Functional patterns of healthy human respiratory dynamics by 3D MR spirometry

Area of Science:

• Pulmonary medicine
• Medical imaging
• Physiology

Background:

• Functional pulmonary MRI assesses regional ventilation pathophysiology.
• Characterizing nominal ventilatory patterns is crucial for baseline assessment.
• 3D MR spirometry offers a method for detailed lung function analysis.

Purpose of the Study:

• Investigate common features of regional ventilation in healthy volunteers.
• Determine the gravity dependence of these ventilatory patterns.
• Evaluate the reliability of 3D MR spirometry for free breathing.

Main Methods:

• 25 healthy volunteers underwent 3T MRI in supine and prone positions.
• Dynamic lung MR acquisitions measured tidal volumes, expiratory flows, and deformation.
• Reproducibility and gravity dependence of spirometry biomarkers were statistically analyzed.

Main Results:

• Ventilatory maps showed spatial inhomogeneity (30-63% variation).
• Key patterns for tidal volume, peak expiratory flow, and expiratory flow at 25% of tidal volume demonstrated significant gravity dependence (p < 0.05).
• Spirometry biomarkers exhibited good global repeatability (ICC: 0.71-0.88) and local repeatability after normalization (ICC: 0.78-0.90).

Conclusions:

• 3D MR spirometry identifies shared, gravity-dependent respiratory features.
• The technique demonstrates reliable intra-volunteer repeatability and global accuracy.
• This study establishes a new baseline for regional lung pathophysiology assessment in free breathing.