To Analyze The Influencing Factors On CTV Examination Of Lower Extremity Vein By Direct Method

Part 1 The Effect of Different Concentrations of Contrast Agent on the Quality of Lower Extremity Vein Image by Direct-scan Multi-slice Spiral CTObjective:To investigate the effect of contrast concentration on the image quality of multi-slice spiral CT in detecting deep venous thrombosis of lower extremities in order to obtain the most suitable scan delay time.Methods:Forty patients in our hospital from September 2016 to October 2017 were enrolled in the study.All the patients underwent multislice spiral CT direct venous venous examination.The veins of the lower extremities developed well and the lesions showed clear.The same scanning conditions were set according to contrast concentrations were randomly assigned to a group of 1:4(contrast but dilution of 370 mg I/ml of saline with normal saline),with concentrations of 1:6,1:7,1:9.The scanned original images and the reconstructed images were graded.The data did not obey the normal distribution,and the median was taken as the median.The scores were statistically analyzed by non-parametric rank-sum test(Kruskal-Wallis H test and multiple independent samples multiple comparison Nemenyi test).Results:A total of 40 patients in this group,80 sides of the deep veins of the lower extremities,the femoral vein as the evaluation object,where the score of each group as follows,the concentration of 1:4(contrast agent iopamidol 370 mg I/ml and saline dilution ratio)group,1 point is 4 sides femoral vein,2 points for the 15 sides,3 points for the 10 sides;concentration 1:6 group,1 point for the side of the femoral vein,2 points for 2 sides,3 points for 6 sides;concentration 1:7 groups,1 point for the 2 side veins,2 points for the 2 sides,3 points for the 7 sides;where in the concentration of 1:9 group,1 point for 0,2 points for the 7 sides of the femoral vein,3 points for the 24 sides of the femoral vein.Statistical analysis of the results of the four groups of scores,independent samples by Kruskal-Wallis test,p <0.05,the differences between the groups were statistically significant(Nemensyi test was used for multiple independent samples).The results showed that there was significant difference between 1:4 and 1:9 groups(p <0.05),while the concentrations were 1:4 and 1:7,1:4 and 1:6,1:7 and 1:6,1:7 and 1:9,1:6 and 1:9 each group compared with each other,p> 0.05,the difference was not statistically significant.Conclusion:This study demonstrates the use of contrast media at a contrast agent concentration of 1:6,1:7,1:9 can get a clear image of blood vessels.But the concentration of contrast agent set 1:9 not only can provide the best clinical image data,but also reduce the amount of contrast agent,can be considered the best venous CTV of the lower extremity concentration.Part 2 The Effect of Contrast Agent Injection Rate on Imaging Quality of Femoral Vein in Direct Vein CTV ExaminationObjective:To investigate the effect of contrast medium injection rate on femoral vein imaging in CTV examination of lower extremity vein by direct method.Methods:80 patients underwent direct venous CTV examination from 2016 to 2017 in our hospital were collected.The scanning parameters of the patients were the same,the normal lower extremity were 82 sides and the diseased lower extremity were 78 sides.The injection rates of 1 to 4 groups of normal lower limbs and ipsilateral lower extremities were set to 1.5ml/s,2.0ml/s,2.5ml/s,3.0ml/s.The original images and the reconstructed images of the femoral vein were scanned and evaluated.The evaluation results were evaluated by non-parametric rank sum test(Kruskal-Wallis H test for multiple samples,Nemenyi test for multiple independent samples and comparison of two samples Wald-Wolfowitz test).Results:The normal lower limb were 82 sides,20 sides of the femoral vein in 1.5 ml/s group,27 sides femoral vein injection in rate 2.0ml/s group,23 sides femoral vein in rate 2.5ml/s group,12 sides of the femoral vein in injection rate 3.0ml/s group.The sick lower limb were 78 sides,1.5ml/s group of 18 sides femoral vein,injection rate 2.0ml/s group of 26 sides femoral vein,rate 2.5ml/s group of 24 sides femoral vein,in the injection rate 3.0ml/s group,a total of 10 siddes femoral vein.The femoral vein as the evaluation object,the Kruskal-Wallis H test was used to compare the results of four groups of venous visualization of normal lower extremity and sick lower extremity.There was no significant difference between the two groups(p>0.05).For the same rate,Wald-Wolfowitz test was used to evaluate the images of normal lower extremities and diseased lower extremities.There was no significant difference(p> 0.05).Conclusion:Contrast injection rate was set to 1.5ml/s,2.0ml/s,2.5ml/s,3.0ml/s in both normal and affected lower limbs can get clear femoral vein imaging,and the development of no significant difference.