How to Find Foreign Bodies

Despite being a relatively common cause for presentation to Emergency Departments, there is often some confusion over the best imaging modality for identification and localisation of foreign bodies.

Of course some foreign bodies don't require imaging at all, but if there is uncertainty as to the presence of a foreign body or its precise location, there are a few basic rules that can help decide the initial modality of choice.

Plain Radiography

• excellent for detection of dense foreign material in the peripheries (glass, metal)
• excellent for detection of foreign bodies within the abdomen (particularly bowel/rectum)
• not useful for plant or other organic material in the peripheries
• can be difficult around the orbits and jaw

Ultrasound

• excellent for subcutaneous foreign bodies of any density
• particularly useful for wood/splinters, marine spines
• good for assessing associated tendon/ligament injuries
• can be used for removal of foreign body in real-time
• can not see through bone and has difficulty seeing through air (for example sand/gravel in messy open wounds can be hard)

Computed Tomography

• modality of choice for swallowed fishbones and orbital foreign bodies
• good for all densities of foreign body
• good for problem solving difficult cases
• good for localising small foreign bodies within joints
• probably overkill for most clinical scenarios

And now for some pretty examples...

Bullet in Brain

Ginger Ale in Rectum

Palm Frond in Shin

Shotgun Pellets to Leg

Stingray Barb to Foot

Fish Bone to Foramen Transversarium

Swallowed Matchbox Car in Descending Colon

Wood in Maxillary Sinus