OB / GYN (YELLOW)

Which of the following is true about the "lemon" sign and neural tube defects?

(A) The "lemon" sign is not as accurate as the "banana" sign. (B) The "lemon" sign may be present in the normal fetus in the third trimester. (C) The "lemon" sign can be artificially produced at the level of the ventricles. (D) The "lemon" sign is a predictor for spina bifida. *(E) All of the above statements are true.*

Which of the following best describes acrania?

(A) abnormal brain tissue with absent calvarium (B) the first stage of anencephaly before prolonged exposure to amniotic fluid

Hemivertebrae may be identified on sonogram

(A) as a narrowing of the individual vertebrae in the coronal plane of view (B) as a narrowing of the individual vertebrae in the sagittal plane of view (C) as a narrowing of the individual vertebrae in the axial plane of view *(D) all of the above*

Dolichocephaly is often associated with what conditions?

(A) breech fetus (B) oligohydramnios

Which of the following might be fetal complications caused by maternal diabetes?

(A) caudal regression syndrome (B) cardiac defects (C) shoulder dystocia (D) both A and B *(E) all of the above*

Complications associated with Dandy-Walker malformation include

(A) chromosomal abnormalities (B) subnormal intelligence after birth (C) increased neonatal death (D) only A and B *(E) all of the above*

The term "neural tube defect" refers to

(A) spinal defect (B) open tube defect (C) anencephaly (D) cephalocele *(E) all of the above*

Brachycephaly is associated with what conditions?

(A) trisomy 21 (B) normal variant (C) myelomeningocele (D) both A and B (E) both A and C *(F) all of the above*

Cystic hygromas are associated with which of the following?

(C) elevated levels of alpha-fetoprotein (D) Turner's syndrome

Congenital hydrocephalus is

*(B) able to be detected in both male and females by DNA testing* *(C) expressed in males only*

The differential diagnosis for hydranencephaly may be

*(B) alobar holoprosencephaly (C) severe hydrocephaly*

Microcephaly is defined as

*both A and B*

The optimal time to assess measurements for nuchal translucency is

11-14 weeks

How early can anencephaly be detected on ultrasound?

14 weeks

Agenesis of the corpus callosum cannot be diagnosed by ultrasound before

18 weeks

The mean measurement for nuchal translucency is

3 mm

What percentage of cephaloceles are occipital?

75

The "banana" sign is present with spinal defects

95% of the time

Macroglossia is present how often in Beckwith-Wiedemann syndrome?

97% of the time

The downward displacement of the cerebellar vermis, the fourth ventricle, and medulla oblongata through the foramen magna is termed

Arnold-Chiari malformation

Findings on ultrasound include an increased cisterna magna, agenesis of the cerebellar vermis with communication to the fourth ventricle and ventriculomegaly. What is the most likely diagnosis?

Dandy-Walker malformation

A patient states she was given a medication called RhoGAM after she had vaginal spotting in pregnancy. This was most likely due to

Rh-negative status of the mother

Hydranencephaly is thought to result from

a vascular accident of the internal carotid arteries

Cyclopia, hypotelorism, proboscis, cebocephaly, and cleft lip/palate are

abnormal facial findings

Intracranial calcifications and microcephaly of the fetus are associated with

agenesis of corpus callosum

A patient presents for an anatomy scan. The fetal head shows a single large cystic cavity with a rim of cerebral cortex. A fused thalamus is also identified. What is the most likely diagnosis?

alobar holoprosencephaly

In a normal fetus, if the middle cerebral artery were sampled, one would expect to find which of the following?

an increased S/D ratio

The most common cause of hypertelorism is

anterior cephalocele

What is the name of the anatomic opening between the third and fourth ventricle?

aqueduct of Sylvius (cerebral aqueduct)

Findings on ultrasound include hydrocephaly, an enlarged cisterna magna, and an intact cerebellar vermis elevated by a cyst in the posterior fossa. What is the most likely diagnosis?

arachnoid cyst

A fetus presents with an anechoic midline lesion in the brain, fetal hydrops, and congestive heart failure. What is the most likely diagnosis for the lesion?

atrioventricular malformation

What is the most common type of isolated cleft lip/palate?

cerebellum

What is the primary infection that causes varicella-zoster virus (VZV)?

chicken pox

Which of the following is usually not a cause of oligohydramnios?

cystic hygroma

Which of the following sonographic findings is not associated with trisomy 18?

cystic hygroma

What is the most common congenital intrauterine viral infection?

cytomegalovirus

If the cephalic index is < 75, it is an indication of what condition?

dolichocephaly

Which of the following best describes the "banana" sign?

flattening of the cerebellum

Hydrosalpinx may be differentiated from a multi-cystic ovarian mass on sonogram by

following the cystic spaces to ensure that they all communicate

A medial cleft lip has a strong association with what abnormality?

holoprosencephaly

The most common cause of hypotelorism is

holoprosencephaly

What other findings are associated with Dandy-Walker malformation?

holoprosencephaly

A patient presents for an anatomy scan. The fetal head shows the cranium filled with anechoic fluid, and no cerebral cortex is identified. The brainstem is identified. What is the most likely diagnosis?

hydranencephaly

Absent cerebral cortex is found in what cranial abnormality?

hydranencephaly

Caudal regression syndrome is associated with

insulin-dependent diabetes mellitus

Which of the following is true regarding the fluid within a cystic hygroma?

lymphatic fluid

Which of the following terms is used in association with cystic hygroma and enlarged nuchal translucency?

mesenchymal edema

Large encephaloceles may be associated with

microcephaly

Sonographic measurements taken between the outer edge of the occipital bone to the outer margin of the skin is called

nuchal fold

Cystic hygromas are caused by which of the following?

obstruction of the lymph system at the level of the jugular veins

Myelomeningocele refers to

protrusion of meninges and neural tissue though a defect

Enlarged nuchal translucency is often associated with all of the following except

rhombencephalon

A patient presents for an anatomy scan. The fetal head shows a single ventricle, single choroid, two cerebellar hemispheres, and fused thalamus. The abnormality is most likely

semilobar holoprosencephaly

In 90% of cases with agenesis of the corpus callosum, what other sonographic finding is present?

teardrop ventricles

The "banana" sign of the fetal cranium in diagnosing spina bifida refers to

the appearance of the cerebellum in the presence of a spinal defect

The "lemon" sign of the fetal cranium in diagnosing spina bifida refers to

the appearance of the fetal skull in the presence of a spinal defect

Eighty percent of cystic hygromas occur in what region?

the cervical region

The nuchal skin fold in the second trimester should be measured at what level?

the level of the cavum septi pellucidi, cerebellum and cisterna magna

The most common chromosomal abnormality associated with holoprosencephaly is

trisomy 13

Choroid plexus cysts, when found with other associated abnormalities, have a strong association with which of the following conditions?

trisomy 18

What cranial finding can cause congestive heart failure and hydrops?

vein of Galen aneurysm