Ob

Front 1

1. At what gestational sac size should the yolk sac be seen? Until what gestational age is the yolk sac seen?
2. At what gestational sac size should be the fetal pole be visible?
3. Fetal heart rate should be detected at what fetal pole size?
4. What is the approximate size ratio of the gestational sac to the fetal pole?
5. Is the yolk sac intra- or extra-amniotic?
6. At what gestational age do the amnion and chorion fuse?

Back 1

1. The yolk sac should be visible when the gestational sac is 10mm in diameter. The yolk sac remains visible till the first trimester. NOTE: The yolk sac confirms that an intrauterine fluid collection represents a gestational sac.
2. Fetal pole should be visualized when the gestational sac diameter is 18 mm.
3. Fetal heart tones should be detected when the fetal pole measures 5mm. NOTE: Fetal heart tones confirm a live intrauterine pregnancy.
4. Normal gestational sac is about twice the length of the fetal pole. If the fetal pole is too small for the sac or too large for the sac, fetal demise often results.
5. Yolk sac is extra-amniotic.
6. 14-16 weeks. This is why you cannot do an amniocentesis in the first trimester.

Front 2

1. What is the normal fetal heart rate?
2. If the heart rate is below the normal fetal heart rate, what should be recommended?
3. When is a lower heart rate normal?

Back 2

1. Normal cardiac activity is between 120-160 bpm.
2. Slower heart rate is associated with pregnancy loss. Therefore, close follow up is recommended.
3. Heart rate of 100-115 is normal between 5 and 6 weeks. Remember this as the heart is just getting started.

Front 3

1. What measurements are used for dating in the first trimester?
2. What measurements are used for dating in the second trimester?
3. What measurements are used for dating in the third trimester?

Back 3

1. In the first trimester, mean gestational sac size is used early on, followed by CRL.
2. BPD
3. BPD

Front 4

1. What is the normal doubling time of beta HCG?
2. What is the normal half life of beta HCG?
3. At what beta HCG levels, should a gestational sac be visible?

Back 4

.
- Half life is 2 weeks. Therefore, with pregnancy loss there is persistence of a positive b-HCG test for a while.
- If b-HCG > 1000-2000, you should see a gestational sac.

Front 5

1. What is the concern if a pt with a miscarriage or D&C has persistent vaginal bleeding?
2. What is the normal endometrial thickness following D&C?
3. What is the differential diagnosis if the endometrial thickness is > 5mm after D&C?

Back 5

1. Retained POC.
2. Following D&C, the endometrial thickness should not be greater than 5mm.
3. If the endometrial thickness is greater than 5mm, consider:
- Retained products of conception: Use color doppler as active trophoblastic tissue will give arterial waveforms with elevated diastolic flow.
- Normal decidua (endometrium)
- Hemorrhage

Front 6

1. What are the imaging features of hydrops fetalis?
2. What is the outcome of hydrops fetalis?
3. What is the underlying etiology of hydrops fetalis?
4. What are the causes of hydrops fetalis?

Back 6

1. Look for pleural and pericardial effusions as well as ascites. There is associated skin/scalp edema and placentomegaly.
2. Outcome of a fetus with fetal hydrops is generally poor with mortality higher than 70%.
3. The underlying etiology of hydrops fetalis is fetal anemia. Due to anemia, the heart needs to pump a much greater volume of blood to deliver the same amount of oxygen.
The increased demand for cardiac output leads to heart failure and corresponding edema.
4. The cause of anemia can be divided into immune vs. non-immune. Most common immune cause is Rh incompatibility which accounts for a minority of cases. Most cases of hydrops fetalis are related to non-immune causes (most common = cardiac)
- Infection = TORCH and Parvovirus
- In the first trimester = most cases are due to a chromosomal defect (Trisomy 13, 18, 21 and Turner syndrome) which results in lymphatic obstruction resulting in pleural/pericardial effusion, skin thickening, etc. Look for nuchal translucency greater than 3mm. Some believe that increased nuchal translucency (>3mm) is the first manifestation of fluid accumulation.
- In the second trimester = structural abnormalities. Cardiac malformation and cardiac arrhythmias are most common. Cystic hygroma in the neck may obstruct venous return to the heart.
- Other common causes of high output cardiac failure include teratomas (especially sacrococcygeal), vein of Galen malformation, hepatic hemangioendothelioma due to arteriovenous shunting.

Front 7

1. What is a normal cervical length during pregnancy?
2. Why is cervical length important?
3. What is funneling? What is the prognostic significance of "V" and "U" shaped funneling?
4. How can bladder distention affect the appearance of the cervix?
5. What provocative maneuver can help distinguish cervical incompetency?

Back 7

1. Normal cervical length is 3 cm or more; 2 to 3 cm is borderline; and less than 2 cm is definitely abnormal.
2. The risk of preterm labor increases as the cervical length shortens.
3. Funneling is defined as dilatation of the internal os. V-shaped funneling is more predictive of preterm delivery than U-shaped funneling.
4. A distended urinary bladder compresses the lower uterine segment creating a false appearance of a long cervix. Therefore to accurately assess for the cervical competency, you should do transvaginal scanning with an empty bladder.
5. Transfundal pressure over the uterus may dilate the cervix if it is incompetent.

Front 8

1. Name some calvarial abnormalities seen in the fetus?
2. Lemon head is associated with what brain abnormality?
3. Strawberry shaped skull is seen in what trisomy?
4. What is the cloverleaf skull associated with?
5. What does the Spalding sign indicate?

