| Objective The aim of this study was to compare the differences on main pulmonary artery(MPA)vessel indices derived from cardiovascular magnetic resonance(CMR)in different phase and direction between patients with pulmonary hypertension(PH)and healthy volunteers,and to investigate the relationship between MPA vessel indices of PH patients and the mean pulmonary arterial pressure(m PAP)measured by right heart catheterization(RHC),and to evaluate the power of MPA vessel indices to predict PH.Methods CMR were performed in 83 patients with PH whose diagnosis were confrmed by RHC and 49 healthy volunteers from January 2012 to October 2016,and the CMR protocol included FIESTA and phase-contrast(PC)imaging.Parameters of MPA were acquired from non-gated FIESTA images,these parameters included MPA diameter(DPA),ascending aorta diameter(DAo),ratio of DPA and DAo(DPA/DAo).PC images were post-processed and the following indices were calculated on the phases with the maximum and minimun area of MPA: max mean diameter(MDmax),min mean diameter(MDmin),fraction transverse diameter(f TD),fraction longitudinal diameter(f LD),and distensibility.In the present study,multivariate general linear model was employed for the comparison of MPA and ascending aorta vessel indices between PH patients and control group.f TD and f LD were compared in PH patients and controls,respectively.Pearson correlation analysis was used to evaluate the correlation between MPA vessel parameters,DPA/DAo and RHC-derived m PAP.The ability of these measurements to discriminate between patients with and without PH was determined by receiver operating characteristic analysis(ROC)by evaluating the cut-off value,area under the curve(AUC),and Youden index of indices.A P value less than 0.05 was considered to be statistically significant.Results: Compared with control group,DPA,DPA/DAo,MDmax,and MDmin were signifcantly higher in patients with PH(P<0.001);f TD,f LD,and distensibility signifcantly decreased(P<0.001).There was no difference on DAo between PH and control group(P=0.225).f TD was lesser than f LD in control group(P<0.001),whereas difference was absent in PH(P=0.305).In patients with PH,the larger DPA,DPA/DAo,MDmax,and MDmin were signifcantly associated with higher m PAP(r = 0.326,r = 0.534,r = 0.315,r = 0.362;P<0.05)and strongest correlation was observed for DPA/DAo(r=0.534,P<0.001).f TD,f LD,and distensibility were negatively correlated with m PAP(r =-0.273,r =-0.290,r =-0.298;P<0.01).By ROC curve analysis,MDmin>28.4 mm and MDmax>32.4 mm(AUC:0.979,0.981;Youden index:0.952,0.904)showed best performance in predicting PH,yielding highest specificity at 100%.The sensitivity and AUC of DPA>30.5 mm was the same to MDmin > 28.4 mm,but the specificity was moderate lower(0.959).Distensibility <26.9% and DPA/DAo >1.1 did not strengthen in predicting PH than other indices.(AUC:0.940,0.932;Youden index:0.775,0.728).Conclusion:There were abvious differences on CMR-determined MPA vessel indices between patients with PH and health people.CMR-determined MPA vessel parameters were associated with m PAP obtained by RHC in PH group.MDmin>28.4 mm and MDmax>32.4 mm,which are acquired from the standard cross-section MPA images,offer advantage in detecting PH.The common transversal CMR-determined DPA>30.5mm and DPA/DAo >1.1 could be used as an reference parameter of predicting PH,which are easy to get and closed to MDmin and MDmax.We believe that these results demonstrate that noninvasive CMR–derived MPA measurements provide excellent clinical value for detecting PH. |
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