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Flashcards in sonography of 2/3 trimester Deck (120):
0

What is the suggested protocol?

survey of uterus, cervix, LUS and adnexa

fetal cardiac activity

fetal position

placental location

AFI 4 quadrants

anatomy survey of fetus

perform biometric measurements of fetus

1

What does the sonographer determine after fetal position is conceptiualized?

Left and right side of fetus

2

Why is it important to constantly be aware of the left and right side of the fetus?

to correctly assess fetal anatomy and situs

3

What are the different fetal presentations?

oblique

transverse lie

breech

vertex (cephalic)

4

What are the different kinds of breech postions?

Complete breech

incomplete breech (one foot down into the pelvis)

frank breech (both feet up by the face, butt into the pelvis

5

What are the longitudinal presentations?

longitudinal lie - cephalic presentation (head down)(aka vertex)

longitudinal lie breech presentation (head up)

6

What are the transverse presentations?

head - maternal left, spine toward mom's head

head - maternal right, spine toward mom's feet

7

What are some ways to keep track of fetal left and right?

if fetal stomach lies on fetal left side, then you can determine left and right based on the position of the stomach

gallbladder on right side and APEX of heart pointing toward fetal left side...verified by their relationship to the stomach

8

What is the roll of the placenta?

to permit exhange of oxygenated maternal blood with deoxygenated fetal blood

maternal vessels coursing posterior to placenta circulate blood into placenta


blood from fetus reaches this point through the umbilical cord

9

what is PCI?

Placenta Cord Insertion

10

What is AFI?

amniotic fluid index

allows fetus to move freely within amniotic cavity

maintains intrauterine pressure and protects developing fetus from injury

umbilical cord and membranes, lungs, skin, and kidneys all contribute to production of amniotic fluid

11

What accounts for most of the total volume of amniotic fluid by second half of pregnancy?

fetal urination into amniotic sac

12

quantity of fluid is directly related to ______

kidney function

fetus

13

what structure is critically dependent on exhange of amniotic fluid within ______

normal lung development

lungs

14

When does the volume of amniotic fluid increase until which week?

34th then slowly diminishes

must be aware of relative differences in amniotic fluid volume throughout pregnancy

fluid surrounding fetus should be readily apparent

15

In the normal fetal brain parenchyma appears ______

hypoechoic

small size reflectors and high water content in tissue

slucus and gyrus more echogenic


16

What brain structures do we need to take pictures of?

cerebellum

choroid plexus

cisterna magna

lateral cerebral ventricles

midline falx

cavum septum pellucidi (CSP)

17

what are the midline structures?

interhemispheric fissure,

midline falx,

falx cerebri -

observed as membrane separting brain into two equal hemispheres

18

What is the fetal ventricular system?

consists of
two paried lateral ventricles,

midline third ventricle,

fourth ventricle adjacent to cerebellum

19

what does the ventricular system contain?

CSF - cerebral spinal fluid

20

How do you measure the ventricle?

locate atrium

measure directly across posterior portion

measure perpendicular to long axis of ventricle rather than the falx

place calipers at junction of ventricular wall and lumen or cavity of ventricle

21

What will fill lateral ventricle in normal pregnancy?

glomus or body of choroid plexus

22

What is the widest transverse diameter of the skull?

biparietal diameter - BPD

this is the proper level to measure the BPD and the HC

23

What is one way to proceed systematically through assessment and measurement of the fetus?

by moving from fetal head to feet obtaining anatomy images and measurement at each level

24

When there is severe oligohydraminos present, inadequate lung development occurs. What is the fetus at high risk for?

developing small or hypoplastic lungs

25

Branches of what artery run within the midline sulci and may be seen to pulsate within echogenic structures?

anterior cerebral artery

26

Why is the midline falx important landmark to visualize?

because its presence implies that separation of cerebrum has occured

27

What is it within the lateral ventricles that produces CSF?

choroid plexus tissue

28

where is choroid plexus tissue located?

within roofs of each ventricle except at frontal ventricular horns

29

In the lateral ventricles, what does a normal atrium measure? this is very important to know...

6.5 mm

if atrium measures >10mm it warrants serial imaging and further evaluation

30

What might the fetus have if the gloms appears to float or dangle within the ventricle cavity?

it is a sign of abnormally enlarged or dilated ventricles

VENTRICULOMEGALY

31

What are frontal horns?

frontal horns of ventricles are seen as two diverging echo-free structures within the frontal lobes of brain

32

When are the frontal horns prominent?

in the presence of ventricular dilation

33

what is the corpus callosum?

echogenic structure seen in transverse plane as a band of tissue between frontal ventricular horns.

