Experimental Study On Evaluation Of Coronary Microcirculation Disorder Model In Goats Based On Dual-energy CT Multi-mode Imaging

Part Ⅰ The preparation of goat coronary microcirculation disfunction modelObjective:To establish a viable model of coronary microcirculation disfunction in saanen dairy goat by percutaneous microcatheter intervention with monodisperse polystyrene microspheres as embolizing agent and explore a simple method to establish animal model of chronic myocardial ischemia.Methods:Ten saneng milk goats were used in the experiment,no limitation of male and female,experimental animals were from 5 to 8 months old.After anesthesia,monodisperse polystyrene microspheres of the same concentration and different doses were slowly injected into the distal end of coronary arteries with different branches through selective intubation of femoral artery.Using air embolism execution of experimental animals,Heart frozen department from apex to the bottom in the vertical direction of ventricular septal after cut into thin slices of about 2 mm thick,flat as a petri dish,Using TTC about 20 min after dyeing,each segment of myocardial tissue line TTC staining and tissue pathology observation,myocardial fixed,HE staining confirmed the presence of myocardial injury,determine the myocardial microcirculation perfusion obstacle areas.Results:The experimental animals were 8 males and 2 females,with a body weight of(18.61±3.01)kg.Three experimental animals died during the modeling,and the remaining 7 successfully completed the experiment.The microsphere count was 1.14 10~6/ml,and the experimental animals could survive for a long time when the total injection volume was 1ml.Myocardial TTC staining and pathology showed myocardial infarction or ischemia in the area of microvascular embolism.Conclusion:By using monodisperse polystyrene microspheres as embolizing agents,the model of coronary microcirculation disturbance in saanen dairy goats was established.Part Ⅱ Multimodal imaging evaluation of coronary microcirculation disorders in goatsObjective: By establishing a model of coronary microcirculatory dysfunction in the saanen dairy goats,employ histopathology serve as the gold standard,using DECT-MPI 、SPECT、PET and MRI to evaluate the accuracy of myocardial perfusion imaging in the diagnosis of coronary microcirculation disfunction,and to explore the clinical application value of multi-mode imaging in the diagnosis of myocardial microcirculation disfunction.Methods: In the first part,DECT-MPI,SPECT/CT myocardial perfusion,PET/CT ammonia myocardial perfusion imaging and MRI myocardial perfusion myocardial delayed enhancement imaging were performed 7days after surgery.Results:(1)Three experimental animals died during the modeling,and the remaining 7 successfully completed the experiment.A total of 119 segments,18 segments of ischemic cardiomyocytes and 101 segments of normal cardiomyocytes.One goat failed to complete SPECT and PET examination.A total of 119 myocardial segments were assessed.(2)Employ histopathology serve as the gold standard,the results showed that DECT-MPI had a sensitivity of 55.56%(10/18),specificity of98.02%(99/101),positive predictive value of 83.33%(10/12),negative predictive value of 92.52%(99/107)and accuracy of 91.60%(109/119)in the diagnosis of coronary microcirculation dysfunction.(3)The sensitivity and specificity of(99m Tc-MIBI)SPECT-MPI in diagnosis of coronary microcirculation disorders were66.75(11/16),98.83%(85/86),91.66%(11/12),94.44%(85/90)and 94.12%(96/102).(4)The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of(13N-NH3)PET-MPI in the diagnosis of coronary microcirculation disorders were 93.75%(15/16)、97.68%(84/86)、88.23%(15/17)、98.82%(84/85)and 97.06%(99/102),respectively.(5)The sensitivity,specificity,positive predictive value,negative predictive value and accuracy of CMR-MPI in the diagnosis of coronary microcirculation disorders were 50%(2/4)、100%(13/13)、100%(2/2)、86.67%(13/15)and 88.24%(15/17),respectively.Conclusion:(1)Histopathology was used as the gold standard to confirmed by the study that there was a good consistency between the evaluation of coronary microcirculation disfunction by multi-mode imaging and the pathological control.(2)DECT can be used for one-stop assessment of coronary artery and myocardial microcirculation,and semi-quantitative assessment of myocardial microcirculation perfusion.The image quality and accuracy of DECT are slightly lower than those of the former two due to the influence of iodide’s linear hardener,myocardial motion induced artifacts,CT time resolution and peripheral cardiac structure.(3)The(13NNH3)PET-MPI has high accuracy in diagnosing CMD,but cannot simultaneously evaluate the situation of coronary arteries.Because of the low spatial resolution,the image quality is affected.(4)(99m Tc-MIBI)SPECT-MPI has better accuracy in diagnosing CMD due to low spatial resolution and image quality.(5)CMR has high accuracy and low sensitivity in the diagnosis of CMD,but has limitations in the evaluation of coronary artery.