Nonpalpable ultrasonographically not detectable Implanon rods can be localized by magnetic resonance imaging

Recently, the contraceptive implant Implanon has been introduced in several European countries. In comparison to the six-capsule preparation Norplant, the removal of this single-rod system should be associated with less compl ications. However, the removal of nonpalpable Implanon rods can be difficul t because the implant is not always visible with ultrasound. The aim of thi s study was to find a radiologic method for the localization of Implanon im plants that are nonpalpable and can not be detected by ultrasound. X-ray, u ltrasound, computed tomography, and magnetic resonance imaging (MRI) were i nvestigated as methods to localize Implanon in a pig chest preparation and in a woman with a nonpalpable implant. The implant in the woman could be lo calized unequivocally only by MRI. We conclude that MRI is the best method for the unequivocal localization of nonpalpable, ultrasonographically not d etectable Implanon rods. To avoid unnecessary scar tissue formation, it may be appropriate to defer surgery for the removal until definitive localizat ion. (C) 2001 Elsevier Science Inc. All rights reserved.