Semiautomatic assessment of respiratory motion in dynamic MRI--comparison with simultaneously acquired spirometry

Abstract

Purpose: Supplementing global spirometry with regional information could allow for earlier and more specific diagnosis of lung disease. Dynamic magnetic resonance imaging (dMRI) makes it possible to derive functional parameters from the visualization of the pulmonary motion of single lungs. The aim of this study was to compare high temporal resolution measurements of left and right thoracic diameters to simultaneously acquired spirometry.

Materials and methods: 10 healthy volunteers underwent 2-dimensional dMRI of both lungs at 1.5 T. Spirometry was performed simultaneously with an MRI-compatible spirometer. Thoracic diameters were measured semiautomatically and compared to simultaneously measured spirometric volumes. A dMRI surrogate for the Tiffeneau Index was compared to the spirometric Tiffeneau.

Results: The volume-time and flow-volume curves from dMRI were very similar to the spirometric curves. The semiautomatically measured diameters correlated well with the spirometric volumes (r > = 0.8, p < 10 - 15). Agreement between the methods at full temporal resolution was not as convincing (width of 95 % limits of agreement interval up to 56 %). Good agreement was found between the Tiffenau surrogate and spirometry (width of 95 % limits of agreement interval of 14.5 %).

Conclusion: DMRI with semiautomatic measurement of thoracic diameters makes measurement of realistic volume-time and flow-volume curves from single lungs possible. The derived single lung Tiffeneau Index shows good agreement to spirometry and could be valuable to supplement global spirometric measurements with functional data from single lungs.