The purpose of this study is to determine whether magnetic resonance imaging (MRI) using inhaled hyperpolarized 129Xe gas, and conventional contrast can help visualize impaired lung function and detect changes over time in patients receiving treatment as well as those who don't. 129Xe is a special type of xenon gas and when inhaled during MRI may be able to show areas of abnormal thickening of parts of the lungs. These images combined with images taken with injected contrast agents or other types of MRI may provide a better way to look at lung structure and function in patients with IPF. The ultimate goal is to predict how a particular patient might respond to a particular therapy and to observe such responses earlier than conventional tests. The investigators anticipate that the images acquired in this study will provide more specific information about lung disease than standard lung function tests. The use of 129Xe MRI is investigational. "Investigational" means that these tests have not yet been approved by the US Food and Drug Administration and are being tested in research studies like this one. In addition, standard MRI with contrast is not typically done as standard of care for monitoring progression of IPF, therefore, its use in this study is also considered investigational.

Healthy volunteers are being asked to participate in this study because the investigators need to develop a database of functional images that are representative of healthy lungs.

Inclusion Criteria:

1. Healthy volunteer (technical optimization)
2. Outpatients of either gender, age > 18.
3. Willing and able to give informed consent and adhere to visit/protocol schedules. (Consent must be given before any study procedures are performed.)
4. Clinical diagnosis of IPF by established means

Exclusion Criteria:

1. Subject is less than 18 years old
2. MRI is contraindicated based on responses to MRI screening questionnaire
3. Subject is pregnant or lactating
4. Respiratory illness of a bacterial or viral etiology within 30 days of MRI
5. Subject has any form of known cardiac arrhythmia
6. Subject does not fit into 129Xe vest coil used for MRI
7. Subject cannot hold his/her breath for 15 seconds
8. Subject deemed unlikely to be able to comply with instructions during imaging
9. Recent exacerbation (within 30 days) defined by the need for antibiotics and/or systemic steroids
10. Medical or psychological conditions which, in the opinion of the investigator, might create undue risk to the subject or interfere with the subject's ability to comply with the protocol requirements