Back 8

1. Lemon head, strawberry calvarium, cloverleaf skull, Spalding sign.
2. Lemon head deformity 2/2 frontal bone concavity is associated with open neural tube defect such as Chiari II malformation. A compressed cerebellum gives a "banana-shaped" appearance to the cerebellum. Associated findings include ventriculomegaly, obliteration of the cisterna magna, spina bifida with myelomeningocele. NOTE: a club foot deformity may also be seen.
3. Trisomy 18.
4. Cloverleaf skull is seen in thanatophoric dwarfism.
5. Spalding sign describes overlapping of skull bones seen with fetal demise.

Front 9

1. What is the most common common cause of small bowel obstruction in a fetus?
2. What numbers are used to define small bowel obstruction?
3. Is duodenal atresia secondary to a vascular insult?
4. What are some other causes of small bowel obstruction in the neonate?

Back 9

1. Small bowel atresia is the most common cause of fetal small bowel obstruction. Atresia can occur in multiple sites and results from in utero vascular compromise.
2. Small bowel obstruction is defined as bowel loops greater than 7 mm in diameter and greater than 15 mm in length.
3. No. Duodenal atresia is secondary to failure of recanalization.
4. Cystic fibrosis (accounts for 33% of cases of SBO), sequelae of malrotation (midgut volvulus and Ladd bands)

Front 10

1. What are the imaging findings of meconium peritonitis?
2. What are some causes of meconium peritonitis?

Back 10

1. Meconium peritonitis results when there is bowel perforation, usually a sequelae of bowel obstruction.
- Complex and echogenic fetal ascites
- Intra-abdominal calcifications (linear or clumped)
- Bowel dilatation
- Polyhydramnios
2. Meconium peritonitis results when an obstructed bowel perforates. In-utero bowel obstruction can be seen in CF, small bowel atresia, stenosis, or volvulus.

Front 11

What is the differential diagnosis of fetal liver calcifications?

Back 11

1. Intrauterine infection: CMV, Toxo
2. Neoplasm if associated with a mass: Hepatoblastoma, Neuroblastoma mets.
3. Ischemic hepatic insufficiency
4. Idiopathic
5. Portal vein calcification

Front 12

1. What is a placental abruption?
2. What are the different types of placental abruption?
3. What are the risk factors for placental abruption?
4. What is the prognosis of placental abruption?

Back 12

1. Placental abruption refers to a retroplacental hemorrhage that separates the placenta from the uterine wall.
2. A placental abruption can be complete, partial, or marginal.
- Partial abruption: partial separation of the placenta from the uterus.
- Marginal abruption: hemorrhage extends from the retroplacental region lateral to the placenta.
3. Risk factors include maternal HTN, cocaine, smoking, alcohol, trauma, and PROM.
4. Prognosis depends on volume of hemorrhage and degree of placental separation. The bleeding can decompress if vaginal bleeding is present. However if hemorrhage remains confined to the retroplacental region (concealed), the outcome can be worse for the fetus and mother.

Front 13

1. What is the most common facial abnormality of the fetus?
2. How often is it associated with cleft palate?
3. What are the different types of cleft palate?
4. What is the DDX of facial mass in a fetus?

Back 13

1. Cleft lip is the most common facial anomaly. Cleft lip can be unilateral, bilateral, or midline. When unilateral, it is more common on the left side.
2. It is associated with cleft palate in 80% of cases.
3.
- Type 1: cleft lip alone
- Type 2: unilateral cleft lip and palate. Most common type.
- Type 3: bilateral cleft lip and palata. A premaxillary protrusion (soft tissue mass arising from the upper lip) may be present.
- Type 4: midline cleft lip and palate
- Type 5: slash type defect 2/2 to amniotic bands leading to randomly placed cleft, body wall/extremity defects, bizarre abdominal wall defects, amputations

4.
- Hemangioma
- Teratoma (nasal or floor of mouth origin)
- Rhabdomyosarcoma
- Encephalocele

Front 14

1. What are some etiologies of swallowing dysfunction in a fetus?
2. What are some causes of non-visualization of the stomach?

Back 14

1. Swallowing dysfunction in a fetus can be caused by:
- facial cleft
- central nervous system or neuromuscular disorders
- neck/thoracic mass
- narrow chest due to skeletal dysplasia

2. Causes of non-visualization of the stomach in the LUQ:
- thoracic location of the stomach (diaphragmatic hernia)
- situs inversus with stomach located in the right abdomen
- oligohydramnios = decreased amniotic fluid for the fetus to swallow.
- esophageal atresia

Front 15

1. What 3 tests comprise the maternal triple screen?
2. What do they screen for?
3. When is it performed?
4. What is the sensitivity for Down syndrome?
5. What is the pattern of the triple screen seen with chromosomal abnormalities and NTD?

Back 15

1. Consists of maternal B-HCG, estriol, a-fetoprotein.
2. Screens for chromosomal anomalies and neural tube defects (NTD)
3. Performed between 15 and 20 weeks.
4. Only 60% sensitivity for Down syndrome (slightly higher when maternal age is considered), with a high false-positive rate leading to amniocentesis of normal pregnancies.
5.
- Down's Syndomre: Elevated hCG, low AFP, low estriol
- Trisomy 18 (Edward's): Low hCG, low AFP, low estriol
- NTD: Elevated AFP; elevated AFP is also seen in abdominal wall defects and multiple gestations.

Front 16

1. Where is nuchal thickness measured?
2. What defines increased nuchal thickening/translucency?
3. When do you assess for nuchal thickening and why is this important?
4. Increased nuchal thickening/translucency is associated with what chromosomal abnormalities?

