Pregnancy Flashcards
1
Q
What is the earliest imaging finding in early pregnancy?
A
Gestational sac
2
Q
What are two findings that may aid in the detection of very early pregnancy?
A
- Intradecidual sign
- Double decidual sac sign
3
Q
What is the intradecidual sign?
A
- The intradecidual sign represents the gestational sac within the thickened decidua, seen at =5 weeks.
4
Q
What is the double decidual sac sign?
A
- The double decidual sac sign represents two echogenic rings encircling the gestational sac. It is most useful when seen, where it confirms the presence of an intrauterine pregnancy (IUP).
- The absence of a double decidual sign is considered indeterminate and may suggest either an IUP or the pseudogestational sac of an ectopic pregnancy.
5
Q
What is a pseudogestational sac?
A
A pseudogestational sac is an intrauterine fluid collection surrounded by a single decidual layer, seen in the context of ectopic pregnancy.
6
Q
At what b-hCG level should a gestational sac be seen via transvaginal US and normally how far along in a pregnancy?
A
- A gestational sac should be seen by transvaginal ultrasound if the b-hCG is greater than 1,500. The gestational sac is normally seen by 5 weeks.
7
Q
What is a subchorionic hematoma, and what is its clinical significance?
A
- A subchorionic hematoma is a potential complication of early pregnancy caused by bleeding of the chorionic attachment.
- A small subchorionic hematoma surrounding the gestational sac is of no clinical significance.
- A large subchorionic hematoma will cause an approximately 40% chance of pregnancy failure.
8
Q
What is the function of the yolk sac?
When is it normally seen?
What is the significance of an abnormally large yolk sac?
A
- Unlike in a chicken’s egg, the fetal yolk sac doesn’t contain any nutrients. It is a vestigial structure that functions in the early circulation before the development of the heart.
- The yolk sac is normally seen by 5.5 weeks.
- If the yolk sac is abnormally large (>6 mm), the pregnancy has a high chance of failure.
9
Q
What is an algorithm to determine chorionicity and amnionicity?
A
10
Q
What would a dichorionic - triamniotic pregnancy look like on US?
A
11
Q
Why do we look at cerebellum/cisterna magna during fetal US?
A
12
Q
What are the landmarks for head circumference measurement for fetal biometrics?
A
- Cavum septi pelucidi
- Thalamus
- Tentorium (not cerebellum)
13
Q
Landmarks for biparietal diameter in fetal biometrics
A
- Third ventricle flanked by thalami
14
Q
What are the criteria anatomic landmarks for abdominal circumference for fetal biometrics?
A
- Portal venous confluence
- The shortest length of the umbilical segment of left portal vein.
- Lower ribs are symmetric
- Stomach usually present
15
Q
Fetal biometric criteria for femur length
A
- only measure the ossified portion of the femur.
16
Q
Enlarged cysterna magna? What should you check for?
Significance?
What about an absent cysterna magna?
A
- Vermis of the cerebellum and 4th ventricle.
- If present, then you know your dealing with a megacisterna or arachnoid cyst.
- If absent then you got a dandi walker bro.
- Absent cisterna magna = chiari! (banana sign) Then check for the lumbar spine for meningomyelocele.
17
Q
Absence of cavum septi pelucidi is associated with what anomalies?
A
- Agenesis of corpus callosum
- Septo-optic dysplasia
- Holoprosencephaly
18
Q
What is the significance of a choroid plexus cyst?
A
- Loose association with trisomy 18
- Very common in the normal fetus
- A huge one is concerning
- Look for other anomalies (ie solitary choroid plexus cyst need not to follow up)
- Document OPEN HAND (since trisomy 18 has that clenched fist)
19
Q
What is the significance of an echogenic intracardiac focus in fetal US?
A
- It is calcification of papillary muscle
- very common in normal fetus
- Associated with down syndrome
- Check nuchal thickness!
20
Q
What is the landmark for obtaining a adequate US fetal image for LVOT?
