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Neuroradiology > Brain 2 > Flashcards

Brain 2 Flashcards

1
Q

Imaging findings of an extra-axial mass

A
  • Buckling of the white matter
  • dural base
  • expansion of adjacent subarachnoid spaces
  • csf cleft sign
  • displacement of vessels
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2
Q

is a meningioma intra or extra dural

A

extra-axial intra-dural

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3
Q

Imaging findings of an intra-axial mass

A
  • expands cortex of brain
  • no expansion of the subarachnoid space
  • vessels seen peripheral to the mass
  • spreads along well defined boundaries
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4
Q

90% of meningiomas occur _______

A

supratentorially. parasagittal dura and convexities most common locations

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5
Q

Typical MRI signal characteristics of meningioma

A 
must be extra-axial
hypo-iso T1, iso-hyper T2, avid contrast enhancement
cleft sign
dural tail
MRS: High alanine, absent NAA
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6
Q

Meningioma vs pituitary adenoma: which one narrows the ICA?

A

Meningioma. A pituitary adenoma will surround the ICA but almost never narrow it.

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7
Q

Causes of intraparenchyma edema secondary to meningioma

A
  • venous stasis
  • compressive ischemia
  • aggressive growth
  • parasitization of pial vessels
  • venous occlusion

meningiomas adjacent to brain parenchyma are more likely to cause edema

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8
Q

Typical location for intraventricular meningioma?

A

Trigone of the lateral ventricle (typically left) around the choroid plexus (80%)

15% third ventricle, 5% fourth ventricle

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9
Q

How to differentiate benign from malignant meningioma (3)

A
  • Faster rate of growth
  • Intraparenchymal invasion
  • Increased diffusion restriction compared to benign meningiomas
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10
Q

What is the mean latency period for radiation induced meningioma?

A

Approximately 35 years

must arise in the radiation field

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11
Q

What is the effect of a hemangiopericytoma on the adjacent bone?

A

Bone erosion

No hyperostosis

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12
Q

How to distinguish meningioma from vestibular schwannoma (7)

A
  • Meningioma has a dural tail
  • Vestibular schwannoma has acute angle /w petrous bone (80%) vs obtuse for meningioma
  • Vestibular schwannoma can be very bright on T2
  • 7-10% vestibular schwannoma also has arachnoid cyst
  • Vestibular schwannomas can show microhemorrhage of SWI, absent in meningioma
  • Vestibular schwannomas expand the IAC, unusual for meningioma
  • 90% of purely intracanalicular lesions are vestibular schwannomas
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13
Q

Typical MRI appearance of vestibular schwannoma (2)

A
  • slightly hypo to isointense to pons on all sequences
  • almost always enhance, homogeneous 70%

Calcification and dural tail extremely rare
cyst/necrosis uncommon (10%)

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14
Q

Which cranial nerve is most commonly affected by a schwannoma? Name the most common branch

A

CN VIII, superior vestibular branch

other common: inferior vestibular branch, CN VII, CN V

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15
Q

Imaging difference between jugular schwannoma and paraganglioma (glomus jugulare tumor)? Specifically bone and vascular (2)

A
  • They both erode the adjacent bone but in jugular schwannoma it is smooth and sclerotic vs irregular and non-sclerotic
  • jugular schwannoma compresses the vein, paraganglioma invades the vein
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16
Q

Typical primaries to give dural metastases? (5)

A
  • breast most common purely dural
  • Lung
  • prostate
  • melanoma
  • lymphoma but sometimes dural lymphoma is primary

IN CHILDREN:

  • adrenal neuroblastoma
  • leukemia
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17
Q

Most common non-CNS malignancies to seed the CSF? (3)

A
  • breast
  • lung
  • melanoma
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18
Q

Classification for cystic meningiomas? (4 types)

A

Type 1: cyst in center of meningioma
Type 2: cyst in periphery of meningioma (intra-tumoral)
type 3: cyst in adjacent brain
type 4: cyst between tumor and brain (arachnoid cyst)

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19
Q

What syndrome is subependymal giant cell astrocytoma associated with?
give WHO grade

