129Xe MR Spectroscopy reveals Abnormal Gas-exchange in Moderate and Severe Asthma

Motivation: Airways disease in asthma is characterized by airway wall thickening, luminal obstruction and smooth muscle hyper-responsiveness. Abnormal CT pulmonary vascular pruning has also been reported. We wondered if 129Xe MRS could identify functional abnormalities related to the pulmonary vascular tree, via the measurement of gas-exchange across the alveolar-capillary membranes, into the red-blood-cells. Goal(s): Measure and compare 129Xe MRS RBC:membrane in healthy volunteers, and patients with moderate or severe asthma. Approach: 129Xe MRI, MRS and pulmonary function measures were acquired in healthy-volunteers and asthma participants. Results: 129Xe MR RBC:membrane was significantly different in healthy-volunteers, moderate and severe asthma. Impact: To our knowledge, this is the first demonstration of significantly different 129Xe MRS RBC:membrane values in healthy volunteers, and patients with moderate or severe asthma. Abnormal pulmonary gas-exchange may play a role in asthma, regardless of disease-severity.