A non-invasive assessment of cardiopulmonary hemodynamics with MRI in pulmonary hypertension

Purpose: We propose a method for non-invasive quantification of hemodynamic changes in the pulmonary arteries resulting from pulmonary hypertension (PH). Methods: Using a two-element Windkessel model, and input parameters derived from standard MRI evaluation of flow, cardiac function and valvular motion, we derive: pulmonary artery compliance (C), mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), pulmonary capillary wedge pressure (PCWP), time-averaged intra-pulmonary pressure waveforms and pulmonary artery pressures (systolic (sPAP) and diastolic (dPAP)). MRI results were compared directly to reference standard values from right heart catheterization (RHC) obtained in a series of patients with suspected pulmonary hypertension (PH). Results: In 7 patients with suspected PH undergoing RHC, MRI and echocardiography, there was no statistically significant difference (. p<. 0.05) between parameters measured by MRI and RHC. Using standard clinical cutoffs to define PH (mPAP. >25. mmHg), MRI was able to correctly identify all patients as having pulmonary hypertension, and to correctly distinguish between pulmonary arterial (mPAP. >25. mmHg, PCWP. <. 15. mmHg) and venous hypertension (mPAP. >25. mmHg, PCWP. >15. mmHg) in 5 of 7 cases. Conclusions: We have developed a mathematical model capable of quantifying physiological parameters that reflect the severity of PH.