CNS Anomalies

Question 0

Anencephaly

Answer 0

Absent brain & calvarium
MC NTD
Fail of close of neural tube

SAB, fetal demise, terminate

Frog appearance
Cerebrovasculosa: malformed top of head
Absent cranial vault cephalad to orbits
Polyhydramnios

Risk: fam hx NTD, twins, female, recurrence

Assoc: spina bifida, cdh, cleft lip/palate, talipes, hydronephrosis, ❤️, GI, omphalocele, *polyhydramnios (can’t swallow)

Fatal

Question 1

Define anencephaly

Answer 1

Absence of brain

Question 2

Acrania / Exencephaly

Answer 2

Absent calvarium. Brain floats. Polyhydramnios

Question 3

Spina Bifida / Myelomeningocele

Answer 3

2nd MC NTD
Fail of close of neural tube

1. Meningocele: opening of spine, meninges protrude
2. Myelomeningocele: opening of spine, meninges and spinal cord protrude. Most severe, most common.

Splaying of post ossification centers. U/V shape trvs spine
Cleft in soft tissue
Buldging sac that may have neural elements
Ventriculomegaly
Arnold Chiari II Malformation: banana sign & lemon sign

Assoc: hydrocephalus, holoprosencephaly, ACC, DWM, facial clefts, GU, CV, talipes, chromosomal

May cause partial paralysis of lower limbs.
Fetal surgery 24-26 weeks
Shunt for ventriculomegaly (fluid from brain shunt down to ABD)

Best ID in trvs scanning plane

Question 4

Encephalocele / Cephalocele

Answer 4

Herniation of brain and or meninges through cranial defect
Mostly post occipital region

1. Cranial meningocele: just meninges
2. Encephalocele: brain & meninges. MC

Assoc: hydrocephalus, spina bifida, microcephaly, ACC, chromosomal, ❤️, genital, clefts

Fluid filled sac extending from calvarium
Defect in calvarium
Polyhydramnios

Question 5

Holoprosencephaly

Answer 5

Fail of fusion of forebrain

1. Lobar: mildest. Absent CSP. Single incisor
2. Semilobar: separate thalamus, LV fused, cerebral hemispheres fused, no CSP
3. Alobar: most severe, may not see cerebrum, absent falx, monoventricle, thalami fused

Assoc:
Facial: cyclopia, hypotelorism, cebocephaly (hypotelorism with single nostril), ethmocephaly (cyclopia or hypotelorism with proboscis), proboscis, bilateral clefts

macrocephaly, microcephaly, ventriculomegaly, monoventricle, absent CSP & ACC

Trisomy 13
Syndromes

Question 6

Cyclopia

Answer 6

1 eye or 2 fused eyes

Question 7

Cebocephaly

Answer 7

Hypotelorism & single nostril

Question 8

Ethmocephaly

Answer 8

Cyclopia or hypotelorism with a proboscis

Question 9

Proboscis

Answer 9

Fleshy appendage that sits above orbits

Question 10

Dandy Walker Malformation

Answer 10

Abnl cerebellum & 4th ventricle. Replacement with posterior fossa cyst. Aplastic / absent/ splaying cerebellar vermis
Enlg CM
Ventriculomegaly

Linked with CMV, rubella, alcohol, diabetes, aneuploidy

Question 11

Agenesis of the corpus callosum / callosal agenesis

Answer 11

Absent CSP
Colpocephaly: frontal horns of LV widely spaced, tear drop shape
Dilated 3rd ventricle

Mental retard, seizures

Question 12

Hydranencephaly / Hydrocephalic anencephaly

Answer 12

Vascular accident. Massive brain destruction. Liquefaction necrosis of cerebral hemispheres.

Toxoplasmosis, herpes

Macrocephaly, intact brain stem, replacement of cerebral hemispheres by cystic cavity.
Remnant falx

Initially brain hemispheres are echogenic due to accident.

Question 13

Porencephaly

Answer 13

Mild
Infarct/hemorrhage of brain parenchyma
Necrosis/cystic resolution communicating with ventricle
No mass effect.

Ugly irregular cystic area in LV

Question 14

Schizencephaly

Answer 14

Abnl migration of neurons

Clefts in cortex extending to calvarium lined with gray matter.

Question 15

Lissencephaly

Answer 15

Abnl neuron migration. Smooth brain.

Agyria: absent/dec brain gyria
Pachygyria: widely spaced gyria

Question 16

Hydrocephaly

Answer 16

Ventriculomegaly and enlg skull
Atria of LV > 1 cm
Dangling choroid

Causes: NTD, DWM, ACC, aqueductal stenosis, arachnoid cyst, vein of Galen aneurysm, torch, intracranial neoplasms, aneuploidy, clover leaf skull (msk abnl), holoprosencephaly, ideopathic

Question 17

Microcephaly

Answer 17

Small head
Underdeveloped brain
Retard

Question 18

Arachnoid cyst

Answer 18

Cystic mass
Does not communicate with ventricle
Assoc hydrocephalus

Question 19

Vein of Galen aneurysm

Answer 19

AV malformation

Cyst with turbulent Doppler flow centrally located.

Question 20

Choroid plexus cyst

Answer 20

Common. May resolve. Assoc trisomy 18.

Question 21

Cystic Hygroma

Answer 21

Congenital malformation of lymphatics
Usually in neck.
Assoc with aneuploidy & Turners Syndrome

Single or multi loculated fluid filled cavity. Usually post/lat of neck.

Assoc hydrops. If hydrops then fatal.

Question 22

Teratoma

Answer 22

50% sacrococcygeal
Malignant or benign
Inc MSAFP

Complex mass, polyhydramnios, hydrops.

Question 23

Craniosynostosis

Answer 23

Premature closure of sutures

Question 24

Aqueduct of Sylvius connects

Answer 24

3rd & 4th ventricle

Question 25

Meckel Gruber Syndrome

Answer 25

Cystic kidneys
Polydactyly
Encephalocele
Microcephaly