A

Tuberous sclerosis

On pathology, SEGA and subependymal nodule of TS are indistinguishable

WHO grade 1

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20
Q

What is l’hermitte-duclos disease and what are the imaging findings?
What is the usual age of presentation?
give WHO grade

A

Dysplastic cerebellar gangliocytoma
Disorder of the normal cerebellar laminar cytoarchitecture
WHO grade 1

Cerebellar mass usually in hemisphere lowT1 highT2 in an alternating striated pattern (thickened cerebellar folia)

No enhancement

Usually non calcified but can have scattered calcification

Usually occurs in the third and fourth decades

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21
Q

What is the histological difference between gangliocytoma and ganglioglioma?

A

They both contain neoplastic neuronal cells.

They both also contain glial cells, which are anaplastic in gangliogliomas, whereas gangliocytomas contain normal nonneoplastic glial cells.

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22
Q

True or false:

Calcification and cyst formation is a frequent finding in gangliocytomas

give WHO grade

A

True

They also frequently enhance
They have variable T1 and T2 signal

WHO grade 1

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23
Q

Which phakomatosis is L’hermitte-Duclos disease associated with (describe it)?

A

Cowden Syndrome (multiple hamartoma syndrome)

Rare autosomal dominant inherited disorder characterized by multiple hamartomas

Other diseases associated with lhermitte-duclos disease:

  • disorders of cortical formation (megalencephaly, grey matter heterotopia, polymicrogyria)
  • polydactyly
  • hydromyelia
  • macroglossia
  • localised gigantism
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24
Q

What is typical location of central neurocytoma?
What is CT/MR appearance?
give WHO grade

A

WHO Grade 2

Typically located in the lateral ventricles near the foramen of Monro with characteristic attachment to the septum pellucidum

inhomogeneously T1 isointense
Iso-hyper T2
about half contain calcium. Can contain cysts, hemorrhage and vessels
enhances

iso to hyperdense on CT

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25
Q

What is imaging ddx of central neurocytoma?

A

other intraventricular tumors that occur in young adults:

oligodendroglioma
SEGA
low-grade/pilocytic astrocytoma
ependymoma

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26
Q

What is a ganglioneurocytoma?

give WHO grade

A

rare variant of central neurocytoma that is characterized by differentiation toward ganglion cells.

WHO grade 2

Frequently forms a cystic lesion, frequently arises extraventricularly

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27
Q

What is the classical appearance of a ganglioglioma?
Also give other imaging findings
give WHO grade

A

Ganglioglioma is rare but remains most frequent of the neuronal-glial CNS neoplasms. WHO grade 1

Cystic mass with a mural nodule (40%). Temporal lobe is most affected region

Most gangliogliomas occur in children and young adults

other imaging findings:

calcification (30%)
scalloped pressure erosion of the overlying calvaria (slow growth)
variable enhancement (nonenhancing, ringlike, intense homogeneous)
usually little mass effect/vasogenic edema

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28
Q

What is DNET? Give WHO grade

Imaging appearance?

A

Dysembryoplastic neuroepithelial tumour
mixed neuronal-glial neoplasm characterized by multinodular architecture and predominantly intracortical location

WHO grade 1

Hypodense cystlike lesion
hypoT1
markedly hyperT2 with soap bubble apperance
enhancement is not a prominent feature but can be present

calcification

29
Q

What is typical location and appearance of oligodendroglioma

Give WHO grade

A

WHO grade 2 glial tumor (grade 3 if anaplastic)

85% are supratentorial, involving white matter and cortex. Most commonly in frontal lobes.

hypo/isodense
hypoT1
hyperT2
no diffusion restriction

70-90% contain calcification
50% enhance, variable degree

30
Q

What happens to the calcification of a pineal gland in a pineal parenchymal tumor?

A

Pineal parenchymal tumors expand and obliteral pineal architecture, “exploding” the normal pineal calcification towards the periphery

31
Q

What is typical CT/MR appearance of pineocytoma? Give WHO grade

A

WHO grade 1

Well demarcated, usually

32
Q

When a pineoblastoma is present or suspected, what other imaging is required?

A

CSF dissemination is a common finding (most common cause of death) and necessitates imaging of the entire craniospinal axis.

