CF pts on MACT for Cystic Fibrosis

The main reason for this research study is to learn more about some new tests that are being developing for patients with Cystic Fibrosis (CF) to measure changes in the lungs. In this study, the focus will be to learn how stopping Airway Clearance (ACT) and re-starting ACT can affect these tests. These new tests include using a breathable gas called Xenon (Xe) with MRI (magnetic resonance imaging) to improve the pictures of changes in the lungs. The Xenon (Xe) gas that has been treated to have a larger MRI signal (also called hyperpolarized). The other new test is called LCI (Lung Clearance Index) that can measure how well the lungs are working. The MRI machine used in this study has been approved by the U.S. Food and Drug Administration (FDA) and is commercially available for sale in the USA. Hyperpolarized Xe gas is an FDA-approved, inhaled contrast agent for lung ventilation MRI. The new Xe MRI techniques that are being developed and used for this research study are investigational, meaning these new Xe MRI techniques are not FDA approved, but they are similar to FDA-approved techniques that are used clinically at Cincinnati Children's Hospital Medical Center (CCHMC). Xe gas and the new MRI techniques used in this research study have been used for many years in research, including in many research studies conducted at CCHMC like this one.