Pneumomediastinum CT

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Trusha Tank, M.D.[2]

Overview

The diagnosis can be confirmed via chest X-ray showing a radiolucent outline around the heart and mediastinum or via CT scanning of the thorax.

The following findings are associated with pneumomediastinum on CT-scan of the chest:^[1]^[2]^[3]^[4]^[5]^[6]^[7]

Subcutaneous emphysema
Naclerio V sign
- Seen in pneumomediastinum occurring often secondary to an oesophageal rupture but it is not entirely specific to that condition.
Pneumopericardium
- Gas anterior to pericardium
Ring around artery sign
- Gas around pulmonary artery and main branches
Tubular artery sign
- Gas outlining major aortic branches
Double bronchial wall sign
- Gas outlining bronchial wall
Continuous diaphragm sign
- Gas trapped posterior to pericardium
Extrapleural sign
- Gas between parietal pleura and diaphragm
Gas in pulmonary ligament

Pediatric pneumomediastinum has different appearances:

Thymic wing sign
- Elevated thymus
Haystack sign (the heart appears like a haystack in a Monet painting)
- Gas crossing the superior mediastinum

Images shown below are courtesy of RadsWiki.

↑ Taveras, J., & Ferrucci, J. (1986). Radiology. Diagnosis/imaging/intervention. 5 volumes. Annual revision service. R. Health Professions,Philadelphia, PA.
↑ Sandler, Carl M.; Llbshltz, Herman I.; Marks, Gerald; Libshitz, Herman I. (1975). “Pneumoperitoneum, Pneumomediastinum and Pneumopericardium Following Dental Extraction”. Radiology. 115 (3): 539–540. doi:10.1148/15.3.539. ISSN 0033-8419.
↑ Kim, Hye Rin; Yoo, Seung Min; Lee, Hwa Yeon; Han, Jin Hee; Frazier, Aletta A; White, Charles S (2016). “Presence of subpleural pulmonary interstitial emphysema as an indication of single or multiple alveolar ruptures on CT in patients with spontaneous pneumomediastinum”. Acta Radiologica. 57 (12): 1483–1489. doi:10.1177/0284185116629830. ISSN 0284-1851.
↑ Moseley, John E. (1960). “Loculated Pneumomediastinum in the Newborn”. Radiology. 75 (5): 788–790. doi:10.1148/75.5.788. ISSN 0033-8419.
↑ Hammond DI (March 1984). “The “ring-around-the-artery” sign in pneumomediastinum”. J Can Assoc Radiol. 35 (1): 88–9. PMID 6725378.
↑ Levin, Bertram (1973). “The continuous diaphragm sign”. Clinical Radiology. 24 (3): 337–338. doi:10.1016/S0009-9260(73)80050-9. ISSN 0009-9260.
↑ Lillard, Richard L.; Allen, Parker (1965). “The Extrapleural Air Sign in Pneumomediastinum”. Radiology. 85 (6): 1093–1098. doi:10.1148/85.6.1093. ISSN 0033-8419.