Evaluation of Respiratory Muscle Dysfunction in Patients with Idiopathic Pulmonary Fibrosis: A Prospective Observational Study with Magnetic Resonance Imaging

Objective: Respiratory muscle dysfunction in patients with idiopathic pulmonary fibrosis (IPF) is a big challenge for treatment and rehabilitation nursing. To quantitatively assess diaphragm and chest wall dysfunction using dynamic Magnetic Resonance Imaging (D-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), and lung area ratios, height (DH) and area (DA) of diaphragm curvature between end-inspiration and end-expiration during 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 of the diaphragm and chest wall in IPF patients and respiratory muscle dysfunction correlates with the severity of IPF.