Metal foreign body
Citation, DOI, disclosures and article data
At the time the article was created Henry Knipe had no recorded disclosures.View Henry Knipe's current disclosures
At the time the article was last revised Henry Knipe had no recorded disclosures.View Henry Knipe's current disclosures
Metal foreign bodies may be present if they are ingested, inserted, or as a result of an injury.
Nearly all metals are radiopaque and can be seen on plain radiographs and CT with the exception of aluminum, which may not be seen on plain radiographs 1,2.
Metal foreign bodies are hyperechoic with posterior acoustic shadowing +/- reverberation artifact 1.
Almost all metals are very high density 1:
- aluminum: 700-800 HU
- iron: ~3000 HU
- lead: 30,000 HU
As a result, metals except aluminum have associated beam hardening and streak artifacts 1.
Metal foreign bodies are typically low signal with most metals generating susceptibility artifact (gold and austenitic stainless steel do not). On GRE sequences blooming artifact can be present 1,2.
Treatment and prognosis
Metal foreign bodies can be treated conservatively, as they readily form foreign body granulomas and become essentially inert 2.
- 1. Bruno C. Carneiro, Isabela A. N. Cruz, Renan N. Chemin, Thiago A. Rizzetto, Júlio B. Guimarães, Flávio D. Silva, Ciro Yoshida Junior, Daniel Pastore, Alípio G. Ormond Filho, Marcelo A. C. Nico. Multimodality Imaging of Foreign Bodies: New Insights into Old Challenges. (2020) RadioGraphics. doi:10.1148/rg.2020200061
- 2. Mohamed Jarraya, Daichi Hayashi, Richard V. de Villiers, Frank W. Roemer, Akira M. Murakami, Alda Cossi, Ali Guermazi. Multimodality Imaging of Foreign Bodies of the Musculoskeletal System. (2014) American Journal of Roentgenology. doi:10.2214/AJR.13.11743