7.2 18 Wk Detailed scan Flashcards

1
Q

what should we be assessing and documenting in our initial overall sagittal sweep?

A

In the over all sweep, sweep from fundus to cervix to assess for fetal lie

  • image the fundus and the cervix (measure the cervix)
  • check for fetal HR
  • check # of fetuses
  • check for amniotic fluid
  • placental location
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2
Q

when we do our overall TRX sweep along the lateral aspect of the uterus and adnexa what are we assessing/looking for?
how would we document these finds?

A

-looking for fibroids on the uterus
… document in 2 planes, measure and doppler

-looking for an adnexal mass on the ovary, usually the corpus luteum or a dermoid cyst
… document in 2 planes, measure and doppler

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3
Q

what is a dermoid cyst

A

cyst that contains all germ cell tissue (endoderm, mesoderm, ectoderm)

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4
Q

what are we assessing/documenting when looking at the placenta?

A
  • postion (low or normal)
  • texture
  • measuring the distance from the lower placenta edge to the internal os
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5
Q

what is the minimum distance that the lower placental edge should be from the internal os of the cervix?

A

minimum 2cm from the internal os

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6
Q

what risks does a short cervix pose?

A

risk for preterm delivery

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7
Q

what should the cervix measure?

A

~30mm

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8
Q

when very superior, how will the fetal head shape appear?

A

round

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9
Q

list the cranial images we take

A
BPD, OFD, HC
ventricular image
bilateral choroid image
cerebellar/posterior fossa image
orbital image
nose, lips image
profile
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10
Q

what does the BPD level assess?

A
cavum septi pellucidi
third ventricle
ambient cistern
falx
head shape
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11
Q

what does the bilateral chord image assess

A

echotexture of both choroids (should be smooth)… check for cysts

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12
Q

what does the cerebellar image or level assess?

A
  • prescence of the vermis
  • cerebellar size
  • cisterna magna
  • nuchal fold
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13
Q

what is micropthalmia?

A

small eyes

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14
Q

what is anopthalima? how do we rule this out?

A

no eyes

R/O by seeing lenses

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15
Q

what is the nose/lip image used to assess?

A

assessing for cleft lip and abnormal nostrils

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16
Q

what is the profile image used to assess?

A

assess chin for micro or retrognathia… and nasal bone to see if its present, absent or hypoplastic

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17
Q

what is micrognathia?

what is retrognathia?

A

micro: small chin
retro: receding chin (normal size)

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18
Q

what should a normal nasal bone measure?

A

> 2.5mm

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19
Q

when you see the three ossification centres of the spine, what does the 1 anterior and 2 posterior ossification centres represent?
are any other areas of the fetal spine visible on US?

A

anterior: vertebral body
post: laminar junctions/lamina

NO

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20
Q

as gestration progresses, how do the laminar junctions ossify?

A

into a linear structure

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21
Q

when is ossification complete?

A

at 18 wks

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22
Q

in what two plane should the spine be imaged?

A

SAG and TRX…. coronal is acceptable is SAG isnt possible

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23
Q

how many images of the spine do we take in SAG?

A

two

1: at the distal end to include the sacrum (lumbar)
2: at the cephalic end to include the cervical spine and skull

include as many vertebral ossifications as possible

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24
Q

is it the most important to sweep the spine in TRX or SAG?

A

TRX

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25
Q

how many images of the spine do we take in TRX?

what must they/it include?

A

one: at the lumbosacral junction/sacrum

must include both iliac crests and 3 ossification centres… must also show bladder

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26
Q

in what area would we see a neural tube defect when scanning the fetal spine?

A

lumbosacral area in SAG

27
Q

what is the AC image used to assess?

A

-presence of stomach and position of organs (cytosinverses- stomach on right)

… dont confuse GB with stomach

28
Q

whats a term used in OB that refers to the confluence of the umbilical vein and the L portal vein?

A

portal sinus

29
Q

which vein becomes the lig theres after birth?

A

fetal umbilical vein

30
Q

in general, what are we assessing when scanning the fetal heart?