A
The anterior wall of the aorta must line up with interventricular septum
21
Q
What may a “lying down adrenal gland” signify
A
Renal Agenesis
22
Q
What would a “key-whole” bladder signifiy?
A
Posterior urethral valves
23
Q
What loose association occurs with mild pelviectasis on fetal ultrasound
A
- Soft marker for Down’s
- Potential for progression
24
Q
What would can echogenic bowel within the fetal US be associated with?
A
- cystic fibrosis
- chromosomal abnormalities
25
Q
Crown rump length vs. fetal heart rate . . . at what length with no hear beat is a pregnancy 100% non-viable?
A
7mm. If the fetus has no heart beat at >/=7mm, then fetus is not viable.
26
Q
Discuss the determination of gestational age of an embryo between 5 and 6 weeks.
A
- Between 5 and 6 weeks gestation, gestational age is determined based on three typical appearances of the early pregnancy.
- gestational sac only (with or without double sac sign): 5.0 weeks.
- gestational sac with a yolk sac, but without an embryo: 5.5 weeks.
- gestational sac with an embryo <3 mm and heartbeat: 6 weeks.
- For embryos >3 mm in length, the crown-rump length is used to assign gestational age using established reference tables. The CRL can estimate gestational age up to 12 weeks. After 12 weeks, dating is estimated using multiple fetal measurements.
27
Q
Give 5 scenarios of guarded pregnancies
A
28
Q
Where is an especially dangerous place for an ectopic pregnancy to occur?
Why is this so?!
How to ID on US?
A
- An especially dangerous location for an ectopic pregnancy is the interstitial portion of the fallopian tube.
- An interstitial ectopic carries an especially high risk of catastrophic hemorrhage due to its propensity for delayed rupture and proximity to the ovarian vessels.
- Ultrasound of an interstitial ectopic shows absent myometrium along the lateral edge. The interstitial line-sign represents a thin, echogenic line extending from the endometrial canal to the center of the interstitial ectopic mass. This echogenic line is thought to represent the nondistended, empty endometrial canal.
29
Q
How to measure amniotic fluid?
A
The trunk should fill up entire amniotic sac + smaller pockets are communicating.
30
Q
What is a heterotopic pregnancy?
Who’s at risk?
A
- A heterotopic pregnancy is a simultaneous IUP and ectopic pregnancy.
- Patients undergoing assistive reproductive techniques are at increased risk for heterotopic pregnancy. Prior to the popularity of these fertilization procedures, heterotopic pregnancies were extremely rare.
- Given the increased prevalence of assistive reproductive techniques, however, the adnexa must be carefully evaluated even in the presence of an IUP.
31
Q
What is a “rule-out ectopic” patient?
What is the algorithm for the “rule-out ectopic” patient?
A
- The classic clinical presentation of ectopic pregnancy is a positive pregnancy test, vaginal bleeding, pelvic pain, and tender adnexal mass. This presentation is seen in less than 50% of patients.
- Any woman with a newly positive pregnancy test and either pain or bleeding is classified as a rule-out ectopic or clinically suspected ectopic patient and has about a 15% chance of having an ectopic pregnancy before any imaging is performed.
- A rule-out ectopic patient may have an intrauterine pregnancy (IUP), ectopic pregnancy, or spontaneous abortion. The IUP may be normal, abnormal, or too early to detect.
32
Q
Discuss image findings of an ectopic pregnancy
A
- In the absence of an IUP, an adnexal mass has a 92% positive predictive value of being an ectopic.
- In the absence of an IUP, an adnexal ring has a 95% positive predictive value of being an ectopic.
- An extrauterine embryo (with or without heartbeat) or mass with yolk sac has a 100% predictive value of being an ectopic.
- The nonspecific ring of fire sign describes increased peripheral color doppler flow surrounding an adnexal mass. This sign is rarely helpful as it can be seen in both ectopic pregnancy and corpus luteum.
