Evaluation Of Pulmonary Blood Flow In Smoking Population With Phase Contrast Magnetic Resonance Imaging:A Pilot Study

ObjectiveThe purpose of this study was to explore the feasibility of two-dimensional phase contrast magnetic resonance(2D-PC MR)method for quantitativly monitoring the pulmonary arterial hemodynamics in normal population in the first affiliated hospital of dalian medical university,China and evaluate the influence of different levels of smoking status on pulmonary hemodynamics,right ventricle(RV)structure and function and RV myocardial strain(MS)in the normal population,and it provides a theoretical basis for further understanding of the effect of smoking on pulmonary hemodynamics Materials and MethodA total of 49 normal male volunteers with different degrees of smoking history who underwent cardiac MR and pulmonary artery 2D-PC examinations at the first affiliated hospital of dalian medical university from May 2019 to January 2020 were included in the study.Their age ranged from 25 to 68 years,with an average age of46.53 ± 11.62 years and they were all educated at college level or above with non-physical workers as the main body.Before the examination,the weight,height,body mass index(BMI),and body surface area(BSA)of each volunteer were accurately measured and recorded.A questionnaire survey was used to record and summarize the occupational history,educational background and detailed smoking status of each volunteer.All volunteers performed routine scans on a GE 3.0T magnetic resonance scanner,including two-chamber,three-chamber,four-chamber,left ventricular(LV)short-axis movies and pulmonary artery Fast Cine PC sequence movies.1.Smoking parameters include: smoking intensity,smoking time and smoking burden.According to smoking time,they were divided into non-heavy smoking group(smoking time <20 years)and heavy smoking group(smoking time ≥20 years).2.Using Report Card software to measured the main pulmonary arterial hemodynamic parameters with 2D-PC method which included positive peak velocity(PPV),negative peak velocity(PNV),average blood flow(AF),average positive blood flow(APF),and average negative blood flow(ANF).3.Completed the measurement of various parameters of RV with CVI 42 software.(1)RV structural and functional parameters include right ventricular end-diastolic volume index(RVEDVi),right ventricular end-stolic volume index(RVESVi),right ventricular cardiac index(RVCI),right ventricular stroke volume(RVSV),right ventricular ejection fraction(RVEF)and heart rate(HR);(2)RV MS parameters included right ventricular global radial strain(RVGRS),right ventricular global circumferential strain(RVGCS)and right ventricular global longitudinal strain(RVGLS).The data obtained were analyzed with SPSS 22.0 software.Firstly,intra-group and inter-group consistency analysis was performed using intraclass correlation efficient(ICC)test on the measurement of the main pulmonary arterial hemodynamic parameters with 2D-PC method and RV MS parameters.An ICC value greater than0.75 indicates good repeatability.Secondly,the Spearman correlation coefficient was used to complete the correlation analysis between smoking parameters and the main pulmonary arterial hemodynamic parameters with 2D-PC method,RV structure,function and MS parameters.Thirdly,the differences of the main pulmonary artery hemodynamic parameters,RV structure,function and MS parameters between the non-heavy smoking group and the heavy smoking group were analyzed.Independent data T test was used when the data conformed to the normal distribution,otherwise Mann-Whitney U test was used and p <0.05 was considered statistically significant.Result1.The intra-group and inter-group ICC values of all the hemodynamic parameters of the main pulmonary artery were above 0.890(ICC range 0.890 ～ 0.987).And the intra-group and inter-group ICC values of all the RV MS parameters were above 0.845(ICC range 0.845 ～ 0.962).2.Smoking time was negatively correlated with PPV,AF and APF,respectively(r=-0.321,p = 0.024;r =-0.350,p = 0.014;r =-0.311,p = 0.029)and there was no correlation between smoking intensity,smoking burden and the main pulmonary arterial hemodynamic parameters.3.Smoking time was only positively correlated with RVGLS(r = 0.324,p = 0.023)and had no correlation with other RV parameters.Smoking intensity was positively correlated with RVGRS and RVGCS(r = 0.374,p = 0.008;r = 0.345,p = 0.015)and had a negative correlation with RVEDVi and RVESVi(r =-0.318,p = 0.026;r =-0.325,p = 0.022).Smoking burden was positively correlated with RVGRS and RVGLS(r =0.298,p = 0.037;r = 0.372,p = 0.009).4.PPV,AF and APF of the heavy smoking group(smoking time ≥20 years)were significantly lower than the non-heavy smoking group(smoking time <20 years)(74.33± 12.01 cm / s vs.81.21 ± 10.60 cm / s;64.62 ± 11.50 ml / beat vs.75.09 ± 17.54 ml /beat;69.72 ± 12.20 ml / beat vs.79.97 ± 18.05 ml / beat;all p <0.05).Meanwhile,RVGLS in the heavy smoking group was significantly higher than that in the non-heavy smoking group(-15.28 ± 2.60 vs.-13.33 ± 3.72,p <0.05).However,there were no statistical differences in PNV,ANF,RVGRS,RVGCS,RVSV,RVEF,RVEDVi,RVESVi and RVCI between the two groups(p> 0.05).ConclusionThe 2D-PC MR technology can be used to monitor the effects of different smoking degrees on the main pulmonary hemodynamics in the normal population.With the prolongation of smoking time,the main pulmonary artery positive flow parameters(PPV,AF,APF)were significantly impaired and decreased,especially in heavy smokers.Furthermore,smoking also affects RV.RVGLS may have a significant compensatory increase with the prolongation of smoking time.