A
  • size of chambers and valve placement

- m mode for fetal HR (though the atria and ventricles to check for heart block)

31
Q

what what level would you do a chest circumference if necessary?

A

4CH view of the heart

32
Q

the heart occupied how much of the fetal chest?

A

1/3

33
Q

what are we assessing when imaging the outflow tracts (RVOT & LVOT) of the heart?

A

looking to R/O great vessel abnormalities
(RVOT and LVOT long axis look the same as PLAX RVOT and PLAX)

also looking at lungs

34
Q

what % of heart abnormalities are detected in the 3 vessel view?

A

90-95%

35
Q

how does the fetal heart lie in the chest?

A

in a horizontal plane

36
Q

whats the purpose of doing a SAG assessment of the abdomen and chest?
what structures are included in this image?

A
  • look for location of stomach compared to diaphragm
  • look at echo texture of lungs compared to liver

heart, diaphragm, stomach,

37
Q

how should the echo texture of lungs compared to liver?

A

liver should be isoechoic to lungs in 2nd trimester then increase in echogenicity when compared to liver in 3rd trimester

38
Q

how does the diaphragm appear on US?

A

hypoechoic b/c theres not air in the lungs

39
Q

how will the sm and lg bowel appear?

diameter of lg bowel at term

A

sm: clusters of rings surrounded by the lg bowel
lg: in the 3rd trimester lg bowel will look hypoechoic and prominent

17mm

40
Q

are the kidneys distinctively seen in 2nd trimester?

3rd trimester?

A

no

yes, pyramids and calyces are well seen

41
Q

upper limit of norm for renal pelvis

what can it indicate if they’re enlarged?

A

5mm is upper limit, normal is 3 mm

T21

42
Q

how do we take the kidney image?

A

in TRX with the spine in the middle, must see renal pelvis

43
Q

when would you do a SAG image of the kidneys

A

if abnormalities like hydronephrosis and renal cysts are detected

44
Q

is kidney length approximately equal to gestation age?

A

yes

45
Q

how often should the bladder empty and fill?

A

very 20 mins

46
Q

at what level do we find and document the 2 umbilical arteries?

A

the level of the bladder… document and use colour doppler or power doppler

47
Q

do the umbilical arteries carry oxygenated or deoxygenated blood?

A

deoxy.

48
Q

how will the waveform of the umbilical arteries appear?

A

will have an arterial waveform due to babys cardiac activity

49
Q

how many vessels does the umbilical cord have?

in what plane do we image the vessels?

A

3: 2 arteries, 1 vein

TRX to document all 3

50
Q

why do we image the cord inserting into the fetal abdo and the placenta?

A
  • checking for abdo wall defects (omphalocele- liver outside the abdo)
  • checking for where the old inserts… should be more than 2 cm in from the edge of the placenta
51
Q

when can the genitalia be seen

A

if fetus is laying face up with legs apart

52
Q

when do testicles descend?

A

28 wks

53
Q

when is the humerus measured?

A

at 2nd trimester detailed scan

54
Q

describe the appear of the radius and ulna on US

A

ulna: medial, thinner and longer
radius: lateral, thicker and shorter

55
Q

what does it indicate if you can image the tib, fib and all toes at the same time?

A

club foot

56
Q

should the tib or the fib be larger?

A

tib is larger

57
Q

when would you measure all long bones?

A

with certain syndromes or chromosomal abnormalities which would make them look abnormal

58
Q

is the AFI performed at the detailed 18 wks scan?

A

no

59
Q

what type of assessment is done at 18 wks?

amniotic fluid volume increases until how many weeks?

A

subjective assessment of fluid (increased or decreased)

34 wks, then it decreases

60
Q

which structures contribute to the amount of amniotic fluid (AF) in the uterus?

A

fetal urinary sys
umbilical cord
lungs
skin

61
Q

what is the vernix?

A

waxy substance that covers babys skin, may be seen floating in AF

62
Q

why does supine hypotension occur?

A

baby is compressing moms IVC

63
Q

where does the fetal umbilical vein course?

A

through the falciform ligament

64
Q

Which long bone in the arm can be missing in a lot of syndromes?

A

Radial bone