Neurology lists Flashcards
Chiari malformations
Chiari 1
- most common
- peg like cerebellar tonsils, displaced into the upper cervical canal
Chiari 1.5
- caudal descent of the cerebral tonsils and brain stem
Chiari 2
- displacement of the medulla, fourth ventricle and cerebellar vermis
- associated with a myelomeningocele
Chiari III
- similar to II but with high cervical encephalocele
Chiari IV
- severe cerebellar hypoplasia without displacement through the foramen magnum
Chiari V
- absent cerebellum, hernia of the occipital lobe through the foramen magnum
MRS - What does creatinine represent
Cellular energy stores
MRS - Peaks occur in what order?
Alphabetical
Choline, creatinine, NAA
Which disorder increases NAA?
Canavan disease - demyelinating disorder
When is a lactate doublet seen?
High grade tumour
- anaebolic metabolism
Periventricular enhancement Ddx
- Primary CNS lymphoma
- rarely involves meninges
- systematic lymphoma commonly involves menenges
- Necrotic in immunocompromised
- Enhances homogenously in the immunocompetent patient
- Infectious ependymitis
- Primary glial tumour
- Multiple sclerosis
Gyriform enhancement - DDx
- Herpes encephalitis
- Decreased diffusion
- Meningitis
- Subacute infarct
- PRES
Ring enhancement ddxx
- Mets
- Abscess
- glioma
- infarc
- contusion
- demyelination
- radiation
Ddx Pachymeningeal enhancement
- Intracranial hypotension
- Postoperative
- post lumbar puncture
- Meningeal neoplasm
- Granulomatous disease
- Sarcoid
- TB
- Fungal
- Occurs at the basal meninges
Letpomeningeal enhancement ddx
- Meningitis
- Letpomeningeal carcinomatosis
- Viral encephalitis
- slow flow vascular
How to differentiate between intra and extra axial mass
Abscence of intervening gray matter between the mass and white matter
Tumours hypointense on T2 weighted imaging
- Containing dessicated mucin
- Hypercellular tumours
- Lymphome
- medulloblastoma
- germinoma
- glioblastoma
Tumours hyperintense on T1 weighted imaging
- Metastatic melanoma
- Fat containing tumours
- Haemorrhagic metastases
- renal cell
- thyroid
- choriocarcinoma
- melanoma
Metastataic disease to the brain
- Lung
- Breast
- Melanoma
Posterior fossa mass in a child
- Medulloblastoma
- Juvenile pilocytic astrocytome
- Epdendymoma
- Haemangioblastoma
- ATRT (atypical teratoid/rhabdoid tumour)
Posterior fossa mass in an adult
- Metastasis
- Haemangioma
- Astrocytoma
- Medulloblastoma
CP angle masses
- Schwannoma
- Meningioma
- Arachnoid cyst
- Aneurysm
- Epidermoid cyst
- Intra-axial neoplasm
Intrinsic pituitary mass
- Macroadenoma
- Microadenoma
- Lymphocytic hypophystitis
- Granulomatous hypophysitis
- sarcoid
- Wegner
- TB
- Rathke’s cleft cyst
Suprasellar mass
- Sarcoid/suprasellar extension of an adenoma
- Aneurysm
- Teratoma
- Craniopharyngioma
- Hypothalamic glioma/Hypothalamic harmatoma
- Meningioma/Mets
- Optic nerve glioma
Intrinsic pineal mass
- Germ cell tumour
- Germinoma
- Teratoma
- Pineal cyst
- Pineocytoma
- Pineoblastoma
- Mets
Pineal regiom masses
- Gliomas
- Vein of galen aneurysm
- Meningioma
- Quadrigeminal plate lipoma
DAI Grading
- Only grey white matter junction
- CC
- Dorsolateral midbrain
Dural AV fistula classification (Cognard classification)
- I - no cortical venous drainage
- IIA - Reflux into dural sinus but not cortical veins
- IIB -Reflux into cortical veins - 10-20% haemorrhage
- III - Direct cortical venous drainage: 40% haemorrhage rate
- IV - direct cortical venous drainage with venous ectasia 66% haemorrhage rate
- V - spinal venous drainage
Fisher grading of SAH
- Gr I - ve on CT
- II - <1mm thick
- III >1mm thick
- IV = diffuse or IV/parenchymal extension
What area of the brain is seen in superior sagittal sinus thrombosis?
