CNS Head & Neck Flashcards
(123 cards)
1
Q
Acute disseminated encephalomyelitis. (ADEM)
A
Acute demyelinating disease that occurs after recent viral infection or vaccination. - Autoimmune - Predominalty children.
10-20% mortablity but early identification and Tx with steroids allows full recovery. If not treated can lead to Acute haemorrhagic leukoencephalitis which is fatal.
Imgaging:
Multiple T2 WML. Brain stem, Deep grey matter nucleu s, cerebellum and GWJ can be involved.
2
Q
Adenoid cystic carcinoma
A
Presentation
- Slow growing tumour in the salivary galnds>parotid.
- Perineural spread with paralysis of the recurrent laryngeal nerve
3
Q
Alzheimers
A
SPECT: Decreased HMPAO perfusion in temperoparieal regions.
FDG PET: Hypometabolism in parietal and medial temporal lobes. - late disease = frontal lobe and preservation of the sensorimotor strip.
4
Q
Ameloblastoma (adamantinoma)
A
Lucent jaw lesion that can erode teeth.
Soap bubble appearance with cortical destruction.
Multilocular with fluid/fluid levels on MR.
5
Q
Anaplastic thyroid cancer
A
Uncommon
Old ladies and post radiation
Rapid growth with primary lympahtic spread.
Does not respond to I-131
6
Q
Antrochoanal polyp
A
Teenagers and young adults.
Weel defined mass extending from maxillary sinus to nasal cavity. Dunbell shaped. Expands the maxillary ostium.
7
Q
Bacterial meningitis
A
Organisms:
Group B Strep and E. Coli - Neonates
Citrobacter - Premature new borns
H. Influenzae - Children
N. Meningitidis - Teenagers
Strep. Pneumoniae - Adults
8
Q
Bells Palsy
A
HSV inflammation of the peripheral facial nerve.
MRI:
Enhancement of the intracanilcular and labyrinthine segements which do not normally enhance.
9
Q
Branchial cleft cyst
A
1st - EAC ( periauricular) or parotid
2nd - most common - anterior border of SCM from tonsillar fossa to carotid bifurcation.
3rd - (rare) posterior cervical space or low anterior border of SCM.
4th - (rare) from priform fossa to crycothroid joint.
10
Q
CADASIL
A
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.
Young patients with recurrent TIA/strokes, seizures and psychiatric symptoms.
MRI - bilateral symmetrical high T2 hyperintensities in external capsule, periventricular and temporal regions.
11
Q
Causes of pulsatile tinnitus
A
Normal vascular variants
- Aberrant ICA
- Jugular bulb anomalies (high, dehiscent or diverticulum)
- Persistent stapedial artery.
Tumours
- glomus jugulare or glomus tympanicum
Vascular abnormalites - AVM, atherosclerosis, carotid-carvernous fistula, FMD etc.
Other - IIH, Pagets, Otoscelrosis and Meniere disease.
12
Q
Central neurocytoma
A
- 20-40yo
- Px with signs and symptoms of hydrocephalus.
- Globular lesion attached to septum pellucidum. Iso to brain, 50% show calcification and dense contrast enhancement.
13
Q
Chiari malformation
A
Chiari I:
- Downward displacement of the cerebellar tonsils with elongated 4th ventricle.
- Assoc with Klippel-Feil.
- Syringohydromeyelia
Chiari II:
- Small posterior fossa
- Herniation of the cerebellar tonsils, vermis and caudual displacementof the brainstem.
- Assoc w/ myelomenigocele, obstructive hydrocephalus and dysgenesis o the corpus collosum.
14
Q
Cholesteatoma
A
Aquired:
- most common - 98%
- arise from Prussak’s space (antero-superior) - pars flaccida cholesteatoma
- displaces ossicles medially and erodes lateral structures.
- errodes head of malleus and long process of incus.
- arise from sinus tympani (postero-superior) - pars tensa
- displaces ossicles laterally
- erodes shor process f incus and stapes.
Congenital:
- 2% - epidermoid - arise from middel ear, EAC, mastoid, petrous and labyrinth.
MRI - restricted diffusion and no enhancement.
15
Q
Cholesterol granuloma.