- In a rule-out ectopic patient, an ovarian mass is overwhelmingly more likely to be a corpus luteum than an ectopic pregnancy unless a definite embryo or yolk sac is identified. In contrast, an extra-ovarian mass would be concerning for ectopic. In ambiguous cases, it may be helpful to gently apply pressure with the ultrasound probe and watch for movement of the mass with respect to the ovary to identify if a mass is ovarian or adnexal in origin.
33
Q
Ectopic locations
A
34
Q
What is a gestational trophoblastic disease?
Classic presentation?
US appearance?
Treatment?
A
- Gestational trophoblastic disease, also called hydatidiform molar pregnancy (or molar pregnancy for short), is an invasive neoplastic overgrowth of the trophoblast into the myometrium or beyond. The trophoblast normally develops into the placenta.
- The classic clinical presentation of molar pregnancy is hyperemesis, markedly elevated hCG, and an enlarged uterus. The patient may also present with painless vaginal bleeding.
- On ultrasound, molar disease causes uterine enlargement with a classic heterogeneous and multicystic snowstorm appearance. visualization of fetal parts suggests a partial mole.
- Treatment of a molar pregnancy is endometrial suction curettage and close follow-up of serum hCG levels.
35
Q
What is a “complete” hydatidiform mole?
What can this progress to?
What are they associated with?
A
- Complete hydatidiform mole does not contain any fetal parts. It is caused by loss of the egg’s DNA prior to fertilization by the sperm and has a diploid karyotype of 46,XX (most commonly) or 46,XY.
Pathoma MNEMONIC: “Completely the dad’s fault and the one that has risk of progressive to metastatic chorioCA
- A complete mole may progress to metastatic choriocarcinoma.
- Molar pregnancy is associated with theca lutein cysts, which arise in response to elevated hCG.
36
Q
What is a Chorioadenoma destruens?
A
- Chorioadenoma destruens is a complete mole that invades the myometrium.
37
Q
What is a partial hydatidiform mole?
A
- Partial hydatidiform mole is associated with some fetal development. It is usually caused by two sperm fertilizing the same egg and has a triploid karyotype of 69,XXX, 69,XXY, or 69,XYY.
- Partial mole is less likely to progress to choriocarcinoma.
38
Q
What is retained products of conception?
What can it lead to?
US appearance?
A
- Retained products of conception are placental or fetal tissues that remain the uterus after delivery, miscarriage, or termination.
- Untreated RPOC can lead to continued maternal bleeding and endometritis.
- The sonographic findings of an endometrial blood clot and RPoC overlap and it is often not possible to differentiate between these two entities. An endometrial mass, with or without Doppler flow, in the appropriate clinical context has only about a 50% positive predictive value. The presence of Doppler flow is not diagnostic of RPOC, as endometrial color doppler flow can be detected in the presence or absence of RPOC.
- Color Doppler flow is seen more commonly with RPOC, however.
- A normal-appearing uterus, with an endometrial thickness of less than 10 mm, is highly unlikely to contain RPoC.
39
Q
What is zygosity?
What are “fraternal” twins?
A
- The zygosity (number of fertilized eggs) cannot always be determined by ultrasound.
- Monozygotic twins can have any placentation type, depending on when the developing zygote splits. dizygotic twins, however, are always diamniotic/dichorionic, and only dizygotic twins can be different sexes.
- Monozygotic (“identical”) twins arise from a single egg fertilized with a single sperm.
- Dizygotic (“fraternal”) twins arise from two individually fertilized eggs.
- Dizygotic twins are always dichorionic/diamniotic.
40
Q
Discuss monozygotic twins and timeline
A
- onozygotic twins are the result of splittng of the blastocyst or embryo, formed by fertilization of a single egg by a single sperm. Although “identical” monozygotic twins are always the same sex, they may not be identical phenotypically due to local differences in the uterine and placental environment.
- 33% split early (0-4 days), before the formation of either the placenta or amnion, leading to dichorionic-diamniotic twins.
