| PartⅠ The Feasibility Study of Computed Tomography Pulmonary Angiography combined Low Kilovolt and ConcentrationContrast Medium with Adaptive Statistical Iterative ReconstructObjective:To investigate the feasibility of low kilovolt computed tomography pulmonary angiography(CTPA) with low concentration contrast medium and adaptive statistical iterative reconstruct(ASIR).Methods:Eighty-four patients without pulmonary embolism(PE) were randomly divided into two groups. There is no significant difference of age and BMI between two groups(X2=-0.090, P=0.928; t=1.33, P=0.187).Image reconstruct with 30% ASIR.And the concentration of contrast medium is 300 mg I/ml.Patients in two groups were compared with respect to the mean radiation dose, pulmonary arterial attenuation values, image quality, and the pulmonary artery branches.Results: No difference was found between 120 k Vp and 80 k Vp with respect to image quality and the pulmonary artery branches(X2=1.714, P=0.190; X2=5.475, P=0.065). With respect to pulmonary arterial attenuation values, imaging with 80 k Vp yielded significantly higher values(P=0.000).There is no difference of image quality,pulmonary arterial attenuation values and the pulmonary artery branches in the different doctors and the same doctor(P>0.05). The effective dose(ED) in 80 k Vp group is lower than that of 120 k Vp group(Z=-7.730,P=0.000).Conclusions: CTPA with 80 k Vp,contrast medium of 300 mg iodine/ml and ASIR,are feasible,because of higher attenuation of pulmonary arteries are higher while lower radiation dose.So it may be conducted conventionally. PartⅡ The oneself comparison study of computed tomographypulmonary angiongraphy with different iodine concentrations as the tube voltage being 80 kilovoltObjective:To investigate the lowest concentration of iodine contast medium,which can ensure computed tomography pulmonary angiography(CTPA) imaging quality,when the tube voltage is 80 kilovolt.Methods: Ten New Zealand rabbits, were conducted four times of CTPA per rabbit every three days.The concentration of contrast medium were 350 mg I/ml、300mg I/ml、270mg I/ml and 250 mg I/ml. The attenuation value of trunk pulmonary artery and air in the same level, as well as right and left pulmonary artery, and the pulmonary artery branches were compared among different groups. Meanwhile, image noise(N), contrast-to-noise ratio(CNR) and signal-to-noise ratio(SNR) were calculated.The pulmonary arterise were divided into large and small arteries and assessed subjectively.Results: All the images of CTPA can demonstrate sixth-order branches of pulmonary artery.The attenuation of pulmonary arteries among different groups are different statistically(P < 0.05).Among those groups,the attenuation of 300-group is the highest.So in the comparison with the attenuation of 300-group’s,only the statistical difference were found between 350-group and 300-group(P<0.05). And when compared with 350-group,the attenuation of sub-segment pulmonary arteries in the 250-group and 270-group are different(P=0.007, P=0.017).The difference of N, CNR and SNR among those groups are significant(F=3.581, P<0.022; F=3.302, P<0.030; F=3.295, P<0.030).With respect to the 300-group,the value of N and CNR in the 270-group and 300-group are different in statistics(P<0.008, P<0.016),while there was no difference for SNR found among them(P=0.088).While with respect to the comparison of 350-group with other groups,no statistical difference was found in N,CNR and SNR(P>0.05).And the subjective score of the large arteries are no statistical difference(X2=6.588, P=0.086),but the subjective score of the small arteries are different(X2=11.988, P=0.007),the average score of the 350-group is the highest.When being multiple comparison,the 300-group of the small arteries are different from the 250-group and 270-group(P=0.030, P=0.030). 6Conclusions: When the tube voltage is 80 kilovolt,rabbits’ CTPA with the contrast medium of 270 mg I/ml is more suitable than others,and it can decrease the iodine dose per unit effectively. PartⅢ Correlation analysis of biological indicator of APE with theright/left ventricle ratio and CT angiographic pulmonary arteryobstruction indexObjective:To correlate biological indicator of APE with the right/left ventricle ratio(RV/LV) and CT angiographic pulmonary artery obstruction index(OI).Methods: In a retrospective study of 71 patients(60.3 ± 11.5 years,men:32 cases,women:39 cases) admitted with APE confirmed by CT pulmonary angiogram(CTPA). And according to RV/LV,patients were divided into right ventricular dilation(RV/LV≥1, A group) and no right ventricular dilation(RV/LV<1, B group).With respect to age,systolic and diastolic blood pressure,there is no statistic difference between the groups. Blood samples,D-dimer,c Tn I and CRP were obtained within 24 hours of presentation. Qanadli pulmonary artery OS and the axial RV/LV ratio of CTPA were assessed by two radiologists.Results: RV/LV is correlated with OI(r=0.283, P=0.018). A relevant correlation between RV/LV and D-dimer(r=0.465, P=0.017) were only found in A group.There is positive association between OI and leucocyte,D-dimer and CRP(r=0.243, P=0.044; r=0.405, P=0.003; r=0.335, P=0.037).In the two groups,a positive association becomes apparent for OI and D-dimer(r=0.429, P=0.029; r=0.382, P=0.031).OI in the A group is higher than B group((43.36±23.72)vs(57.57±21.89); t=-2.603, P=0.011).NLR is correlated with leucocyte,D-dmier and CRP(r=0.602, P=0.000; r=0.548, P=0.00; r=0.252, P=0.047).In the A group, NLR is correlated with leucocyte,D-dmier and c Tn I(r=0.564, P=0.000; r=0.568, P=0.002; r=0.425, P=0.034).And in the B group, NLR is correlated with leucocyte,D-dmier and CRP(r=0.591, P=0.000; r=0.427, P=0.026; r=0.542, P=0.003).In Logistic analysis,OI is a independent predictor of right ventricular dilation(OR 1.03, P=0.011). In a ROC analysis the AUC for the prediction of right ventricular dilation of OI were 0.729(95% CI 0.586-0.872, P=0.007).Conclusions: OI is an independent predictor of right ventricular dilation,and can accurately predict right ventricular dilation.D-dimer could reflect the severity of thrombosis, and is associated with inflammation.So it can guide clinical treatment. |
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