E1412. Expecting the Unexpected: A Review of Various Subtypes of Ectopic Pregnancy in an Emergency Setting
  1. Chinky Patel; University of Tennessee
  2. Asif Jamal; University of Tennessee
  3. Andrew Mitchell; University of Tennessee
  4. Bhumin Patel; University of Tennessee
  5. Jenson Ma; University of Tennessee
  6. Muhammad Afzal; University of Tennessee
  7. Ashley Cahoon; University of Tennessee
Ectopic pregnancy is defined as the implantation of a fertilized ovum outside the uterine endometrial cavity. It comprises 2% of all reported pregnancies and accounts for 9% of all pregnancy-related deaths. Classic symptoms are abdominal or pelvic pain, vaginal bleeding, and a tender adnexal mass. It is mostly diagnosed with a combination of serum beta-human chorionic gonadotropin (ß-HCG) assay and pelvic ultrasound findings. The most common complication is rupture, which occurs in 15 - 20% of cases and can result in life-threatening hemorrhage. Advanced abdominal pregnancy carries a risk of hemorrhage, disseminated intravascular coagulation, bowel obstruction, and fistulae to the gastrointestinal and/or genitourinary tracts. This exhibit will review the various subtypes of ectopic pregnancy encountered in an emergency setting. Familiarity with features of various types of ectopic pregnancy is important for early diagnosis and treatment.

Educational Goals / Teaching Points
Ultrasound is the imaging modality of choice in an ectopic pregnancy, with cross-sectional imaging utilized in indeterminate cases. MRI is more suited for diagnosis due to its superior spatial resolution; however, CT is often the more readily available cross-sectional modality in the emergency setting. The goal is to be aware of the imaging patterns on all of these modalities in different subtypes of ectopic pregnancy such as tubal, cervical, ovarian, cesarean scar, secondary abdominal, and heterotopic pregnancy.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
There are various imaging features that are characteristic of ectopic pregnancy on ultrasound. The most specific finding is the presence of an extrauterine gestational sac, which is seen as a cystic saclike structure surrounded by a thick wall with peripheral ring-like vascularity. However, findings may often be indeterminate even in advanced ectopic pregnancy due to the inherently limited resolution and poor field of view with ultrasound. In such cases, cross-sectional imaging aids diagnosis. MRI features of tubal pregnancy include a heterogenous adnexal mass with tubal dilatation, hematosalpinx, and hemoperitoneum. CT findings of ectopic pregnancy are not as well recognized; however, CT may be performed in cases of abdominal or pelvic pain in patients with unknown pregnancy status. Findings include a pelvic or adnexal heterogeneous mass with or without hemoperitoneum.

In a woman of reproductive age, a history of pelvic pain and rising b-hCG titers should raise suspicion of ectopic pregnancy. Although CT and MRI are not commonly utilized in such cases, there are certain features that aid diagnosis when ultrasound features are indeterminate. It is important to be aware of the imaging findings in tubal pregnancies, which account for up to 95% of cases, and also rarer subtypes, which comprise 5% of cases and are often more challenging to diagnose. Early diagnosis and initiation of appropriate treatment are critical for preventing complications and avoiding the need for surgical management, which leads to overall decreased maternal morbidity and mortality.