Parasagittal high convexity cortex
What area of the brain is seen in deep venous system thrombosis?
Infarction of bilateral thalami
What area of the brain is seen in transverse sinus thrombosis?
Posterior temporal lobe infarct
Causes of intraparenchymal haemorrhage
- Hypertensive haemorrhage
- Amyloid angiopathy
- Aneurysmal haemorrhage
- AVM
- dAVF
- Cavernous malformation
- Venous thrombosis
- Haemorrhagic neoplasm
- Haemorrhagic infarct
- CNS vasculitis
- Moyamoya
Dilated perivascular spaces ddx
- Mucopolysaccharidoses
- Gelatinous pseudocysts in cryptococcal meningitis
- atrophy
Brain myelination
- Babies are born with the brainstem and posterior limb of the internal capsule myelinated
- Order of myelination
- inferior to superior
- posterior to anterior
- Central to peripheral
- sensory before motor
Sinus development
- Maxillary (5 months)
- Ethmoid (1 year)
- Sphenoid (6 years)
- Frontal (4 years)
Chiari 1 differentials
Chiari type II malformation: Chiari type II malformation presents with deformity of the brainstem and enlargement of the foramen magnum. It is associated with myelomeningocele.
• Spinal hypotension syndrome: This is characterized by downward displacement of the cerebellar tonsils secondary to low pressure within the spinal canal. The brainstem and 3rd ventricle “sag” inferiorly, and the pituitary gland is upwardly convex. If contrast is administered, dural thickening and enhancement are demonstrated
Chiari 1 associated anomalies
Associated anomalies are shortening of the clivus, basilar
invagination, C1 assimilation, and fused cervical vertebrae (Klipper-Feil syndrome)
Crowding of the posterior fossa ddx
Chiari type II malformation:
Chiari type II malformations are complex developmental disorders of the posterior brain that can be associated with closure defects of the neural tube, myelomeningocele, and dysgenesis of the corpus callosum.
• Chiari type III malformation:
Chiari type III malformations have the same characteristics as Chiari type II malformations but are associated with encephalocele instead ofmyelomeningocele.
• Medulloblastoma:
Medulloblastomas are malignant primitive neuroectodermal tumors of the posterior fossa thatarise from the roof of the 4th ventricle. They can be similar to Chiari type II malformations, as they efface the 4th ventricle and can be isointense to the cerebellum on T1-weighted noncontrasted images. Contrast helps to differentiate them, as more than 90% of medulloblastomas enhance.
Chiari II associations
Skull: lacunar skull; concave clivus; low-riding torcula; wide foramen magnum and upper cervical canal
• Dura: fenestrated falx causing interdigitating sulci; heartshaped incisura; hypoplastic cerebellar tentorium
• Posterior fossa: towering cerebellum; downward vermian displacement; slitlike 4th ventricle; tectal beaking; wrapping of cerebellum around brainstem; medullary kink
• Other common associated defects: myelomeningocele (90%); dysgenesis of the corpus callosum (85%); hydrocephalus (75%); syringomyelia (50%); aqueductal stenosis (50%); holoprosencephaly; tethered cord
Dandy walker associations
Agenesis of the corpus callosum, migration anomalies, cephalocele, holoprosencephaly, hydrocephalus, and porencephaly, among others
Abnormal cerebellar size
Cerebellar atrophy: the cerebellum is small and the cerebellar fissures are enlarged.
• Cerebellar hypoplasia: the cerebellum is small, but the fissures are normal in size compared with the folia.