Back 16

1. Nuchal region refers to the soft tissue posterior to the cervical spine or occipital bone.
2. Thickness equal to or greater than 3mm.
3. Assessed from 10-14 weeks gestation. After 14 weeks, the nuchal thickening may resolve but the risk of chromosomal abnormality remains increased.
4. Associated with trisomies 13, 18, and 21 and Turner's syndrome.

Front 17

1. What is the etiology of ovarian vein thrombosis?
2. What is the usual clinical scenario?
3. Which vein undergoes thrombosis more frequently? What is its anatomic course?
4. What are the imaging findings of ovarian vein thrombosis?
5. What are some complications of ovarian vein thrombosis?

Back 17

1. Ovarian vein thrombosis occurs secondary to an ascending infection following an ectopic pregnancy, abortion, vaginal delivery, or cesarean section.
2. Patients usually present in the first week postpartum with fever, lower abdominal pain, or a tender mass.
- The right ovarian vein is thombosed in most cases. The right ovarian vein courses adjacent and lateral to the psoas muscle and inserts into the IVC below the right renal vein.
4. The distended right ovarian vein can appear masslike. Look for associated ovarian enlargement.
5. Complications include right sided hydronephrosis from enlarged ovarian vein compressing the ureter, pulmonary emboli, renal vein or IVC thrombosis.

NOTE: Knowledge of the anatomic position of the right ovarian vein, its oblique course adjacent and lateral to the psoas muscle, and its insertion into the inferior vena cava 4 cm below to the right renal vein origin, helps to improve its identification.

Front 18

1. What is the most common cause of large bowel obstruction in a neonate?
2. What some other etiologies of large bowel obstruction?
3. What syndromes are associated with anorectal atresia?
4. How do you differentiate the colon from small bowel in the fetus?

Back 18

1. Hirschsprung disease
2. Anorectal atresia, Meconium plug sydrome
3. Anorectal atresia can be seen with VACTERL and caudal regression syndrome.
4. A dilated colon is often peripheral in location; Small bowel loops more commonly show peristalsis. It is unusual for colonic loops to show peristalsis.

Front 19

1. What is the normal ventricular size ratio of LV to RV?
2. What structure in the RV can make the RV appear smaller?

Back 19

1. The ventricles typically measure 1:1. The sizes of the ventricles are very important and can indicate various cardiac malformations.
2. Prominent moderator band (normal variant) is a hypoechoic to isoechoic (relative to myocardium) band of tissue in the apex of the right ventricle that makes the ventricular cavity appear smaller than the left in a normal heart.

Front 20

Twin Gestation

Back 20

3 types of twinning:

Dichorionic-Diamniotic:
- 80% of twinning
- completely separate environments
- look for a thick chorion (> 2mm) separating the two pregnancies best seen in the first trimester. Lambda sign on US (placental tissue extending between the chorion layers of the dividing membrane). There may be 2 separate placentas or placentas may fuse.
- a first-trimester loss of one of the twins may not be noticed. If incidentally detected by ultrasound, the demised twin will show either an abnormal gestational sac or an empty gestational sac or a sac containing an embryo without heart motion or an abnormal yolk sac. In these cases, if the pregnancies are followed, the demised twin will "vanish" leaving one developing gestational sac.
- twins may be dizygotic (more common) or monozygotic

Monochorionic-Diamniotic:
- partially shared environment. Therefore, death of one twin may adversely affect the living twin.
- additional problems because of the shared placental circulation could lead to a twin-twin transfusion.
- always monozygotic.
- separating amniotic membrane is thin (<2mm)
Monochorionic-Monoamniotic:
- completely shared environment. Therefore, death of one twin may adversely affect the living twin.
- the most common cause of death is cord entanglement.
- conjoined twins
RISKS COMMON TO ALL TWIN PREGNANCIES = growth restriction, preterm labor, perinatal mortality.

Front 21

1. What is osteogenesis imperfecta?
2. What organ systems are involved?
3. Describe the classification.

Back 21

1. Connective tissue disorder attributed to defective type I collagen.
2. Various organ systems may be involved, including the eyes (sclerae), skin, teeth, and ears; however, the most widely recognized abnormalities involve the skeletal system.
3. Classification:
Type I: autosomal dominant; non lethal; mildly fragile bones without significant deformity.
Type II: autosomal dominant; lethal; demineralization (particularly of the calvarium) and multiple fractures. Demineralization cannot be quantitated but is suggested by the lack of normal bone brightness.
Type III: autosomal recessive; non lethal; fractures that result in deformed bones and spine. Vertebral bodies may be flattened, called platyspondyly, caused by softening of the vertebral bodies. A "wrinkled appearance" has been used to describe the femur with multiple fractures.
Type IV: autosomal dominant; non lethal; presents with osteoporosis and fragile bones that bow.

Front 22

What is the ddx of a cystic pelvic mass in the female fetus or neonate?

Back 22

OVARIAN CYST:
- Induced by maternal hormones crossing the placenta.
- May spontaneously resolve or increase in size.
- Larger size increases risk of torsion.
- Occur in association with long standing hypothyroidism.

TERATOMA:
- NOTE: cystic teratoma is known as a dermoid. Typically there is soft tissue component as well.

HYDROMETROCOLPOS:
- may be 2/2 imperforate hymen, transverse vaginal septum, vaginal atresia.

Front 23

1. What patient population is at increased risk for heterotopic pregnancy?
2. What is the incidence of heterotopic pregnancy in these high risk patients?
3. What condition can mimic a heterotrophic pregnancy?

