Plain film imaging of Baerveldt glaucoma drainage implants.

A glaucoma drainage implant was detected on plain skull radiographs before MR imaging examination of the brain. The patient was denied the MR imaging for fear of dislodging the "metallic foreign body." The Baerveldt glaucoma drainage implant was mistakenly identified as an orbital metallic object based on its radiographic characteristics. Because none of the current glaucoma drainage implants contain ferromagnetic material, patients with these devices can undergo MR imaging without special precaution.