34

How do you image the cerebral peduncles?

as transducer moves toward base of skull, heart-shaped cerebral peduncles imaged

similar in shape to thalamus but smaller

35

What artery is observed between lobes of peduncles at the interpeduncular cistern?

basilar artery

36

Where is the cerebellum located?

in back of cerebral peduncles within posterior fossa

37

what are the cerebellar hemispheres joined together by?

cerebellar vermis

38

why is it important to recognize usual configuration of cerebellum?

distortion my represent findings suggestive of OPEN SPINA BIFIDA

39

Where is the Cisterna magna located?

lies directly behind cerebellum

posterior fossa cistern filled with CSF

40

What does a normal appearing cisterna magna exclude?

almost all open spinal defects

41

The Cisterna magna is almost always effaced (thinned out) or obliterated in fetuses with what condition?

the Arnold-Chiari malformation changes associated with spina bifida

42

When you are evaluating the nuchal skin fold, what other anatomy will be in the plane where you will measure the thickness?

CSP

Cerebellum

Cisterna Magna

43

What is the normal thickness of the nuchal skin fold up to 20 weeks gestation?

5mm or less

44

What are fetuses with thickened nuchal skin at an increased risk for?

aneuploidy

45

What is aneuploidy?

a condition in which the chromosome number is not an exact multiple of the number characteristic of a particular species

an extra or missing chromosome

46

What cavity lies between the thalami?

the third ventricle

(in the same scanning plane, box shaped CSP observed anterior to thalamus)

47

What position does the fetus need to be in order for the orbital distances to be measured?

occipitoposterior position (fetal orbits directed up)

in this view orbital rings, lens, nasal structures may be demonstrated

48

What two planes are the orbits observed and measured in?

coronal scan: posterior to glabella-alveolar line

transverse scan: at level below BPD (along orbitomeatal line)

49

What is the IOD measurement?

inner orbital distance

medial border of orbit to opposite medial orbit

50

What is the OOD?

outer orbital or binocular distance

lateral border on one orbit to opposite lateral wall

51

What are you assessing in the profile view?

contour of frontal bone

nose

upper and lower lips

chin

52

What are some abnormalities you may seen in the forehead?

anterior cephaloceles

abnormal slopes

frontal bossing

abnormally small chin (MICROGNATHIA)

53

The coronal view of the face will help you see what craniofacial anomalies?

cleft lip

54

When you take an abdominal circumference what needs to be in the picture?

Left Portal Vein

spine

stomach

55

What is the sonographer required to document concerning the ACI (abdominal cord insertion)?

the ACI site and number of vessels in the umbilical cord

56

What does the normal human umbilical cord contain?

one umbilical vein

two umbilical arteries

57

Which vessel in the umbilical cord transports oxygenated blood from the placenta?

umbilical vein

58

What do the paired umbilical arteries do ?

return deoxygenated blood from iliac arteries of fetus to placenta for purification

59

Where should the umbilical cord be identified?

at cord insertion into placenta

at junction of cord into fetal umbilicus

60

What surrounds the arteries that spiral with larger umbilical vein?

Wharton's jelly (material that supports the cord)

61

If the cord is seen on both sides of fetal neck, what can you used to visualize nuchal cord or encirclement of cord around fetal neck?

color doppler

multiple loops of nuchal cord have been identified with color doppler

62

What does 3VC mean?

3 vessel cord

63

What plane is the diaphragm commonly viewed in?

longitudinal plane

64

What shunts blood away from fetal lungs?

DUCTUS ARTERIOSUS

65

how does fetal circulation run?

fetal circulation shunts oxygenated blood arriving from placenta away from abdomen directly to heart and then to brain

66

How does the hepatobiliary system function fro shunting oxygen-rich blood arriving from the placenta?

directly to heart through DUCTUS VENOSUS

67

What anatomy changes after the baby is born?

the foramen ovale, ductus venosus and ductus arteriosus CLOSE

68

What carries oxygen-rich blood from the umbilical vein directly to IVC, which empties directly into the right atrium?

ductus venosus

69

How does IVC blood flow through the heart?

from right atrium through left atrium by way of FORAMEN OVALE

70

Where does the less oxygenated blood from the superior vena cava and small portion from IVC empty into?

right atrium and into right ventricle

71

Both ventricles pump blood into systemic circulation at the same time...true or false?

true

72

Where does blood ejected from the left ventricle flow to?

ascending aorta and to fetal brain

73

How does oxygenated blood get to the abdominal organs?

from rt ventricle, blood courses from pulmonary artery into DUCTUS ARTERIOSUS and through descending aorta

74

Why is the left lobe of the liver larger than the right lobe in the fetus?

because of larger quantity of oxygenated blood flowing through it

75

How is the liver discerned?

pebble gray

corresponding portal and hepatic vessels

76

When can small bowel be differentiated from large bowel?

beyond 20 weeks gestation

77

how are the large intestine with ascending, transverse, and descending colon and rectum identified?

by their peripheral locations in lower pelvis

78

how will the colon measure?

up to 20mm or larger as time of birth nears

may contain meconium particles

79

What is greater, the echogenicity of fetal bowel or fetal liver?

bowel

80

What is hyperechoic bowel?

when fetal bowel is as echogenic as fetal bone

**has an associated risk for aneuploidy and neonatal/childhood pathology**

81

How does the renal pelvis appear?

as an echo-free area in center of kidney

82

What are the abnormal measurements for the renal pelvis?