Back 23

1.
- Assisted reproduction techniques (ART)
- Intrauterine contraceptive devices
- Pelvic inflammatory disease
- Previous tubal surgery
2. 1:3000. For women undergoing ART, this complication occurs in 1% to 3%.
3. Normal intrauterine pregnancy with a ruptured corpus luteum cyst which can result in a moderate amount of hemoperitoneum.

Front 24

What is the ddx of calvarial demineralization?

Back 24

1. Osteogenesis imperfecta
2. Congenital hypophosphatasia:
- also associated with poor ossification of the spine.
- ranges from skeletal hypomineralization and respiratory compromise to a milder, progressive osteomalacia later in life.
3. Achondrogenesis:
- also associated with poor ossification of the spine.
- deficient enchondral ossification resulting in a short trunk, arms, legs, and neck.
- absence of ossification of spine, ileum, sacrum.
- abdominal ascites
- Prognosis is generally very poor. Many infants with achondrogenesis are stillborn or die shortly after birth because of breathing problems related to the abnormally small chest.

Front 25

1. What are the benign cardiac masses seen in infancy?
2. What are some characteristics of rhabdomyoma?

Back 25

1. Rhabdomyoma, fibroma, myxoma
2. Rhabdomyoma:
- most common cardiac mass in the fetus, infant, and child.
- Ninety percent are multiple and occur along the interventricular septum.
- Greater than 50% of pts have tuberous sclerosis.
- Single or multiple, homogeneously hyperechoic masses seen in the right or left ventricle.
- Complications of larger masses include intracardiac flow obstruction and arrhythmia.

Front 26

What is the ddx of posterior head/neck mass?

Back 26

1. Cystic hygroma:
- "spoke-wheel" appearance of septations is pathognomonic
- elevated AFP
- Cystic hygroma can be complicated by serous effusions and subcutaneous edema (hydrops)
- Approximately 2/3 of fetuses with cystic hygroma will have aneuploidy. Turner syndrome is the most common diagnosis when a cystic hygroma is present.
2. Encephalocele/Cervical myelomeningocele:
- look for a cranial defect and associated central nervous system (CNS) abnormalities.
- CNS abnormalities including ventriculomegaly, lemon-head deformity, beaked tectum, flattened basioccipital bone, and microcephaly suggest a cephalocele or cervical meningomyelocele.
- AFP is usually normal in encephaloceles but can be elevated in a cystic hygroma or cervical meningomyelocele.

Front 27

1. What is the ddx of a mass in the lower uterine segment?
2. Why is it essential to differentiate a cervical ectopic pregnancy from an abortion in progress?
3. What are the features of abortion in progress?

Back 27

1. Cervical ectopic pregnancy, abortion in progress, retained products of conception, degenerating leiyomyoma.
2. It is essential to differentiate cervical ectopic pregnancy from abortion in progress due to the risk of severe hemorrhage requiring hysterectomy if a cervical ectopic is treated simply with a dilatation and evacuation.
- A cervical ectopic pregnancy is first treated with methotrexate. Then, a uterine artery embolization is performed followed by dilatation and evacuation. Alternatively, ultrasound-guided potassium chloride injection can be performed.
- In a cervical ectopic, ultrasound demonstrates a normally shaped gestational sac in the lower uterine segment with a yolk sac and fetal heart activity.
3. In an abortion in progress,
- sac is centrally placed within the endometrial cavity whereas in cervical ectopic pregnancy, the gestational sac is eccentric.
- sac is abnormally shaped without any recognizable fetal pole or fetal heart motion.
- Cardiac activity will be absent and color Doppler imaging will not show normal trophoblastic flow in a spontaneous abortion.
- on a follow-up scan in 24 hours, an abortion in progress should show some change, but a cervical ectopic pregnancy will not.

Front 28

1. What is the succenturiate lobe of the placenta?
2. What is the significance of succenturiate lobe?

Back 28

1. Accessory placental lobe that is removed from but in vascular continuity with the main placenta.
2.
- If not prenatally detected, the connecting vessels can rupture leading to life-threatening fetal hemorrhage.
- If the succenturiate lobe is not delivered (retained products of conception), it can lead to postpartum maternal hemorrhage and infection.
- A succenturiate lobe should be suspected at the time of delivery if severed fetal vessels are present at the torn edge of the membranes of the placenta.

Front 29

1. What is twin-twin transfusion syndrome?
2. What is the ultrasound criteria for twin-twin transfusion syndrome?

Back 29

1.
- Serious complication of monochorionic gestations.
- 2/2 interconnecting placental vessels between the two twins, which result in umbilical arteriovenous shunting of blood from one twin to the other.
2.
- Monochorionic twinning, i.e. twins of the same gender.
- Growth discordance between the twins of at least 20%
- When significant shunting occurs,
- One twin (donor) becomes small with anemia and oligohydramnios. When the fluid is so severly restricted that the fetus is immobile whthin the gestational sac, the fetus will appear in a static position referred to as stuck twin.
- Other twin (recipient) enlarges and develops polycythemia, volume overload, heart failure, polyhydramnios. Tricuspid regurgitation is often present.
- If the donor twin dies, the recipient can suffer an embolic phenomenon through the arteriovenous connections, resulting in cerebral damage.

Front 30

What are the manifestations of Downs Syndrome in the fetus?

Back 30

MSK:
- short humerus and femur
- Widening of the iliac angle in the pelvis/pelvic flaring

CHEST/ABDOMEN:
- Dilatation of the renal pelves
- Echogenic bowel
- Papillary muscle calcification
- AV Canal defect resulting in atrial and ventricular septal defects.

Front 31

What are the congenital lung abnormalities seen in utero?

