USS in Ectopic Pregnancy

Dr.V.Ravimohan

Figure 1.  Diagram of the various locations of an ectopic pregnancy.

Lin E P et al. Radiographics 2008;28:1661-1671Source

©2008 by Radiological Society of North America

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

Gestational sac vs Pseudosac

Gestational sac Pseudosac

Eccentric Central

Surrounded by echogenic ring of trophoblast-Double Decidual Sac sign(link)

Surrounded by single layer of tissue

Endometrial midline echo is seen separately

midline echo can’t be seen

More : The Intradecidual Sign: Is It Reliable for Diagnosis of Early Intrauterine 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).

Lin E P et al. Radiographics 2008;28:1661-1671Source

©2008 by Radiological Society of North America

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;28:1661-1671Source

©2008 by Radiological Society of North America

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.

Normal gestational sac should be located above the level of internal os otherwise consider

miscarriagecervical ectopiccaesarean section scar pregnancy

Internal os is indentified by the insertion of uterine arteries

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

Figure 9.  Cervical pregnancy.

Lin E P et al. Radiographics 2008;28:1661-1671

Source

©2008 by Radiological Society of North America

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

Interstitial pregnancyInterstitial pregnancy Intrauterine pregnancy located in the

upper lateral part of uterine cavity(angular pregnancy)

Gestational sac is surrounded by thin myometrial mantle

Endometrial myometrial junction extend around the sac.

Narrow communication between the gestational sac and endometrial cavity

Communication between the gestational sac and uterine cavity is wide.

At laparoscopy the pregnancy is located medial to the round ligament

Interstitial pregnancy

• Criteria by Timor-Tritsch 1) an empty uterine cavity2) a gestational sac >1 cm from the most lateral point of the

endometrial cavity*3) a gestational sac surrounded by a thin myometrial layerMost 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.

Figure 8b.  Interstitial pregnancy.

Lin E P et al. Radiographics 2008;28:1661-1671

Source

©2008 by Radiological Society of North America

Figure 8a.  Interstitial pregnancy.

Lin E P et al. Radiographics 2008;28:1661-1671

Source

©2008 by Radiological Society of North America

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 themain 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

Cervical ectopic pregnancy

1) No evidence of intrauterine pregnancy2) Hourglass uterine shape with ballooned

cervical canal3) Presence of a gestational sac or placental

tissue within the cervical canal4) Closed internal os

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

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.

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.

Caesaren section scar Pregnancy

• Other Diagnostic tools– 3D ultrasound scan– Magnetic resonance imaging

Differentiation from cervical pregnancyIn cervical pregnancy healthy myometrium visible between the bladder and gestational sac.

Abdominal ectopic pregnancy

• Criteria*absence of an intrauterine gestational sacno evidence of tubal dilatation or a complex

adnexal massa gestational sac surrounded by loops of

bowel and separated from the uterusfree 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.

Ovarian Pregnancy

• Ectopic pregnancy surrounded by ovarian cortex

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

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)

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)

Resources

(i)Catch me if you scan: ultrasound diagnosis of ectopic pregnancy

D. JURKOVIC and D. MAVRELOS (ii) Imaging of Pelvic Pain in the First Trimester

of Pregnancy

• Useful Presentations– Presenation 1– Presenations2

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