| Part1Myocardial Viability of Myocardial Ischemic Canine with No-reflow: An Experimental Study Based on Dual-Source Computed TomographyObjective: Using dual-source CT (dual-source computed tomography, DSCT) myocardial perfusion scan to observe the CT manifestations of myocardial ischemia with no-reflow in canine models, and explore its relationship with myocardial viability. Method: Establishing the canine models (n=6) of myocardial ischemia with no-reflow by blocking the mid-distal segment of left anterior descending artery using balloon and gelatin sponge particles. DSCT was performed with first-pass myocardial perfusion and multi-phase delay scan (3min,5min,10min,15min) to observe the CT manifestations of the infarct segments. The specimens of canine heart were taken after DSCT scan and later stained with triphenyl tetrazolium chloride (TTC) and hematoxylin-eosin (HE). The results were compared with the CT scan. Result:2canine models died during surgery.4canine models were succesfully established. Tht average heart rate was135bpm. DSCT scan showed that the CT attenuation of infarct segments was significantly lower than that of the normal segments. And the infarct segments showed fixed hypoperfusion in the first-pass and the multi-phase delay scan. The area of infarct segments was similar with that of TTC staining. And the HE staining showed myocardial necrosis in the central and peripheral area in the infarct segments.100kV images were best at differentiating the myocardial attenuation,140kV images had the best quality with minimal noise, and the140kV/100kV fusion images could maintain low noise while having good image quality. Conclusion: DSCT can clearly demonstrate myocardial perfusion with fast heart rate. Fixed hypoperfusion during DSCT myocardial perfusion scan may be associated with total myocardial necrosis. Part2Myocardial Transmural Perfusion Gradient in Healthy Adults: a Clinical ResearchObjective:Obtain the transmural perfusion gradient value (TPG) of each left ventricular segment using Dual-source computed tomography in healthy adults. Methods: The DSCT data of20healthy adults were collected, an adjusted17segmentation were used to divide the myocardial into16segments. The transmural perfusion gradient of each left ventricular segment were calculated by using the CT attenuation of subepicardial myocardial/CT attenuation of subendocardial myocardial as TPG value. Analysis of variances or Kruskal-Wallis test was used to compare the TPG of each segment. Results: The TPG value of each segment was0.74±0.06,0.91±0.06,0.89±0.07,0.80±0.07,0.93±0.07,0.90±0.08,0.86±0.07,0.94±0.05,0.91±0.05,0.85±0.08,0.88±0.06,0.94±0.07,0.90±0.09,0.95±0.04,0.85±0.07,0.85±0.10, respectively. The difference of the TPG value between each segment was significant (F=13.104, P=0.000). The TPG value of the segments in anterior (0.83±0.10) and posterior (0.83±0.07) wall was lower than those of the segments in lateral (0.90±0.08) and septum (0.92±0.06) wall. And the TPG value of the septum was the lowest. The TPG value of the segments in the area that corresponded to each major branches was also different. The TPG value of the segments that corresponded to LAD, CX and RCA was0.88±0.09±0.90±0.08and0.86±0.08, respectively. The difference of the TPG value in the area that corresponded to RCA and that in the area corresponded to LAD and CX was significant (LAD vs RCA, P=0.036<0.05. CX vs RCA, P=0.001<0.05), and the difference of the TPG value in the area corresponded to LAD and CX was insignificant (P=0.506>0.05). Conclusion:The high quality myocardial images could be obtained during DSCT coronary angiography scan. The TPG value of each left ventricular segment was different. When compared with abnormal myocardial segments, the TPG data of each segment cannot be used as the same. Part3Myocardial Transmural Perfusion Gradient of DSCT in Patients withCoronary Heart Disease: Comparison with Conventional Coronary Angiography Abstract Objective: Study the relation between transmural perfusion gradient value and the stenosis degree of coronary arteries, and analyze the ability of TPG value in predicting myocardial ischemia. Methods:The DSCT coronary angiography and coronary angiography data of51patients with confirmed coronary heart disease were collected. The TPG value of each left ventricular segment and tTPG value of each area corresponded to the major branches were calculated by using the same method as that in part two. The TPG and tTPG in patients with different degree of coronary stenosis and the control group were compared by using Kruskal-Wallis test. Spearman rank correlation analyze was applied to study the relation between TPG value and stenosis degree. The best cut-off value of TPG and tTPG were calculated, and their diagnostic efficiency were analyzed. Results: The differences of TPG and tTGP value between patients with coronary heart disease and the control group were significant. The TPG/tTPG value of most segments and area were significantly different with the TPG/tTPG value in normal segments and area when there was mild stenosis in the corresponding coronary artery. The tTPG value of each area had a positive correlation with the stenosis degree of the corresponding coronary artery, the correlation coefficient in LAD, CX, and RCA area was0.724,0.577,0.712, respectively. The diagnostic efficiency of quantitative analysis of TPG/tTPG was better than that of semi-quantitative analysis. Using tTPG value to predict myocardial ischemia was more efficient than using TPG value. The cut-off value of tTPG in LAD, CX, and RCA area was5.65,4.66,4.69, respectively, when considering severe stenosis of coronary artery was related to myocardial ischemia. The sensitivity, specificity, positive predictive value and negative predictive value were90.5%,100%,100%,90.9%in LAD area,100%,97.0, 70.0%,100%in CX area,94.1%,100%,100%,95.2%in RCA area. Conclusion: When predicting myocardial ischemia, the change of the TPG and tTPG value is more sensitive than the analysis of the stenosis of coronary arteries. tTPG value could be used as a quantitative indicator in the analysis of myocardial perfusion. Part4Myocardial Transmural perfusion Gradient of DSCT in Patients withCoronary Heart Disease: Comparison with Myocardial Perfusion Scintigraphy Objective: Study the relation between transmural perfusion gradient value and the myocardial perfusion scintigraphy score, and analyze the ability of TPG value in predicting myocardial ischemia. Methods:The DSCT coronary angiography and MPS data of21patients with confirmed coronary heart disease were collected. The TPG value of each left ventricular segment and tTPG value of each area corresponded to the major branches were calculated. Kruskal-Wallis test was used to compared TPG and tTGP value in the segments and areas with different MPS score. And Spearman rank correlation analyze was applied to study the relation between TPG/tTPG value and MPS score. The best cut-off value of TPG and tTPG were calculated, and their diagnostic efficiency were analyzed. Results: The differences of TPG and tTGP value between segments and areas with abnormal and normal MPS score were significant. The TPG value of the left ventricular segment which had a MPS score0,1, and2was0.92±0.11,1.00±0.10, and1.08±0.09, respectively. The TPG and tTPG value had a positive correlation with the MPS score (P<0.001, TPG vs MPS score, R2=0.423. tTPG vs summed MPS score, R2=0.66). The cut-off value of TPG was0.91when considering an abnormal MPS score was related to myocardial ischemia. The sensitivity, specificity, positive predictive value and negative predictive value of TPG value in predicting myocardial ischemia was86.8%、44.6%、31.3%、92.0%, respectively. Conclusion:There was a well defined correlation between TPG/tTPG value and MPS score. The TPG value could be used as a preliminary indicators of myocardial ischemia at the same time as the CT coronary angiography images were acquired. |
PDF Full Text Request