Use of ultrasound to diagnose and monitor interstitial lung disease in rheumatic diseases

Interstitial lung disease (ILD) is one of the most relevant extra-articular manifestations of rheumatic diseases resulting in a substantial increase in morbidity and mortality. Early diagnosis and close monitoring to identify patients at high risk of progression are crucial to establish the need for targeted treatment with immunomodulatory and antifibrotic drugs, with potential ability to change the course of the disease. However, there are unmet needs in this field as pulmonary auscultation, chest radiography, or pulmonary function studies do not allow identification of the most incipient stages of the disease. High-resolution computed tomography (HRCT), which is the current gold standard for diagnosis and evolutionary control, is problematic owing to ionizing radiation, cost, and accessibility. In this context, lung ultrasound (LUS) is an attractive tool in a growing research and validation process. The identification of vertical artifacts, such as B lines, and alterations of the pleural line present a good correlation with the presence of ILD by HRCT and have a good concordance with the extent and severity of the disease, with sensitivity and negative predictive values of up to 100%. Regarding the monitoring of the evolution, the validation process of LUS is in a more preliminary phase but data is encouraging. All this, together with its safety, accessibility, low cost, and good patient acceptance, postulate LUS as a useful tool for the screening of ILD and for the optimization of the indications of HRCT.