biostudies-literatureBjarnadottir KJALF Research FundVetenskapsrådet81https://www.ebi.ac.uk/biostudies/studies/S-EPMC12334779biostudies-literatureUnknown13(1)<h4>Background</h4>Acute respiratory distress syndrome (ARDS) is characterised by significant morphological heterogeneity. Morphological sub-phenotyping can potentially be used to personalise mechanical ventilation. Current methods to classify lung injury as focal or diffuse rely on subjective image interpretation, which risks misclassification and suboptimal treatment. This study aimed to investigate the morphological appearance features of lung injury objectively. The focal index, an objective quantitative tool, was introduced to assess focality in lung injury.<h4>Methods</h4>In this single-centre retrospective study, we included lung computed tomography (CT) scans from COVID-19 ARDS patients on invasive mechanical ventilation, classified as diffuse lung injury. CT data were analysed to Intensive care medicine experimentalThe focal index: a quantitative approach to morphological sub-phenotyping of COVID-19 patients with acute respiratory distress syndrome: a pilot study.PMC12334779SG-22-0086-H-03ALF-977974ALF-977586Bjarnadottir KJCovaciu LPellegrini MKawati Rvon Seth MTovedal MPerchiazzi GLipcsey MfalseThe focal index: a quantitative approach to morphological sub-phenotyping of COVID-19 patients with acute respiratory distress syndrome: a pilot study.<h4>Background</h4>Acute respiratory distress syndrome (ARDS) is characterised by significant morphological heterogeneity. Morphological sub-phenotyping can potentially be used to personalise mechanical ventilation. Current methods to classify lung injury as focal or diffuse rely on subjective image interpretation, which risks misclassification and suboptimal treatment. This study aimed to investigate the morphological appearance features of lung injury objectively. The focal index, an objective quantitative tool, was introduced to assess focality in lung injury.<h4>Methods</h4>In this single-centre retrospective study, we included lung computed tomography (CT) scans from COVID-19 ARDS patients on invasive mechanical ventilation, classified as diffuse lung injury. CT data were analysed to 2025-01-01T00:00:00Z2025 Aug2026-04-07T18:41:10.152Z2026-04-07T16:46:32.375ZS-EPMC123347794077915210.1186/s40635-025-00794-0