NONINVASIVE ASSESSMENT OF REGIONAL VENTILATION IN THE HUMAN LUNG USING OXYGEN-ENHANCED MAGNETIC-RESONANCE-IMAGING

The imaging of regional ventilation in the lungs is essential for the evaluation of a variety of pathological conditions, such as emphysema, pneumonia and pulmonary embolism. We propose a novel approach for ven tilation scanning, using magnetic resonance imaging (MRI) and inhaled molecular oxygen as a contrast agent, that directly depicts transfer o f oxygen across the alveolus into the pulmonary vasculature. Molecular oxygen is only weakly paramagnetic but produces substantial signal ch anges in the lungs because of their large surface area. Ventilation de fects were shown in a patient with bullous emphysema, and ventilation- perfusion mismatches were shown in two patients with pulmonary embolis m.