- 66% split intermediate (4-8 days), after formation of the placenta but before the amnion has developed, leading to monochorionic-diamniotic twins.
- 1% split late (>8 days), after formation of the chorion and amnion, leading to monochorionic-monoamniotic twins.
- Very late splitting may result in conjoined twins, which are always monochorionic/monoamniotic.
41
Q
Di/di twins
US findings
A
- Di/di twins each have a separate placenta and amniotic sac.
- On ultrasound, two placentas can usually be separately identified.
- The inter-twin membrane will be relatively thick as there are two layers of chorion and two layers of amnion separating each twin.
- In the second and third trimesters, the thickness of the inter-twin membrane is less reliable to determine chorionicity because the membrane becomes thinner as gestation progresses.
- The twin peak sign (also called lambda sign) represents a triangle-shaped placental infolding at the interface of the placenta and the thick inter-twin membrane that is seen in di/di twins. The twin peak sign is most useful when it is difficult to distinguish two placentas.
- If the twins are different sexes, they must be dizygotic twins, which are always di/di.
42
Q
Mono/di twins
US appearance
A
- Mono/di twins share a placenta, but have separate amniotic sacs.
- The shared placenta is usually apparent on ultrasound.
- The inter-twin membrane is thin, as it is composed of only two layers of amnion.
43
Q
Mono/mono twins
US appearance
A
- ono/mono twins share both a placenta and a single amniotic sac.
- mono/mono twins have a shared placenta with no intervening membrane between the twins. Intertwined cords are diagnostic of mono/mono placentation when seen.
- Isolated lack of visualization of an inter-twin membrane is not sufficient to diagnose mono/mono twins. If no inter-twin membrane (or intertwining cord) is seen, then the amnionicity cannot be determined. Because mono/mono twins are so rare, it is more common to have mono/di twins with non-visualization of the inter-twin membrane.
44
Q
What are conjoined twins and when does incomplete splitting occur for this to happen?
A
- Conjoined twins are caused by late (>13 days) incomplete division of the embryo.
45
Q
What is twin-twin transfusion syndrome?
US appearance and criteria?
A
- Twin-twin transfusion syndrome (TTTS) is a complication of monochorionic twins (either mono- or di-amniotic) caused by disproportionate blood flow between the fetuses.
- The donor twin transfers excess blood flow to the recipient twin. The donor twin is small and has oligohydramnios. The recipient twin is larger and has polyhydramnios.
- There are three criteria to diagnose TTTS by ultrasound:
- Disproportionate fetal sizes, with at least 25% discrepancy.
- Disproportionate amniotic fluid, with the small twin having oligohydramnios and the large twin having polyhydramnios.
- Single shared placenta (monochorionic).
- There is a spectrum of severities of TTTS. In the earliest stages, the donor twin’s bladder is still visible and the direction of umbilical artery doppler flow is normal. Later stages are marked by fetal hydrops or death.
46
Q
Treatment options for twin-twin transfusion syndrome?
A
- Treatment options of TTTS include laser ablation of placental arteriovenous fistulas, therapeutic amniocentesis from the recipient (large, poly) twin, or selective coagulation of the umbilical cord of the less viable twin.
52
Q
Evaluation of the first-trimester embryo:
Ventral abdominal wall
A
- The midgut normally herniates through the ventral abdominal wall in the first trimester. during this herniation, the midgut rotates 270 degrees around the axis of the superior mesenteric artery.
- Physiologic midgut herniation is usually complete by 12-13 weeks. Therefore, a pathologic ventral wall defect, such as omphalocele or gastroschisis, is generally not diagnosed before 13 weeks.
- It is common to see some fullness at the base of the umbilical cord before 13 weeks, which usually represents physiologic midgut herniation. If the fullness is especially prominent then it may be prudent to bring the patient back for a follow-up at 13 weeks to evaluate for a true ventral wall defect.
