The Value Of New Echocardiography Technique For The Diagnosis Of Close Cardiac Muscle Contusion In Pigs

Chapter 1 Study of animal model on close cardiac muscle contusionAim:Build a pig model on close cardiac muscle contusion by using a self made small impactor striking on experimental pigs' chest.Method:16 healthy small Guizhou-Panama pigs were studied.A small impactor(average power is 7.01KN,compress depth is 3cm-5cm)was applied to strike pigs' chest area.A two-dimensional ultrasound echocardiography(2DE)was used to find the striking area,striking angle and the power of the strike thus a close cardiac muscle injury animal model was built.During the experiment,a 2DE was used to look for the location and the area of the da- mage,also the changes were observed by drawing the animal's serum.After the experiment,animals were sacrificed and their hearts were got out to have a gross estimate and the pathological changes of the damage.Results:After the striking,10 of the 16 animals showed close cardiac muscle contusion animal model was successfully built,contusion of different degrees were observed in the cardiac muscle s of those animals.Immediately after the striking,thickness of cardiac muscle,enhancement of the echo, decreased movement or no movement,even contradiction movement were observed by the 2DE on damaged area.We also found that the echo sound of area around the damaged muscle and anterior papillary muscle were increas-ed,embolisms were found in some of the experimental pigs.About 2h after the striking,the serum showed changes.Pathology of the gross anatomy: spotted or patched hemorrhage below endocardium and exdocardium after severe cardiac muscle contusion,it also combine to big patches or even hematoma inside the cardiac muscle,or crack of the endocardium,embolisms inside the heart.Under the light microscope:the broken of thec ardiac muscle fiber,broad hemorrhage,red blood cells or the hematomas were seen between cardiac muscle fibers or below endocardium and exdocardium after severe cardiac muscle contusion.Under the electronic microscope:edema of the cardiac muscle fibers and stroma,a large number of neutrophil(PMN)in the cardiac muscle,micro vascular embolisms in cardiac muscles,split of nucleolus and dissolution of the cells were found.Conclusion:In our model,we used small impactor strike the experimental animals,applied 2DE to choose striking location and angle, observed the damaged location and area,also we studied the changes of the serum and other vital signs.This model is accurate,controllable and stable.It is a good animal model for next step of the experiment.Chaper 2 The Value of Echocardiography for the early diagnosis of close cardiac muscle contusion in pigsAim:Study the value of two-dimensional Echocardiography(2DE), doppler tissue synchronization imaging(TSI)and myocardial contrast echocardiography(MCE)during the early diagnosis of close myocardial contusion.Methods.10 small Guizhou-Panama pigs were used.Successfully built the close myocardial contusion animal model by using the small impactor.Applied echocardiography before and after the injury 0.5h,2h,4h,8h and 12h respectively,these data were analyzed together with the TTC pathological results.Results.0.5h after the strike,the location and area of the damage can be directly and rapidly shown by 2DE,TSI and MCE,which all showed that after myocardial contusion(MC),main damaged areas are anterior and lateral myocardial walls.After myocardial contusion MC,three echocardiography techniques were used to observe the scale of the abnormal segment,the movement of the myocardial wall,Time to Peak of Systolic Velocity,contrast score and wall motion segmental inder(WMSI),Time to Peak of Systolic Velocity index(TPI),contrast score index(CSI),which were all increased than pre-injury.Compared and confirmed with the TTC stain pathological data, among those three techniques for the diagnosis of myocardial contusion,the sensitivity of 2DE is 83.3%,specificity is 66.7%;TSI,sensitivity is 92.9%and specificity72.2%;MCE,sensitivity is 97.6%and specificity 88.9%.Conclusion:2DE,TSI and MCE can be used accurately for the early diagnosis of the degree and location of myocardial contusion.MCE is more specific for the diagnosis of myocardial contusion. Chapter 3 strairlstrain rate imaging technique for the left Ventricular function of pigs after close myocardial contusionAim:Study the value of applying strairlstrain rate imaging(SRI) technique on left ventricular function before and after close myocardial contusion of pigs.Methods:9 small Guizhou,Panama pigs were used.Successfully built the close myocardial contusion animal model by using the small impactor.Applied SRI before and after the injury 0.5h,2h,4h,8h and 12h respectively,LVEF and the apical four-chamber view and longaxis view of the left ventricle.Tissue velocity imaging(TVI)were measured and went to EchoPAC station and changed to SRI mode and the left ventricle PSSR were measured.LVEF and PSSR before and all the time period after the MC were analyzed to find out the change and relativity.Results:There are no significant difference for the PSSR level between the anterior wall,posterior wall,lateral wall and ventrical septum of left ventricle before the MC(P＞0.05).0.5h,2h,4h after MC,PSSR levels in the anterior wall are decreased than pre-myocardial contusion(P＜0.05,even more after 8h,12h,P＜0.01),4h after MC,PSSR levels in the lateral wall,posterior wall,and ventrical septum are decrease than pre-myocardial ontusion (P＜0.05),8h and 12 h after MC,PSSR levels in the posterior wall,and ventrical septum have a tendency to recover,but still not to the level of premyocardial contusion yet.4h after MC,LVEF was decreased than premyocardial contusion(P＜0.05)and There were direct correlation between LVEF and PSSR(r=0.851).Conclusion:Compared with LVEF,SRI was relatively sensitive to study the change of myocardial function after close myocardial contusion,which is of significant importance for local and whole study of myocardial function after close myocardial contusion of pigs.Chapter 4 two dimensional strain echocardiography technique for the left Ventricular function of pigs after close myocardial contusionAim:Before and after close myocardial contusion of pigs two dimensional strain echocardiography technique(2D-SE)technique was applied to estimate the movement at different segments of the short axis of the left ventricle.Our aim was to evaluate its role to quantitatively estimate the left ventricle function.Method:9 small Guizhou-Panama pigs were used.Successfully built the close myocardial contusion animal model by using the small impactor. Applied 2DS before and after the injury 0.5h,2h,4h,8h and 12h respectively, 2DE images(frequency＞40frame/second)of left ventricle at mitral valve, papillary muscle and apical levels were analyzed by 2DS technique,went to EchoPAC work station,2DS analysis software was used to get the left ventricle RS,CS and Rot at different levels before and after the MC,also the degree of the LVEF decrease was observed.The change of RS,CS and Rot and the relativity of which to LVEF were analyzed.Results:There are no significant difference for the RS,CS and Rot of the levels mentioned above on left ventricle before the MC under normal state (P＞0.05).2DS nalysis software showed that RS,CS and Rot are gradually decreased 0.5h after the strike and are significantly decreased compared with pre- myocardial contusion(P＜0.05,P＜0.01).There were no significant difference for LVEF between pre-myocardial contusion and 4h after MC, while 8h and 12h after MC,the LVEF were significantly decreased than pre-myocardial contusion(P＜0.05).Left ventricle was divided into contusion area and non-contusion area according to the pathological results,within which there are 121 non injury segments and 41 injury segment,injury segments mostly were at anterior wall and lateral wall at papillary muscle level and mitral valve level of the left ventricle.There were significant difference between all the time periods after MC for RS and Rot(P＜0.05, P＜0.01),no significant difference for CS(P＞0.05).Conclusion:2DS technique can be used whole and locally to measure the change of left ventricle quantitatively.It is a new method to quantitatively estimate the left ventricle function rapidly,accurately,easily,repeatable and not angle reliant.