速度向量成像技术检测兔腹主动脉粥样硬化易损斑块的初步研究

目的 探讨速度向量成像(VVI)技术评价兔腹主动脉粥样硬化斑块生物力学参数的价值.方法 45只雄性新西兰大白兔,随机选择10只作为正常对照组,余35只制成动脉粥样硬化模型.分别对其行常规超声检查及VVI脱机分析,测量右肾动脉分支1 cm以下处腹主动脉内-中膜厚度(IMT)或斑块厚度,记录此处收缩期最大切向速度(Vmax)、应变(Smax)及应变率(SRmax).最后行病理及免疫组化检查.结果 根据病理分为4组:正常对照组(A组,10只)、病理性内膜增厚组(B组,9只)、厚帽纤维粥样斑块组(C组,15只)及薄帽纤维粥样斑块组(D组,11只).C、D组间斑块厚度差异无统计学意义(P>0.05),均大于A、B组IMT(P<0.05).各组间Vmax、Smax、SRmax差异有统计学意义(P<0.05).以Smax>0.37%检测易损斑块的灵敏度为 84.4%,特异度为 91.7%.结论 VVI技术有望成为临床早期发现易损斑块的可靠方法.

Abstract：

Objective To explore the value of biomechanics parameter of rabbit abdominal aortic atheroma using velocity vector imaging(VVI).Methods Ten of 45 male New Zealand rabbits were chosen as normal control group randomly,the rest experimental rabbits were made atheromatous plaque model.The rabbits were examined by two-dimensional ultrasound and VVI respectively.The intima-media thickness(IMT) or thickness of plaques of abdominal aorta 1 cm from right renal artery branch were recorded.Maximum tangential velocity,strain and strain rate of IMT or plaques were measured using VVI.Then the rabbits were killed for pathological and immuno-histochemical examination.Results Based on pathology,the rabbites were divided into 4 groups:control group(group A,n=10),group of pathological endometrial thickening(group B,n=9),group of thick fibrous cap atheromatous plaques (group C,n=15) and group of thin fibrous cap atheromatous plaques (group D,n=11).The difference of plaques thickness and biochemical indicators had no statistically significant between group B and C(P>0.05),both bigger than group A and B (P<0.05).The difference of Vmax,Smax and SRmax had statistically significant each group(P<0.05).With Vmax>0.46×10-2 cm/s,Smax>0.37%,SRmax>1.415×10-2 s-1 to find the vulnerable plaques,the sensitivity were 75.0%,84.4%,84.4% respectively,specificity were 70.8%,91.7%,83.3% respectively.Conclusions VVI can identify plaque biomechanics parameter of different progression periods,which is expected to be a reliable method to find vulnerable plaques earlier in clinic.

Preliminary study on velocity vector imaging detection rabbit abdominal aortic atherosclerotic vulnerability plaques

Objective To explore the value of biomechanics parameter of rabbit abdominal aortic atheroma using velocity vector imaging(VVI).Methods Ten of 45 male New Zealand rabbits were chosen as normal control group randomly,the rest experimental rabbits were made atheromatous plaque model.The rabbits were examined by two-dimensional ultrasound and VVI respectively.The intima-media thickness(IMT) or thickness of plaques of abdominal aorta 1 cm from right renal artery branch were recorded.Maximum tangential velocity,strain and strain rate of IMT or plaques were measured using VVI.Then the rabbits were killed for pathological and immuno-histochemical examination.Results Based on pathology,the rabbites were divided into 4 groups:control group(group A,n=10),group of pathological endometrial thickening(group B,n=9),group of thick fibrous cap atheromatous plaques (group C,n=15) and group of thin fibrous cap atheromatous plaques (group D,n=11).The difference of plaques thickness and biochemical indicators had no statistically significant between group B and C(P>0.05),both bigger than group A and B (P<0.05).The difference of Vmax,Smax and SRmax had statistically significant each group(P<0.05).With Vmax>0.46×10-2 cm/s,Smax>0.37%,SRmax>1.415×10-2 s-1 to find the vulnerable plaques,the sensitivity were 75.0%,84.4%,84.4% respectively,specificity were 70.8%,91.7%,83.3% respectively.Conclusions VVI can identify plaque biomechanics parameter of different progression periods,which is expected to be a reliable method to find vulnerable plaques earlier in clinic.