Current evidence for lung ultrasound elastography in the field of pneumology: a systematic review.

Background and objectives: Elastography is a technology that has strongly impacted several medical specialties; however, it is not yet applied as part of standard clinical practice in the field of pulmonology. The objective of this systematic review is to analyse the evidence available to date in relation to pleuropulmonary ultrasound elastography, focusing on the three pathologies with the most publications: subpleural consolidations, interstitial lung diseases and pleural effusion. Methods: Original in vivo studies published up until 12 August 2023 in the Embase, MEDLINE or Web of Science databases were included. The QUADAS-2 tool was applied to analyse bias. Results: We found 613 records in database search. After duplicates removal, we screened 246 records and finally included 18 papers. The average cohort sample size was 109 patients. The elastography modes most frequently used were strain (22.2%), transient elastography (22.2%), point shear-wave elastography (38.9%) and two-dimensional shear-wave elastography (22.2%). The possibility of a meta-analysis was ruled out because of the heterogeneity of the studies included. Discussion: The currently available literature indicates that pleuropulmonary ultrasound elastography produces promising and consistent results, although the lack of standardisation in the use of the technique and in the elastography modes employed still impedes its use in daily clinical pneumology practice. The development of a clinical guideline establishing a common nomenclature and standardised techniques for pleuropulmonary elastography will be imperative to generate quality scientific evidence in this field.

Multicentre study on the accuracy of lung ultrasound in the diagnosis and monitoring of respiratory sequelae in the medium and long term in patients with COVID-19.

Introduction: Lung ultrasound (LUS) has proven to be a more sensitive tool than radiography (X-ray) to detect alveolar-interstitial involvement in COVID-19 pneumonia. However, its usefulness in the detection of possible pulmonary alterations after overcoming the acute phase of COVID-19 is unknown. In this study we proposed studying the utility of LUS in the medium- and long-term follow-up of a cohort of patients hospitalized with COVID-19 pneumonia. Materials and methods: This was a prospective, multicentre study that included patients, aged over 18 years, at 3 ± 1 and 12 ± 1 months after discharge after treatment for COVID-19 pneumonia. Demographic variables, the disease severity, and analytical, radiographic, and functional clinical details were collected. LUS was performed at each visit and 14 areas were evaluated and classified with a scoring system whose global sum was referred to as the "lung score." Two-dimensional shear wave elastography (2D-SWE) was performed in 2 anterior areas and in 2 posterior areas in a subgroup of patients. The results were compared with high-resolution computed tomography (CT) images reported by an expert radiologist. Results: A total of 233 patients were included, of whom 76 (32.6%) required Intensive Care Unit (ICU) admission; 58 (24.9%) of them were intubated and non-invasive respiratory support was also necessary in 58 cases (24.9%). Compared with the results from CT images, when performed in the medium term, LUS showed a sensitivity (S) of 89.7%, specificity (E) 50%, and an area under the curve (AUC) of 78.8%, while the diagnostic usefulness of X-ray showed an S of 78% and E of 47%. Most of the patients improved in the long-term evaluation, with LUS showing an efficacy with an S of 76% and E of 74%, while the X-ray presented an S of 71% and E of 50%. 2D-SWE data were available in 108 (61.7%) patients, in whom we found a non-significant tendency toward the presentation of a higher shear wave velocity among those who developed interstitial alterations, with a median kPa of 22.76 ± 15.49) versus 19.45 ± 11.39; p = 0.1). Conclusion: Lung ultrasound could be implemented as a first-line procedure in the evaluation of interstitial lung sequelae after COVID-19 pneumonia.