- Contraindications to 3-Helium MRI (including significant anemia [hemoglobin less than or equal to 12 g/dL, with the last testing within 1 month of the MRI scan] or marked oxyhemoglobin desaturation at rest when breathing room air [requiring more than 4 liters per minute of supplemental oxygen to keep saturation of oxygen (SaO2) at least 90%]).However, patients deemed to be low risk kfor complications of cerebrovascular disease, cardiovascular disease, heart dysrhythmias, and seizures through the thorough lung transplant evaluation will be eligible for testing. Since most of the patients with these contraindications to 3-Helium MRI will be ineligible for lung transplantation, we expect few patients to have such contraindications to testing.