ALB and pulmonary arterial hypertension: AM, adrenomedullin; CT, computed tomography; CTEPH, chronicthromboembolic pulmonary hypertension; MAA, macroaggregates of albumin; PA,pulmonary artery; PAH, pulmonary arterial hypertension; PH, pulmonary hypertension;ROI, region of interest; SPECT, single photon emission computed tomography; Tc,technetium