A
Mix of haemorrhage, cholesterol crystals and granulation tissue.
expansile errosive lesion with smooth edges arising from the pertous apex.
MR - T1 bright ofn MR due to mHb and cholesterol. Does not fat supress.
CT - iso dense to brain and does not enhance.
16
Q
Choroid plexus papilloma / carcinoma
A
Adults:
4th ventricle
Children:
Trigone
- Enhance
- Calcify
- Secretes CSF (hydrocephalus)
17
Q
CJD
A
Classic:
- Older Adults
- Progressive dementia (4-5 m)
- DWI and T2/FLAIR in caudate, putamen and GM.
Variant:
- Young adults (20-30)
- psychiatric and behavioral symptoms over a year.
- Pulvinar (Hockey stick) sign - T2/FLAIR in posteromedial thalamus.
18
Q
Cleidocranial dysostosis
A
Hypoplastic, malformed or absent clavicles
Large head
Underdeveloped facial bones
19
Q
CNS Herpes simplex virus.
A
Most common cause of viral encephalitis.
HSV2 - Neonatal transmission from mother via vaginal delivery.
HSV1 - Usually reactivation of latent infection. Commonly effects the trigeminal nerve.
Presentation: Herpes eephalitis. Seizure and coma with CLASSIC EEG finding = ‘Localised spike and slow wave pattern’ in temporal lobes.
Dx and Mx: Early acyclovir and CSF PCR confirm Dx and reduce mortality. (Up 70% if untreated)
Imaging:
MR show gyriform high T2 and FLAIR in temporal lobes. May effect the cingulate gyrus and frontal lobes. +/- diffusion restriction.
20
Q
CNS imaging manifistation of Wilson’s disease
A
Disorder of copper metabolism.
MRI - 1. white matter atrophy.
- T2 hyperintensities affecting the basal ganglia and thalami.
21
Q
CNS mets
A
Intra-axial:
Lung, Breast, Melanoma, Colon
Extra-axial:
Breast, Lymphoma, Prostate, Lung and neuroblastoma.
Most are suprartentoral apart from RCC (Posterior cranial fossa.
Haemorrhagic :
Melanoma, Thyroid and Renal.
22
Q
CNS Varicella Zoster Virus
A
Presentation can be similar to HSV encephalitis. Typically follow an ilness with a skin rash.
Can cause herpes zoster opthalmicus = Compilcated ipsilateral cerebral angiitis causing cerebral infarction and contralateral hemiparesis. Angiography shows beading of medium/large arteries +/- Mycotic aneurysms.
Cranial nerve neuritis = commonly VII and VIII = Ramsay Hunt syndrome = ear pain + facial paralysis + vsicular eruption about the ear. MRI shows abnormal enhancement of these nerves.
23
Q
Coats disease
A
Exudative retinopathy. -lipoprotein accumulation and telangiectasia leading to retinal detachment.
Predominatly unilateral. Occurs in 1st decade of life.
MR: T1 and T2 hyper. calcification is rare.
24
Q
Congenital CMV
A
Caused by reactivation or primary maternal infection
Spread transplacentally or in breast milk
Symptoms:
Hepatomsplenomegaly, Jaundice, Psychomotor retardation, Deafness
Imaging:
- Periventricular calcifications.
- Ventrculomegaly and polymicrogyria
- Agyria, cortical dysplasia and heterotopia (if infection in first trimester- disruption of neuronal migration)
25
Congenital CNS Rubella
Transplacental spread
Causes diffise microencephalitis, brain infarction and necrosis.
Presentation - microcephaly, ocular abnormalities and deafness.
**_Imaging:_**
CT - dytrophic calcifications of deep grey nuclei.
MRI - Infarcts, WM volume loss, delayed myelination
26
Congenital HIV
Transplacental or breast feeding spread/
Present with encephalopathy, developmental delay, and failure to thrive.
**_Imaging:_**
Affects white matter resulting diffuse cerebral volume loss.
* CT - symmetric calcifications of BG (GP)
* MRI - WM T2 hyperintensities
* MRA - fusiform ectasia of arteries
27
Congenital HSV
Encephalitis following infection during descent from the birth canal when mother has HSV2.
Diffuse encephalitis with infarction. Fatal-severe.
