Study On The Value Of Chest Quantitative CT ”Emphysema Index” In The Diagnosis Of Asthma-Copd Overlap

ObjectiveTo investigate the distribution of emphysema index（EI）and distribution on patients with asthma,COPD and normal inhabitants by chest quantitative CT,and to study the acute attack,pulmonary function and airflow restriction of high EI asthma patients,and to further explore the value of chest quantitative CT on asthma-copd overlap,（ACO）.MethodFrom July 2017 to July 2018,150 asthmatic patients were selected as group A,150COPD patients were selected as B group,and 150 normal non-smokers in physical examination center were selected as C group.The basic data were collected and critical values were determined by EI level of normal people.A group was divided into A₁ group（high EI level）and A₂ group（low EI）.The smoking history,Body mass index（BMI）,acute exacerbation,pulmonary function index,EI and distribution were compared.Result（1）The Emphysema index value of B group was significantly higher than that of A and C group（P<0.05）,and Emphysema index value of A group was significantly higher than that of C group（P<0.05）.There were statistical differences among three groups on emphysema distribution types features（P<0.05）.In group B,the superiority of upper lung area was main.（2）With 9.59%as the threshold of high EI,male proportion of A₁ group was significantly higher than that proportion of A₂ and B group（P<0.05）,and male proportion of B group was significantly higher than that proportion of A₂ group（P<0.05）.Body Mass Index values of A₁ group and B group was significantly lower than that Body Mass Index values of A2 group（P<0.05）,and frequency of acute exacerbation of A1 group was significantly higher than that frequency values of A₂group（P<0.05）.FVC%and FEV1.0 values of A₁ and A₂ group were significantly higher than those values of B group（P<0.05）,and FEV1.0%and FEV1.0/FVC values of A₁ and B group were significantly lower than those values of A₂ group（P<0.05）.Emphysema index value in A₁ and B group were significantly higher than those in A₂group（P<0.05）,and△FEV1.0%in A₂ and B group was significantly lower than that in A₁ group（P<0.05）.（3）Logistic analysis showed that smoking frequency,FEV1%and acute exacerbation frequency were the high risk factors on emphysema index of asthmatic patients（P<0.05）,and BMI was the protective factor（P<0.05）.Conclusion（1）The EI level of COPD patients is higher than that of asthma patients and normal persons.The higher EI level of asthma patients,the more serious condition,and the worse pulmonary function.The pulmonary function index and emphysema of high EI asthma patients are similar to those of COPD patients,and lower than those of low EI.（2）There are differences on the emphysema distribution types between asthmatic and COPD,the former is mainly LLP and MHE,and latter is ULP.（3）The higher frequency of smoking and acute exacerbation,the lower the FEV1%and BMI,the higher EI of asthmatic,and the more likely ACO.