• Cerebellar dysplasia: disorganized development; an abnormal folial pattern ranging from absence of fissures to large folia with shallow fissures to foliation in abnormal directions or heterotopic nodules of gray matter may be present.
• Cerebellar hypogenesis: the superior portions of the cerebellum are formed, but the inferior portions are not; this term should not be used because it overlaps with dysplasia
Dysgenesis of the corpus callosum
Bundles of Probst: tracks of white matter that run parallel to the ventricle as an alternative to the CC
• High-riding 3rd ventricle
• Absent cingulate sulcus with radially oriented fissures
• Crescent-shaped lateral horns; small (“bullhorns”) appearance of the frontal horns
• Enlarged occipital horns (colpocephaly)
• Absence of the septum pellucidum or severe widening of the cavum septum pellucidum
• The precursors of the CC develop between 8 and 20 weeks. Many different genes control the movement of axons across the midline, and numerous mutations can result in callosal defects.
Canavan disease
Autosomal-recessive condition, most common in Ashkenazi Jews
• Deficiency of aspartoacylase
• Hypotonia, macrocephaly, and seizures in newborn period
• Spasticity, optic atrophy, and intellectual failure as disease progresses
• Death usually by second year of life
• Computed tomography: diffuse low attenuation in cerebral and cerebellar white matter
• MR imaging: White matter has high T2 and low T1 signal.
The thalami and basal ganglia can be affected.
• The peripheral white matter is preferentially affected early in the course of the disease.
• In severe cases, there may be an extensive lack of myelination with relative sparing of the internal capsules.
Intracranial lipoma
There are two types of pericallosal lipomas: bulky (tubulonodular), which are associated with agenesis of the corpus callosum, and ribbon-like (curvilinear).
High T1 signal
Hemorrhage
◦ Early subacute (3–7 days): intracellular methemoglobin
◦ Late subacute (7–14 days): extracellular methemoglobin
• Lesions with a high protein content
• Melanin
• Lipids
• Minerals (manganesium)
• Slow flow
Intracranial lipoma locations
interhemispheric
(40–45%), suprasellar-infundibular (25%), quadrigeminal
cistern (25%), and CPA (14%)
Lissencephaly types
Type I (classic) lissencephaly: Type I lissencephaly is a migration disorder of the gray matter, with the formation of a smooth, four-layered cortex (a normal cortex has six layers). Type I lissencephaly may be isolated or part of a syndrome, most frequently Miller-Dieker syndrome. • Type II lissencephaly (cobblestone complex):
Type II lissencephaly has a disorganized, unlayered cortex and no ribbons of band heterotopia. Neurons migrate past the cortical plate to the subpial space. No subependymal heterotopia should be present. Type II lissencephaly is associated with congenital muscular dystrophy (Walker-Warburg syndrome). Ocular defects are common
Types of heterotopia
Three types
• Subependymal
◦ Normal development; seizures
◦ Smooth, ovoid masses isointense to gray matter in all
sequences
• Focal subcortical
◦ Motor and intellectual disturbance, epilepsy
◦ Large heterogeneous mass, isointense to cortical gray
matter
◦ The affected hemisphere is small with thin cortex and
shallow sulci .
◦ Associated hypogenesis of the corpus callosum and
dysplastic basal ganglia
Band (laminar) heterotopia
• Considered a mild form of classic lissencephaly
• Variable developmental delay and seizures
• Female preponderance (90%)
• Homogeneous bands of gray matter between the
lateral ventricles and cerebral cortex, separated from
both by a layer of normal-appearing white matter
• May have foci of high T2 signal in the white matter
Anomalies associated with schizencephaly
Concomitant anomalies are polymicrogyria outside the cleft, white matter volume loss, septal and optic anomalies, callosal anomalies, and hippocampal anomalies
Septo-optic dysplasia
Associated with schizencephaly: usually, a remnant of the septum pellucidum is present.
