Fetal CNS Flashcards
What is the Dandy-Walker malformation?
Nonspecific congenital brain malformation:
Hypoplasia of the cerebellar vermis
Cystic dilation of the 4th ventricle communicating with the cisterna magna
Enlarged posterior fossa
How is mega cisterna-magna defined?
Greater than 10 mm
What is Dandy-Walker variant?
Variable hypoplasia of the cerebellar vermis without enlargement of the posterior fossa
What is a Blake’s pouch cyst?
Normal anatomic entity, formed from normal dorsal expansion of the 4th ventricle into the CM, detected by transverse lines/septa within the CM behind the cerebellar vermis
When can a diagnosis of a cerebellar malformation be made?
After 18 weeks, bc before 18w development of the vermis may be incomplete
Management of Dandy-Walker malformation/variant
Careful sono exam for concurrent abnl (found in 60% in one study)
Karyotype (abnl in 20%)
Remember that false-positives have been found (57% in one series)
Offer termination
Genetic disorders associated with Dandy-Walker malformation?
Joubert-Boltshauser, Walder-Warburg, Meckel-Gruber, Aicardi, Smith-Lemli-Opitz
Chromosome abnl associated w/ Dandy-Walker malformation?
Trisomy 9
Triploidy
45, X
49, XXX
T13/18
Teratogens associated w/ Dandy-Walker malformation?
Rubella, CMV, Toxo, Coumadin, Alcohol, Isotretinoin, Maternal diabetes
What are isolated choroid plexus cysts and how common are they?
What are isolated choroid plexus cysts and how common are they?
What are the major clinical implications of an isolated choroid plexus cyst?
What are the major clinical implications of an isolated choroid plexus cyst?
What is the association between choroid plexus cysts and aneuploidy?
What is the association between choroid plexus cysts and aneuploidy?
When an isolated choroid plexus cyst is detected, how is counseling different for women with a normal screen versus those whose screening indicates increased risk?
When an isolated choroid plexus cyst is detected, how is counseling different for women with a normal screen versus those whose screening indicates increased risk?
What is the vein of Galen?
A single, midline structure formed by convergence of the 2 internal cerebral veins and the basal veins of Rosenthal, posterior to the splenium of the corpus callosum; the vein courses posteriorly to empty into the straight sinus
What is the vein of Galen malformation?
An extremely rare anomaly, a complex AV malformation affecting the vein of Galen
How does vein of Galen malformation aneurysm?
Size of the aneurysm determines clinical presentation. A large aneurysm can result in as much as 50-60% of the cardiac output shunting thru the lesion that may cause high-output congestive heart failure -> hydrops or neonatal cardiac failure
What cerebral anomalies can be associated with vein of Galen aneurysm?
Cerebral parenchymal injury including cerebral infarction, periventricular leukomalacia, and hemorrhagic infarction
US findings of vein of Galen aneurysm?
Cystic or tubular mass is noted in the midline ofthe brain just above and behind the thalamus. Turbulent venous or arterial flow may be demonstrated using color Doppler within the draining vessel.Generalized cardiomegaly or right ventric- ular enlargement is commonly notedCoarctation of the aorta and transposition of the great vessels occur with increased frequency in infants with vein o fGalen aneurysm and may also be responsible for cardiomegaly Massive hydrops has been reported as early as 31 weeks ofgestation
Differential diagnosis of vein of Galen aneurysm
Other midline cystic structures within the brain such as an arachnoid cyst or an interhemispheric cyst associated with agenesis ofthe corpus callosum.
Antenatal management of vein of Galen aneurysm
Serial antenatal ultrasound examinations should be performed q 2w to determine a change in size of the aneurysm and to monitor for hydrocephalus or congestive heart failure. Joint management with a pediatric cardiologist and pediatric neurosurgeon is suggested.The approach to therapy for a patient with a vein of Galen aneurysm will depend on the age of the patient, the clinical symptoms, and the angiographic architecture of the malformation.
