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BACKGROUND. Hyperpolarized (129)Xe MRI provides a non-invasive assessment of regional pulmonary gas exchange function. This technique has demonstrated that chronic obstructive pulmonary disease (COPD) patients exhibit ventilation defects, reduced interstitial barrier tissue uptake, and poor transfer to capillary red blood cells (RBCs). However, the behavior of these measurements following therapeutic intervention is unknown. PURPOSE. To characterize changes in (129)Xe gas transfer function following administration of an inhaled long-acting beta-agonist/long-acting muscarinic receptor antagonist (LABA/LAMA) bronchodilator. STUDY TYPE. Prospective. POPULATION. 17 COPD subjects (GOLD ll/lll classification per Global Initiative for Chronic Obstructive Lung Disease criteria) were imaged before and after 2 weeks of LABA/LAMA therapy. FIELD STRENGTH/SEQUENCES. Dedicated ventilation imaging used a multi-slice 2D gradient echo sequence. 3D images of ventilation, barrier uptake and RBC transfer used an interleaved, radial, 1-point Dixon sequence. Imaging was acquired at 3T. ASSESSMENT. (129)Xe measurements were quantified before and after LABA/LAMA treatment by ventilation defect+low percent (ven(def+low)) and by barrier uptake and RBC transfer relative to a healthy reference population (bar(%ref) and RBC(%ref)). Pulmonary function tests, including diffusing capacity of the lung for carbon monoxide (DL(co)), were also performed before and after treatment. STATISTICAL TESTS: Paired t-test, Pearson correlation coefficient (r). RESULTS. Baseline ven(def+low) was 57.8±8.4%, bar(%ref) was 73.2%±19.6%, and RBC(%ref) was 36.5%±13.6%. Following treatment, ven(def+low) decreased to 52.5±10.6% (p |
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