>5mm before 20 GA

>8MM between 20-30 weeks GA

>10mm beyond 30 weeks GA

83

how often does a fetus void its bladder?

generally at least ONCE AN HOUR

failure to visualize bladder should prompt sonographer to recheck later for bladder filling

84

What should you suspect if you cannot identify urinary bladder in the presence of oligohydraminos?

renal abnormality

PROM

possible the bladder may not be full because of decreased ingestion of fluid

85

What planes is the longitudinal spine studied in?

coronal

sagittal

transverse

86

how many ossification points are there in each vertebra?

3

87

How many ossification points are seen on the spine in coronal and sagittal planes?

typically only 2

88

in sagittal section how does the spine appear?

two curvilinear lines extending from cervical spine to sacrum

89

In the normal fetus where does the spine taper? widen?

taper: near sacrum

widen: near base of skull

*double line appearance of spine referred to as RAILWAY SIGN - generated by echoes from posterior and anterior laminae and spinal cord

90

in the transverse plane, how many ossification points are visible?

3

spaced equidistant and spinal column appears as closed circle (indicating closure of neural tube)

91

What three echoes from circle or equilateral triangle?

represents center of vertebral body and posterior elements (laminae or pedicles)

92

Fluid filled fetal lungs are observed as solid, homogeneous masses of tissue, what borders them?

medially: heart

inferiorly: diaphragm

laterally: rib cage

93

The heart occupies the midline position within the chest. what would you want to exclude as reasons for its displacement?

possible mass of the lung

subdiaphragmatic herina

94

Why does the heart lie more transversely in the fetua than in an adult?

because the lungs aren't inflated

95

What is the directionality of the apex, right ventricle and left atrium?

Apex: directed toward left anterior chest

Right ventricle: closest to chest wall

Left atrium: closest to spine

96

what technique will you use to view the 4 chamber heart?

angling cephalad after obtaining trv view of fetal abd that displays stomach

beam perpendicular to the septum

or

view with beam perpendicular to valves

97

What are you assessing when viewing the 4 chamber heart?

cardiac position, situs, axis

apex ---->fetal left side

presence of right and left ventricle

98

What size do you want the ventricles of the heart to be?

equal size

99

by the end of pregnancy, why might the rt ventricle be larger than the left?

because its the chamber that pumps blood through ductus arteriosus to descending Ao and to placenta

100

When you identify presence of equal sized right and left atria, what do you want to see opening toward the left atrium as blood shunted from right atrium bypasses the lungs?

foramen ovale

101

What should appear uninterrupted in the heart?

interventricular septum

102

Septum appears _________ toward ventricles and _________as it courses cephalad within heart

wider

thins

103

What valves of the heart need to have normal placement?

tricuspid

mitral

104

How do you tell the tricuspid from the mitral valve?

tricuspid valve inserts lower or closer to apex than mitral valve

105

What should the valves should do what during diastole and systole?

diastole: open

systole: close

106

What is the normal heart rhythm?

120-160 bpm

107

What is FHR?

Fetal Heart Rate

108

What do you used to measure FHR?

m-mode

109

What is a short femur and short humerus associated with?

increased risk for aneuploidy

110

What issues are you looking for when you assess fetal bones?

measurements

anatomic configurations of individual bones

bowing

fractures

demineralization - seen in skeletal dysplasias

111

What is the normal cervix measurement in pregnancy?

3 cm or longer

112

When would you monitor and/or intervene when it comes to the cervix?

shortened

V shape

U shape

113

In what plane might you see female genitalia?

transverse plane

114

thighs and labia are identified _________ to bladder

ventral

115

How early can you possibly see male genitalia?

12th week

116

What is a common benign finding in male fetuses during intrauterine life?

fluid around testicles - HYDROCELE

117

How does a genetic sonogram differ from a normal anatomy scan?

includes all standard elements with special attention to "anatomy markers" for aneuploidy

118

What markers are typically elevated for aneuploidy?

nuchal fold

echogenic bowel

humerus/femur length

echogenic intracardiac foci (EIF)

renal pyelectasis

119

What is the risk for a 35 yr old woman entering a genetic sonogram?

1 in 200

if echogenic bowel is found - 1 in 33

if two or more markers documented - risk increased even more