53
Q
Evaluation of the first-trimester embryo:
Nuchal translucency
A
- Increased thickness of the nuchal translucency is associated with increased risk of down syndrome and other chromosomal abnormalities. With a fixed false-positive rate of 5%, nuchal translucency alone can detect approximately two-thirds of cases of trisomy 21.
- The nuchal lucency must be measured properly to obtain an accurate value.d
- At 11 weeks, the upper limit of normal is 2.2 mm.
- At 14 weeks (CRL 79 mm), the upper limit of normal is 2.8 mm.
- Nuchal translucency is combined with maternal serum testing to calculate an overall risk of trisomy 21.
54
Q
Nuchal fold (second trimester only)
A
- A thickened nuchal fold is the most sensitive and specific ultrasound finding to suggest down syndrome.
- Compared to nuchal lucency, measurement of nuchal fold is performed later in pregnancy. In contrast to the nuchal lucency, the nuchal fold is measured in the axial plane at the level of the posterior fossa.
- The nuchal fold is only measured from 16-20 weeks.
- 5 mm is normal.
- 5-5.9 mm is borderline.
- 6 mm is a major marker for trisomy 21.
- A very thick nuchal fold may represent a cystic hygroma, which is associated with Turner syndrome (45,X).
55
Q
What is the measurement for cervical shortening?
Treatment?
A
- Shortening of the cervix is a risk factor for pre-term delivery. A cervical length <3 cm is abnormal. The presence of cervical funneling (change in shape) is an ancillary finding.
- The mnemonic trust your vaginal ultrasound can be used to remember the sequence of cervical funneling. A T -shaped cervix is normal. As funneling progresses, the cervix resembles Y, V, and U shapes.
- Prior to viability (24 weeks), treatment is cervical cerclage. After 24 weeks, treatment tends to be conservative (bedrest) due to concern for membrane rupture with any procedure.
58
Q
What is vasa previa?
What two kinds are there?
How do you check for this via US?
A
- Vasa previa is the traversing of fetal placental vessels across the internal cervical os, which can be caused by velamentous insertion or a placental succenturiate lobe.
- Velamentous insertion is the insertion of the umbilical cord outside the margin of the placenta.
- A succenturiate lobe is an island of placental tissue separate from the main placenta, connected to the main placenta by blood vessels.
60
Q
US appearance of acute placental abruption
A
61
Q
US appearance of chronic placental abruption
A
63
Q
US appearance of placenta accreta
A
- Ultrasound findings of accreta include loss of the normal retroplacental clear space, abnormalities at the bladder/placental interface, and prominent vascular lacunar spaces. The presence of a moth-eaten placenta with vascular lacunar spaces near the bladder is highly specific for accreta.
64
Q
What is fetal hydrops?
A
- Hydrops is a fluid-overload state characterized by at least two of the following:
- Ascites, pleural or pericardial effusion, skin thickening, polyhydramnios, and placental enlargement.
- Hydrops may be classified as immune or non-immune. Prognosis is variable but tends to be poor for non-immune hydrops.
77
Q
What is ventriculomegaly?
Measurements?
What is a “dangling choroid”?
What are the etiologies of ventriculomegaly?
A
- Throughout gestation, the lateral ventricles should each measure less than 10 mm when measured at the atrium. The atrium is the confluence of the lateral ventricle, temporal horn, and occipital horn. The normal choroid plexus has a rounded border in this location.
- Ventriculomegaly is >10mm; Mild ventriculomegaly: 10-12 mm; moderate: 12-15 mm; marked: >15 mm
- Normally, the choroid plexus fills the lateral ventricle. The dangling choroid sign represents the dependent drooping of choroid plexus seen in ventriculomegaly.
- ventriculomegaly may be present even in a ventricle measuring <10 mm if there is >3 mm of fluid between the medial margin of the ventricle and the choroid.
- Ventriculomegaly is a sign that something else is wrong, with a diverse array of etiologies:
- Primary CNS structural (aqueductal stenosis, Dandy-Walker, Chiari II, holoprosencephaly, agenesis of the corpus callosum).
