Diagnostic Ultrasound - Abdomen and Pelvis

Tubal Ectopic Pregnancy
Diagnoses: Female Pelvis
TERMINOLOGY
• Synonyms: Ectopic pregnancy (EP); tubal pregnancy
IMAGING
• Adnexal findings seen in majority of cases
○ Commonly heterogeneous adnexal mass
○ Tubal ring sign: Less common but more specific,
especially if clearly distinct from ovary
• May see pseudosac in uterus (only 10-20% of cases)
○ Intrauterine fluid collection more likely represents
intrauterine pregnancy (IUP)
• Pregnancy not definitively identified in 5-10% of cases
TOP DIFFERENTIAL DIAGNOSES
• Exophytic corpus luteum of pregnancy
• Incidental adnexal mass
• Bowel
• Intrauterine pregnancy
KEY FACTS
CLINICAL ISSUES
• Must correlate US findings with human chorionic
gonadotropin (hCG) levels
○ hCG > 3,000 mIU/mL and no IUP
– EP vs. failing IUP vs. early multiple gestation
○ Lower hCG level and no IUP
– EP vs. early or failing IUP
○ Single hCG measurement in unreliable in distinguishing
IUP (nonviable or viable) from EP
○ Follow serial hCG levels in indeterminate cases, with
repeat US if rising
DIAGNOSTIC CHECKLIST
• Confirm extraovarian origin of adnexal ring-like mass
• Reserve treatment for visualized abnormality
• Be cautious in considering nonspecific intrauterine
collection to be pseudosac of EP
• Consider favoring more likely diagnosis of IUP in medically
stable patient and follow with US
(Left) Sagittal transvaginal
ultrasound shows an empty
uterus and an echogenic
ring-like mass adjacent to
the ovary with a hemorrhagic
corpus luteum ſt. Note the
small amount of echogenic
fluid in the pelvis st. (Right)
Transverse transvaginal color
Doppler ultrasound shows an
echogenic round mass
adjacent to, and separate
from, the right ovary ſt with
a ring of blood flow, described
as the "ring of fire" st of an
ectopic pregnancy (EP).
(Left) Tranverse transvaginal
ultrasound shows a
heterogeneous mass in the
right adnexa consistent with a
blood clot ſt encasing an
echogenic tubal ring .
(Right) Sagittal transvaginal
ultrasound shows a large
amount of echogenic fluid ſt
surrounding the uterus,
compatible with clot in a
patient with ruptured EP. Note
the small pseudosac st in the
uterus.
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