Background: Congenital high airway obstruction syndrome (CHAOS) is a rare life-threatening condition characterised by complete or near-complete developmental obstruction of the foetal airway. Although antenatal imaging findings have been described, the postmortem MRI findings have not been reported.
Objective: To present postmortem MRI features of CHAOS.
Materials and methods: We retrospectively reviewed our hospital pathology and imaging databases for cases of CHAOS over a 2-year period.
Results: We identified two cases of CHAOS. In both cases, postmortem plain radiographs demonstrated gross abdominal distension with distortion and splaying of the rib cage. Both foetuses had characteristic postmortem MRI findings including large-volume fluid-filled lungs on T2-weighted imaging, diaphragmatic eversion, fluid-filled airway dilatation below the level of obstruction, centrally positioned and compressed heart, and massive ascites. One foetus had an associated limb abnormality.
Conclusion: Postmortem MRI in foetuses suspected of having CHAOS allows confirmation of the diagnosis, determination of the anatomical level of the atresia or stenosis, and identification of associated abnormalities without the need for invasive autopsy.