- Genetic (trisomies 13 and 18).
- Destructive (due to infection, hemorrhage, or infarct).
- Idiopathic.
78
Q
What is anencephaly?
What marker is elevated?
What can this do to amniotic fluid?
What is angiomatous stroma?
What is the main differential and how to tell the difference?
A
- Anencephaly is a lethal anomaly with complete lack of development of fetal cerebral cortex and calvarium above the orbits.
- AFP is elevated in anencephaly, as there is direct exposure of neural tissue to the amniotic fluid.
- Anencephaly may cause polyhydramnios due to impairment in swallowing.
- Angiomatous stroma is residual neural-type tissue that may be tethered above the head and may be confused with an encephalocele.
- The differential of anencephaly is amniotic band syndrome, which is almost always asymmetric.
81
Q
Chiari malformation
What is it?
Which malformation is the one associated with what other findings?
US appearance/signs?
A
- Chiari II is the combination of a small posterior fossa and a neural tube defect. By far the most common associated neural tube defect is a lumbar myelomeningocele. A myelomeningocele contains both neural elements and meninges.
- The banana sign describes the characteristic flattened cerebellar hemispheres in the small posterior fossa. The banana sign is very specific for Chiari II. In fact, if the banana sign is seen, then a myelomeningocele is presumed to be present even if not identified on ultrasound.
- The lemon sign describes flattening of the frontal bones, causing the calvarium to have the morphology of a lemon when seen axially. Unlike the banana sign, the lemon sign is not specific for Chiari II.
82
Q
Holoprosencephaly
What is it?
What is the characteristic finding in most severe form?
Associations?
A
- Holoprosencephaly is failure of midline cleavage of the primitive prosencephalon in early embryologic development. The most severe form, alobar holoprosencephaly, leads to fused thalami and a single monoventricle that may communicate with a large dorsal cyst. Brain tissue surrounds the monoventricle, forming a characteristic boomerang shape.
- Holoprosencephaly is associated with trisomy 13, facial hypoplasias, and midline facial anomalies including clefts.
84
Q
Choroid Plexus Cyst
What is it?
Potential mimickers?
A
- Cysts within the choroid plexus are common (seen in 1-5% of fetal surveys). The vast majority of choroid plexus cysts are present in normal fetuses and resolve on follow-up scans. However, up to 50% of trisomy 18 fetuses will have choroid plexus cysts.
- Choroid plexus cysts can be considered an incidental finding in the absence of any other sonographic abnormality and with a normal maternal serum screen.
- A potential mimicker of a choroid plexus cyst is the spongy choroid, which describes a heterogeneous echogenic choroid that is a normal variant.
- Also, a scary pitfall is subependymal hemorrhage! (ie from minifellow) A more chronic SEH looks cystic! Use anatomy to differentiate this (ie the choroid plexus is not in the frontal horns it’s in the atrium).
85
Q
What is a vein of Galen malformation?
What causes it?
What might it cause?
A
- Vein of Galen malformation is dilation of the vein of Galen (in the pineal region) caused by an arteriovenous fistula.
- Vein of Galen aneurysm is a shunt lesion that may cause high-output cardiac failure, leading to hydrops.
92
Q
Duodenal Atresia
- What is it?
- Association?
- Classic US appearance?
- DDx for the classic sign as above?
A
- Duodenal atresia causes duodenal obstruction from lack of recanalization of the duodenal lumen. duodenal atresia is the most common cause of fetal duodenal obstruction.
- Approximately one-third of babies with DA will have down syndrome. If a double bubble sign is seen, a careful screen for additional findings of down syndrome should be performed (e.g., thorough heart exam, nuchal fold if 16-20 weeks, etc.).
- The classic appearance of DA is the double bubble sign, representing a dilated stomach and dilated proximal duodenum. The differential diagnosis of the double bubble sign includes duodenal web, stenosis, and annular pancreas.
98
Q
Gastroschisis
- What is it? Location?