4 subtypes of vein of Galen aneurysm
- Neonates with severe heart failure and cranial bruit.2. Children with mild heart failure and cranial bruit.3. Children younger than 1year of age with cranial bruit and hydrocephalus.4. Patients with headaches and syncope.
Postnatal treatment of vein of Galen aneurysm
Transvenous and transarterial embolization techniques have been increasingly described in the literature. In the infant with congestive heart failure the initial procedure of choice appears to be endovascular, with a venous approach, either transfemoral or transtorcular. The immediate goal is to increase resistance in the aneurysm to right ventricular output.
Long-term outcome of vein of Galen aneurysm
Little information is available on the long-term follow-up of prenatally diagnosed cases of vein of Galen aneurysm. In one series of 18 patients diagnosed prenatally, 13 infants survived the immediate neonatal period and 12 underwent embolization of the aneurysm. Total occlusion ofthe aneurysm was obtained in eight cases. Sixty-seven percent of the surviving newborns were neurologically normal when assessed with Denver Development Tests. Infants who require shunting for hydrocephalus with vein of Galen aneurysm appear to have a less favorable neurologic outcome.
What is the vein of Galen?
A single, midline structure formed by convergence of the 2 internal cerebral veins and the basal veins of Rosenthal, posterior to the splenium of the corpus callosum; the vein courses posteriorly to empty into the straight sinus
What is the vein of Galen malformation?
An extremely rare anomaly, a complex AV malformation affecting the vein of Galen
How does vein of Galen malformation aneurysm?
Size of the aneurysm determines clinical presentation. A large aneurysm can result in as much as 50-60% of the cardiac output shunting thru the lesion that may cause high-output congestive heart failure -> hydrops or neonatal cardiac failure
What cerebral anomalies can be associated with vein of Galen aneurysm?
Cerebral parenchymal injury including cerebral infarction, periventricular leukomalacia, and hemorrhagic infarction
US findings of vein of Galen aneurysm?
Cystic or tubular mass is noted in the midline ofthe brain just above and behind the thalamus. Turbulent venous or arterial flow may be demonstrated using color Doppler within the draining vessel.Generalized cardiomegaly or right ventric- ular enlargement is commonly notedCoarctation of the aorta and transposition of the great vessels occur with increased frequency in infants with vein o fGalen aneurysm and may also be responsible for cardiomegaly Massive hydrops has been reported as early as 31 weeks ofgestation
Differential diagnosis of vein of Galen aneurysm
Other midline cystic structures within the brain such as an arachnoid cyst or an interhemispheric cyst associated with agenesis ofthe corpus callosum.
Antenatal management of vein of Galen aneurysm
Serial antenatal ultrasound examinations should be performed q 2w to determine a change in size of the aneurysm and to monitor for hydrocephalus or congestive heart failure. Joint management with a pediatric cardiologist and pediatric neurosurgeon is suggested.The approach to therapy for a patient with a vein of Galen aneurysm will depend on the age of the patient, the clinical symptoms, and the angiographic architecture of the malformation.
4 subtypes of vein of Galen aneurysm
- Neonates with severe heart failure and cranial bruit.2. Children with mild heart failure and cranial bruit.3. Children younger than 1year of age with cranial bruit and hydrocephalus.4. Patients with headaches and syncope.
Postnatal treatment of vein of Galen aneurysm
Transvenous and transarterial embolization techniques have been increasingly described in the literature. In the infant with congestive heart failure the initial procedure of choice appears to be endovascular, with a venous approach, either transfemoral or transtorcular. The immediate goal is to increase resistance in the aneurysm to right ventricular output.
Long-term outcome of vein of Galen aneurysm
Little information is available on the long-term follow-up of prenatally diagnosed cases of vein of Galen aneurysm. In one series of 18 patients diagnosed prenatally, 13 infants survived the immediate neonatal period and 12 underwent embolization of the aneurysm. Total occlusion ofthe aneurysm was obtained in eight cases. Sixty-seven percent of the surviving newborns were neurologically normal when assessed with Denver Development Tests. Infants who require shunting for hydrocephalus with vein of Galen aneurysm appear to have a less favorable neurologic outcome.
