This study is a prospective, non-randomized, longitudinal, observational study that will recruit about 5 lung transplant patients per year for 3 years. We will follow these patients at 6 months and 1 year with Hyperpolarized Helium-3 Magnetic Resonance Imaging and image guided bronchial biopsies to detect early BOS and to better understand BO disease progression. The biopsies will provide future research for rapid determination of cellular and molecular mechanisms that lead to BOS and to facilitate identification and validation of translatable pharmaceutical targets.