Observational StudyAdvanced Imaging for Pulmonary Fibrosis

Inclusion Criteria:

1. Age 18-80 with a diagnosis of chronic hypersensitivity pneumonitis, connective tissue-associated ILD (due to rheumatoid arthritis, systemic sclerosis, mixed connective tissue disease), or undifferentiated ILD.
2. On stable dose immunosuppression treatment (with prednisone, mycophenolate mofetil, mycophenolate sodium, and/or rituximab) for at least 3 months.
3. Pulmonary fibrosis, defined as honeycombing, traction bronchiectasis, or reticular opacities on HRCT performed within 1 year to or at Visit 1.
4. FVC of >/= 45% and DLCO >/= 25% predicted on PFTs performed at Visit 1.

Exclusion Criteria:

1. Current or prior exposure to FDA approved anti-fibrotic therapy.
2. Extent of emphysema greater than extent of fibrosis.
3. Pregnancy or plans to become pregnant at baseline or during follow-up.
4. Contraindications to MRI.
5. Contraindications to receiving gadolinium-based contrast agents.
6. Research-related radiation exposure exceeds 50 mSv in the prior year.
7. Estimated glomerular filtration rate (eGFR) < 30 mL/min (only for individuals with a history of chronic kidney disease).
8. Clinically significant PH defined by use of pulmonary vasodilatory therapy.
9. Respiratory infection within the prior 6 weeks.
10. Smoking of any kind within the prior 6 months.