1. After the patient has been informed about the standard of care and signed a consent form, the patient will be asked if they wish to participate in an experimental study. If the patient is interested, they will be questioned about potential structural heart defects, congenital heart defects, recent worsening of heart or lung conditions, pulmonary hypertension, potential pregnancy, attempts to become pregnant, if they are nursing, or allergies to the contrast. If they report any of these relative contraindications, we will exclude them from participating in the study.