Magnetic resonance imaging characteristics of a lead pencil foreign body in the hand.

Foreign body detection and removal from the hand can present a challenging problem for the hand surgeon. Imaging studies often are of little help and may even be misleading regarding the size and location of the object. This article reports imaging techniques used in the detection of foreign bodies and presents a case in which magnetic resonance imaging was used to localize a lead-pencil foreign body in the hand prior to surgical removal. We also present the results of magnetic resonance imaging analysis of several lead pencils, showing a similar signal that indicates that iron and magnesium were responsible for the artifact seen on the magnetic resonance image.