Evaluation of respiratory muscle dysfunction in patients with idiopathic pulmonary fibrosis: a prospective observational study with magnetic resonance imaging.

Abstract

Objective: Respiratory muscle dysfunction in patients with idiopathic pulmonary fibrosis (IPF) is a big challenge for treatment and rehabilitation. To quantitatively assess diaphragm and chest wall dysfunction using dynamic Magnetic Resonance Imaging (Dyn-MRI) in patients with IPF.

Methods: Ninety-six patients with IPF and 50 gender- and age-matched controls were prospectively included and underwent D-MRI with a dynamic fast spoiled gradient-recalled echo sequence. Respiratory muscles function were assessed with thoracic anterior-posterior (AP), left-right (LR), cranial-caudal (CC) metrics. Moreover, lung area ratios, height (DH), and area (DA) of diaphragm curvature between end-inspiration and end-expiration during both quiet and deep breathing.

Results: During quiet breathing, the functional metrics of the diaphragm and chest wall were comparable between IPF patients and controls. However, during deep breathing, IPF patients exhibited significantly reduced ratios of AP, CC, and lung area compared to controls. Moreover, the median ratios of DH and DA were higher in IPF patients than in controls (DH: 0.96 vs. 0.81, p < 0.001; DA: 1.00 vs. 0.90, p < 0.001). Furthermore, the ratios of AP, CC, and lung area during deep breathing were found to correlate with pulmonary function, total lung volume, and 6-minute walk distance.

Conclusion: D-MRI demonstrated dysfunction in the diaphragm and chest wall among IPF patients, with respiratory muscle dysfunction showing a correlation with the severity of disease.

Trial registration: This article presents a prospective observational study that does not include the outcomes of any healthcare interventions on human participants. The study was registered on September 11, 2018, under the registration number NCT03666234.