Ultrasound Flashcards

1
Q

What’s the lemon sign on fetal ultrasound? Significance?

A

indentation in the bilat frontal bones
Chiari II
(others include Dandy-Walker, encephalocele, cystic hygroma, etc.)
Say you’d look at the spine for meningocele, prognosis involves brainstem (get decompressed) and LE paralysis.

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2
Q

What’s the banana sign of fetal head imaging? Significance?

A

the way the cerebellum is wrapped tightly around the brain stem as a result of spinal cord tethering and downward migration of posterior fossa contents
Chiari II and spina bifida

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3
Q

Large midline posterior fossa cyst:

Associations?

A

Dandy Walker: absent cerebellar vermis, associated with other problems in 70-90% (cortical dysplasia, dysplasia of corpus callosum, lipoma of CC, scizencephaly)

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4
Q

What’s a Blake pouch cyst?

A

posterior ballooning of the superior medullary velum into the cisterna magna, below and posterior to the vermis. It is thought to be secondary to failure of perforation of the foramen of Magendie
In ddx for Dandy Walker

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5
Q

Joubert syndrome is what?

A

(aka vermian aplasia or molar tooth midbrain-hindbrain malformation) is an autosomal recessive disorder where there is a variable degree of cerebellar vermis agenesis

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6
Q

How do you diagnose fetal hydrops?

A

accumulation of fluid + / - edema involving at least two fetal components. This may manifest as:
pleural effusion
pericardial effusion
generalised body edema - fetal anasarca / nuchal edema / cystic hygroma
ascites

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7
Q

Causes of fetal hydrops:

A

fetal anemia (alloimmunization, Rx is fetal blood transfusion, parvovirus), genetic (Trisomy 21, Turner causing lymphatic obstruction), circulatory failure (AVM, vascular tumor), heart defect, infection (CMV, syphilis)

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8
Q

Multicystic dysplastic kidney - what associations?

A

80% are unilateral
bilateral is lethal from pulmonary hypoplasia
other kidney has an anomaly in 40%

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9
Q

Ddx for polyhydramnios

A

Duodenal or esophageal atresia, facial abnormalities (Pierre Robin), trisomy 18, holoprosencephaly, anencephaly, myotonic dystrophy, arthrogryposis

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10
Q

Describe Pierre Robin syndrome

A

micrognathia
glossoptosis (retracted tongue)
posterior cleft palate or arched palate
Not genetic, associated with polyhydramnios from impaired swallowing

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11
Q

What’s a normal cervical length?

A

2.5 cm or greater

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12
Q

What’s double bubble? Associations?

A

Duodenal atresia (look for polyhydramnios), only 30% have Downs

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13
Q

communication between atria and ventricles =

associations?

A

AV canal

50% have Downs

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14
Q

What’s a normal lateral ventricle measurement in a fetus?

A

10mm or less

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15
Q

What’s an omphalocele? What’s gastroschisis?

When does bowel normally herniate?

A

Omphalocele: membrane covered defect, cord inserts into sac. Associated abnormalities (80%) - esp. cardiac, including chromosomal
Gastroschisis: free-floating bowel, cord inserts to the left (it’s on the right). 5% chance of other anomalies (usually don’t offer amnio)
Normal herniation is before 12 weeks

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16
Q

vessels run through membranes across the internal cervical os =
When especially should you look for this?

A

vasa previa

Often seen in: low-lying placenta, vellamentous cord insertion, succenturiate lobe

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17
Q

High resistance/reversal in umbilical artery - what’s the problem?

A

IUGR, placental insufficiency. Deliver if near term.

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18
Q

What does “monochorionic” mean? “Monozygotic”? What are the types of twins?

A

Chorion Contains it All (Chorion outside Amnion)
Chorion encloses fetus and amnion. Can have two amnions in one chorion
Monochorionic monoamniotic: no membrane (always identical twins)
Monochorionic, diamniotic: thin membrane, usually single placenta
Dichorionic, diamniotic: twin peak, thicker membrane, usually two placentas, but can be fused

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19
Q

What type of twins are at risk for twin-twin transfusion?

A

Monochorionic -15% Also at risk for IUGR, villamentous cord insertion.
Does not occur in dichorionic
Rx laser coag the connecting vessels

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20
Q

small left ventricle prenatally. Called?

A

Hypoplastic left heart (requires a lot of surgery postnatally)

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21
Q

What’s the normal thickness of a nuchal translucency? When can it be measured?

