实验组中S1组与S4组ADC值差异均有统计学意义（P=0．03，P=0．044），其余实验组间差异无统计学意义（P〉0．05）。结论ADC值以及EADC值可能是肝纤维化诊断和量化的一个潜在标准。

Objective To evaluate the role of MRI diffusion imaging in the diagnosis of hepatic fibrosis. Methods Fifty-eight rabbits were divided randomly into a blank control group （n = 10） and a model group （n = 48）. Carbon tetrachloride was injected intraperitoneally into the animals of the model group to induce liver fibrosis. SE-EPI sequence was used in diffusion weighted imaging for all the rabbits. Then apparent diffusion coefficient （ADC） and exponential apparent diffusion coefficient （EADC） of their livers were obtained with Functool 2.0 software. The degrees of liver fibrosis of the rabbits were graded with histological examinations. Statistical analysis was performed by SPSS 11.0 statistical software. One-way analysis of variance was used to compare every rank data respectively. P 〈 0.05 was considered statis- tically significant. Results When the b value was 300 s/mm2, ADC of diffusion-weighted imaging （DWI） was （2.460 ± 0.424） × 10^-3 in the control group （SO）. ADCs were （2.170 ± 0.311） × 10^-3, （1.950 ± 0.248） × 10^-3, （1.635 ± 0.296） × 10^-3, （1.566 ± 0.353） × 10^-3 in the model group （S1, S2,S3 and S4）. EADC of DWI was 0.102 ± 0.044 in the control group and were 0.167 ± 0.047, 0.183 ± 0.042, 0.216 ± 0.054, 0.219 ± 0.048 in the model group （S1, S2, S3 and S4）. ADC and EADC of the control group and model group had significant differences （F = 12.13, P = 0.0006; F = 10.06, P = 0.004 respectively）. When the b value was 500 s/mm^2, ADC of DWl was （2.044 ± 0.215） × 10^-3 in the control group, ADC were （1.907 ± 0.223）× 10^-3, （1.785 ± 0.232）× 10^-3, （1.542 ± 0.268）× 10^-3, （1.312 ± 0.212）× 10^-3 in the model group （S1, S2, S3 and S4）. EADC of DWI was 0.1106 ± 0.069 in the control group and EADCs of DWI were 0.1764 ± 0.073, 0.1889 ± 0.056, 0.2421 ± 0.079, 0.2657 ± 0.037 in the model group （S1, S2, S3 and S4）. ADCs and EADCs of the control group and model group had significant differences （F = 14.57, P = 0.0002; F = 10.42, P = 0.003 respectively）. There was a significant difference of ADCs between S1 and S4 of the model group when b value were 300 s/mm^2 and 500 s/mm^2 （P = 0.03, P = 0.044 respectively）. No differences were found between other subgroups in the model group. Conclusion Our preliminary study shows that measuring ADCs and EADCs has a good potential in diagnosing and quantifying hepatic fibrosis, especially when using b values of 300 sec/mm^2 and 500 sec/mm^2.