Neuro - Vasc Flashcards
What connects superior sagittal sinus into superficial middle cerebral vein?
Trolard
Additional
Labbe - transverse sinus and superfical middle cerebral
Top Trolard
Lower Labbe
Where do basal veins of rosenthal drain?
Deep veins, pass lateral to midbrain within ambient cistern draining into vein of Galen.
Additional:
Vein of Galen formed by two internal cerebral veins. Drains into the staight sinus.
Nenatal Brain MRI
Is Baby brain T1 bright or T1 dark?
T1 dark
T2 bright
Why?
Immature myelin has high water content (ie T2 bright)
As it matures water descreases and fat increases (ie T1 bright(
Nb. T1 changes precede T2.
Decribe myelination pattern
Inferior to superior
Posterior to anterior
central to peripheral
Subcortical white matter last to myelinate.
What gives steer horn (coronal) or racing car (axial) ventricular appearance?
Corpus callosum agenesis
additional:
You will see asymmetric occipital horn dilatation (Colpocephaly)
Other association: Pericallosal lipoma
Callosum forms from genu to splenium (then rostrum last)
Heriation of brain tissue through cranial defect (neural tube)
Meningioencephalocele
Fronto ethmoidal is common
What is cause of ‘single lobed’cerebellum?
Rhomboencephalosynapsis
(vermis is absent)
Associated with holoprosencephaly spectrum.
Addition: Remeber normal primary fissure (dorsal) and fastigial point (v
Name the conditon:
Vermis hypoplasia
Vermis elevation and rotation
Dilated 4th Ventricle
Dandy walker malformation
(Torcula, lamboid inversion)
Most common manifestation is macrocepahly
The cerebellar volume is preserved - just displaced anterior & lateral
Normal varient - mega cisterna magna.
Holoprosencephaly
Least Severe : Lobar
Semi-Lobar
Most Sever: Alobar
What?
Failure of midline cleavage.
Lobar - Variable frontal horn fusion (absent septum pellucidum)
Semi - lobar : Back is cleaved, not the front. occiptal and temporal horns partially developed.
Alobar : zero midline cleavage
What causes anterior falx absence, absent septum pellucidum and anterior interhemispheric fissure. Partial thalmus fusion.
Semi-Lobar holoprosencephaly
What casues absent falx, absent corpus callosum and interhemispheric fissure?
Alobar holoprosencephaly.
What is polymicrogyria PMG
Overfolding of superficial layers of cortex. Resulting nodular bumpy cortex.
(can be caused by Zika virus)
What is split brain?
Schizencephaly
-secondary to vascular insult
closed lip (20%)
open lip (80%)
Differentiate schizencephaly and porencephalic cyst
Schizencephaly cleft is lined by gray matter
Porencephalic cyst is not
Porencephalic cyst is caused by ischaemic/traumatic event - encephalomalacia (looks developmental)
Most severe - hydraencephaly (cerebelleum, falx and midbrain remain)
Differentiate:
MENINGOCELE
MENINGO-ENCEPHALOCELE
CYSTOCELE
MYELOCELE
meningocele - csf, meninges NO BRAIN
meningo-encephalocele - csf, meninges, brain
cystocele - csf, meninges, brain, ventricle
myelocele - spinal cord
cephalocele - hernial of cranial contents
Cerebellar tonsillar descent (5mm ) and syrinx
Chiari I malformation
Cervical syrinx not always associated
Can have either occipital headache secondary to pressure or weakness, spasticitym proprioception loss from cord pressure.
Less classic association - Klippel - Feil syndrome (congenital c-spine fusion)
Features:
Thin 4th ventricle
Interdigitated gyri
Myelomeningocele
Chiari II
- result of neural tube defect and lumbar myelomeningocele causing downward cerebellar displacement
- clival hypoplasia
- long skinny 4th ventricle
- interdigitated cerebral gyri
- low lying torcula (opposite DW)
Has to have neural tube defect
Associations - lumbar myelomeningocele/spina bifida
Chiari III = Chiari II + occipital encephalocele.
Most common cause of partial complex epilsepy.
Mesial temporal sclerosis
- Hippocampal volume loss
- Scar / gliosis - high T2 signal
- Temporal horn ex vacuo
what is pseudotumour cerebri?
IIH (Idiopathic intracranial HYPERtension)
-too much csf
CT findings:
slit like ventricles
venous sinus compression
partially empty sella
vertical optic nerve tortuosity
flattened posterior sclera
Clinical: downward brainstem displacement may result in 6th nerve palsy.
What causes
-ataxia
and incontinence in elderly persion
Normal pressure hydrocephalus
Imaging features:
Out of proportion ventricular size
Trans-ependymal oedmea
Upward bowing corpus callosum.
Most common cause of obstructive hydrocephalus?
Cerebral aqueduct stenosis
Na/K pump malfunction and gray/white matter differentiation loss
Cytotoxic ordema
Classic: Ischaemia
also with trauma
BBB malfunction with white matter oedema
Vasogenic oedema (extracellular)
Classic: Tumour, infection and late ischameia
Which is more asscoiated with ACA compression: cingulate or uncal herniation
Cingulate (Subfalcine) herniation
Uncal (transtentorial) herniation, can causes ipsilateral suprasellar effacement and CN3 compression.
Lissencephaly
High T2/FLAIR medial/dorsal thalamus, peri-aqueductal gray matter.
Wernicke Encephalopathy
B1 deficiency
T2 bright central pons
Central Pontine Myelinolysis
T2 bright signal corpus callosum
Body - genu - splenium
Thinned corpus callosum, cystic cavities - genu and splenium
Marchiafava - Bignami
CT hypodensity/ T2 bright Globus Pallidus
Carbon monoxide (causes global warming)
T2 bright putamen
Methanol
Post partum, eclampsia, subcortical and cortical asymmetric white matter oedema parietal and occipital lbes
PRES Posterior Reversible Encephalopathy Syndrome
Other classic history: acute HTN, chemotherapy.
Transverse Myelitis + Optic neuritis
Neuromyelitis optica
Young patient (30-40), migraines, strokes, dementia.
CADASIL
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy
High T2 / FLAIR - frontal and temporal lobes. (Tempoal lobe involvement is classic!!)
Caudate head atrophy and frontal horn ex vacuo dilatation
Huntington disease
Lactic acidosis, Seizures, Strokes
MELAS syndrome
Tegmentum atrophy, sparing of tectum and peduncles
Progressive supranuclear palsy
Parkinson plus
T1 high in substantia nigra
DAT scan - loss of commas
Parksinons disease
Panda sign - bright tegmentum with normal dark nuclei and substantia nigra
T1 bright basal ganglia
Wilson disease
Most common solitary brain tumour in adult population?
Metastatic carcinoma
Blue mass behind tympanic membrane
Bright on T1
Cholesterol granuloma
T1 bright as it contains mix of blood and cholesterol crystals
A glomus tympanicum will present with pulsatilla tinnitus, and red lesion behind TM.
Cholesteatoma - white behind TM + I so intense on T1.
Sinus mass differentials ..
Older -
1. SCC - generally involves maxillary antrum. Low T2 signal
2. Sinonasal lymphoma - Usually nasal cavity rather than sinus.
Adolescent/Young adults7 -
1. Nasopharyngeal angiofibroma - dark flow voids on T1 + mass will be brightly enhancing.
