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Similaire à First trimester ultrasound
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First trimester ultrasound
- 2. TVS advantages Shorter probe-target distance Allows use of higher frequency probes Better image resolution Avoids problem of under/over distended bladder Earlier dx of fetal viability / ectopic pregnancy Very useful in retroverted uterus or obese patients
- 3. TVS disadvantages Cost Limited depth of penetration Lacks global picture Difficulty in evaluation of large masses ? Relatively invasive
- 6. INDICATION • First Trimester Ultrasound Screening –Should be selective and restricted to specific indications
- 7. Confirmation of pregnancy viability Established accurate gestational age Determine the number of fetuses Assess chorionicity and amniocity fetuses Imaging as an adjunct to chorionic villus sampling, embryo transfer, and localization and removal of an intrauterine device
- 8. Common Indications • Amenorrhoea • Pelvic pain • Vaginal bleeding • Unknown last normal menstrual dates • Subjective feeling of pregnancy • Uterus greater or smaller than dates on clinical evaluation • Pregnancy test positive or increased hCG values • Nuchal translucency measurement
- 9. ?Last Menstrual Period The LMP is unreliable (and therefore Naegele’s formula cannot be used) if the: ● date of the LMP is not accurately known ● menstrual cycle is not 28 days long ● menstrual cycle is irregular ● woman has only stopped taking the combined oral contraceptive pill (‘the pill’) within the last 3 months ● woman has bled in early pregnancy ● woman is breast feeding or has been pregnant in the preceding 3–6 months.
- 10. Pregnancy Development in Early TM Gestational weeks Ultrasound Features TVS TAS 4 4-5 gestational sac Round shape, internal cystic echo Two layers wall - 5 6-7 Embryo - fetal pole and yolk sac 5-6 7-8 Fetal heart beats, fetal head,body and extremities are observed 8-9 9-10 Placenta and ventricles are seen
- 11. Intrauterine GS
- 17. problem Should see on TVS Time of visualization Findings Gestation week or measurement Beta HCG level Gestation sac 5 menstrual weeks Yolk sac when MSD is >7mm Embryonic pole 5 weeks 2000 mIU/mL Fetal heart activity when CRL is >5 mm
- 18. Estimation of Gestational Age
- 19. Estimation of gestational age
- 21. Crown Rump Length (CRL) • This measurement can be made between 7 to 13 weeks and gives very accurate estimation of the gestational age. • Dating with the CRL can be within 3-4 days of the last menstrual period
- 25. T sign Lambda sign
- 29. Diagnostic Signs of Early Pregnancy Failure in the First Trimester MSD of equal to or greater than 25 mm without an embryo Crown-Rump length of equal to or greater than 7 mm without cardiac activity Absence of embryo with heartbeat at 2 or more weeks after an ultrasound that showed a gestational sac without a yolk sac Absence of embryo with heartbeat at 11 days or more after an ultrasound that showed a gestational sac with a yolk sac
- 30. TVS TAS GS > 25 mm without yolk sac EMBRYO > 7 mm > 9 mm
- 31. Transvaginal ultrasound Embryonic demise Blighted ovum Transabdominal ultrasound Embryo >5mm No cardiac activity Embryo >9mm No cardiac activity Gestational sac > 8 mm No yolk sac Gestational sac > 20mm No yolk sac Gestational sac > 16 mm No embryo Gestational sac > 25 mm No embryo Blighted ovumEmbryonic demise
- 34. 4 – 5 weeksTAS TVS
- 35. 5 – 6 weeks
- 38. 6 – 7 weeks
- 39. 7 – 8 weeks
- 40. 7 – 8 weeks
- 41. 9 weeks
- 42. 10 weeks
- 45. NUCHAL TRANSLUCENCY (NT) • 11 to 14 wks • =/> 3 mm • Abnormal NT may indicates: – 1. chromosamal abnormality • Trisomy 21 or 18 or 13 • Turners Syndrome – Cardiac abnormality – Prediction of TTTS (4 fold increase in risk)
- 46. First Trimester Fetal Defect • Acrania/Anencephaly • Holoprosencephaly • Encephalocele • Dandy-walker Syndrome • Univentricular heart • Gastrochisis • Exomphalos • Multidysplastic kidneys
- 48. Should First Trimester US be routine? • Determination of EDD • Optimise the time for fetal anomaly scan • Enhance performance of serum screening test • H/O ectopic pregnancy/miscarriage • Intrauterine / ongoing pregnancy • Diagnosed early unanticipated miscarriage • Better informed when to deliver which complication arise in second or third trimester • Minimise false positive IOL for postmaturity • Multiple pregnancy and chorioamniocity can be determined
- 50. • 35 - 50% with TAS • 95% with TVS • Gestational sac with viable embryo in fallopian tube (12%) • complex mass high sensitivity (98%) Adnexal Mass
- 51. • Not seen in 20% of ectopics • May be seen in normal patients Fluid in POD
- 52. consider • patient not pregnant • early pregnancy • ectopic pregnancy • Use beta hCG • Must see IUGS with TVS if hCG levels of 2000 IU and above • KIV repeat hCG every 2 days if very early Failure to visualize intrauterine GS
- 53. GUIDELINES FOR DATING PREGNANCY STAGE OF DEVELOPMENT GESTATIO-NAL AGE (WEEKS) LEVEL OF B-HCG Gestational sac 5 weeks 1,000-2,000 mIU/L Gestational sac with yolk sac 5.5 weeks 7,200 mIU/L Gestational sac with yolk sac & embryo 6 weeks 10,800 mIU/L
- 58. Molar pregnancy
- 59. Complete Mole
- 61. Theca Lutein Cyst in Molar Pregnancy
- 64. Biometric Measurements of the Basic Obstetric Ultrasound Examination Mean sac diameter if no embryo is seen Crown-Rump Length up to 13 6/7 weeks gestation Biparietal Diameter >13 6/7 weeks gestation Head Circumference >13 6/7 weeks gestation Abdominal Circumference >13 6/7 weeks gestation Femur Length >13 6/7 weeks gestation
- 66. THANK YOU