33
Q

For pineoblastoma:

1- What is most common age of presentation?
2- WHO grading?
3- What differentiates it from pineocytoma on imaging?

A

1- first 2 decades of life, but can occur at any age

2- WHO grade IV

3-
Typically >3cm
poorly circumscribed
solid portion on MR similar to pineocytoma
heterogeneous in appearance because of necrosis and hemorrhage (hemorrhage rare in pineocytoma)
heterogeneous enhancement
extensive cystic change is rare
may restrict on DWI
CSF dissemination common (rare in pineocytoma)
almost all have hydrocephalus
parenchymal involvement

34
Q

What are the typical locations of an intracranial ependymoma?

A

Usually in the posterior fossa (60%), arising from the floor of the fourth ventricle and insinuating itself into the foramen of luschka and magendie.

In 40% of cases it is supratentorial, with half of those being intraparenchymal.

35
Q

What is the orbital septum?

A

The orbital septum is a thin sheet of fibrous tissue that originates from the orbital rim periosteum and blends with the tendon of the levator palpebrae superioris superiorly and inserts into the tarsal plate inferiorly.

The orbital septum separates the intra-orbital fat from eyelid fat and orbicularis oculi muscle, and also provides a barrier against spread of infection between the preseptal space to postseptal space.

36
Q

What is the most common cause of orbital cellulitis?

A

Paranasal sinusitis

37
Q

TRUE OR FALSE

Bone destruction is not usually seen in orbital cellulitis secondary to spread of paranasal sinusitis.

A

TRUE

The infection spreads to the orbit via a perivascular pathway, not direct spread through the bone.

38
Q

When assessing a patient with orbital cellulitis, what complications should you look for?

A 
Orbital subperiosteal abscess (intraconal abscess)
venous sinus thrombosis 
         - cavernous sinus
         - superior ophthalmic vein
bacterial meningitis
epidural/subdural abscess
parenchymal brain abscess
39
Q

What are the imaging findings of CMV induced retinitis

A

Presents in patients with UNTREATED HIV

Uveal enhancement
Retinal detachment
Calcifications in the retina
Starts in 1 eye and progresses to the contralateral eye

If untreated, leads to blindness.

40
Q

Name this pathology:

Complication of acute sinusitis characterised by subperiosteal abscess and osteomyelitis, usually related to the frontal sinus but sometimes also related with the mastoid.

A

Pott’s puffy tumor.

Forehead swelling is seen, which explains the name of this pathology.

Other rare causes, besides sinusitis, are trauma, intranasal cocaine/methamphetamine abuse and craniotomy.

41
Q

What are the imaging findings in Graves ophthalmopathy?

A 
Bilateral involvement (unilateral poss.)
Enlargement of the extra-ocular muscles with sparing of the tendinous insertions (IM SLO)
Increased orbital fat
Lacrimal gland enlargement
Eyelid edema
Stretching of the optic nerve
Tenting of the posterior globe
42
Q

On MRI, what is the difference between acute and chronic optic neuritis?

A

Acute optic neuritis: T2 hyperintense, enlarged and enhancing nerve.

Chronic optic neuritis: T2 hyperintense, atrophic non-enhancing nerve.

43
Q

Name this pathology:

Thickening and enhancement of the optic nerve sheath on MRI

A

Perineuritis: Inflammation of the optic nerve sheath.

44
Q

What are the MRI findings of cavernous sinus fistula?

A

Proptosis
Enlarged superior ophthalmic vein
Cavernous sinus distention
Cavernous sinus flow voids

45
Q

What is the most common benign orbital tumor in adults?

A

Cavernous hemangioma

46
Q

What underlying pathology should you search for in patients with retinal/choroidal detachment?

A

An underlying ocular mass such as:

  • retinoblastoma in childrens
  • uveal melanoma in adults
  • metastases
47
Q

What is a trochlear calcification?

A

It is an aging related normal finding. Superomedial location within the orbit. It represents calcification of the trochlea of the superior oblique.

48
Q

What are scleral plaques?

A

They are typically seen in elderly patients. Incidental finding.
They are scleral calcifications located at the insertion sites of the medial and lateral rectus muscles.

