Table 6.

Correlation between foreign bodies’ depths and their visibility scores

Foreign body	Relationship between depth and visibility in US		Relationship between depth and visibility in CT
	r*	P	r	P
Wood	-0.926	< 0.001	N/A†	N/A†
Glass	-0.909	< 0.001	N/A†	N/A†
Metal	-0.894	< 0.001	N/A†	N/A†
Plastic	-0.930	< 0.001	N/A†	N/A†
Stone	-0.791	0.006	N/A†	N/A†

*: Spearman’s correlation coefficient,

^†: foreign body’s visibility remained fixed at all depths on CT examinations; therefore, no correlation coefficient could be computed.

US: ultrasonography