A

3.0mm or less. 11-14 weeks only. After this, can measure nuchal fold/thickening (<6mm).

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22
Q

what’s blood between the placenta and uterus called?

A

Placental abruption

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23
Q

What are normal renal pelvis measurements in a fetus?

A

<7mm after ~30 weeks

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24
Q

Two vessel cord - what’s missing? Significance?

A

Single umbilical artery (check by bladder)
20% have other malformations eg trisomy 13,18, cardiac and renal malformations
Risk of IUGR and prematurity

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25
Fetal ehogenic bowel - what's it from?
Must be bright as bone! Often normal variant, but could be: | CMV, CF, trisomy 21, bowel ischemia
26
Fetal tumor arising from sacrum/coccyx
Sacrococcygeal teratoma AV shunting may lead to hydrops must know before delivery!
27
What's a cystic hygroma? Significance?
congenital lymphovascular malformation. Associated with turner and trisomy 21. Commonly have hydrops.
28
Keyhole bladder in male fetus =
posterior urethral valves. Causes oligohydramnios and pulmonary hypoplasia
29
Early pregnancy: when should you see the following? Yolk sac embryo fetal cardiac activity
Yolk sac: sac diameter >10mm Embryo: sac diameter 15-18mm Cardiac activity: fetal pole >5mm
30
Significance of clenched fist in fetus:
Trisomy 18 | trisomy 13
31
Findings of trisomy 18 on fetal ultrasound
``` clenched fist with overriding index finger heart defect (VSD) strawberry skull CP cyst single umbilical artery clubfoot micrognathia hypoplastic nasal bone ```
32
fetal long bone fracture
OI
33
Placenta accreta, percreta, increta:
accreta: villia attached to myometrium but no invasion increta: partially invade percreta: invade through and outside serosa
34
What lab value is useful to check for neural tube defects?
AFP (elevated in neural tube defects)
35
Name the three neural tube defects
Anencephaly 47% myelomeningocele 47% encephalocele 5%
36
Where are encephaloceles located?
posterior midline most common | next most common nasal/frontal
37
Vein of Galen malformation - what do you want to check for?
Heart failure/hydrops
38
Causes of antenatal ventriculomegaly:
TORCH infection, aqueductal stenosis, Chiari II, Dandy-Walker, trisomy 21
39
What's a porencephalic cyst? Caused by?
focal cystic area of encephalomalacia that communicates with the ventricular system and/or the subarachnoid space typically lined with white matter Caused by perinatal cerebral ischaemia, trauma, infection, antenatal intraparenchymal hemorrhage
40
Holoprosencephaly is associated with what genetics? What are the features of alobar holoprocensephaly?
Trisomy 13 | Fused thalami, absent falx and CC, monoventricle. Assoc with cyclopia and cleft lip.
41
What's the term for isolated enlargement of the occipital horns of the lateral ventricles? What does this indicate?
Colpocephaly | Agenesis of the corpus callosum
42
If the falx is present but there's no or very little brain tissue, what is it?
Hydranencephaly. | Ischemic insult early, no genetic component
43
``` Cleft lip (unilateral) - what are the chances of other problems? Cleft palate - now what chance of abnormalities? ```
lip: 20% chance palate: 50% chance (assoc with trisomy 13)
44
micrognathia - what associations?
trisomy 18, Treacher-Collins (others, but forget about them)
45
macroglossia - what associations
trisomy 21, Beckwith-Wiedeman, maternal DM, omphalocele
46
fetal pericardial effusion - what syndrome comes to mind?
trisomy 21
47
isolated pleural effusions - associated with:
trisomy 21, Turner's
48
cystic hygroma - associated with
Turner's, trisomy 21, 18, 13
49
definition of fetal hydrops: | What are the 4 compartments?
Fluid in two or more compartments | pericardium, pleural, abdomen, body (anasarca, cystic hygroma)
50
Dilated bowel in a fetus - ddx
ileal atresia, volvulus, ileal obstruction (meconium ileus) | Colon problems don't cause dilated bowel in a fetus!!
51
Ddx of echogenic bowel in fetus
Can be normal trisomy 21, CF, TORCH infxn 25% chance of future IUGR
52
2 most common causes of hydronephrosis
1: UPJ obstruction 2: Reflux
53
Causes of dilated ureter
Primary megaureter, reflux, posterior urethral valves (if bilateral)
54
What's the Spalding sign and what does it mean?
Overlap of the skull bones on fetal ultrasound, means fetal demise
