Molecular Imaging Study Of Pulmonary Hypertension Associated With Congenital Heart Disease

Objective:To investigate the value of ¹⁸F-fluorodeoxyglucose(FDG)PET imaging in evaluating the ¹⁸F-FDG influx rate of lungs and its relationship with pulmonary hemodynamics in patients with pulmonary arterial hypertension(PAH)related to congenital heart disease(PAH-CHD).Methods:From January 2018 to June 2019,a total of 16 PAH-CHD patients(6 males,10 females,age(29.2±10.6)years)and 22 health controls(8 males,14 females,age(45.4±3.8)years)were respectively enrolled.All cases underwent dynamic ¹⁸FFDG PET imaging for lung ¹⁸F-FDG influx rate(presented as Ki).Right heart catheterization was performed to evaluate pulmonary hemodynamic parameters such as pulmonary vascular resistance(PVR),mean pulmonary vascular pressure(mPAP)in PAH-CHD patients after imaging within one week.Independent-sample t test was used to compare Ki of two groups.Pearson correlation analysis was used to test the relationship between Ki and PVR,mPAP in PAH-CHD patients.Results:Ki of the lungs was significantly higher in PAH-CHD patients than that of health controls((0.0006±0.0003)vs(0.0004±0.0003)ml·min^(-1)·g^(-1);t=2.15,P=0.038).In addition,Ki was not correlated with PVR and mPAP in PAH-CHD patients(r values:0.202 and 0.006,both P>0.05).Conclusions Pulmonary vascular remodeling could lead the increased lung ¹⁸F-FDG uptake in patients with PAH-CHD.¹⁸F-FDG PET may have the ability in monitoring and evaluating pulmonary vascular remodeling in PAH-CHD.Objective:To compare the absolute quantitative glucose metabolic rate between patients with idiopathic pulmonary arterial hypertension(IPAH)and patients with pulmonary arterial hypertension related to congenital heart disease(PAH-CHD)via dynamic ¹⁸F-fluorodeoxyglucose positron emission tomography(I8F-FDG PET)myocardial metabolic imaging.Methods:From November 2016 to December 2018,26 patients with IPAH(9males,17 females,28.23±8.92 years old)and 16 patients with PAH-CHD(6 males,10 females,29.19±10.62 years old)were enrolled and underwent dynamic ¹⁸F-FDG PET myocardial metabolic imaging.The rate of myocardium glucose utilization(rMGU)of both the right and left ventricles was quantified via Patlak analysis.Within 1 week,right heart catheterization was performed in all subjects to evaluate pulmonary hemodynamic parameters.rMGU and other parameters were compared via independent sample t test.The relationship between rMGU and pulmonary vascular resistance and mean pulmonary artery pressure(mPAP)in patients with PAH-CHD or IPAH was analyzed via Pearson correlation analysis.Results:No significant difference in mPAP was observed between patients with IPAH(59.85± 16.46 mmHg)and patients with PAH-CHD(69.75± 18.93 mmHg)(t=1.79,p=0.81).The right ventricular rMGU ofpatients with PAH-CHD(0.135±0.165(?mol*g_-I*min_-I)was not significantly different from that of patients with IPAH(0.095±0.074 ?mol*g_-I·min_-I)(t=1.07,P=0.29).Similarly,the left ventricular rMGU between the former(0.070±0.047 (?mol·g_-I*min_-I)and the latter(0.057±0.065?mol·g_-I·min_-I)was not significantly different(t=0.77,P=0.49).rMGU was significantly correlated with mPAP in patients with IPAH(r=0.42,P<0.05)but not in patients with PAH-CHD(r=0.02,P=0.95).Conclusion:Increased right ventricular rMGU is a marker of prognosis in IPAH.In patients with PAH-CHD and IPAH with no difference in mPAP,no significant difference in rMGU was found in both the right and left ventricles.Objective:To establish SPECT quantitative method for assessment of right ventricular myocardial blood flow(MBF)and investigate the relationship between right ventricular MBF and pulmonary hemodynamics in patients with pulmonary arterial hypertension.Methods:From January 2018 to June 2019,14 patients(13 females,1 male;age:(30.9±13.5)years)in Fuwai Hospital with pulmonary arterial hypertension related to congenital heart disease(PAH-CHD),whose right ventricular function were preserved,were enrolled in this study.All subjects underwent dynamic SPECT myocardial perfusion imaging using CdZnTe(CZT)SPECT.Full physical correction was applied for imaging reconstruction.One-tissue two compartmental model was used for kinetic analysis and the spill-over effect from right ventricular blood pool to right ventricular myocardium was considered into the correction,thus right ventricular MBF and left ventricular MBF was calculated.Right heart catheterization was performed within one week after SPECT imaging to evaluate the pulmonary hemodynamic parameters,and the right ventricular end-diastolic dimension(EDD)was measured by transthoracic echocardiography.Correlations between the MBF and other parameters were analyzed with Pearson correlation.Results:The right ventricular MBF was(0.70±0.19)ml·min^(-1)·g^(-1),which was significantly correlated with mean pulmonary artery pressure((68.64±18.18)mmHg(1mmHg=0.133 kPa);r=0.716,P<0.05)and pulmonary vascular resistance((14.10=t7.81)Wood units;r=0.768,P<0.05).The right ventricular MBF was also significantly correlated with right ventricular EDD((32.00±7.75)mm;r=-0.624,P<0.05).Meanwhile,there was no significant relationship between left ventricular MBF and hemodynamic parameters(r values:-0.350 to 0.310,all P>0.05).Conclusions A method using SPECT to quantitively measure right ventricular MBF in patients with PAH-CHD is preliminarily established.Right ventricular MBF is increased with the increased pulmonary artery pressure and pulmonary vascular resistance in patients with PAH-CHD and preserved right ventricular function.