Table 1.

Guidelines for imaging of foreign bodies ingested/inhaled23

Class	Clinical problem	Investigation	Recommendation	Comment
K 28	Soft tissue injury: FB (metal, glass, painted wood)	XR	Indicated	All glass is radio-opaque; some paint is radio-opaque. Radiography and interpretation may be difficult; remove blood-stained dressings first. Consider US, especially in areas where radiography difficult.
K 29	Soft tissue injury: FB (plastic, wood)	XR	Not indicated routinely	Plastic is not radio-opaque: wood is rarely radio-opaque. Soft-tissue US may show non-opaque FB.
		US	Indicated
K 30	Swallowed FB suspected in pharyngeal or upper esophageal region (for children see Section M-23)	XR soft tissues of neck	Indicated	After direct examination of oropharynx (where most FBs lodge), and if FB likely to be opaque. Differentiation from calcified cartilage can be difficult. Most fish bones invisible on XR. Maintain a low threshold for laryngoscopy or endoscopy, especially if pain persists after 24 hours (see K33).
		AXR	Not indicated routinely
K 31	Swallowed FB: smooth and small (eg, coin)	CXR	Indicated	The minority of swallowed FBs will be radio-opaque. In children a single, slightly over-exposed, frontal CXR to include neck should suffice. In adults, a lateral CXR may be needed in addition if frontal CXR negative. Majority of FBs that impact, do so at crico-pharyngeus. If the FB has not passed (say within 6 days), AXR may be useful for localization.
		AXR	Not indicated routinely
K 32	Sharp or potentially poisonous swallowed FB: (eg, battery)	AXR	Indicated	Most swallowed foreign bodies that pass the esophagus eventually pass through the remainder of the gastrointestinal tract without complication. But location of batteries is important as leakage can be dangerous. Unless AXR negative.
		CXR	Not indicated routinely
K 33	Swallowed FB: large object (eg, dentures)	CXR	Indicated	Dentures vary in radio-opacity; most plastic dentures are radiolucent. AXR may be needed if CXR negative, as may barium swallow or endoscopy. Lateral CXR may be helpful.
M 23	Inhaled FB (suspected) in children	CXR	Indicated	History of inhalation often not clear. Bronchoscopy is indicated, even in the presence of a normal CXR. NM/CT may be helpful to show subtle air trapping. Wide variation in local policy about expiratory films, fluoroscopy, CT and NM (ventilation scintigraphy).

Abbreviations: FB, Foreign body; XR, Plain radiography one or more films; CXR, Chest radiograph; AXR, Abdominal radiograph; US, Ultrasound; CT, Computed tomography; NM, Nuclear medicine.