Pulmonary Emphysema By MSCT Pulmonary Perfusion Imaging Study On The Changes Of Pulmonary Blood Flow

objectiveObjective to study the difference of perfusion parameters（blood flow volume,blood volume,mean passage time,peak time）and time density curve between multi slice spiral CT（MSCT）lung perfusion imaging in patients with emphysema and normal subjects.The correlation between the perfusion parameters of the sick group and the index of lung function was studied.MethodPerfusion scan:The use of MSCT were all pulmonary perfusion imaging scans of 40 cases of emphysema patients and 35 cases of normal people,scanning mode to"SHUTTLE cradle"spiral scanning,contrast injection delay 5 s startup dynamic scanning procedures,double tube injector will contrast agent iohexol injection（370mg/ml）through the median cubital vein at the rate of 4 ml/s.The image postprocessing using CT perfusion4 D software,set the region of interest,so as to obtain the perfusion parameters of lung tissue throughout,including blood flow（BF）,blood volume（BV）,mean transit time（MTT）,time to peak（TTP）and the time density curve（TDC）,analysis of the differences between emphysema patients and normal persons of various parameters.Pulmonary function tests:Determination of pulmonary function in patients with emphysema,including forced expiratory volume in one second（FEV₁）,forced vital capacity（FVC）and a second rate（FEV₁/FVC）,and total lung residual volume ratio（RV/TLC）.Result1,the area where the lung parenchyma was destroyed in the emphysema was consistent with that in the lung perfusion area.The more severe the damage of the lung parenchyma,the more significant the blood perfusion defect was in the corresponding area,that is,the less blood perfusion.2,The density curve of pulmonary emphysema patients and normal people of the time（TDC）there are differences in morphology,peak of TDC in emphysema patients than the normal lower peak,peak time prolonged,the time density curve of the form to reflect the measured parts enhanced value of the trend,the morphology of TDC changed by hemodynamics.3,The patient with emphysema BF（43.80±13.57）ml（min/100·g）^-1,BV（4.32±1.36）ml/100g,normal BF（236.72±52.80）ml（min/100·g）^-1,BV（20.22±4.67）ml/100g,BF P<0.01,BV P<0.01,the difference was statistically significant;emphysema patients with TTP（20.35±3.73）s higher than normal TTP（13.63±3.78）s,the difference was statistically significant（P<0.01）;MTT patients with emphysema（9.17±2.20）s and normal people（8.20±2.16）s between the two groups did not change significantly,little difference was not statistically significant（P=0.0.113>0.05）.4,In patients with emphysema,FEV₁ was（1.90+0.43）L,FVC was（2.06+0.49）L,FEV₁/FVC（53.43+9.75）%,RV/TLC（57.47+8.28）%.Among them,BF and FEV₁（r=0.47,P=0.002）,TTP was positively correlated with RV/TLC（r=0.36,P=0.023）.BF and FEV₁（r=-0.62,P=0.000）,TTP was negatively correlated with FVC（r=-0.41,P=0.009）.conclusion1,CT lung perfusion imaging can accurately reflect the changes of blood flow in the lung tissue and provide valuable quantitative information for clinical application.2,part of the results of CT lung perfusion imaging have certain correlation with some pulmonary function results,which can be complementary to the lung function examination,and have certain guiding significance to the clinic.