Objective: Intrauterine contraceptive devices (IUDs) are reemerging as common methods of birth control in the United States. Imaging, especially sonography, has an important role in their evaluation. This review illustrates the normal and abnormal imaging appearances of IUDs.
Methods: We describe and illustrate the appearance of different types of IUDs on different imaging modalities as well as radiologically relevant complications associated with IUDs.
Results: On sonography, the IUD should be visualized as centrally located within the endometrial cavity, with the crossbar (if present) in the fundal portion of the endometrial cavity. Some older patients have IUDs in place that are no longer commonly used, such as the Lippes Loop (Ortho Pharmaceutical, Raritan, NJ) and Saf-T-Coil (Julius Schmid Laboratories, Little Falls, NJ), which have a pathognomonic appearance. Newer IUDs, such as the early version of the Mirena IUD (Leiras Oy, Turku, Finland), may be difficult to visualize on sonography. Patients from China frequently have a ring-shaped IUD. Sonography is important in assessing the complications of IUDs, including a low position, associated infection, myometrial migration, uterine perforation, intrauterine or extrauterine pregnancy associated with the IUD, and retention and fragmentation of the IUD. If an IUD is known to be present but not visualized sonographically, plain radiography is helpful in assessing the location. Computed tomography and magnetic resonance imaging are not typically used to assess IUDs, but the appearances of IUDs should be recognized with these modalities.
Conclusions: Imaging, specifically sonography, has a crucial role in the evaluation and management of IUDs and associated complications.