Diagnostic Ultrasound - Abdomen and Pelvis

Intrauterine Device
TERMINOLOGY
Abbreviations
• Intrauterine device (IUD)
• Levonorgestrel-releasing intrauterine system (LNG-IUS)
Definitions
• IUD
○ Device inserted into endometrial cavity to prevent
pregnancy
○ T-shaped polyethylene frame with polyethylene
monofilament string
○ 2 types of IUDs in United States
– Copper-containing (Paragard, Ortho-McNeil
Pharmaceutical, Inc., Raritan, NJ)
□ Copper wire wrapped around stem
– Levonorgestrel-releasing (Mirena, Shering, AG
Pharmaceutical, Germany)
□ Levonorgestrel-containing collar around stem
○ Other IUDs
– Plastic IUDs and Lippes loop IUD (older)
– Round IUD of stainless steel ring in fundus with
straight shaft in lower endometrium (commonly used
in China)
○ Mechanism of action: Primarily prevents fertilization
– Also has spermicidal effects and implantation
inhibiting effects
– Partially inhibit ovulation (Mirena only)
– Copper devices ↑ copper levels → change in cervical
mucus, affecting sperm motility and irritating
endometrium
IMAGING
General Features
• US
○ Longitudinal image
– IUD stem is straight and aligned with endometrial
cavity
– ≤ 3 mm between top of IUD and fundal endometrium
– Copper IUD is echogenic and easily seen as linear
bright echo
– Levonorgestrel-containing IUD is harder to see, often
seen as shadowing between echogenic proximal and
distal ends
○ Transverse image
– IUD arms/cross bars extend laterally at fundus
towards cornua
○ String may be seen as linear bright echo or reverberation
in cervix
• Radiography
○ Radiopaque: Image from diaphragm to pelvis
○ Differentiates expulsion from perforation when IUD is
not seen in uterus on US
○ Perforation
– IUD above pelvic brim, far lateral, or anterior/posterior
– 90° or 180° rotation of IUD is less specific
• CT: May be helpful in select cases to evaluate for
complications related to perforation and intraabdominal
IUD
• MR: IUD can be seen as signal void but should not be used
primarily to evaluate position
Imaging Recommendations
• Best imaging tool
○ Transvaginal ultrasound for IUD position
○ KUB for IUD expulsion/perforation
• Protocol advice
○ Ultrasound for IUD
– If IUD is difficult to visualize sonographically, look for
shadowing
– Posterior shadowing best visualized when scanning
perpendicular to long axis of IUD
– 3D sonography helpful for diagnosis of embedment
and displacement
– 3D is helpful for reconstructing true coronal imaging
of uterus
CLINICAL ISSUES
Presentation
• IUD
○ Pain and abnormal bleeding is common within 1st few
months of placement
○ Indications for imaging
– String not visualized on exam
– Prolonged pain/dyspareunia
□ Malpositioned or perforated
– Irregular menses/dysmenorrhea
– Infection
• IUD complications
○ Displacement (25%)
– Low IUDs may spontaneously migrate into more
appropriate position
○ Uterine expulsion (10%)
– Confirm expulsion with KUB
○ Embedment (18%)
– IUD penetrates endometrium into myometrium
without extension through uterine serosa
○ Complete perforation (0.1%)
– IUD penetrates through uterine serosa and is partially
or completely in peritoneal cavity
Demographics
• Epidemiology
○ IUDs are most common method of reversible
contraception worldwide
– Used by 23%
○ Less common in US
– Used by 7.7%
○ Synchronous pregnancy
– 2/100 women per year of IUD use
SELECTED REFERENCES
1. Boortz HE et al: Migration of intrauterine devices: radiologic findings and
implications for patient care. Radiographics. 32(2):335-52, 2012
2. Benacerraf BR et al: Three-dimensional ultrasound detection of abnormally
located intrauterine contraceptive devices which are a source of pelvic pain
and abnormal bleeding. Ultrasound Obstet Gynecol. 34(1):110-5, 2009
Diagnoses: Female Pelvis
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