Evaluation Of The Therapeutic Efficacy Of Dual-energy CT In The Thrombolytic Therapy Of Pulmonary Embolism

Background and purposePulmonary embolism was the third most common acute cardiovascular disease after myocardial infarction and stroke,it was more insidious,there was no definite clinical signs in the early stage,lack of typical specificity,if not diagnosed and treated,the mortality rate was as high as30%.Early diagnosis and appropriate treatment could greatly reduce the mortality rate.At present,many studies reported that CT pulmonary angiography combined with dual-energy perfusion imaging could be used in the diagnosis of pulmonary embolism,but the evaluation of the therapeutic effect of pulmonary embolism was rare.The purpose of this study was to evaluate the value of DECT in evaluating the efficacy of PE thrombolytic therapy by quantitative analysis of related parameters before and after PE thrombolytic therapy.Materials and MethodsFrom 2017.01—2018.05,60 patients with PE were clinically confirmed,There were 36 males and 24 females,the age-bracke ranged from 31 to 86 years,with an average age of 58.2 ±13 years.According to the clinical evaluation criteria,the patients were divided into three groups: group A(cured),14 cases;group B(effective),37 cases;group C(ineffective),9 cases.All subjects received DECT scan before and after treatment to obtain CTPA and DEPI images.the scanning interval was(14.8 + 2.4)days.60 patients with PE who have been treated with thrombolytic agent or not,the charts on pre or post treatment in CTPA and DEPI of the patients,was obtained by the post-processing of Dual-energy software,the PE correlation parameters in CTPA and DEPI charts were recorded,The number of embolus,pulmonary embolism evaluation,pulmonary embolism index,pulmonary perfusion defect evaluation,pulmonary perfusion defect index,right ventricular/left ventricular diameter ratio(RVd/LVd),reinforcement value and relative rate of reinforcemen,the differences of the parameters above in the patients who were before or after thrombolytic therapy were compared.patients were divided into the cured group,the effective group and the invalid group according to different degree of thrombolytic reaction.the differences of change rate of PE correlation parameters among three groups were compared.The diagnostic accuracy of DECT in prediction of benefit from thrombolytic therapy was represented by means of receive operating characteristic(ROC)curves.Statistical software SPSS17.0 was used to analyze the data.Quantitative data conforming to normal distribution were tested by two paired samples t test.Quantitative data no-conforming to orthodox distribution were analyzed by nonparametric rank sum test.Signal noise ratio,contrast noise ratio,dose length product,CT dose Index of volume,effective dose,image quality score,The number of embolus,pulmonary embolism evaluation,pulmonary embolism index,pulmonary perfusion defect evaluation,pulmonary perfusion defect index,right ventricular/left ventricular diameter ratio(RVd/LVd),reinforcement value and relative rate of reinforcemen,the differences of the parameters above in the patients who were before or after thrombolytic therapy were compared.Correlation between the change rate of PE-related parameters,RVd/LVd value and the evaluation criteria of thrombolytic efficacy was analyzed by Spearman rank correlation analysis when before and after thrombolysis.The ROC curve was drawn to calculate the sensitivity and specificity of different cut off points,etimating the cut-off point of PE-related parameters before and after thrombolytic therapy to determine the ideal cut-off point of thrombolytic therapy.There were statistical significance(p<0.05).ResultsThere were statistical significance differences in the related parameters of pulmonary embolism and ratio(RVd/LVd)before and after thrombolytic therapy(P < 0.05).There were statistical significance differences in the related parameters of PE after thrombolytic therapy from three groups of patients with PE(p < 0.05).Among the change rate of PE related parameters with the CTPA and DEPI images showed correlation with the degree of thrombolytic reaction,the correlation factor was highest in percenta?ge of pulmonary perfusion defect evaluation or pulmonary perfusion defect index reduction of the DEPI images(r=-0.881,p <0.001).When the optimal cutoff value of pulmonary perfusion defect evaluation or pulmonary perfusion defect index reduction rate of patients with PE determined was 15.6 %(the area under the curve was 0.896),a sensitivity of 86.7%,and specificity of 84.4% were achieved.There were statistical significance between the differences of the number of embolus in the subsegmental pulmonary artery(level IV),pulmonary embolism(perfusion defect)evaluation,pulmonary embolism(perfusion defect)index with the CTPA and DEPI images(p < 0.05),after treatment.ConclusionThe therapeutic efficacy of thrombolytic therapy in patients with PE could be accurately evaluated with the quantitative analysis method of PE correlation parameters based on the DECT.CTPA could reflect the changes of emboli before and after the PE treatment.The detection rate of embolus in subsegmental pulmonary artery could improve with the supplement of CTPA based on DEPI.The therapeutic efficacy of PE treatment could be accurately evaluated with the quantitative analysis method of PE correlation parameter based on the combination of CTPA and DEPI.