Foreign bodies

  • Created by: Emmatjies
  • Created on: 15-01-20 17:23


Soft tissues- Nothing bony

Foreign bodies- A mass or particle of material that is not normal to the place where it is found.

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Principles of Foreign body imaging

  • Get a good pt history
  • Ensure Image receptor is clean and artefact free
  • Use radiopaque marker to show entry wound on resultant images
  • Take a flexible approach.
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Conventional Radiography/ Fluoroscopy

Limited use for imaging soft tissue

Reduce kVp for penetrating foreign body/ies in throat.

Cassette and IR must be clean

Utilise image manipulation as much as possible

Fluoroscopy is 65% sensitive and is usefuk to guide the removal, glass and metal, Not good for wood or plastic.

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Computerised Tomography

Very sensitive for soft tissue imaging.

Image manipulation and windowing are excellent

Good visualisation of FB in the orbit

Very high dose

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Excellent for soft tissue

Useful to isolate foreign bodies not seen on isolation

Contact is required. Wounds can be a problem

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Magnetic Resonance imaging

Excellent for soft tissue imaging

Very disease sensitive

More scan planes to aid detection

Never for metallic foreign bodies


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Classification of foreign bodies


  • Glass
  • Metal
  • Wood
  • Plastic

Accidental ingestion/ Deliberate ingestion- double condom sign, button vs battery

Inhalation/aspiration- 3 year olds most at risk

FB in the eye

FB post-surgery

FB inserted into various body cavities.

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Coin vs Button battery- 3 year olds are most at risk of ingestion. Button batteries are v dangerous. They can be differentiated by looking for a double rim sign.

Drug conveyance-

Double condom sign -  A lucent rim of air trapped between multiple layers of latex, which may be less evident with well machine wrapped packages.

Tic Tac Sign- Multiple oblong uniformly shaped packages

Rosette sign - Air trapped in the knot where the condom is tied

Radiographic density of packages- The density of the ingested packet is variable and is determined by the type of wrapping material used, ranging from densely radio-opaque aluminium to radiolucent wax and the contents of the packet.

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