Evaluation of pulmonary artery blood flow and right heart function using phase-contrast magnetic resonance imaging in elderly patients with chronic obstructive pulmonary disease

Abstract

Objective To investigate the value of phase-contrast magnetic resonance imaging(PC-MRI)in evaluating pulmonary artery blood flow and right ventricular(RV)function in elderly patients with chronic obstructive pulmonary disease(COPD). Methods Twenty-four elderly patients with COPD admitted to Beijing Anzhen Hospital between February 2016 and June 2017 were enrolled in this retrospective study.Based on pulmonary artery pressure evaluated by right heart catheterization, COPD patients were divided into a pulmonary hypertension group(PH group, n=12)and a non-PH group(n=12). Pulmonary artery blood flow velocity and volume, pulmonary arterial compliance and right heart function parameters including ejection fraction, end-diastolic volume, end-systolic volume and cardiac output, and 6-min walking distance evaluated by PC-MRI were compared between the two groups. Results There were significant differences in peak flow velocity[(88.1±16.0)cm/s vs.(59.8±13.8)cm/s, P=0.005], flow volume[(80.7±22.0)ml/s vs.(53.2±26.7)ml/s, P=0.012], main pulmonary artery compliance[(42.3±14.6)vs.(22.7±10.8), P=0.001], right ventricular ejection fraction[(48.4±13.4)% vs.(37.6±11.1)%, P=0.000], end-diastolic volume[(64.6±22.5)ml vs.(72.5±22.8)ml, P=0.030]and end-systolic volume[(50.6±33.1)ml vs.(41.7±33.1)ml, P=0.040]between the non-PH and PH groups, while there was no significant difference in cardiac output between the non-PH and PH groups[(34.2±10.8)ml vs.(34.4±8.3)ml, P=0.080]. Pearson's correlation analysis showed that 6-minute walking distance had good correlations with right ventricular ejection fraction(r=0.49), forced expiratory volume in 1 s(FEV1)(r=0.60)and main pulmonary artery diameter(r=-0.61). Conclusions PC-MRI is a noninvasive imaging method for quantitative analysis of pulmonary artery dynamics and right heart function for the elderly with COPD, and it can provide information for evaluating therapeutic effects and prognosis. Key words: Magnetic resonance imaging; Pulmonary disease, chronic obstructive; Pulmonary artery; Ventricular function