Volumetry of ventilated airspaces by He-3 MRI preliminary results

RATIONALE AND OBJECTIVES. TO develop a validated postprocessing routine for volumetry of the ventilated airspaces by He-3 MRI. METHODS. (3)Helium MRI and pulmonary function tests were performed in seven healthy volunteers, After segmentation of ventilated airspaces, their volu mes were calculated. Functional residual capacity (FRC) was used as a refer ence. For comparison of absolute volumes, correction factors were evaluated . RESULTS. Mean lung volume (+/- standard deviation) calculated from He-3 MRI was 4082 +/- 908 mL and mean FRC was 3696 +/- 1166 mL, with a mean differe nce of 386 mL (r = 0.88). After correction for the relative pulmonary air c ontent (factor 0.82), posture (0.72), and the individual tidal volume, He-3 MRI volume was 3348 +/- 744 mL and mean FRC was 3422 +/- 817 mL, with the mean difference down to -74 mL (r = 0.9), Comparison on an individual basis confirmed an improvement in the estimation of absolute lung volume. CONCLUSIONS. Volumetry of ventilated lung from 3He MRI shows high correlati on and good agreement with the results of pulmonary function tests.