Presents with fever, rash, lethargy and seizures in the first few weeks of life.
CSF: pleocytosis, Increased protein and decreased glucose.
**_Imaging:_**
* Cystic encephalomalacia
* Enlarged ventricles.
* Diffuse brain swelling
* Multiple low densities/high T2 sparing the BG, thalami and posterior cranial fossa structires.
28
Congenital Toxoplasmosis
Necrotising encephalitis of the fetal brain following haematogenous spread from mother.
Destruction occurs during 2-3rd trimester.
Born with microcephaly, chorioretinitis and mental retardation.
Imaging:
- Atrophy and dilatied ventricles.
- Dystrophic calcifications scattered throughout the white matter, basal ganglia and cortex.
29
Congential CNS infections
TORCH
**_T_**oxoplasmosis
**_O_**ther - Syphilis and variccella
**_R_**ubella
**_C_**ytomegalovirus
**_H_**erpes and HIV
30
Corticobasal degeneration.
50-70yo.
motor, sensory and cognitive symptoms.
Parkinsonism, non-fluent apphasia and alien limb phenomenon.
MRI:
* Asymetric volume loss in the perirolandic cortex.
* Patchy T2/FLAIR hyperintensity in subcortical WM of the pre- and post-central gyri.
31
Cowden Syndrome
1. Hamartomas (Brain = Lhemitte-Dulcos)
2. Breast Ca
3. Thryroid Ca
32
Craniopharygioma
Sellar mass.
1. Childhood calcifies
2. Adult solid tumour
33
Creutzfeldt-Jakob Disease (CJD)
Prion disease - uniformly fatal rapidly progressing neurodegenrative disorder.
Sporadic type = elderly worldwide
Iatrogenic type = post surgery.
New variant type = meat from infected cows. Young.
Presentation: Variable neurological signs, rapidly progressive dementia with myoclonic jerks and akinetic mutism.
80% mortality in first year.
**CLASSIC** EEG = period of shape waves
**_Imaging:_**
* FLAIR and T2 high in caduate and putamen. Ribbon like hyperintensities around scattered around the cortex.
* nv CJD - medial thalami 'hockeystick' T2 hyperintesities.
34
CT features of hyperaemia?
1. Ill-defined mass effect.
2. Effacement of sulci
3. Normal attenuation of brain.
35
Cysticercosis
Tenia solium. Faeco-oral from pig faeces.
Humans intermediate hosts.
Present with headaches and seizures.
Dx: CSF serology.
**_Imaging:_**
* Early = Minimal oedema with nodular enhancement.
* Vesiucular stage = viable paracytic cysts at GWJ. (1cm or less) Hypodense on CT and iso to CSF on MR. +/-scolex.
* Colloid stage = dead cyst and fluid leaks causing inflammation. Ring enhancement with vasogenic oedema = encephalitis. The cust beome dense on CT and hyper intense to CSF on MR.
* Nodular granular stage = smaller cyst. with increasing nodular peripheral enhancement.
* nodular calcified stage.
*
36
Desmoplastic Infantile Ganglioglioma
* RARE - fist year of life.
* Large peripheral heterogenous mass (solid / cystic)
* M:F = 2:1
* Presentation: Rapidly expanding head circumference.
37
DNET ( Dysembryoplastic Neuroepithelial Tumour)
* Kid with epilepy (refractory complex partial seizures)
* 10-30 yrs
* CORTICALLY BASED in the temporal lobe
* Bubbly T2 lesion - no oedema
* Low grade
38
Echinococcosis (Hydatid Disease)
Dog tape worm. People from non-industrialised world countries.
Lungs, liver and brain.
Present with raised intracranial pressure symptoms.
Large, round, smooth, uni-or multilocular cysts.
39
Facial nerve
Four parts:
1. Intraxial
2. Cisternal segment
3. Intrastemporal segment
* meatal IAC - anterior superior (7 up)
* labyrinthine
* tympanic (horizontal) - gives off greater petrosal nerve.
* mastoid (vertical) - gives off nerve to stapedius and chorda tympami.
4. Extracranial
* Exits stylomastoid foramen immediatly giving off the posterior auricular nerve
* The splits in the parotid giving off 5 branches.
40
Follicular thyroid cancer
Second most common thyroid ca.
