Beaded septum sign

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Beaded septum sign is a finding on chest CT scans. It shows irregular, nodular thickening of the interlobular septa—the walls between the tiny air sacs of the lungs—giving a beaded or string-of-pearls look. This sign is most often linked to pulmonary lymphangitic carcinomatosis, but it can also be seen in other diseases that affect the lung lymphatics, whether cancerous or not.