What are the imaging features of intrauterine devices (IUDs)?
Multiple imaging modalities are used to visualize IUDs including radiography, hysterosalpingography, US, CT, and MRI. The most commonly used IUDs are copper, hormonal, and intratubal devices. A copper IUD is seen on US as a hyperechoic T-shaped device in the uterine cavity and a radiopaque T-shaped device on radiography and CT ( Figure 38-15, A ). A hormonal IUD such as the Mirena is less echogenic and therefore may be difficult to visualize on US. Instead, US can be used to demonstrate the echogenic string attached to a hormonal IUD. On radiography and CT, a hormonal IUD is seen as a radiopaque T-shaped device. An intratubal device such as the Essure (Bayer Healthcare) contains a stainless steel inner coil that appears echogenic on US. If correctly positioned, two curvilinear echogenic structures can be identified on US between the proximal fallopian tube and the border between the myometrium and endometrium. On radiography and CT, Essure devices are identified as radiopaque curvilinear structures ( Figure 38-15, B ). If a patient with an IUD presents with pelvic pain, migration of the IUD should be suspected