Downstream Effects of Airway Mucus Plugs on 129Xenon MRI in Severe Asthma

Who May Qualify: - Adequate completion of willing to sign a consent form process with written documentation - Patients 18 - 65 years old - Physician diagnosis of asthma for \> 1 year - Able to perform reproducible spirometry according to ATS criteria based on clinical PFTs within previous 30 days of enrollment - All racial/ethnic backgrounds may participate - Blood eosinophil count \> 300 cells/μL - Smoking history \<10 pack years - No smoking history (including vapes, cigar, or marijuana use) in the last 3 months - About to initiate asthma therapy with either dupilumab, tezepelumab, or benralizumab as part of their standard of care Who Should NOT Join This Trial: - Respiratory tract infection within the 4 weeks prior to Visit 1 - Body mass index (BMI) \> 30 at Visit 1 - One-time doses such as intra-articular injections require a 4-week washout prior to Visit 1 - Asthma-related ER visit within the previous 4 weeks of Visit 1 or at any time while on the study - Significant concomitant medical illness, including (but not limited to) heart disease, cancer, uncontrolled diabetes, other chronic lung diseases (determined by the Investigator.) - Resting O2 saturation \<90% with maximum supplemental O2 delivered by nasal cannula - Positive urine pregnancy test at Visit 1 or at any time while on the study - Participation in an intervention study (including bronchoscopy) or use of investigative drugs within the past 30 days or plans to enroll in such a trial during the study - Unable or unlikely to complete study assessments in the opinion of the Investigator - Study intervention poses undue risk to patient in the opinion of the Investigator - Conditions that will prohibit MRI scanning determined by the MRI safety screening. Always talk to your doctor about whether this trial is right for you.