ThOracic Ultrasound in Idiopathic Pulmonary Fibrosis Evolution (TOUPIE): research protocol of a multicentric prospective study.

Introduction Idiopathic pulmonary fibrosis (IPF) is the most common and severe interstitial lung disease (ILD). It is a progressive disease that requires a regular follow-up: clinical examination, pulmonary function testing (PFT) and CT scan, which is performed yearly in France. These exams have two major disadvantages: patients with severe dyspnoea have difficulties to perform PFT and repeated CT scans expose to high dose of radiations. Considering these limits, it would be relevant to develop new tools to monitor the progression of IPF lesions. Three main signs have been described in ILD with lung ultrasound (LUS): the number of B lines, the irregularity and the thickening of the pleural line. Cross-sectional studies already correlated the intensity of these signs with the severity of fibrosis lesions on CT scan in patients with IPF, but no prospective study described the evolution of the three main LUS signs, nor the correlation between clinical evaluation, PFT and CT scan. Our hypothesis is that LUS is a relevant tool to highlight the evolution of pulmonary lesions in IPF. The main objective of our study is to show an increase in one or more of the three main LUS signs (total number of B lines, pleural line irregularity score and pleural line thickness) during the follow-up. Methods ThOracic Ultrasound in Idiopathic Pulmonary Fibrosis Evolution is a French prospective, multicentric and non-interventional study. Every 3 months, patients with IPF will have a clinical examination, PFT and LUS. CT data will be collected if the CT scan is performed within 3 months before the inclusion; the second CT scan will be performed from 9 to 12 months after the inclusion. The presence, location and severity of LUS signs will be recorded for each patient, and their correlation with clinical, functional and CT scan evolution will be evaluated. 30 patients will be enrolled. Ethics and dissemination The protocol was approved by the French Research Ethics Committee (Comite de Protection des Personnes SUD OUEST ET OUTRE MER II, reference RIPH3-RNI19-TOUPIE) on 11 April 2019. Results will be disseminated via peer-reviewed publication and presentation at international conferences. Trial registration number NCT03944928;Pre-results.