Mets haematogenously - bones, lungs, liver...
Does not respond to I-131
41
Fungal meningitis
Thick meningeal enhancement of the basal cisterns. Similar to TB.
42
Gangliogioma
* Presents - Kid with seizures.
* M\>F and under 30
* Most common tumor in chronic tempral lobe epilepsy.
* Cortically based.
* Temporal lobe\>anywhere\>spinal cord.
* Cyst with an enhancing nodule
* Low grade
43
Glioblasoma Multiforme
* Most malignant form of astrocytoma.
* Peak age 45-55
* M\>F
* Frontal\>Temporal\>Basal Ganglia
_Imaging:_
- Expansile Mass
- Central necrosis
- Ring enhancement
- Vasogenic oedema
MRI:
- T1 Dark T2 Bright
- Cystic
- Flow voids
44
Gliomatosis Cerebri
* Rare neuroepithelial neoplasm
* Widespread infiltration of neoplastic cells.
* At least 3 lobes have to be affected.
* Mild clinical symptoms.
* Peak incidence 40-50.
MRI:
- T1 Dark and T2 bright diffuse white matter and grey matter.
- Centrum semiovale, hypothalamus, thalamus and basal ganglia.
- Loss of grey/white matter differentiation with little mass effect.
45
Glomus tumours (distribition)
**Tympanicum** - cochlear promontary - commonest tumour to casue tinnitis
**Jugulare** - jugular foramen (JF) - causes permeative bone changes in JF and has characteristic S&P T2 MR appearance due to flow voids - most common GT overall.
**Vagale** - vagus nerve in the nasopharangeal carotid space DISPLACES THE CAROTID ANTEROMEDIALLY AND THE JUGULAR VEIN POSTEROLATERALLY.
**Carotid body** - SPLAYS THE ECA AND ICA
46
Gradenigo syndrome
1. Otitis media 2. Retro-orbital pain 3. Abducens nerve palsy. Results from abscess in petrous apex. Causes pseudomonas or enterococcus
47
Hallervorden-Spatz
Pantothenate kinase-associated neurodegeneration (PKAN)
Extrapyramidal and pyramidal signs
Iron accumilation on the globus pallidi and brain stem nuclei.
Low T2 GP and T2\* in areas of iron accumilation.
'eye of the tiger' sign.
48
HIV encephalopathy
AIDS
Vacuolation of white matter with demyelination and multinucleated giant cells.
Centrum semiovale \> brain stem \> cerebellum. **(spares subcortical U fibres)**
Present with subcortical dementia, cognitive, behavioral and motor decline.
Predominantly WM atrophy.
Imaging:
MR Deep WM/periventricular symmetrical hazy highT2 - No contrast enhancement.
49
Huntington's disease.
1. Atophy of the heads of the caudate nuclei and consequential 'box like' prominence of the frontal horns.
2. PET - low activity in caudate and putamen.
50
Hypothalamic hamartoma
1. Hamartoma of the tuber cinerium (between mamilary bodies and chiasm)
2. Gelastic seizure and precocious puberty.
51
Imaging features of Alzheimers disease.
MRI - Mesial temporal lobe atrophy.
PET - 1. reduced metabolism in posterior cingulate gyrus and precuneus 2. can also affect the posterior parietal and temporal lobes. 3. sparing of the anterior cingulate gyrus, basal ganglia and occipital lobes.
52
Imaging features of LB dementia.
1. Mirrors that of AD
2. PET shows reduced metabolism in the posterior cingulate gyrus and the posterior temporal and parietal lobes. The occipital cortex can also be invovloved which usually spared in AD.
53
Intracranial hypotension.
Postural headache exacerbated by standing.
* Diffuse dural enhancement.
* downward displacement of ceebellar tonsils and mid brain.
* flattening of the pons.
* enlarged pituitary gland.
* draping of optic chiasm.
* distension of dural venous sinuses.
54
Intraxial high T1?
1. Melanin
2. Protein
3. Contrast
4. Fat
5. Methaemoglobin (subacute haemorrhage)
55
Inverted Papilloma
Emerging from lateral nasal wall (region of middle meatus.
MRI: Classic convluted or cerebreform appearance. Variable internal enhancment
56
Juvenile Angiofibroma
Almost exclusively in boy/young men.
