MSCT Study On The Grade Of COPD

Objective:To assess the value of MSCT in grading COPD undergone CT scan at full inspiration and full expiration and pulmonary function tests.Material and method:Fifty four COPD patients verified by clinic and pulmonary function tests were scanned by MSCT at full inspiration and full expiration,the patients were classified three groups with 20 in grade2,24 in grade3,10 in grade 4.Measure and calculate the results respectively:①lung density at full inspiration and full expiration(Din,Dex),density difference, density ratio;②lung volume at full inspiration and full expiration(Vin,Vex), volume difference,volume ratio;③pixels indexes at inspiration and full expiration(the PI value is the sum of the pixes under-900HU,Plin,Plex),PI difference,PI ratio.(among these target,Din,Dex,Vin,Vex,Plin,Plex are absolute indication,the others are relative indexes).The repeatability was tested by SPSS13.0,and the CT indexes were analyzed the correlation with the FEV1% obtained by pulmonary function tests.The ANOVO was taken to select the useful indexes for grading COPD,which were performed discriminant analysis.Result:Paired-t tests was carried to assess the difference between the data got from the two analysis of the same scan by the same operator or the different operator in different time:the difference of average lung density,total capacity,PI has no statistical significance(p＞0.05).Lung density at full expiration,lung volume at full expiration,PI both at full inspiration and full expiration,density difference,density ratio,volume difference,volume ratio,PI difference,PI ratio have relativity with FEV1%,the difference has statistical significance(P＜0.05),rvalues are respectively:0.448,-0.276,-0.312,-0.578, -0.659,-0.640,0.516,-0.555,0.344,-0.615.Among the indexes,lung density at expiration,PI both at inspiration and expiration are useful for the grade of COPD,F values are 5.487,3.889,13.398(P＜0.05).All the relative indexes are useful to grade the COPD,F values are 11.759,11.223,5.665,8.027,3.378, 15.178.The accurate rate obtained by discriminant analysis with the absolute indexes is 70.3%,while the relative indexes is 66.7%,the total is 77.7%.Conclusion:MSCT scan is proved to be convenient and accurate to measure the pulmonary function.The values got from MSCT have a good relativity with the grading of COPD,which can partially take place of the clinical pulmonary function.MSCT is of value to grade the COPD.