Unit 5- Sonographic Evaluation: 30-47

When is the typical visualization of embryonic development?

During 5th week

What is sonographic appearance of the embryonic development during the 5th week of embryonic development?

• 1-2 mm sac with echogenic ring and sonolucent center

• Anechoic center is chorionic cavity

What are these images showing?

Decidual Reaction

decidual reaction happens after ________&________

fertilization and implantation

Decidual reaction is when the sac has

attached itself to uterine/endometrial wall

decidual reaction is also called

double sac sign

what layers press against each other to form decidual reaction

capsularis and parietalis

What are the different amniotic/chorionic cavities?

• Decidua Basalis

• Decidua Capsularis

• Decidua Parietalis

• Decidua Vera

  • Decidua Capsularis

  • Decidua Parietalis

What is this image showing?

• Decidua Capsularis

• Decidua Parietalis

When is the best visualization of the amniotic membrane transvaginal?

Visualization after 5.5 weeks

When visualizing amniotic and chorionic cavities later, what do the cavities do?

Amniotic cavity expands, chorionic cavity decreases in size with eventual chorioamnionic fusion occurring at approx. 16-17 weeks.

Where does the embryo/fetus grow?

Grows inside the amniotic cavity

When should the amnion/chorion separation fuse?

Around 16-17 weeks

What is this image showing?

Double Decidual sac sign

What is the sonographic appearance of the gestational sac?

• Round or oval shape

• Fundal position in the uterus

• Central portion of uterus

• Smooth contour

• > 3mm decidua wall

If the MSD is > 10 mm (5-5.5 wks) what is it considered?

Yolk sac

If the MSD is > 16 mm ( 6-6.5 wks) what is it considered?

Embryo

How much does the gestational sac grow?

1 mm/day in early pregnancy

What is this image showing?

Gestational Sac

What are these images showing?

Yolk Sac

When is the mean yolk sac diameter identified transabdominally?

20 mm or greater

When is the mean yolk sac diameter identified transvaginaly?

8 mm or greater

If the yolk sac is not visualized, what is it suspicious for?

Suspicious of abnormal pregnancy

If the yolk sac is >5.6 mm what is it associated with?

Associated with poor outcome from weeks 5-10

When does the yolk sac disappear?

10-12 weeks

What are these images showing?

Yolk sac

What are these images showing?

Double Bleb Sign

What is the double bleb sign

yolk sac and amnionic cavity - normal

The yolk sac is between ____________ and amniotic cavity contains __________.

Membranes; Embryo

What are these images showing?

Yolk Sac

The embryo conceptus should be seen when the embryo MSD measures __________ TA?

25 mm or greater

The embryo conceptus should be seen when the embryo MSD measures __________ TV.

16 mm or greater

What is a sac highly suspicious for when it measures greater than 25mm without contents

Anembryonic gestation

Cardiac activity should be identified TA at what week and measurement?

• 7 weeks

• 9mm

Cardiac activity should be identified TV at what week and measurement?

• 5-6 weeks

• 2-5 mm embryo

  • 7mm new absolute criteria

What should be identified on a 7-8 week embryo

• Skeletal, muscle, heart and limb buds forming

• Fetal head and trunk can be differentiated

• Intermittent movement noted

• Recognition of the spine

heart beats at ___ days

36

What are these images showing?

Embryo at 8 weeks

formation of organs at week

5

What are these images showing?

Embryo spine at 8 weeks