Estimation of gas and tissue lung volumes by MRI: Functional approach of lung imaging

Purpose: The purpose of this work was to assess the accuracy of MRI for the determination of lung gas and tissue volumes. Method: Fifteen healthy subjects underwent MRI of the thorax and pulmonary function tests [vital capacity (VC) and total lung capacity (TLC)] in the s upine position. MR examinations were performed at inspiration and expiratio n. Lung volumes were measured by a previously validated technique on phanto ms. Both individual and total lung volumes and capacities were calculated. MRI total vital capacity (VCMRI) was compared with spirometric vital capaci ty (VCSP). Capacities were correlated to lung volumes. Tissue volume (V-T) was estimated as the difference between the total lung volume at full inspi ration and the TLC. Results: No significant difference was seen between VCMRI and VCSP. Individ ual capacities were well correlated (r = 0.9) to static volume at full insp iration. The V-T was estimated to be 836 +/- 393 ml. Conclusion: This preliminary study demonstrates that MRI can accurately est imate lung gas and tissue volumes. The proposed approach appears well suite d for functional imaging of the lung.