Evaluation Of Lung Volume Using Multi-slice CT In Patients With Chronic Obstructive Pulmonary Diseases

Objective:To study the volume changes of groups of COPD and volunteers, pulmonary function-imaging control study was done using MSCT.To study the possibility of using MSCT to evaluate volumes of whole lung and single lobes,51 subjects were done low dose volume scanning.To study the changes of different lobes in different stages and its possible clinical value,the volume changes of lobes in different stages and the corelationships between volume changes and CT attenuation parameters were compared.Mathod:20 volunteers and 31 COPD patients were done the dual phase volume MSCT and pulmonary function test.The scanning parameters were:120kV,50mA, pitch 1.375:1,layer thickness 10mm,septa 10mm.The reconstitution was standard algorithm,reconstituted thickness 1.25mm,septa 0.6mm.The post processing was used threshold limitation combine three dimensional lung model and threshold limitation combine semi-automatic method to measure lung volumes.The lower threshold was -1024HU,the upper limit was -300HU.The volumes of left or right lung in full inspiration and full expiration using the two methods separately were compared using two paried sample document t test.The threshold limitation combine semi-automatic method was used to mearsure the left and right lung and all lobes in different stages,then computed the percentage of left and right lung and different lobes,Analysis of variance was used to compare volume changes of different lobes of moderate and heavy groups of COPD patients and voluteers.Analysis of variance was used to compare the PIs(volumes below -910HU in expiration)of different lobes between groups of COPD and volunteers.Pearson correlation analysis was used to compare the changes of MLD and PIs with volume changes.Result:1.There were no differences between the volumes of left or right lung in full inspiration and full expiration using the two methods separately.2.There were no differences between the percentage of left or right lung and right middle lobe in different stages,the moderate group had the similar tendency with volunteers,but the heavy group had no regularities.3.The volume changes of moderate and heavy groups of COPD were smaller than volunteers,especially heavy group.Besides right middle lobe,there were differences between other lobes by comparing the volume changes of different lobes among different groups of COPD and volunteers.4.The changes of MLD could reflect volume changes.5.Besides right middle lobe,there had differences among other lobes by comparing PIs of different lobes between groups of COPD and volunteers,and there also had correlations between volume changes and PIs.Conclusion:1.There was no difference in volume measurements between using threshold limitation combine 3D-lung model and semi-automatic methold demonstrated the possibility of lung volume mearsurement using semi-automatic method.2.The percentages of left or right lung and different lobes in different stages were recommended,and there were no differences between the percentage of left or right lung and right middle lobe in different stages,the moderate group had the similar tendency with normal group,but the heavy group had no regularities.3.The changes of MLD correlated with volume changes which reflected ventilation changes.4.There were differences in volume changes between COPD groups and normal group,and emphysema degree differences made volume changes different.