Diamagnetic susceptibility artifact associated with graphite foreign body of the orbit.

Imaging in traumatic injury to the orbits plays an important role to identify malformation of the globe, retrobulbar pathology, such as hematoma, the presence of fractures, and identification of foreign bodies. MRI can be especially useful in characterizing soft tissue abnormalities without the use of ionizing radiation. The authors report a case of penetrating injury to the orbit with a retained foreign body where the graphite core of a pencil ("pencil lead") resulted in metal-like diamagnetic susceptibility artifact. This was proven to have no metallic components by CT and surgical exploration. MRI performed in the setting of penetrating injury could aid in localization of a graphite foreign body, and if there is a known graphite foreign body, evaluation of immediately adjacent structures may be obscured.