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?
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
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.
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.
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
Figure 1. Diagram of the various locations of an ectopic pregnancy.
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).
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).
Figure 10. Abortion in progress in a patient with a history of vaginal bleeding. Transvaginal US image of the uterus demonstrates a low-lying gestational sac (arrow) with mixed hyper- and hypoechoic contents in the endometrial cavity of the fundus (arrowheads), which represent decidual reaction and hemorrhage. The patient experienced a complete spontaneous abortion a few hours after the US examination. (Reprinted, with permission, from reference 16.)
Figure 9. Cervical pregnancy. Transvaginal US image of the uterus obtained along the longitudinal axis reveals a gestational sac that contains the fetal pole (arrow) within the cervix. Fu = uterine fundus. (Reprinted, with permission, from reference 25.)
Figure 11. Scar pregnancy in a patient with a history of cesarean section. Transvaginal gray-scale US image of the uterus, obtained with M-mode scanning along the longitudinal axis, reveals a gestational sac with a fetal pole (arrowhead) in the anterior wall of the uterus. There was no fetal cardiac activity, a finding suggestive of fetal demise.
Figure 8b. Interstitial pregnancy. (a) Transvaginal US image obtained along an oblique axis shows the yolk sac (arrowhead) within a gestational sac, which is located in the interstitial portion of the fallopian tube. The interstitial line sign (arrow) is also seen. (b) Diagram of the interstitial pregnancy and the interstitial line sign. (c) Transverse gray-scale US image of the uterus in another patient shows a gestational sac (arrow), which contains an embryo (arrowhead), in the cornua/interstitial portion of the fallopian tube. (Fig 8a reprinted, with permission, from reference 25.)
Figure 8a. Interstitial pregnancy. (a) Transvaginal US image obtained along an oblique axis shows the yolk sac (arrowhead) within a gestational sac, which is located in the interstitial portion of the fallopian tube. The interstitial line sign (arrow) is also seen. (b) Diagram of the interstitial pregnancy and the interstitial line sign. (c) Transverse gray-scale US image of the uterus in another patient shows a gestational sac (arrow), which contains an embryo (arrowhead), in the cornua/interstitial portion of the fallopian tube. (Fig 8a reprinted, with permission, from reference 25.)