The document discusses various ultrasound features that can help diagnose different types of ectopic pregnancies, including tubal, cervical, interstitial, abdominal, and caesarean scar pregnancies. Key diagnostic criteria include gestational sac location, presence of healthy myometrium tissue, and Doppler flow characteristics. The document provides diagrams and descriptions to illustrate differences between pseudosacs, normal intrauterine pregnancies, and ectopic pregnancies located in fallopian tubes, ovaries, and other abnormal locations. Careful ultrasound examination is important for accurately identifying ectopic pregnancies.

1. USS in Ectopic Pregnancy
Dr.V.Ravimohan

2. Figure 1. Diagram of the various locations of an ectopic pregnancy.
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

3. USS Features of Normal Uterus
• Convex appearance of the uterine fundus
• No significant fundal indentation of the
uterine cavity
• Presence of two interstitial portions of the
Fallopian tubes.
– This helps in
• excluding the diagnosis of unicornuate uterus
• making the diagnosis of interstitial pregnancy

4. Gestational sac vs Pseudosac
Gestational sac Pseudosac
Eccentric Central
Surrounded by echogenic ring of Surrounded by single layer of tissue
trophoblast-Double Decidual Sac sign
(link)
Endometrial midline echo is seen midline echo can’t be seen
separately
More :
The Intradecidual Sign: Is It Reliable for Diagnosis of Early Intrauterine Pregnancy?

5. Figure 7a. Diagrams show a pseudo–gestational sac in an ectopic pregnancy (a) and a
double decidual sac sign in a normal intrauterine pregnancy (b).
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

6. Figure 7b. Diagrams show a pseudo–gestational sac in an ectopic pregnancy (a) and a
double decidual sac sign in a normal intrauterine pregnancy (b).
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

7. Questions to answer..
• (i) Is this gestational sac?
• (ii)Where is the gestational sac located?
– Examine the longitudinal section of uterus to
establish the connection between cervical canal &
gesational sac.

8. Normal gestational sac should be located above
the level of internal os otherwise consider
miscarriage
cervical ectopic
caesarean section scar pregnancy
Internal os is indentified by the insertion of
uterine arteries

9. Figure 10. Abortion in progress in a patient with a history of vaginal bleeding.
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

10. Figure 9. Cervical pregnancy.
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

11. Figure 11. Scar pregnancy in a patient with a history of cesarean section.
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

12. Interstitial pregnancy
Interstitial pregnancy Intrauterine pregnancy located in the
upper lateral part of uterine
cavity(angular pregnancy)
Gestational sac is surrounded by thin Endometrial myometrial junction extend
myometrial mantle around the sac.
Narrow communication between the Communication between the gestational
gestational sac and endometrial cavity sac and uterine cavity is wide.
At laparoscopy the pregnancy is located
medial to the round ligament

13. Interstitial pregnancy
• Criteria by Timor-Tritsch
1) an empty uterine cavity
2) a gestational sac >1 cm from the most lateral point of the
endometrial cavity*
3) a gestational sac surrounded by a thin myometrial layer
Most useful diagnostic feature is Interstitial line sign –see the
next lide
* a strict application of a 1-cm cut-off may lead to an interstitial pregnancy being misdiagnosed as intrauterine pregnancy -Hafner T, Aslam
N, Ross JA, Zosmer N, Jurkovic D. The effectiveness of non-surgical management of early interstitial pregnancy: a report of ten cases
and review of the literature. Ultrasound Obstet Gynecol 1999; 13: 131–136.

14. Figure 8b. Interstitial pregnancy.
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

15. Figure 8a. Interstitial pregnancy.
Lin E P et al. Radiographics 2008;28:1661-1671
Source
©2008 by Radiological Society of North America

16. Cornual ectopic pregnancy
• Pregnancy in the rudimentary cornu
• Failure to diagnose a cornual pregnancy can lead to
serious complications
• Criteria can be used to diagnose cornual pregnancy on
ultrasound examination:
1) a single interstitial portion of Fallopian tube in the
main uterine body
2) a gestational sac, mobile and separate from the uterus,
surrounded by myometrium;
3) a vascular pedicle adjoining the gestational sac to the
unicornuate uterus

17. Cervical ectopic pregnancy
1) No evidence of intrauterine pregnancy
2) Hourglass uterine shape with ballooned
cervical canal
3) Presence of a gestational sac or placental
tissue within the cervical canal
4) Closed internal os

18. Criteria for Cervical and Caesarean
Ectopic pregnancy
• Gestational sac located below the level of the
internal os or within a visible myometrial
defect at the site of the previous lower
segment Cesarean section scar
• Evidence of functional trophoblastic/placental
circulation on color Doppler examination,
characterized by high-velocity (peak velocity
>20 cm/s) and low impedance (pulsatility
index <1) blood flow

19. Criteria for Cervical Ectopic
Pregnancy....
• Negative sliding organs sign- Inability to move
the gestational sac from its position at the
level of the internal os using gentle pressure
applied by the transvaginal probe.

20. Caesaren section scar Pregnancy
• Combined approach
– TVS : Fine details of the sac and its relation to the
scar
– Transabdominal scan with the full bladder:
• To get the panoramic view of the uterus
• To get the accurate measurement of the distance
between the sac & the bladder.
• Maymon R, Halperin R, Mendlovic S, Schneider D, Vaknin Z, Herman A,et al. Ectopic pregnancies in Caesarean scars: the 8
year experienceof one medical centre. Hum Reprod 2004;19:278–84.

21. Caesaren section scar Pregnancy
• Other Diagnostic tools
– 3D ultrasound scan
– Magnetic resonance imaging
Differentiation from cervical pregnancy
In cervical pregnancy healthy myometrium visible
between the bladder and gestational sac.

22. Abdominal ectopic pregnancy
• Criteria*
absence of an intrauterine gestational sac
no evidence of tubal dilatation or a complex
adnexal mass
a gestational sac surrounded by loops of
bowel and separated from the uterus
free mobility of the gestational sac
*Gerli S, Rossetti D, Baiocchi G, Clerici G, Unfer V, Di Renzo GC. Early ultrasonographic diagnosis and laparoscopic treatment of abdominal pregnancy.
Eur J Obstet Gynecol Reprod Biol 2004; 113: 103–105.

23. Ovarian Pregnancy
• Ectopic pregnancy surrounded by ovarian
cortex

24. Tubal Ectopic pregnancy
• If the uterus is empty at the time of the initial
scanning, we should look for the corpus
luteum.
• Ectopic pregnancy has been shown to be on
the ipsilateral side of corpus luteum in 70 to
85% of cases

25. Tubal ectopic pregnancy Vs Corpus
luteum
(I) Gentle pressure with the ultrasound probe
combined with abdominal palpation may
demonstrate free movement between the
adnexal mass(tubal ectopic pregnancy) and
the ovary (sliding organs sign)

26. Tubal Ectopic pregnancy....
(II) The tubal ring of an ectopic pregnancy is
usually more echogenic than ovarian
parenchyma, and the corpus luteum is usually
equal to or less echogenic than the ovary.
Echogenicity of an adnexal mass may help
distinguish the tubal ring of an ectopic
pregnancy from a corpus luteum.(Source)

27. Resources
(i)
Catch me if you scan: ultrasound diagnosis of ecto
D. JURKOVIC and D. MAVRELOS
(ii)
Imaging of Pelvic Pain in the First Trimester of Preg

28. • Useful Presentations
– Presenation 1
– Presenations2
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