Laboratory of Biomedical Imaging and Signal Processing, University of Hong Kong, Pokfulam, Hong Kong SAR, China.
J Magn Reson Imaging. 2010 Nov;32(5):1141-8. doi: 10.1002/jmri.22367.
To characterize changes in diffusion properties of liver using diffusion tensor imaging (DTI) in an experimental model of liver fibrosis.
Liver fibrosis was induced in Sprague-Dawley rats (n = 12) by repetitive dosing of carbon tetrachloride (CCl(4)). The animals were examined with a respiratory-gated single-shot spin-echo echo-planar DTI protocol at 7 T before, 2 weeks after, and 4 weeks after CCl(4) insult. Apparent diffusion coefficient (ADC), directional diffusivities (ADC(//) and ADC(⊥)), and fractional anisotropy (FA) were measured. Liver histology was performed with hematoxylin-eosin staining and Masson's trichrome staining.
Significant decrease (P < 0.01) in ADC was found at 2 weeks (0.86 ± 0.09 × 10(-3) mm(2)/s) and 4 weeks (0.74 ± 0.09 × 10(-3) mm(2)/s) following CCl(4) insult, as compared with that before insult (0.97 ± 0.08 × 10(-3) mm(2)/s). Meanwhile, FA at 2 weeks (0.18 ± 0.03) after CCl(4) insult was significantly lower (P < 0.01) than that before insult (0.26 ± 0.05), and subsequently normalized at 4 weeks (0.26 ± 0.07) after the insult. Histology showed collagen deposition, presence of intracellular fat vacuoles, and cell necrosis/apoptosis in livers with CCl(4) insult.
DTI detected the progressive changes in water diffusivities and diffusion anisotropy of liver tissue in this liver fibrosis model. ADC and FA are potentially valuable in detecting liver fibrosis at early stages and monitoring its progression. Future human studies are warranted to further verify the applicability of DTI in characterizing liver fibrosis and to determine its role in clinical settings.
利用扩散张量成像（DTI）在肝纤维化的实验模型中描述肝脏扩散特性的变化。
用四氯化碳（CCl(4)）重复给药在 Sprague-Dawley 大鼠（n = 12）中诱导肝纤维化。在 CCl(4)损伤前、损伤后 2 周和 4 周时，使用呼吸门控单次自旋回波回波平面 DTI 方案对动物进行检查。测量表观扩散系数（ADC）、各向异性扩散系数（ADC(//)和 ADC(⊥)）和分数各向异性（FA）。肝组织学采用苏木精-伊红染色和 Masson 三色染色进行。
与损伤前（0.97 ± 0.08 × 10(-3) mm(2)/s）相比，CCl(4)损伤后 2 周（0.86 ± 0.09 × 10(-3) mm(2)/s）和 4 周（0.74 ± 0.09 × 10(-3) mm(2)/s）时 ADC 显著降低（P < 0.01）。同时，CCl(4)损伤后 2 周时 FA（0.18 ± 0.03）明显低于损伤前（0.26 ± 0.05），随后在损伤后 4 周时恢复正常（0.26 ± 0.07）。组织学显示 CCl(4)损伤肝脏有胶原沉积、细胞内脂肪空泡和细胞坏死/凋亡。
DTI 检测到该肝纤维化模型中肝组织水扩散率和扩散各向异性的进行性变化。ADC 和 FA 可能有助于在早期阶段检测肝纤维化并监测其进展。需要进行未来的人体研究，以进一步验证 DTI 在描述肝纤维化中的适用性，并确定其在临床环境中的作用。