- Associations?
- Seen more commonly in what kind of mothers?
- Prognosis?
A
- Gastroschisis is a paraumbilical (usually right-sided) anterior abdominal wall defect, through which bowel herniates without a peritoneal covering. Gastroschisis is the second most common abdominal wall defect.
- Unlike omphalocele, gastroschisis is usually seen as an isolated anomaly.
- Gastroschisis is seen more commonly in very young (teenage) mothers.
- Prognosis is similar to a simple omphalocele (with no other associated abnormalities).
100
Q
p545 - Fetal GU tract
A
106
Q
What is ARPKD?
US findings?
Prognosis?
Association?
A
- ARPKD is a congenital disorder of diffuse collecting tubule dilation, leading to innumerable tiny renal cysts that are too small to be resolved by sonography.
- Ultrasound findings include very large and echogenic kidneys and severe oligohydramnios, caused by markedly reduced renal function.
- Prognosis is poor. ARPKD is associated with hepatic fibrosis if the baby survives infancy.
MNEMONIC: “cysts in kidney, cysts in liver (leading to congenital hepatic fibrosis and protal htn, cystic dilation in brain (aneursym), butt (diverticuli) and the heart (MVP)!
108
Q
What is osteogenesis imperfecta?
What does it cause and how does it appear on US during pregnancy?
Contrast OI to thanatophoric dysplasia.
A
- Osteogenesis imperfecta (OI) is a spectrum of congenital bone anomalies characterized by multiple fractures due to abnormal type I collagen. There are several types, with type 2 being lethal. Type 2 can be diagnosed in the second trimester, but types 1, 3, and 4 are not typically diagnosed until the third trimester
- OI causes severe shortening of the long bones (>3 SD below the mean). The long bones and ribs appear “wrinkled” due to multiple fractures. The thorax is usually small due to broken and structurally soft ribs.
- Unlike thanatophoric dysplasia, bony mineralization is decreased. Decreased calvarial mineralization causes the entire brain (including the nearfield) to be visualized well.
110
Q
What is a sacrococcygeal teratoma?
US appearance?
Association?
Primary differential consideration?
A
- Sacrococcygeal teratoma is a germ cell tumor of the sacrum. It often presents prenatally as a mixed solid and cystic complex mass.
- Sacrococcygeal teratoma may be associated with high output cardiac failure.
- The other primary differential consideration for a distal fetal spinal mass is a myelomeningocele, which is associated with spine abnormalities and a dorsal skin defect.
112
Q
Trisomy 13 - from head to toe
A
- Holoprosencephaly and midline facial anomalies.
- Encephalocele.
- Congenital heart disease.
- Omphalocele.
- Horseshoe kidney.
- Polycystic kidneys.
- Polydactyly.
113
Q
Trisomy 18 - from head to toe
A
- Strawberry sign: Inward bowing of the frontal bones creates a strawberry shape to the calvarium, with the tip of the strawberry projected anteriorly.
- Choroid plexus cysts.
- Facial cleft.
- Micrognathia.
- Cardiac anomalies.
- Omphalocele.
- Congenital diaphragmatic hernia.
- Horseshoe kidney.
- Hydronephrosis.
- Clenched hand that never opens, with overlapping fingers.
- Rocker bottom feet.
114
Q
Trisomy 21 - from head to toes
A
- Increase in nuchal fold (>6mm) measured between weeks 15 and 21, is the single most sensitive and specific ultrasound finding for trisomy 21.
- In contrast, nuchal translucency is measured earlier in the pregnancy (11–14) weeks, and is less specific for trisomy 21
- Absent ossification of nasal bone.
- Cystic hygroma (although more common in Turner syndrome).
- Congenital heart disease: VSD and endocardial cushion defect in particular.
- Echogenic bowel.
- Duodenal atresia.
- Echogenic intracardiac focus.
- Shortened femur and humerus.
- Hypoplasia of the middle phalanx of the little finger.
- Sandal gap toes.
