Diverse Cardiopulmonary Diseases are Associated with Distinct Xenon MRI Signatures.

Abstract

BACKGROUND:As an increasing number of patients exhibit concomitant cardiac and pulmonary disease, limitations of standard diagnostic criteria are more frequently encountered. Here, we apply noninvasive 129Xenon MR imaging and spectroscopy to identify patterns of regional gas transfer impairment and hemodynamics that are uniquely associated with chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), left heart failure (LHF), and pulmonary arterial hypertension (PAH). METHODS:Healthy volunteers (n=23) and patients with COPD (n=8), IPF (n=12), LHF (n=6), and PAH (n=10) underwent 129Xe gas transfer imaging and dynamic spectroscopy. For each patient, 3D maps were generated to depict ventilation, barrier uptake (129Xe dissolved in interstitial tissue), and red blood cell (RBC) transfer (129Xe dissolved in RBCs). Dynamic 129Xe spectroscopy was used to quantify cardiogenic oscillations in the RBC signal amplitude and frequency shift. RESULTS:Compared to healthy volunteers, all patient groups exhibited decreased ventilation and RBC transfer (p≤0.01, p≤0.01). Patients with COPD demonstrated more ventilation and barrier defects compared to all other groups (p≤0.02, p≤0.02). In contrast, IPF patients demonstrated elevated barrier uptake compared to all other groups (p≤0.007) and increased RBC amplitude and shift oscillations compared to healthy volunteers (p=0.007, p≤0.01). Patients with COPD and PAH both exhibited decreased RBC amplitude oscillations (p=0.02, p=0.005) compared to healthy volunteers. LHF was distinguishable from PAH by enhanced RBC amplitude oscillations (p=0.01). CONCLUSION:COPD, IPF, LHF, and PAH each exhibit unique 129Xe MR imaging and dynamic spectroscopy signatures. These metrics may help with diagnostic challenges in cardiopulmonary disease and increase understanding of regional lung function and hemodynamics at the alveolar-capillary level.