Lobulated vascular mass arising spenopalatine fossa - most commonly extends to PPF.
Contains flow voids on MR
Supplied by the internal maxillary artery.
57
Klippel-Feil syndrome
Cervical fusion
Short neck
Low posterior hairline
Limited cervical motion
Deafness.
58
Larygocele
Dilation of the larygeal saccule. Thin walled fluid or air or both filled.
Internal in paraglottic space
External protrudes through thyrohyoid membrane.
Glassblower - Trumpet players - Excessive coughers.
59
Leigh Disease
Children with lactic acidosis.
Basal ganglia low attenuation ond CT and T2 Hyper on MR.
60
Ludwig angina
Rapidly progressive polymicrobial inection of the soft tissue of the flooor of the mouth and neck.
Can dissect along fascial planes in to the mediastinum and caise airway obstruction.
Usually an odontogenic source.
61
Lyme disease
Spirochete - *Borrelia burdorferi*
Presentation: Flu-like symptoms and rash and expanding lesion around tick bite site. Borad range of neurological symptoms can present.
MR: cranial nerve thick and enhancing in cranial neuritis. Facial nerve most common. (3-8) Multiple WML with ring enhancement.
62
Medullary thyroid cancer
Assoc. w/ MENII
Calcitonin producing
Local invasion \> lymph nodes \> haematogenous spread
Does not respond to I-131
63
Medulloblastoma
1. Spherical arising from the medullary velum (roof) of the 4th ventricle.
2. Under 10 years
3. Densly cellular and restrict diffusion
4. Homogenous (20% calcify)
5. HIGH grade (WHO IV)
64
Meningobasal Cysticercosis
From pork tapeworm larvae. *Taenia solium* infection of thesubarachnoid space.
Larval cysts that grow in clusters.
Imaging:
Cystic lesions that are iso dense and iso intense to CSF.
Diffuse meningeal inhancement and mural enhancement.
65
Metachromatic leukodystrophy (MLD)
* The most common hereditary (autosomal recessive) leukodystrophy
* Peri-atrial and to a lesser extent frontal horns leukodystrophy as well as periventricular perivenular sparing results in "tigroid pattern" on fluid-sensitive MRI sequences.
66
Moyamoya
1. Unilateral progressive occlusion/arteritis of the distal ICA. Forms a large network of tiny colaterals which appear as a puff of smoke on angio.
2. young adults and children affected.
67
MR features of Parkinson's disease
1. T2 - appears as blurring of the intermediate signal intensity line which separates the SN and pars compacta 2. general cerebral atrophy. ( less specific)
68
MS
Selective destruction of myelin sheaths and periventricular inflammation.
20-40yrs. Female 2:1.
FLAIR best modality. STIR and PD best for posterior fossa and spine.
69
Myxopappilary ependymoma
* 35 yo M\>F
* most common neoplasm of the conus medullaris - originating from the glai of the filum terminale
* hyper T2, iso-hyper T1 (mucin), Always enhance.
70
Nasopahryngeal carcinoma.
Commonly arises in fossa of Rosenmuller (lateral oharyngela recess).
Nodal spread.
Type II (non-keratinising) is most common and assiciated with EBV.
71
Nasopharyngeal lymphoma
Walgdeyers ring lymphoma.
Palatine tonsils \> Nasopharyngeal tonsils \> Lingual tonsils.
Intermediate-low T2
72
Neurosarcoidosis.
Granulomatous disease of unknown eitiology.
Presentation: Headaches, cranial neuropathies, pituitary dysfunction, seizures and other.
Dx: CSF ACE and pulmonary involvement.
Imaging:
* Leptomeningeal and dural enahancement.
* Chranial nerve and hypothalamic-pituitary axis enhancement and thickening,
* Focal non enhancing small WML or enhancing intraxial lesions. (isoT1 and hypo T2)
73
Neurosyphilis
Spirochete - *Treponema pallidum*
Presentation:
* Asymptomatic
* Tabes dorsalis
* Progressive dementia
* Stroke
* Headches, meningitis, cranial neuropathies.
Dx: Serolgical markers.
**_Imaging:_**
* MR - Nonspecific WML +/-meningela enhancment. Cranial nerve enhancement in syphilitis cranial neuritis.
