Palla sign (1983) right descending pulmonary artery enlargement and ‘sausage-shaped’ appearance as a potential sign of pulmonary embolism on chest XR
Palla sign 1983 Fig 2
- A: Chest radiograph of embolic patient with ı sausage ı appearance of right descending pulmonary artery.
- B: Right descending pulmonary artery is very enlarged and dense with clear-cut borders (white arrows). Lowest white arrow points to abrupt ending of vessel: branches for middle and lower lobes appear distorted and lumped (black arrows).
1983 – Review 374 consecutive CXR of patients admitted to ICU with suspicion/confirmed diagnosis of pulmonary embolus. Measured the diameters of descending pulmonary arteries at the superior venous angle and 1cm distal with significant diminution in size compared to recovery CXR
From the practical point of view, the enlargement of descending pulmonary artery may be useful to raise the suspicion of pulmonary embolism. As documented here, the descending pulmonary artery was wider in patients with confirmed pulmonary embolism than in those without confirmation.The typical ‘ ‘sausage’ ‘ appearance of the descending pulmonary artery, easily recognizable without any measurement,was present in about one-fourth of the patients with confirmed pulmonary embolism and it was never observed in patients in whom the original clinical suspicion of pulmonary embolism was rejected subsequently.Palla 1983
Palla sign 1983 Fig 5
- A: CXR of patient with PE with ‘sausage’ appearance of right descending pulmonary artery (solid arrows). Lowest solid arrow points to cut-off ending; branches for middle and lower lobes are hardly visible (open arrows).
- B: 30 days later. Right descending pulmonary artery appears smaller and less dense than in previous film, with cylindrical appearance (solid arrows). Branches for middle and lower lobes appear more regular and clearly visible (open arrows).
- Nils Westermark (1892 – 1980) [Westermark sign 1938]
- Aubrey Otis Hampton (1900 – 1955) [Hampton hump 1940]
- Felix George Fleischner (1893 – 1969) [Fleischner sign 1959]
- C. H. Joseph Chang (1929 – 2017) [Chang sign 1965]
- Antonio Palla (1950 – ) [Palla sign 1983]
- Chang sign
- Palla’s sign
- Used the baseline measurements from Chang’s 1962 review without reference to Chang’s 1965 review and assertion regarding right descending pulmonary artery dilatation as a sign of pulmonary infarction secondary to pulmonary embolus [Chang sign]
- Chang CH, Davis WC. A Roentgen sign of Pulmonary Infarction. Clin Radiol. 1965 Apr;16:141-7. [PMID 14272525]
- Palla A, Donnamaria V, Petruzzelli S, Rossi G, Riccetti G, Giuntini C. Enlargement of the right descending pulmonary artery in pulmonary embolism. AJR Am J Roentgenol. 1983 Sep;141(3):513-7. [PMID 6603760]