Back 31

1. CCAM
2. Congenital diaphragmatic hernia
3. Sequestration
4. Congenital lobar emphysema

Front 32

1. What are the imaging findings in interstitial ectopic pregnancy?
2. Why does a cornual (interstitial) ectopic pregnancy have a worse prognosis?

Back 32

1.
- On axial images of the uterus, the gestational sac will be in the region of the cornua, bulging the fundal contour.
- Endometrium is seen as a thin line, which is not distended by the gestation.
- The non-distended endometrium can be followed to the gestation in the cornua of the uterus (the interstitial line sign).
- Very thin myometrium covers the gestational sac.
2. Cornual ectopic pregnancy has a later presentation than typical ectopic pregnancy because uterine cornua is partially protected by the myometrium and is capable of expanding more than the fallopian tube. As a result of the late presentation, a rupture can be catastrophic and can lead occasionally to life threatening hemorrhage.

Front 33

1. What is an obligate cord?
2. What is the risk with an obligate cord?

Back 33

1. Presentation of the umbilical cord before the fetus at the time of birth. The umbilical cord is identified overlying the internal os. It is more common in the setting of breech presentation. 2. Diagnosis of this condition is essential because prolapse of the cord into the cervix during delivery can be catastrophic for the fetus. The positioning of the cord results in cord compression and variable fetal cardiac decelerations or bradycardia during uterine contractions.

Front 34

What is the pentalogy of Cantrell?

Back 34

1. Ectopia cordis: partial or complete displacement of the heart outside the thorax.
2. Cardiac defects (conotruncal abnormalities)
3. Supraumbilical omphalocele
4. Distal sternal cleft
5. Ventral diaphragmatic hernia

Front 35

1. Whatis the etiology of endometritis?
2. Is endometritis/endomyometritis more common after C-section or vaginal delivery?
3. What are the imaging findings of endometritis?
4. What looks similar to endometritis?

Back 35

1. Recent delivery, post instrumentation (D&C), IUD, and PID.
2. Endometritis/endomyometritis is more common after cesarean section compared with a vaginal delivery.
3. US may be normal in 50% of cases with clinical dx of endometritis.
- endometrial fluid/debris
- gas (endometrial gas is more commonly a normal postpartum finding). Look for increasing amount of gas over time.
4. Retained products of conception and blood products. However, simple RPOC present with heavy vaginal bleeding rather than fever and purulent discharge post partum. RPOC can become infected, in which case the appearance could be identical to endometritis.

Front 36

What is the most common intracranial mass in a fetus?

Back 36

Teratoma. Although histologically benign, the potential complications from mass effect and high-output cardiac failure yield a very poor prognosis.

Front 37

1. What are the imaging findings of caudal regression syndrome?
2. What are the imaging findings of sirenomelia?

Back 37

1. Caudal regression syndrome occurs in fetuses of diabetic mothers.
- sacral agenesis and variable degree of L-spine hypoplasia.
- varying degrees of lower limb hypoplasia
- both kidneys are present but the bladder and collecting systems may be dilated.
- associated with an imperforate anus.
2. Sirenomelia:
- rare lethal malformation with variable degrees of agenesis of the spine and pelvis as well as a single or fused lower extremity.
- aberrant single umbilical artery from the aorta
- distal aortic atresia
- renal agenesis results in marked oligohydramnios

Front 38

Umbilical cord abnormality

Back 38

1. Allantoic duct:
- represents a patent urachus which may be cut during delivery.
- associated with bladder obstruction with the allantoic duct allowing for decompression of the bladder
2. Omphalomesenteric duct:
- may be lined with gastric mucosa resulting in acid secretion.
- gives rise to Meckel's diverticulum
3. VASCULAR ABNORMALITY
- Two vessel cord: associated with growth restriction and cardiac and GU anomalies. Therefore when found, do a thorough survey to look for additional malformations. There may be 2 vessels in part of the umbilical cord...as long as there are 3 vessels near the fetal end of the umbilical cord, it is considered normal.
- Cord hematoma: usually iatrogenic in nature from amniocentesis. High risk of fetal demise as the mass effect from the hematoma may compress the umbilical vessels.
- Cord hemangioma: hyperechoic/multicystic mass that occurs near the placental end. May exert mass effect on the umbilical vessels and spontaneously hemorrhage.
- Color doppler imaging can also reveal if the vessels of the cord are compressed or thrombosed. If a cystic structure is found, use color doppler to determine if it is vascular in nature.
- Umbilical vein varix: defined as a focal dilatation of the umbilical vein. May thrombose and lead to fetal demise. Therefore, some recommend delivery as soon as lung maturity permits.
4. Pseudocysts:
- AKA Wharton's jelly cysts.
- Wharton jelly is a substance that insulates and supports umbilical cord vessels, protecting them from injury.
- Wharton jelly cyst is a focal thickening of Wharton jelly.
- associated with omphalocele and trisomy 13/18.

Front 39

1. What is criteria for calling bowel abnormal?
2. What are the etiologies of echogenic bowel?

Back 39

1. For bowel to be considered abnormal,
- bowel is expected to have an echogenicity greater than bone.
- echogenic bowel is expected to be longer than 4 cm
- exhibit mass effect on adjacent structures.
2.
- Intrauterine infection
- Cystic fibrosis/meconium ileus
- Chromosomal abnormalities (Trisomy 13, 18, 21, triploidy)

Front 40

Variations in placental morphology.

Back 40

- Single lobed discoid placenta: most common type.
- Bilobed placenta: two near equal size lobes.
- Succenturiate lobe: one of more smaller accessory lobes.
- Circumvallate placenta: rolled placental edges with smaller chorionic plate. Associated with increased risk of placental abruption.
http://radiopaedia.org/articles/variation-in-placental-morphology

Front 41

What is the ddx of anterior neck mass in a fetus/newborn?

