Lung ultrasound elastography, microvascularization and metabolomic as non-invasive quantitative biomarkers for the aetiological diagnosis of pulmonary consolidations in children (LUSMET study)

Abstract

Background: Lung ultrasound (LUS) and invasive blood biomarkers have been evaluated to improve bacterial pneumonia (BP) diagnosis, but it is still needed to assess the efficacy of some novel biomarkers such as Lung Shear Wave Elastography (LSWE), quantification of lung microvascularization ratio pattern by Superb Microvascular Imaging (SMI) or determination of urine metabolomic profile. These biomarkers, in conjunction with LUS findings, may be useful for the approach and diagnosis of patients with BP suspicion. After validating the image and biomarkers values acquisition procedure, the study will differentiate these values from the healthy ones and from other causes of lung consolidation. The aim of this study is to define a new non-invasive quantitative diagnostic protocol combining LSWE and SMI with LUS and, at once, urinary metabolomic profile to accurately diagnose BP.Method and design: This is a cohort study for validating the use and the utility of three novel non-invasive biomarkers, including a medical device. The study recruitment period will be from September 2024 up to September 2026. It will be conducted at the Paediatric Intensive Care Unit (PICU) of a tertiary children’s hospital in Spain and is planned to be developed in four phases. First, a biomarker measurement protocol will be defined (phase 1). After that, patients under 18 years of age without pulmonary pathology admitted to the PICU will be recruited to define the normal biomarker values (phase 2). Subsequently, patients under 18 years of age with lung consolidation admitted to the PICU will be recruited in order to determine the biomarker values in pathological lung tissue (phase 3). Finally, all results will be collected to define a new diagnostic BP score based on these non-invasive imaging and analytical biomarkers (phase 4).Conclusion: Our working group foresees that the new image non-invasive biomarkers (LSWE and SMI) and the determination of urinary metabolome will be capable of diagnosing BP without the need of the current invasive diagnostic methods (analytical variables and irradiating image tests). These new tools may be particularly useful in the paediatric population and, in addition of diagnosing BP, may allow differentiating between several aetiologies of lung consolidation.