MRI-assessed Dynamic Hyperinflation Induced by Tachypnea in Chronic Obstructive Pulmonary Disease: The SPIROMICS-HF Study

Purpose: To assess the repeatability of real-time cine pulmonary MRI measures of metronome-paced tachypnea (MPT)–induced dynamic hyperinflation and its relationship with chronic obstructive pulmonary disease (COPD) severity. Materials and Methods: SubPopulations and InteRmediate Outcome Measures In COPD Study (SPIROMICS) (ClinicalTrials.gov identifier no. NCT01969344) is a multicenter prospective cohort study that recruited individuals with COPD with 20 or more pack-years smoking history and controls aged 40–80 years. SPIROMICS-HF is a cross-sectional study evaluating cardiopulmonary interactions in COPD from December 2019 to April 2024. Two-dimensional coronal real-time cine pulmonary MRI (3.2 frames/sec) was performed during MPT twice. Lung masks and lung MR images from an independent study were used for transfer learning to segment real-time cine pulmonary MR images. Dynamic hyperinflation was evaluated as the increase in end-expiratory lung volume (EELV) during tidal breathing to the end of MPT. Repeatability was assessed with intraclass correlation coefficients, and multivariable associations with COPD severity were examined. Results: Of the 70 participants (mean age, 67 years ± 10 [SD]; 37 male, 33 female) included in the study, 59% had COPD. The transfer learning model achieved high accuracy in lung segmentation (Dice similarity coefficient, 0.94 ± 0.03). There was good scan-rescan agreement for EELV and dynamic hyperinflation (intraclass correlation coefficient, 0.99 and 0.87, respectively). Dynamic hyperinflation was associated with COPD severity (P trend = .01, with a mean difference between severe COPD and controls of 0.24 L). Conclusion: A transfer learning model yielded reproducible quantification of MPT-induced dynamic hyperinflation at real-time cine pulmonary MRI, with greater dynamic hyperinflation in participants with more severe COPD.