Imaging the acute respiratory distress syndrome: past, present and future

Abstract

In patients with the acute respiratory distress syndrome (ARDS), lung imaging is a fundamental tool in the study of the morphological and mechanistic features of the lungs. Chest computed tomography studies led to major advances in the understanding of ARDS physiology. They allowed the in vivo study of the syndrome’s lung features in relation with its impact on respiratory physiology and physiology, but also explored the lungs’ response to mechanical ventilation, be it alveolar recruitment or ventilator-induced lung injuries. Coupled with positron emission tomography, morphological findings were put in relation with ventilation, perfusion or acute lung inflammation. Lung imaging has always been central in the care of patients with ARDS, with modern point-of-care tools such as electrical impedance tomography or lung ultrasounds guiding clinical reasoning beyond macro-respiratory mechanics. Finally, artificial intelligence and machine learning now assist imaging post-processing software, which allows real-time analysis of quantitative parameters that describe the syndrome’s complexity. This narrative review aims to draw a didactic and comprehensive picture of how modern imaging techniques improved our understanding of the syndrome, and have the potential to help the clinician guide ventilatory treatment and refine patient prognostication.

Advanced Point-of-care Bedside Monitoring for Acute Respiratory Failure

“…during mechanical ventilation, 97 even if the loss of lung sliding in the nondependent lung zone may be suggestive of hyperinflation, especially if pleural line movements reappear after PEEP reduction. 98 An integrated approach involving other advanced respiratory monitoring technologies, i.e., electrical impedance tomography, could overcome ultrasound limits.…”

Differences in clinical characteristics and quantitative lung CT features between vaccinated and not vaccinated hospitalized COVID-19 patients in Italy

“…Alternatively, the quantitative analysis previously applied in patients with acute respiratory failure, although time consuming and requiring a dedicated software, is considered the best standard lung imaging technique [ 27 , 42 ]. This analysis is able to accurately assess the lung gas volume, lung weight and the different lung regions (from not aerated to hyperinflated), which are associated with the severity of lung impairment, degree of hypoxemia and hospital outcome [ 27 – 29 ]. To date, there is no study which has evaluated the possible difference in the lung characteristics and impairments in spontaneous breathing fully vaccinated and not vaccinated patients.…”

“…In addition, through quantitative lung CT analysis it is possible to accurately compute lung weight, gas volume, and the amount of aerated and non-aerated lung tissue, which have been previously associated with outcome in patients with non-COVID-19 ARDS [ 27 , 28 ]. Few studies applied quantitative lung CT analysis in mechanically ventilated COVID-19 patients [ 29 , 30 ] and it is unclear whether vaccination affects the clinical and radiological severity of hospitalized COVID-19 patients and their survival.…”

Use of radiolabeled hyaluronic acid for preclinical assessment of inflammatory injury and acute respiratory distress syndrome

“…ARDS is characterized by increased vascular permeability, pulmonary edema, severe arterial hypoxemia, and impaired carbon dioxide excretion. Lung imaging is a fundamental tool for assessing the morphological and mechanistic features of ARDS and plays a crucial role in diagnosing and managing ARDS [1] , [2] , [3] , [9] . In recent years, inflammation and molecular imaging have provided new insights into ARDS pathophysiology and may lead to new approaches to managing ARDS patients [9] , [10] .…”