55
What's a low lying placenta?
Within 2 cm of internal cervical os
56
associations with club foot?
Many, including Trisomy 18
57
Placental mass - looks cystic but is highly vascular = ? Associations? Concern?
Chorioangioma Beckwith-Wiedemann (others) anemia, heart failure
58
What is choriocarcinoma?
Aggressive, highly vascular tumor Sometimes in gestational trophoblastic dz sometimes in non-pregnant (ovary) or men (testes) Causes high b-HCG
59
a fetus appears to have a cardiac abnormality on ultrasound. Do you offer amnio?
Yes - for all congenital heart disease!
60
Findings of trisomy 21 / Downs on ultrasound:
``` thickened nuchal translucency (>3mm) short femur and humerus small/absent nasal bone echogenic bowel cardiac - ECD, ASD, VSD, echogenic focus duodenal atresia sandal gap toes ```
61
findings in trisomy 13
``` CNS - holoprosencephaly and others, spina bifida cardiac - HLHS, VSD cleft lip and palate micrognathia polydactyly, rockerbottom feet clenched hands ```
62
Internal carotid artery - what velocity indicates normal to 70%?
Peak systolic of up to 125 is normal Above 230 is >70% stenosis But always ask to see contralateral side - velocities increase to compensate if other side is occluded.
63
What causes the wild color of a color doppler of a carotid stenosis?
Aliasing - the inability to detect the true peak velocity because the Doppler sampling rate is too slow
64
You see a diaphragmatic hernia in a fetus. What now?
Determine side (usually L), look for other problems. Mention concern regarding pulmonary hypoplasia, including other lung from compression. CDH is associated with abnormal karyotype.
65
What's a complete placenta previa? Marginal? Low-lying?
Complete: covers internal cervical os Marginal: partly covers Low: less than 2 cm
66
What counts as endometrial thickening in a postmenopausal woman? What are the causes?
>4mm unless on hormones, so ask | Hyperplasia, polyps, cancer
67
Gestational trophoblastic disease - types, what to do about it. What else to look for/confirm?
Complete mole - sperm + empty egg hyperechoic/heterogeneous tissue, no fetal parts. 85% noninvasive, but the rest invade and 2% met as choriocharcinoma Partial mole: 2 sperm + egg may see fetal parts, especially early Ovaries: theca lutein cysts from high b-HCG
68
Thyroid ultrasound - see a hypoechoic mass just behind the thyroid - what is it? What do you say?
Probably parathyroid adenoma. You would check for hypercalcemia.
69
What's a target lesion in the liver on ultrasound? What might it be?
Hyperechoic center and hyopechoic periphery. Most likely malignancy - mets or HCC. Less likely adenoma or FNH or hemangioma (more typically reverse target). Also lymphoma, fungal microabscesses.
70
What is an echogenic intracardiac focus? What do you do if you see one?
Must be as bright as bone - calcification of a papillary muscle. May be normal variant, but look for Down's syndrome
71
Renal artery doppler - what's the normal peak velocity max?
Max 200cm/s - but must be careful of angle | Also check for parvus tardus post stenosis
72
Discuss transplant renal vein thrombosis
Usually within 1st week | Enlarged kidney, absent flow in vein, reversal of flow in diastole in artery.
73
Adrenal lesion in fetus or neonate
Hemorrhage | Neuroblastoma (met)
74
Hyperechoic (calcified) renal pyramids in an infant
Lasix is most common
75
causes of oligohydramnios
``` AFI less than 8, often just obvious Fetal demise bilateral renal abnormalities PROM postmaturity ```
76
Ddx for echogenic kidneys
In general, renal parenchymal disease If small: diabetic nephropathy, chronic glomerulonephritis, interstitial nephritis If large: HIV nephropathy
77
Incompetant cervix - findings? How diagnosed?
V or U shaped cervical funneling. US with EMPTY bladder. Don't press too hard (may artificially lengthen cervix)
78
Fluid collection around kidney - what do you need to ask? What's the ddx for early postop?
Time since transplant and is the patient infected Early postop: hematoma (document size, monitor for decrease, concern for page kidney) Seroma Urinoma (w/in 1st 1-2 weeks. check fluid for creatinine, requires surgery) Abscess (may have gas) Lymphocele (usually not for at least 3 weeks postop)
79
Intracardiac mass in utero
Most likely cardiac rhabdomyoma in TS
80
What causes gallbladder adenomyomatosis?
Cholesterol crystals in dilated Rokitansky-Aschoff sinuses