Knuckle sign (pulmonary embolism)
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At the time the article was created Pradosh Kumar Sarangi had no recorded disclosures.View Pradosh Kumar Sarangi's current disclosures
At the time the article was last revised Mostafa El-Feky had no recorded disclosures.View Mostafa El-Feky's current disclosures
The knuckle sign refers to the abrupt tapering or cutoff of a pulmonary artery secondary to a pulmonary embolus (PE). It is better visualized on CT pulmonary angiography (CTPA) than chest x-ray. This is an important ancillary finding in pulmonary embolism, and often associated with the Fleischner sign of dilated central pulmonary arteries.
It is one of several described signs of pulmonary embolus on chest radiographs.
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