• White matter hypoplasia, including optic radiations. There is no schizencephaly. Hypopituitarism may be present.
NF1
NF1 is a chromosome 17 abnormality.
• Spinal NF1 is associated with dural ectasia, lateral meningoceles, and posterior scalloping of the vertebral bodies.
• NF1 is also associated with the following:
• Plexiform neurofibromas
• Optic gliomas (30%)
• Osseous dysplasias
• Skin findings (café au lait spots, freckling, skin neurofibromas)
NF2
A defect in the NF2 gene on chromosome 22q11 is inherited in an autosomal-dominant fashion.
• Intracranial lesions include vestibular schwannomas (in 95% of adults, they occur in the internal auditory canal or porus acusticus); multiple meningiomas; and calcifications of the choroid plexus, cerebellar cortex, and occasionally cerebral cortex.
• Spinal lesions include cord ependymomas, multiple schwannomas of exiting nerve roots, and meningiomas
VHL
The VHL gene on chromosome 3 is inherited in an autosomal-dominant fashion.
• Central nervous system (CNS) neoplasms include hemangioblastomas in the cerebellum, brainstem, spinal cord, and retina as well as endolymphatic sac tumors.
• Non-CNS lesions include clear cell renal carcinoma, pheochromocytoma, pancreatic neuroendocrine tumors, and
epididymal cystadenoma.
• Hemangioblastomas are solid, cystic, hemorrhagic, or mixed. They are frequently cystic with a mural enhancing nodule.
• Hemangioblastomas may have flow voids from feeding arteries
Diastematomyelia
Type 1 (with septum): 25%
◦ A bony septum results in separate dural tubes, each containing a hemicord.
◦ The usual location is the thoracic or lumbar spine.
◦ Scoliosis is present.
◦ Hydromyelia is common.
• Type 2 (without septum): 75%
◦ There is no bony spur; a fibrous septum may be present.
◦ Only one thecal sac contains both hemicords.
Oligodendroglioma
This is a tumor of glial origin presenting as a mass in the cortex or subcortical white matter with coarse calcification (20–90% of cases) and occasional cystic degeneration or hemorrhage. Most do not enhance,
but there may be subtle enhancement in 20%. They are more frequently supratentorial in location (90% of cases).
Vasogenic edema is uncommon
DNET
DNETs are benign, well-demarcated cortical lesions. They present as partial seizures in patients younger than 20 years. They occur more frequently in the temporal lobe (60%) or frontal lobe (30%). Cortical dysplasia is often noted adjacent to the lesion. Calcification is rare (20%). DNET appears as a
multilobulated “bubbly” lesion with high signal on T2WIs and low signal on T1WIs. There is no surrounding vasogenic edema. Thirty percent show enhancement
Normal suture size
- >10mm at birth
- >3mm at 2 years
- >2mm at 3 years
Congential underossification of the sutures
- Osteogenesis inperfecta
- Hypophosphatasia
- Rickets
- Hypothyroidism
- pyknodystostosis
- cleidocranial dysplasia
Metabolic causes leading to wide sutures
- Hypoparathyroidism
- lead intoxication
- Abnormal vitamin A
Infiltration of sutures
- Neuroblastoma
- leukaemia
- Lymphoma
Craniosynostosis
- Secondary causes
- Haematologic
- Sicke cell
- Thalassemia
- Metabolic
- Rickets
- hypercalcaemia
- hypervitaminosis D
- Bone dysplasia
- Hypophosphatasia
- achrondoplasia
- metaphyseal dysplasia
- mongolism
- Huler disease
- skull hyperostosis
- Rubinstein-Taybi syndrome
