OB (Late 1st Trimester Sono Appearance) Flashcards
1
Q
When is the later 1st trimester assessment done?
A
-11 to 14 weeks
2
Q
Late 1st Trimester Assessment
A
- assess nuchal translucency enlargement
- fetal anatomy
- done in conjunction with maternal blood tests
- positive findings can suggest chromosomal abnormalities
3
Q
Crown-Rump Length
A
- top of head to bottom
- ideally want baby in neutral position, perpendicular to the beam, with neutral alignment of spine
- CRL correlated to GA
4
Q
What structures can we visualize from the profile?
A
- nasal bone
- separation of chin/chest
- formation/jaw angle
- formation/skull size
5
Q
Biparietal Diameter
A
- due to fetal flexion and extension, BPD and femur length will be more accurate
- correlates with GA
- OUTER TO INNER
6
Q
Rhombencephalon (hindbrain)
A
- anechoic structure seen within posterior head @ 9 weeks
- normal at this stage
7
Q
Diencephalon
A
- midline
- hypoechoic
- contains 3rd ventricle
8
Q
What do ventricles contain?
A
- CSF
- chorioid plexus (produces CSF)
9
Q
Nuchal Translucency (NT)
A
- anechoic space
- collection og fluid under the skin of fetal neck
10
Q
When can NT be seen and assessed?
A
Seen: 9 to 10 weeks
Assessed: 11 weeks to 13 weeks, 6 days
**assessed for size, not appearance (may have septations)
