| ObjectiveThe patients with COPD were selected and underwent chest 64 slices SCT Low-dose scanning at full inspiration and full expiration, respectively.The total lung was measured by CT pulmo software and the indexes were contrasted with the PFT results.To explore the clinical value of the density,volume and pixel index from 64 slices SCT images in evaluation of pulmonary function of patients with COPD.Materials and MethodsBetween March 2010 and September 2010,36 COPD patients (COPD group) who are partial out-patient clinic and partial hospitalization from the heping Hospital of Changzhi medical college and the second xiangya Hospital of central south University were enrolled in this study.All the patients were underwent PFT and were essentially verified COPD. The patients included 19 males and 17 females ranging in age from 51 to 84,with an mean age of 65.5±12.3 years.All the patients were underwent PFT and 64 slices SCT within 3 days.30 healthy people (control group) were selected and 64 slices SCT chest scanning results were normal.The group included 18 males and 12 females ranging in age from 50 to 75,with an mean age of 60.5±10.5 years.The two groups were underwent chest 64 slices SCT (Siemens,Germanny) low-dose scanning at full inspiration and full expiration.After the scanning,the total lung was measured by CT pulmo software. The lung was divided into three equal regions. Measure and calculate the results of each region (include upper,middle,lower field and the total lung) respectively:(1)lung density at full inspiration and full expiration (Din,Dex), density difference (Dex-Din), density ratio (Dex/Din), density variation percentage (Din-Dex)/Din;lung volume at full inspiration and full expiration (Vin,Vex),volume difference (Vin-Vex), volume ratio (Vex/Vin), volume variation percentage (Vin-Vex)/Vin; (2)pixels indexes with five groups of-1024～-960,-960～-910,-910～-800,-800～-700,-700～-400.Ca-lculate the pixels indexes at full inspiration and full expiration (the PI value is the sum of the Pixels under-910HU), (PIin-910,Plex-910),PI-910 difference (PIin-910-PIex-910), PI-910ratio (PIex-910/PIin-910),PI-910 variation percentage (PIin-910-PIex-910)/PIin-910.Their pulmonary function were tested by Master Lab (Jaeger,Germany).The indexes were forced expiratory volume at the first second%pre (FEV1%) and ratio of the first second forced expiratory volume to forced vital capacity (FEV1/FVC). We selected 20 patients with COPD and 20 healthy people.All subjects were underwent 64 slices SCT scanning of the total lung at routine-dose with inspiration,extrally.When the scanning was finished,CT machine calculated computed tomography dose index(CTDIvol) and dose-length product(DLP) automatically. We compared radiation dose at different tube currents and different breath condition and invited a salty doctor and a salty technician to observe every image and evaluate the section image quality. The results were analyzed statistically by the SPSS 17.0. CTDI Vol and DLP at different scanning condition were tested by paired t-test.Image quality evaluation at different scanning condition was tested by X2 test. Compared with the CT indexes between the COPD group and the normal group by t-test and the CT indexes were analyzed the correlation with the FEVI%and FEV1/FVC by pearson correlation analysis..Results1. Compared with CTDIVol in single phase of 100 mAs and the sum of CTDIvoLin two phases at low-dose of 50mAs, the difference between them was not statistically significant (p>0.05).DLP was the same result. Section image fineness ration at 100mAs at inspiration,50mAs at full inspiration,50 mAs at full expiration was 100%,97.5%,92.5%,the difference between them was not statistically significant (p>0.05)2.Compared with density indexes of each region and the total lung in normal group and the case group,the difference between them was statistically significant (p<0.05 or p<0.01); the difference of lung volume at full inspiration at each region was not statistically significant(p>0.05); the difference of the other lung volume indexes at each region and the total lung was statistically significant (p<0.05或p0.01); the difference of the all PI-910 indexes except the PIin-910-PIex.910 was statistically significant (p<0.01).3.Compared with Plin indexes of the total lung that were in-960～1024,-910～-960,-800～-910, three regions in normal group and all the case groups, the difference between them was statistically significant (p<0.01);but the difference of the all PIex indexes was statistically significant (p<0.01)4.There was statistical significance between the correlation with PI-960～-1024, PI-910～-1024 and FEV1%, FEV1/FVC (p<0.01), the PI-910～-1024 is Better.5.Excellent correlation was found between all the expiratory indexes with FEV1% and FEV1/FVC (p<0.01). There was statistical significance between the correlation with density difference,each indexes ratio, indexes variation percentage and FEV1%, FEV1/FVC (p<0.01),Conclusions1. The data and image quality obtained from 64 slices SCT chest scanning at low-dose in full inspiration and full expiration meets the requirements of pulmonary function assessment of patients with COPD and healthy people. It can replace the scanning of two phases at routine-dose to evaluate pulmonary function.2.64 slices SCT chest scanning at low-dose at full inspiration and full expiration can be used to evaluate pulmonary function of COPD and healthy people.Among all the indexes, Dex,Vex,PL-910, Dex-Din,the ration and the variation percentage were all the useful indexes to evaluate pulmonary function. (There was statistical significance between the correlation with all the indexes, FEV1%and FEVl/FVC.But PIex-910 and PIex-910/PIin-910were better.(The correlation coefficients were larger than 0.64)... |
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