Preliminary Evaluation Of Main Pulmonary Artery Changes In Chronic Mountain Sickness Patients With Phase Contrast MR Imaging

Objective To evaluate the clinical application value of structure and hemodynamics of main pulmonary artery(MPA)and mean pulmonary artery pressure(MPAP)in patients with chronic mountain sickness(CMS)by using phase contrast MR imaging(PC-MRI).Method 22 male adult patients with CMS(CMS group)and 20 healthy male adult volunteers(control group)from the same altitude were recruited.The 2D/QF sequence of Philips 1.5 T magnetic resonance scanner was used for main pulmonary artery to obtain its cross-sectional area(CSA),peak positive velocity(PPV),peak negative velocity(PNV),right ventricular stroke volume(RVSV)and regurgitant fraction(RF).Then,relative dilatation degree(RDD)and MPAP were calculated.Independent sample’s t-test and Pearson’s correlation(r)was applied.P<0.05 was considered significant.Results(1)Structure parameters:the CSA and RDD of CMS group were(7.52±0.71)cm~2 and(36.11±11.27)%respectively,and those of the control group were(6.34±1.12)cm~2 and(52.08±7.54)%respectively.CSA increased by(P<0.01)compared with the control group,and RDD decreased by(P<0.01).(2)Hemodynamics parameters:the PPV,PNV,RVSV and RF of the CMS group were(72.19±9.41)cm/s,(28.61±4.16),(64.43±21.48)ml and(7.11±0.93)%respectively,and those of the control group were(80.32±11.15)cm/s,(22.64±6.14),(59.12±19.34)ml and(4.31±0.48)%respectively.The PPV decreased by(P=0.015)compared with the control group,the PNV increased by(P<0.01),the RVSV increased by(P=0.411),the RF increased by(P=0.004).(3)MPAP(36.71±12.36)mmHg in the CMS group was significantly higher than that(15.77±6.69)mmHg in the control group by(P<0.01).Conclusion Long-term hypobaric and hypoxic conditions in CMS patients resulted in MPA dilatation,flexibility decrease,changes of blood flow velocity and increase of RF and MPAP.PC-MRI can non-invasively and accurately provide the information of the MPA structure,hemodynamics and pressure,so as to preliminarily achieve the purpose of assessment of the characteristics of the MPA changes in CMS patients.