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目的评价斑点追踪成像技术(speckle tracking imaging,STI)的速度、位移和形变(应变及应变率)在检测2型糖尿病大鼠左心功能的灵敏性和应用价值。方法雄性SD大鼠按照30 mg/kg给予链脲佐菌素尾静脉注射后喂以高脂饲料,期间检测空腹血糖(fasting plasma glucose,FPG)及2 g/kg葡萄糖溶液灌胃2 h后的血糖(plasma glucose 2 h,PG2 h),以确定大鼠2型糖尿病模型建立成功;建模6周后用STI检测左心室6个不同节段收缩期、舒张期径向和周向速度、位移、形变(应变和应变率),并比较其变化情况。结果建模3周后,8只测得FPG>7.0 mmol/L和(或)PG2 h>11.1 mmol/L的大鼠被纳入模型组。建模6周后,STI分析显示模型组左心室收缩期和舒张期部分节段的径向、周向速度和位移较对照组显著降低,差异具统计学意义(P<0.05)。但左心室6个不同节段的收缩期和舒张期径向、周向整体速度,收缩期和舒张期径向、周向整体位移与对照组相比,差异均无统计学意义(P>0.05);形变分析显示模型组舒张期各节段径向、周向应变及其6节段的整体径向和周向应变,收缩期、舒张期径向整体应变率较对照组显著降低,差异有统计学意义(P<0.05)。结论 STI能够在早期检测到2型糖尿病大鼠左心室心肌部分节段收缩及舒张功能受损,采用形变参数评估心功能比速度和位移更为灵敏。
Objective To evaluate the sensitivity and the value of velocity, displacement and deformation (strain and strain rate) of speckle tracking imaging (STI) in the detection of left ventricular function in type 2 diabetic rats. Methods Male Sprague-Dawley rats were given streptozotocin intravenous injection at a dose of 30 mg / kg and fed with high fat diet. Fasting plasma glucose (FPG) and 2 g / kg glucose solution were administered for 2 h. Plasma glucose 2 h (PG2 h) was used to confirm the successful establishment of type 2 diabetic rat model. Six weeks after modeling, systolic, diastolic and circumferential diastolic velocities , Deformation (strain and strain rate), and compare their changes. Results After 3 weeks of modeling, 8 rats with FPG> 7.0 mmol / L and (or) PG2h> 11.1 mmol / L were included in the model group. Six weeks after modeling, STI analysis showed that the radial, circumferential velocity and displacement of left ventricular systolic and diastolic segments in the model group were significantly lower than those in the control group, with statistical significance (P <0.05). However, there was no significant difference in systolic and diastolic radial, circumferential global velocities, systolic and diastolic radial and circumferential global displacements in 6 different segments of left ventricle compared with the control group (P> 0.05 ). Deformation analysis showed that radial and circumferential strain in each segment of diastolic segment of the model group and overall radial and circumferential strain in 6 segments, systolic and diastolic radial global strain rates were significantly lower than those in the control group Statistical significance (P <0.05). Conclusions STI can detect the contraction and diastolic function of some segments of left ventricular myocardium in type 2 diabetic rats in early stage. It is more sensitive to assess cardiac function than velocity and displacement by using the deformation parameters.