49
Q

What is optic drusen?

A

Benign incidental finding.

Punctate calcification near the optic disc.

50
Q

What is phthisis bulbi?

A

Shrunken globe with ocular calcification or ossification. It is a sequela of infection, inflammation or trauma.

51
Q

What is the key CT finding in corneal laceration?

A

Decreased volume of the anterior chamber, which appears as a diminished anterior-posterior dimension.

Carefully assess the position of the lens to ensure it is not an anterior lens subluxation.

52
Q

What is nontraumatic lens dislocation associated with?

A

Systemic connective tissue disorders such as:
- Marfan syndrome
- Ehlers Danlos
Homocystinuria

Suspect a systemic cause if there is bilateral lens dislocation

53
Q

What is a coloboma?

A

Focal congenital defect of the eye which can involve several structure such as the iris, lens, optic nerve insertion, etc.

54
Q

A deep anterior chamber in the setting of trauma should raise the possibility of what kind of ocular injury?

A

Globe rupture. The finding is secondary to posterior dislocation of the lens, which can happen in the setting of a globe rupture.

55
Q

An intracranial lesion with incomplete ring enhancement suggests what type of pathology?

A

Tumefactive demyelinating lesion

56
Q

What is Devic’s disease?

A

Neuromyelitis optica (NMO), also known Devic’s disease, is a severe demyelinating disease caused by an autoantibody to aquaporin-4 water channel.

Classic presentation is with the triad of optic neuritis, longitudinally extensive myelitis and positive NMO-IgG.

57
Q

What is ADEM?

A

Acute disseminated encephalomyelitis (ADEM) is featured by a monophasic acute inflammation and demyelination of white matter typically following a recent (1-2 weeks prior) viral infection or vaccination.

The imaging appearance can be identical to MS, but it is monophasic, not multiphasic like MS. ADEM most often presents in children and adolescents.

58
Q

What causes Wernicke-Korsakoff syndrome?

A

Vitamin B1 deficiency (alcoholism most common)

59
Q

What are the imaging findings of Wernicke encephalopathy?

A

T2/FLAIR: symmetrically increased signal intensity in mamillary bodies, dorsomedial thalami, tectal plate, periaqueductal area and around third ventricle.

Gado: contrast enhancement can also be seen in the same regions, most commonly of the mamillary bodies.

DWI/ADC: restricted diffusion can also be seen in the same regions

Mamillary body atrophy

60
Q

What is the DDx of a long segment of demyelination of the posterior spinal column?

A

B12 vitamin deficiency
HIV myelopathy
Nitrous Oxide abuse

61
Q

TRUE OR FALSE

Heroin leukoencephalopathy is caused by heroin inhalation, not injection.

A

TRUE

62
Q

What is the bearded skull sign?

A

Demyelination of descending cortico-spinal tracts and bilateral cerebellar hemispheres. It is associated with heroin leukoencephalopathy

63
Q

What is the characteristic distribution of heroin induced toxic leukoencephalopathy

A

AKA chasing the dragon. There is widespread white matter T2 hyper. Characteristic distribution:

  • Symmetrical involvement of the posterior limb of the internal capsules extending inferiorly into the pontine corticospinal tracts, and superiorly into the peri-rolandic subcortical white matter
  • Subcortical U-fibers are also usually spared
  • Symmetrical butterfly wing pattern involvement of the cerebellar white matter
  • Sparing of adjacent grey matter structures
64
Q

What is the most common location of supratentorial ependymoma?

A

Intraparenchymal

65
Q

What is the difference on imaging between ependymoma and subependymoma?

A

Ependymoma enhances more, subependymoma shows little enhancement
Ependymoma 0-20yr, subependymoma >40yr

Both arise most commonly in fourth ventricle

66
Q

What percentage of developmental venous anomalies are associated with cavernous malformations?

A

30-50%

67
Q

TRUE OR FALSE

Pial arteriovenous malformations are congenital

A

TRUE

68
Q

What is the bleed risk per year of a pial arteriovenous malformation?

A

3% bleed risk per year

Neuroradiology (4 decks)

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