Back 41

1. Cystic hygroma:
- classically arises from the posterior and lateral parts of the neck.
- subtype can arise anteriorly and extend into the superior mediastinum.
2. Thyroid gland enlargement:
- may be associated with hypothyroidism or hyperthyroidism.
- If mother has Graves disease, the thyroid stimulating immunoglobulins cross the placenta and cause fetal hyperthyroidism.
- If mother is on PTU for hyperthyroidism, PTU can cross the placenta and result in fetal hypothyroidism.
3. Thyroglossal duct: midline cystic mass; below the level of the hyoid bone, it may be located within the strap muscles.
4. Branchial cleft cyst: found in the lateral neck
5. Cervical teratoma:
- can arise anywhere in the body; the cervical region is rare (5%).
- look for a cystic and solid mass with or without calcifications.

Front 42

1. Describe the 3 degrees of placental invasion?
2. What are the predisposing risk factors for placental invasion?

Back 42

1. Placental invasion of the uterine wall is categorized as placenta accreta, percreta, or increta depending on the depth of the myometrial invasion.
- Accreta: Myometrial contact by placental villi without invasion.
- Increta: Invasion into the myometrium without serosal penetration
- Percreta: Invasion through the myometrium with serosal penetration. Invasion can involve adjacent organs such as bladder and rectum.
2. Previous uterine surgery (cesarean section, myomectomy, or curettage)

Front 43

Describe the variations in cord insertions.

Back 43

In 99% of cases the umbilical cord inserts on the placental mass. However, the insertion site may vary from the center of the fetal surface to the border of the placenta (marginal = 1-2 cm from the placental edge). Rarely, the cord inserts onto the chroion rather than on the placental mass (velamentous insertion). The velamentous umbilical vessels may be placed over the internal os below the presenting part and are thus at risk for rupture.

Front 44

What are the causes of oligohydramnios?

Back 44

1. Demise
2. Renal abnormalities
3. IUGR
4. Premature rupture of membranes
5. Post dates
6. Chromosomal abnormalities

Front 45

1. What do Mullerian ducts give rise to?
2. What do Wolfian ducts give rise to?

Back 45

1. Mullerian duct form female structures. They form the entire female genitalia except the distal third of the vagina.
2. Wolfian ducts forms the male structures. They form the epididymis, vas deferens, and seminal vesicles.

Front 46

1. What is gestational trophoblastic disease?
2. What are clinical findings in hydatidiform mole?
3. What are the different types of hydatidiform moles? What are their genetic karyotype?

Back 46

1. Spectrum of diseases arising from placental trophoblastic tissue. The most common forms of GTD are hydatidiform mole (complete vs. incomplete), invasive mole, and choriocarcinoma.
2.
- Vaginal bleeding, vaginal discharge of hydropic trophoblastic villi
- Severe prolonged hyperemesis gravidarum.
- Hyperthyroidism may occur as a consequence of thyroid stimulating effects of HCG.
- Disproportionately enlarged uterus and ovaries with multiple theca lutein cysts.
3. Complete and partial moles
- Complete molar pregnancy: 46XX resulting from fertilization by two spermatozoa; no fetal parts can be identified.
- Partial hydatidiform mole: triploid or tetraploidy 2/2 fertilization of a normal egg by two different spermatozoa.
- The endometrium is expanded with a SNOWSTORM appearance, which is caused by tiny vesicles that have increased through transmission. If the vesicles enlarge, the appearance becomes more heterogeneous.
- Old machines: snowstorm of tiny vesicles that have increased through transmission, expands endometrial cavity
Current machines:
Multiple, anechoic (cystic) spaces seen in heterogeneous echogenic mass. Cystic spaces correlate to hydropic villi

US documentation of extension into the myometrium is important; myometrial nodules reflect invasion.

Front 47

What is the management of ectopic pregnancy?

Back 47

The decision to treat an ectopic pregnancy with methotrexate versus surgical management is often based on sonographic findings. If the ectopic pregnancy has not ruptured, the size of the adnexal ectopic is less than 3.5 cm, and there is no detectable heartbeat, then the patient may be a methotrexate candidate. The beta hCG (human chorionic gonadotropin) level should also be less than a predetermined value.

A ruptured ectopic pregnancy is an emergency! This patient should be imaged quickly and sent back to the emergency department as soon as possible where the patient can be carefully monitored and prepared for surgery. A ruptured ectopic pregnancy is a contraindication for methotrexate therapy.

Front 48

What is the DDX of micromelia (abnormally small and imperfectly developed extremities)

Back 48

NOTE: all micromelic disorders have small chest and thus the heart looks enlarged.

1. Campomelic dysplasia
- normal ossification
- severe angulation of the femora, tibiae, and fibulae with anterolateral bowing
- absent or hypoplastic scapula

2. Achondrogenesis
- lack of vertebral ossification.
- head is disproportionately large with normal (type II) or deficient ossification (type 1) depending on the subtype.
- Hydrops and cystic hygroma are common
- Rib fxs may be seen.

3. Osteogenesis imperfecta
- multiple subtypes of OI with the most severe manifestations seen in the perinatal lethal form (OI type II).
- Generalized decrease in ossification of all bones
- Multiple fractures in utero.
- Ribs look "beaded,"
- Long bones may be irregularly angulated due to fractures
- Underossified calvarium allows for very clear visualization of the brain in OI; this is described as seeing the brain "too well."
- The contour of the head can be altered by direct transducer pressure in OI.

