超声声衰减成像评估兔脂肪肝模型肝脂肪变性程度的实验研究

Experimental study of ultrasound attenuation imaging to assess the extent of hepatic steatosis in a rabbit fatty liver model

目的:探讨超声声衰减成像(attenuation imaging,ATI)技术在定量评估兔脂肪肝模型肝脂肪变性程度中的应用价值。方法:高脂高胆固醇饲料喂养20只雄性新西兰大白兔,构建不同程度兔脂肪肝模型。在高脂饲料喂养前(第0周)及喂养后(1~36周)每4周随机取2只实验兔进行灰阶超声及ATI检查,从第4周开始,2只实验兔在灰阶超声及ATI检查后处死并行肝组织取材。以病理学检查为金标准,观察并分析脂肪肝形成及发展过程中ATI技术测得的声衰减系数(attenuation coefficient,AC)值的变化。结果:兔脂肪肝形成及发展过程中肝脏AC值呈逐渐上升趋势,于第12周开始,兔肝脏AC值[(0.909±0.189)dB/(cm·MHz^(-1))]与第0周AC值[(0.592±0.131)dB/(cm·MHz^(-1))]相比差异有统计学意义(P=0.015)。以病理学检查结果为参照,AC值随肝脂肪变性程度的增加而增加,其中S0与S2、S3之间,S1与S2、S3之间的AC值差异有统计学意义(P<0.008),S0与S1、S2与S3之间差异无统计学意义(P=0.030,P=0.021)。进一步分析发现兔肝脏AC值与肝脂肪变性程度呈显著正相关(r=0.912,P<0.001)。结论:AC值在脂肪肝形成及发展过程中呈稳定上升趋势,AC值与肝脂肪变性程度的相关性高,ATI技术能够定量检测肝脂肪变性程度并动态监测其病程变化。

Objective:To discuss the value of ultrasound attenuation imaging(ATI)technique in the quantitative assessment of hepatic steatosis in a rabbit fatty liver model.Methods:Feeding 20 male New Zealand white rabbits with high fat and high cholesterol diet to construct a rabbit model of fatty liver.Every four weeks,two rabbits were randomly selected for conventional ultrasound and ATI examinations before high fat and high cholesterol diet feeding and after high fat and high cholesterol diet feeding.From the 4th week,the two experimental rabbits who had undergone ultrasound and ATI examinations were executed.Pathological results were used as the gold standard to observe and analyze the changes of attenuation coefficient(AC)value measured by the ATI technique in the formation and development of fatty liver in rabbit liver.Results:The AC value of the rabbit liver showed a gradual increase during the formation and development of fatty liver.The significant difference of AC value in the rabbit liver was detected began the 12th week[(0.909±0.189)dB/(cm·MHz^(-1))]compared with the 0th week[(0.592±0.131)dB/(cm·MHz^(-1))](P=0.015).The pathological results showed that the rabbit liver had obvious steatosis from the 12th week.Using pathology as a reference,the differences between S0 and S2,S0 and S3,S1 and S2,S1 and S3 were statistically significant(P<0.008),the differences between S0 and S1,S2 and S3 was not statistically significant(P=0.030,P=0.021).In addition,the AC value of rabbit liver was significantly positively correlated with the degree of hepatic steatosis(r=0.912,P<0.001).Conclusion:The AC value showed an upward trend during the formation and development of fatty liver in the rabbit liver,and the AC value was highly correlated with the degree of hepatic steatosis.The ATI technique is capable of quantifying the extent of hepatic steatosis and dynamically monitoring the course of the disease.