Chang sign
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Chang sign is a radiologic sign for detecting pulmonary embolism in X-ray films. It refers to the dilatation and abrupt change in calibre of a previously normal descending pulmonary artery on a chest X-ray film.[1] Chang sign usually appears within 24 hours of the onset of chest pain due to pulmonary embolism,[2] and the maximal dilatation of the descending pulmonary artery often occurs in two to three days after the onset of pain.[3]
Chang sign is absent in case of co-existing pneumonia or other conditions causing central opacities, where the descending pulmonary artery cannot be visualised in the X-ray image.[3]
References[edit]
- ^ Mossbock, R (December 1980). "[Experience with corrective operations for dysgnathia in cleft lip, palate and jaw]". Osterreichische Zeitschrift fur Stomatologie. 77 (12): 466–9. PMID 6938914.
- ^ Saliba, Thomas; Tack, Denis (15 February 2023). "Central Pulmonary Embolism Detected on a Chest X-Ray: A Case Report". Journal of the Belgian Society of Radiology. 107 (1): 11. doi:10.5334/jbsr.3052. PMC 9936914.
- ^ a b (Joseph) Change, C.H.; Davis, W. Clayton (January 1965). "A roentgen sign of pulmonary infarction". Clinical Radiology. 16 (2): 141–147. doi:10.1016/S0009-9260(65)80007-1.