4. Thanatophoric dysplasia
- most common prenatally diagnosed lethal skeletal dysplasia.
TYPE 1:
- normally shaped calvarium
- short, curved "telephone receiver" shaped femora
- trident hand
- ossification is normal, therefore, no rib or extremity fractures
- Platyspondyly (flattened vertebral bodies)
TYPE II:
- cloverleaf-shaped calvarium (kleeblattschädel)
- femora are slightly longer and straighter than in type I thanatophoric dysplasia

Front 49

Linear echoes within the amniotic fluid:

Back 49

AMNIOTIC BAND SYNDROME:
- appear as fine linear structures in the amniotic fluid.
- bands "tether" the fetus to the uterine wall and entangle and disrupt fetal parts.
- lead to limb constriction, amputation, and swelling of the entagled extremity
SYNECHIAE:
- sequelae of prior uterine inflammation from infection or surgery
- have no impact on fetal development.
- do not attach to the fetus
CHORIOAMNIOTIC SEPARATION:
- normal before 16 weeks gestation
- abnormal when it occurs during the 2nd and 3rd trimester.
HEMORRHAGE:
- may result in fibrin strand formation.
- may be 2/2 previous amniocentesis.
- have no effect on fetal development

Front 50

What is iniencephaly?

Back 50

- Extensive open neural tube defect characterized by a defect in the occiput and inion.
- Associated with cervical spine dysraphism, which often extends into the thoracic and even lumbar areas.
- Head is held in fixed hyperextension, or the "stargazer" position.

Front 51

Sonographic findings of Trisomy 18

Back 51

BRAIN:
- **choroid plexus cyst
- strawberry shaped skull due to frontal bone hypoplasia
FACIAL:
- cleft lip
- absence of nasal bone
- hypertelorism
- micropthalmia
CARDIAC:
- Atrioventricular septal defect
EXTREMITIES:
- flexed hands and wrists
- clenched hands
- overlapping index finger
- club foot

CHEST/ABD:
- hydrops fetalis
- esophageal atresia
- omphalocele

Front 52

Sonographic findings in Trisomy 13

Back 52

BRAIN:
- **holoprosencephaly

FACIAL:
- more likely to have a midline or bilateral cleft lip/palate, rather than the unilateral cleft lip/palate
- cyclopia or hypotelorism
EXTREMITIES:
- polydactyly

Cardiac defects are also common
50% of pts have cystic renal dysplasia

Front 53

Cesarean section scar ectopic

Back 53

a Cesarean section scar ectopic, the sac implants eccentrically in the anterior myometrium at the site of a Cesarean section scar. There is minimal or no myometrium between the gestational sac and the bladder, the uterine cavity is empty, and color Doppler shows marked peritrophoblastic flow around the ectopic gestational sac in a Cesarean section scar ectopic

Front 54

Twinning

Back 54

MONOCHORIONIC MONOAMNIOTIC TWINS:
- 1 echogenic chorionic ring containing 2 embryos, both residing in a single amniotic sac.
- Only 1 yolk sac should be seen.

MONOCHORIONIC DIAMNIOTIC TWINS:
- 1 echogenic chorionic ring containing 2 embryos, each surrounded by their own amnion.
- Presence of 2 yolk sacs (outside the amnions but inside the chorion), as well as 2 amnions and embryos.

DICHORIONIC DIAMNIOTIC TWINS:
- Echogenic chorionic ring around each embryo.
- Yolk sac between the amnion and chorion of each gestational sac.

Front 55

Sacral mass

Back 55

SACROCOCCYGEAL TERATOMA:
- extragonal germ cell tumor
- solid and cystic mass
- Type 1 are entirely external; Type 4 are entirey intrapelvic; Types 2 and 3 have both internal and external components.
- most tumors are benign; however, primarily internal tumors are more likely to contain malignant elements.
- solid tumors have arteriovenous shunting that may lead to fetal hydrops fetalis.
MYELOMENINGOCELE AND VARIANTS
- Myelomeningocele or myelocele (associated with Chiari II malformation)
- Anterior meningocele: anterior bony defect that allows herniation of CSF though the defect
RHABDOMYOSARCOMA
DUPLICATION CYST
- MC location is near the ileum
- may occur near the rectum and present as a cystic sacral mass.

Front 56

Twin pregnancy with asymmetric fetal sizes

Back 56

- Twin twin tranfusion syndrome
- Fetal demise: look for absence of cardiac activity and fetal movement
- Normal variation: the estimated fetal weight should not differ by more than 20%

Front 57

Cardiac mass

Back 57

ECHOGENIC INTRACARDIAC FOCUS/PAPILLARY MUSCLE CALCIFICATION:
- commonly seen in the left ventricle
- in pts at low risk of chromosomal abnormalities = normal variant
- in pts at higher risk of chromosomal abnormality = suggestive of Down's syndrome and T13.
RHABDOMYOMA
- MC benign cardiac neoplasm of infants and children
- majority associated with Tuberous sclerosis
- spontaneosly regress during pregnancy
FIBROMA
- echogenic mass in the ventricular septum
- low T2 SI on MRI due to presence of fibrous tissue
TERATOMA
- large heterogeneous mass + pericardial effusion
HEMANGIOMA
- most commonlh located in teh RA
- associated with pericardial effusion

Front 58

Enlarged cerebral ventricles

Back 58

- Ventriculomegaly: defined as dilation of the lateral ventricles > 10mm in width at the atrial level.
- Congenital acqueductal stenosis: may be caused by webs/septations or secondary to prior intraventricular bleeding or infection.
- Chiari malformation
- Agenesis of CC
- Dandy Walker malformation
- Holoprosencephaly

