Mechanistic 129 Xe MRI Study to Assess Therapeutic Response in Fibrotic Interstitial Lung Disease

This is a prospective, single site, observational study in adults aged 18-80 who have fibrotic interstitial lung disease (fILD), and are scheduled to start antifibrotic therapy as prescribed by their treating respirologist. Therapeutic treatment will be assigned in a non-randomized manner by the treating respirologist. There will be no control intervention or blinding.

Each participant will participate in three study visits over a one-year period; Visit 1 - before start of treatment Visit 2 - after 24 weeks of therapy Visit 3 - after 48 weeks of therapy

Each visit will include; a blood test - Complete Blood Count (CBC), C-reactive Protein (CRP), Erythrocyte Sedimentation Rate (ESR); Pulmonary Function testing (PFT) that includes spirometry, plethysmography, diffusion capacity, oscillometry; urine pregnancy test (if indicated); St George's Respiratory Questionnaire (SGRQ-I) and King's Brief Interstitial Lung Disease (K-BILD) questionnaire; 129Xenon Magnetic Resonance Imaging (129Xe MRI); Low-dose chest Computed Tomography (CT) /High Resolution Computed Tomography (HRCT) scan; Six-Minute Walk Test (6MWT) with Borg rating of perceived exertion and dyspnea (BORG) questionnaires.

Inclusion criteria

• Patient understands study procedures and is willing to participate in the study as indicated by the patient's signature.
• Provision of written, informed consent prior to any study specific procedures.
• Males and females >/= 18 years of age
• Patient has a current diagnosis of fILD by a respirologist according to the 2022 ATS/ERS guidelines and is eligible for antifibrotic therapy.
• Women of childbearing potential must ensure that they are using an effective form of birth control for at least 2 months prior to each imaging visit.
• Women of childbearing potential must agree to use a highly effective form of birth control from enrollment, throughout the study duration, with negative urine pregnancy test result at Visits 1, 2, and 3.

Exclusion criteria

• Patient has an implanted mechanically, electrically, or magnetically activated device or any metal in their body which cannot be removed, including but not limited to pacemakers, neurostimulators, biostimulators, implanted insulin pumps, aneurysm clips, bioprosthesis, artificial limb, metallic fragment or foreign body, shunt, surgical staples (including clips or metallic sutures and/or ear implants)
• In the investigator's opinion, subject suffers from any physical, psychological or other conditions that might prevent performance of the MRI or CT, such as severe claustrophobia.
• Participants who are pregnant, breastfeeding or have a positive pregnancy test at initial screening visit.
• Participant is unable to perform spirometry or plethysmography maneuvers.
• Participant is unable to perform MRI and CT breath-hold maneuvers.