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 PseudosacGestational sac PseudosacEccentric CentralSurrounded by echogenic ring of Surrounded by single layer of tissuetrophoblast-Double Decidual Sac sign(link)Endometrial midline echo is seen midline echo can’t be seenseparatelyMore :The Intradecidual Sign: Is It Reliable for Diagnosis of Early Intrauterine Pregnancy?
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 considermiscarriagecervical ectopiccaesarean section scar pregnancyInternal os is indentified by the insertion of uterine arteries
Interstitial pregnancyInterstitial pregnancy Intrauterine pregnancy located in the upper lateral part of uterine cavity(angular pregnancy)Gestational sac is surrounded by thin Endometrial myometrial junction extendmyometrial mantle around the sac.Narrow communication between the Communication between the gestationalgestational sac and endometrial cavity sac and uterine cavity is wide. At laparoscopy the pregnancy is located medial to the round ligament
Interstitial pregnancy• Criteria by Timor-Tritsch1) 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.
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 pregnancy1) 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 pregnancy In 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 ecto D. JURKOVIC and D. MAVRELOS(ii) Imaging of Pelvic Pain in the First Trimester of Preg
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