Front 59

Cystic posterior neck mass

Back 59

- Cystic hygroma; lymphatic malformation characterized by thin walled multiseptated mass
- Occipital encephalocele and cervical myelomeningocele: look for adjacent bony defect in the occipital bone or posterior elements of C-spine.
- Cystic teratoma

Front 60

Enlarged hyperechoic kidneys

Back 60

ARPKD:
- affects medullary portions of the kidneys with sparing of the cortex which appears hypoechoic.
- results in oligohydramnios, lung hypoplasia.
TRISOMY 13
- 30% of pts with trisomy 13 have enlarged echogenic kidneys similar to ARPKD
MECKEL-GRUBER SYNDROME:
- rare, lethal syndrome
- occipital encephalocele + polydactyly, dysplastic enlarged cystic kidneys.
ADPKD
- enlarged echogenic kidneys are seen in utero and in childhood
- cysts do not appear till later in childhood and adolescence.

Front 61

Placenta previa

Back 61

- Occurs when the placenta lies near or over the cervical internal os.
4 types:
- Complete: placneta completely covers the internal os)
- Partial: placenta partially covers the internal os.
- Marginal: placenta reaches the edge of but does not cover the internal os.
- Low lying placenta: lies close to but does not reach the edge of the internal os -- usually defined as within 2 cm of the internal os on ultrasound.

Vasa previa occurs from a vilamentous insertion of the cord resulting in fetal vessels crossing the internal os.

Also requires C-section due to risk of fetal hemorrhage.

Front 62

Cranial/calvarial defect

Back 62

ANENCEPHALY:
- neural tube defect
- absence of the calvarial bones + reduction or absence of cerebrum and cerebellum with preservation of a portion of the hindbrain.
- tissue located above the orbits is referred to as angiomatous stroma.
ACRANIA:
- AKA exencephaly
- partial or complete absence of the bony cranium.
- underlying brain typically forms to some degree.
AMNIOTIC BAND SYNDROME:
- result in constriction and amputation.
- may cause asymmetric amputation of the cranium.
ENCEPHALOCELE/ MYELOMENINGOCELE

Front 63

Abdominal wall defect

Back 63

OMPHALOCELE:
- herniation of abdominal contents into the base of the umbilical cord.
- associated with other malformations, especially cardiac.
GASTROSCHISIS
- lateral to the umbilical cord insertion, more common on the right.
LIMB-BODY WALL COMPLEX:
- fatal condition
- Omphalocele + craniofacial defect + limb reductions + spinal defects
PENTALOGY OF CANTRELL:
- Omphalocele + ectopia cordia (heart outside the chest) + diaphragmatic defect + pericardial defect + cardiovascular malformation
BLADDER/CLOACAL EXSTROPHY
- absence of a normal bladder with protruding soft tissue mass and pubic diastasis.
- cloacal extrophy: involves bladder and bowel.

Front 64

Choroid plexus cyst

Back 64

INCIDENTAL FINDING
- found in 1-2% of the population.
- isolated choroid plexus cyst with otherwise normal fetal anatomy and a normal triple screen is likely an incidental finding.
TRISOMY 18

TRISOMY 21

Front 65

Polyhydramnios

Back 65

- Amniotic fluid volume is a balance between production (urine) and swallowing.
- Amniotic fluid index of >8cm or an amniotic fluid index >25cm.
- CAUSES:
IDIOPATHIC: Most common
FETAL GASTROINTESTINAL ANOMALIES: esophageal, duodenal, and small bowel atresia
FETAL CNS ANOMALIES: any CNS anomalies that prevent normal swallowing. Includes anencephaly, hydranencephaly, encephalocele
MATERNAL DIABETES MELLITUS: likely related to fetal hyperglycemia causing osmotic diuresis and polyuria.
FETAL HYDROPS

Front 66

Oligohydramnios

Back 66

- Amniotic fluid index of <5cm and a maximum vertical pocket of <1-2cm.
- NOTE: amniotic fluid is necessary for normal lung development, therefore, fetuses with prolonged oligohydramnios will have pulmonary hypoplasia
CAUSES:
Bilateral renal failure or outlet obstruction:
- Renal failure (ARPKD, renal agenesis, MCDK)
- Outflow obstruction (PUV, UPJ obstrxn)
Premature rupture of membranes
Intrauterine growth restriction: decreased placental perfusion (which can result from many causes) will produce hypoxic state within the fetus. When the fetus becomes hypoxic, there is redistribution of cardial output preserving blood flow to the brain. The remaining organs are consequently underperfused.
Fetal demise

Front 67

Prenatal Hydrocephalus

Back 67

- Aqueductal stenosis
- Dandy-Walker malformation
- Chiari II
- Communicating Hydrocephalus (e.g., prior hemorrhage)

Front 68

Chorioangioma of placenta

Back 68

A solid mass arises from the surface of the placenta, with considerable blood flow demonstrated on color Doppler
Most cause no fetal problems, although fetal growth restriction and hydrops (from high-output CHF) may occur

Front 69

Congenital cardiac mass

Back 69

- Rhabdomyoma: MC mass
- Teratoma
- Fibroma
- Hemangioma

Front 70

1. What is the imaging appearance of anencephaly?

Back 70

1. Prominent eyes and an absent calvaria

Front 71

Anencephaly

Back 71

- Complete absence of cranial vault and cerebral hemispheres
- Angiomatous stroma covers base of the skull; seen superior to the orbits.
- Diagnose after 14 weeks when skull is ossified.