Loss of pulmonary capillaries in idiopathic pulmonary arterial hypertension with low diffusion capacity is accompanied by early diffuse emphysema detected by 129Xe MRI

This study evaluated the potential association between pulmonary capillary loss and early diffuse emphysema in idiopathic pulmonary arterial hypertension (IPAH) patients with low diffusion capacity (DLCO). Researchers recruited four patient groups (IPAH with preserved DLCO, IPAH with low DLCO, combined pulmonary fibrosis and emphysema with pulmonary hypertension, and isolated emphysema) between 2019 and 2023 for comparative analysis. Using 129Xe MRI, they assessed lung surface-volume ratios and the ratio of 129Xe in red blood cells (RBC-M) through dissolved-phase and diffusion-weighted imaging. Results showed that IPAH patients with low DLCO exhibited reduced lung surface-volume ratio and RBC-M, indicating pulmonary capillary loss and early alveolar tissue destruction. Aview software was utilized to automatically quantify low-attenuation area (LAA) percentages from clinical CT scans. This study contributes to understanding the pathological mechanisms in IPAH patients with low DLCO.