- Syndromes
- Crouzon
- Apert
- Carpenter
- Treacher Collins
- Cloverleaf skill
- craniotelencephalic dysplasia
- arrhinencephaly
- Microcephaly
- Post shunting
- Haematologic
Wormian bones
- Pyknodystostosis
- Osteogenesis imperfecta
- Rickets (healing phase)
- Kinky hair syndrome
- CLeidocranial dysostosis
- Hypothyroidism/hypophosphatasia
- Otopalatodigial syndnrome
- Primary oacroosteolysis - Hadju Cheyney/Pachydermiperostosis/progeria
- Syndrome of Down
- Idiopathic
Generalised increased skull thickness
- Chronic severe aenaemia
- Cerebral atrophy
- Englemann disease - skull base
- Hyperparathryoidism
- Acromegaly
- Osteopetrosis
Focal increased skull thickness
- Meningioma
- Fibrous dysplasia
- Paget disease
- Dyke-Davidoff-Mason syndrome
- Hyperostosis frontalis interna
Hair on end skull
HI NEST
- Hereditary spherocytosis
- Irion deficiency anaemia
- Neuroblastoma
- Enzume deficiency (G6PD)
- Sickle disease
- Thalassemia major
Abnormally thin skull - Generalised
- Obstructive hydrocephalus
- Cleidocranial dysostosis
- Progeria
- Rickets
- Osteogenesis imperfecta
- Craniolacunia
Focally thin skull
- Neurofibromatosis
- Chronic subdural haematoma
- Arachnoid cyst
Osteolytic lesion of the skull - categories
- Normal variant
- Trauma
- Infection
- Congenital
- Benign tumour
- Malignancy
Osteolytic lesion - normal variant
- Emissary vein
- Venous lake
- Fossa lacunae
- Parietal foramina
Osteolytic lesion - trauma
- Surgical burr hole
- Leptomeningeal cyst
Osteolytic lesion - Infection
- Osteomyelitis
- Hydatid disease
- Syphilis
- TB
Osteolytic lesion - congenital
- Epidermoid/dermoid
- NF
- Meningoencephalocele
- Fibrous dysplasia
- Osteoporosis circumscripta of paget’s disease
Osteolytic lesion - benign tumours
- Haemangioma
- Enchondroma
- Brown tumour
- Eosinophilic granuloma
Osteolytic lesion - malignant tumour
- Solitary/multiple mets
- Multiple myeloma
- Leukaemia
- Neuroblastoma
Solitary lytic lesion in skull
HELP MFT HOLE
- Haemangioma
- Epidermoid/dermoid
- Leptomeningeal cyst
- Post-op, paget
- Metastasis, myeloma
- Fibrous dysplasia
- TB
- Hyperparathyroidism
- Osteomyelitis
- Lambdoid defect
- Eosinophilic granuloma
Multiple lytic skull lesions
BAMMAH
- Brown Tumour
- AVM
- Myeloma
- Mets
- Amyloid
- Histiocytosis
Button sequetrum (skull)
TORE ME
- TB
- Osteomyelitis
- Radiation
- Eosinophilic granuloma
- Metastasis
- Epidermoid
Absent greater sphenoid wing
M is FOR MARINE
- Meningioma
- Fibrous dysplasia
- Optic flioma
- Relapsing haematoma
- Metastasis
- Aneurysm
- Retinoblastoma
- Idiopathic
- NF
- Eosinophic granuloma
Widened superior orbital fissure
A FAN
- Aneurysm (ICA)
- Fistula (cavernous sinus)
- Adenoma (pituitary)
- Neurofibroma
Central skull base tumours - categories
- Developmental
- Infection/inflammation
- Benign
- Malignancy
Central skull base tumours - developmental
Encephalocele
Central skull base tumours - Infection/inflammation
- Extension from sinus/mastoid infection
- Trauma complication
- Fungal disease
- Sinus/nasopharyngeal sarciod
- Radiation necrosis
Central skull base tumours - benign
- Juvenile angiofibroma
- Meningioma
- Chordoma
- Pituitary tumour
- Paget disease
- Fibrous dysplasia
Central skull base tumours - malignancy
- Mets: prostate, lung, breast
- Chondrosarc
- NPA carcinoma
- Rhabdomyosarcoma
- Perineural tumour spread
