TWIN EMBOLIZATION SYNDROME

1. Dr. A. JEYARAMAN, D.M.R.D., TUTOR, Dr. S. THIYAGARAJAN, II YR D.M.R.D. – PG DEPARTMENT OF RADIOLOGY GOVERNMENT RAJAJI HOSPITAL MADURAI INTERESTING CASE PRESENTATION

2. A 21 year old previous LSCS lady • G2P1L1A0 • LMP-GA 30 weeks 5 days • Intrauterine Monochorionic twin pregnancy which is confirmed by ultrasound at 11th week of pregnancy • No family history of twin pregnancy • Previous child was normal.

11. US findings • Intrauterine monochorionic twin gestation • Twin 1 • Gross ventriculomegaly with thinned out cerebral mantle • Multiple dilated small bowel loops s/o small bowel atresia • Non visualisation of left kidney • No e/o spinal anomaly • No e/o cardiac anomaly

12. US findings… • Twin 2 • Fetus papyraceous • Side to side compressed head • Compressed body

13. Diagnosis • Twin embolisation syndrome / vanishing twin syndrome

22. Discussion

23. Multiple gestation

24. Zygosity • Zygosity • Genetic makeup of the pregnancy • Is determined by type of fertilization, i.e. monozygotic or dizygotic • Zygosity can only be determined by genetic analysis of both fetuses • USG can be used to determine the likelihood of zygosity

25. Chorionicity • Chorionicity • Membrane complement of the pregnancy • Is determined by the occurrence and timing • Determined non-invasively by ultrasound

27. Dizygotic Pregnancy • Twins resulting from 2 ova fertilized by 2 sperm • These are ALWAYS dichorionic • Fused or separated

28. Monozygotic Pregnancy • One ovum fertilized by one sperm that subsequently splits

31. Chorionicity

32. Chorionicity - USG • Ultrasound detection of two separate placentas. • Confirms a dichorionic pregnancy • The detection of different-sex fetuses.

33. Chorionicity • Ultrasound detection of a single placenta • Either monochorionic or dichorionic (fused placenta)

34. Chorionicity • Thick inter-twin membrane • Often taken as > 2 mm • All membranes look thin in third trimester • Count layers with high resolution transducer, if ≥ 2 must be DC

37. "Twin peak" or Lambda sign • Chorionic tissue extends into inter-twin membrane at placenta • Chorionforms echogenic triangle • Triangle base on placental surface, apex fades into inter-twin membrane • Reliableindicator of dichorionicity

39. Chorionicity

40. "T" sign • Absent "twin-peak" • Membrane abuts placental surface without triangle of chorionic tissue • Does NOT exclude dichorionicity • Monochorionic pregnancies have a thin wispy membrane between the sacs made up of two layers of amnion and generally less than 1 mm in thickness

42. Chorionicity

44. Zygosity - USG • Twins are definitely dizygotic if they are of different sexes.

45. Monozygotic twins • Single gestational sac with only one placenta • Intertwined two umbilical cords • Conjoined twin

46. Complication of multiple pregnancy • DICHORIONIC DIAMNIOTIC TWINS • Maternal complications> singleton pregnancy o Hypertension o Preeclampsia o Antenatal hemorrhage • Placenta previa • Placental abruption • Other causes

47. o Postpartum hemorrhage • Perinatal mortality reported 10% o Preterm delivery • Median gestational age (GA) twins at delivery 36 weeks o Intrauterine growth restriction o Anomalies

48. MONOCHORIONIC TWIN • MONOCHORIONIC DIAMNIOTIC TWIN • Vanishing twin • Discordant twin growth • TTTS • Twin embolisation syndrome • Parasitic twin (acardiacacranius)/(TRAP sequence)

49. MONOCHORIONIC TWIN • MONOCHORIONIC MONOAMNIOTIC TWIN • Discordant twin growth • TTTS • Conjoined twins • Tangled umblical cords

50. Discordant twin growth • May occur in monochorionic or dichorionic pregnancies • Monochorionic more common • Discordant growth One twin with intrauterine growth restriction • EFW < 10th percentile • AC difference > 20mm • EFW difference > 20%