Cystic fibrosis is a life shortening genetic disease that has dramatic effects on the lung function of patients.[1] Despite aggressive therapies, lung dysfunction remains the primary cause of morbidity and results in an average lifespan of 38 years. Over time, irreversible damage from chronic infection manifests in the lung as bronchiectasis and fibrosis. Eventually, the only chance of survival is a lung transplant. Imaging could play an important role in evaluation of the lungs, since lung function tests only provide a global estimate of lung function. For example, the forced expiratory volume in one second (FEV1) measure offers a global estimate of the patient’s ventilation, but is severely limited in its ability to detect small, local changes. Computed tomography and nuclear medicine ventilation perfusion scans can provide anatomic and functional information, respectively, but at a relatively high radiation dose. Fluorine-enhanced MRI using perfluropropane (PFP) has the potential to assess dynamic lung ventilation without the need for ionizing radiation or a hyperpolarizing system.[2] The goal of this study was to evaluate PFP imaging in patients with cystic fibrosis.Cystic fibrosis patients and normal were recruited for this IRB approved study. Patients were fitted with a mask through which they inhaled a PFP/oxygen mixture through an MR compatible gas delivery system.[3] Imaging was performed on a Siemens 3T Trio with broadband capability. Conventional 1H anatomic imaging was performed for localization, followed by 19F PFP imaging with a custom thorax coil (ScanMed, LLC, Omaha NE). Repeated 19F GRE images were obtained during breath-holds every 3rd respiratory cycle. After steady state 19F signal was achieved, the gas source was switched to room air and dynamic imaging repeated until the 19F signal was exhausted. Offline fitting of the inhalation and exhalation curves was performed to obtain wash-in/out time constants. Histogram maps were also computed.A total of 10 subjects (5 normal subjects, 5 cystic fibrosis patients) have been successfully imaged for this study thus far. FEV1 for the CF subjects ranged from 36% to 80%, representing a range from very severe disease to normal. No adverse events occurred, even in patents with severely diminished lung function. Significant qualitative differences are seen in individual steady state images and throughout the dynamic image sets. CF patient images show areas of both hyper- and hypo ventilation, as well as gas trapping. Preliminary histogram analysis demonstrates a correlation of histogram spread with lung function as defined by FEV1. Ongoing recruitment is being performed for an exacerbation study to detect the sensitivity of 19F MRI Ventilation imaging to changes in lung function.Conventional approaches to assessing lung structure or function rely on ionizing radiation. This severely limits its use in the pediatric pulmonary diseases, such as cystic fibrosis. 19F MRI ventilation imaging offers a potential alternative with true 3-D imaging of lung function. The procedure is well tolerated by subjects, even those with relatively poor lung function.19F MRI ventilation imaging offers the ability to directly evaluate lung ventilation without the need for ionizing radiation or a external polarization system as required for hpMRI.