Functional and Structural Assessment of Endobronchial Valve Recipients Using Dynamic Hyperpolarized Xenon-129 MRI
brief summary
This study proposes to use hyperpolarized xenon-129 Magnetic Resonance Imaging (MRI) to study lung function of COPD patients who will receive endobronchial valve (EBV) therapy as part of their clinical standard-of-care. Once inhaled, HP xenon can provide information to imagers regarding functionality across specific regions of the lungs through the assessment of the replacement of air during the normal breathing cycle, how much oxygen is in the airspaces, and if the normal spongy tissue structure has been compromised by lung disease. Pre- (baseline) and post-EBV (follow-up) lung function imaging with HPXe will potentially lead to be better understand disease progression and treatment mechanism.
detailed description
This study will be assessing the pulmonary function of COPD patients receiving endobronchial valve (EBV) therapy as part of their clinical care by using HP 129Xe MRI in an effort to evaluate the imaging technique's performance in identifying abnormal lung function and micromorphology in patients receiving this therapy. HP Xe MRI study visits will last 1-2 hours for each subject, with the possibility of multiple follow-ups in longitudinal studies. The investigators plan to recruit volunteer patients who are scheduled to receive EBV therapy for the treatment of COPD as part of their clinical standard-of-care. Patients will be imaged at at least two time point, pre-EBV (baseline), and \~45 days post-EBV (follow-up).
Subjects will provide a brief medical history and perform pulmonary function testing (PFT) prior to inhalation of HP xenon-129. If a subject has performed a PFT at the Hospital of the University of Pennsylvania or Temple University Hospital within one month of the study visit and the results are accessible by the research team, subjects will not be required to repeat PFTs for the purpose of imaging.
During a typical HXe MRI session, subjects will first be imaged using standard 1H MRI to generate an anatomical reference image. This will be followed by the inhalation of a small amount (\~200 ml) of HP 129Xe from a Tedlar™ bag to perform a frequency calibration, as well as determine the effective flip-angle to be used for the subject. Finally, the subject will sequentially inhale up to 50 breaths of hyperpolarized 129Xe from a gas mixing apparatus designed to oxygenate and dilute the gas, maintaining near normoxic conditions and approximately 10% xenon concentration. During this period, the lungs will be continuously imaged using a 3D sequence and a very low flip-angle (\~3 degrees) pulse. The subject will be coached to maintain a reasonably steady breathing cadence of 10-15 breaths per minute, depending on their size and natural breathing rate, but will be otherwise unconstrained with respect to breath timing and volume.