Abstract
PURPOSE: The diagnosis of connective tissue disease-associated interstitial lung diseases (CTD-ILD) is connected to radiation exposure due to periodical CT scans. This study aims to investigate the alternative imaging method, Phase-Resolved Functional Lung (PREFUL), regarding its performance in low-field MRI. A comparison of PREFUL, photon-counting CT (PCCT) and pulmonary function tests (PFT) was performed to identify correlations that could restructure the diagnostics of CTD-ILD. MATERIALS AND METHODS: In this prospective single-center study, free-breathing PREFUL acquisitions of CTD-ILD patients were done after clinically indicated PCCT imaging. The severity and extent of CTD-ILD in PCCT were assessed via the Warrick score and used as a reference. Spearman's correlation coefficient ( r ) was calculated to examine the association between PREFUL, PCCT, and PFT. RESULTS: The data of 31 CTD-ILD patients (64.32±12.36 y, 10 men) were evaluated. Most correlations of PREFUL parameters with PFT were found with the Tiffeneau-Pinelli index (FEV1/FVC). The Warrick score showed excellent inter-rater agreement and correlations ( P <0.05) with the PFT parameters forced vital capacity (FVC) and the diffusing capacity of the lung for carbon monoxide corrected for hemoglobin (DLCOc) [FVC: r =-0.43, DLCOc SB: r =-0.65, DLCOc/VA: r =-0.50]. No correlation was found between PREFUL parameters and PCCT. CONCLUSIONS: The feasibility of PREFUL using low-field MRI was demonstrated in patients with CTD-ILD. Several correlations between PREFUL and PFT parameters were found, indicating that MRI can quantify lung function impairment. Nevertheless, CT remains the gold standard for CTD-ILD assessment and further research in PREFUL is needed.