* Meningovascular syphilis shows thickened meninges, medium/large vessel arteritis = small infarct in basal ganglia, WM and cortex.
74
NF1 Associations
1. Optic nerve glioma (or Pilo)
2. Anterior tibial bowing with pseudoarthrosis.
3. Lateral meningocele
4. Sphenoid wing dysplasia (can be pulsatile)
5. Renovascular hypertension
75
NF2
**_M_**eningiomas
**_E_**pendymomas
Multiple **_S_**chwanommas
It's a MESs
76
Ocular melanoma
Most common primary ocular malignancy - arises from choroidal layer - retinal detachment common.
MR
* biconvex, exophytic mass
* T1 hyper and T2 hypo
77
Odontogenic keratocyst (KOT)
Young patients (20-40)
Unilocular smooth maxilla/mandibular cyst. (usually posterior mandible)
Arises from denal lamina.
Associated with Gorlin-Goltz syndrome = Multiple BCC's in young patients.
78
Oligodendroglioma
* Peak age 30-50
* 80% supratentoral often frontal.
* CALCIFY 100%
* Can extend to the cortex and erode the calvarium.
* EXPAND the cortex
* MRI - T1 Dark and T2 Bright with little oedma. 2/3 enhance.
* 1p 19q deletion genetic prognostic predictor
79
Oppertunistic CNS parechymal fungal infections.
* Cryptococcus
* Aspergillus
* Mucormycosis
* Candida
Usually present as meningitis.
80
Orbital pseudotumour
Commonest intraorbital mass in adults
Unilateral painful opthalmoplegia. Involves the musculotendonous junctions and - Low on T2.
Acute - responds to steroids
Chronic - chemo and radiotherapy.
81
Orbital pseudotumour
Px: Unilateral painful proptosis that responds to steroids.
inflammation of extraocular muscles ( superior and medial rectus most commonly invloved) INVOLVES TENDONS \> lacrimal gland
MR: differentiated from lymphoma or malignant disease by it lack of restriction.
82
P-NET (Primitive Neuroectodermal Tumour)
* Childhood (\<5) M\>F
* Presentation: Raised ICP and seizures.
* High grade
* Supratentorial (cerebral hemispheres and supra sellar)
_Imaging:_
Large well-demarcated heterogenous mass (solid/cystic)
CT: Calc, Mild oedema, haemorrage and necrosis.
MRI: T1 Dark T2 Iso-dark with enhancement.
83
Papillary thyroid cancer
Most common (papillary is popular)
Microcalcifications in cancer and nodes.
Lyphatic mets
Good prognosis - responds to I-131.
84
Parkinsons disease
Decreased width of T2 dark pars compacta.
Signal loss of basal ganglia on T2 SE
* PD = Globus pallidus
* PD plus = Putamen
Lewy bpdy overlap.
* cererbral atrophy
* occipital lobe hypometabolism on FDG PET
Multisystem atrophy:
* Volume loss of pons and cerebellum
* 'Hot-cross bun sign' of pons on axial T2/FLAIR
Progressive supranuclear palsy:
* Vertical gaze abnormality, extrapyramidal and cognitive symptoms.
* 'Hummingbird sign'- volume loss of midbrain.
85
Parotid tumours
Benign:
* Pleomorphc adenoma. (most common)
* Warthin tumour (papillary cystadenoma lymphmatosum)
* (rare) = myoephithelioma, oncocystoma, basal cell adenoma.
Mailgnant:
* Mucoepidermoid, malignant ransformation of PA, adenocarcinimoa, SCC and lymphoma.
86
Picks disease
Frontotemporal dementia
Affects the Frontal and temporal lobes as well as the anterior cingulate gyrus.
These areas show low metabolism on PET.
87
Pineal tumours
**Germinoma** - Most common - M\>F - 10-30yo - hyperdense, central calc, homogenous enhancement. - Radiosenstive with excellent surivial rates. Precocious puberty in children.
**Teratoma** - Male children - heerogenous w/fat and calc, little/no enhancement.
**Pinealoblastoma** - kids - highly malig - explosive calc with dense enhancment.
**Pineocytoma** - 35 yo - slow growing cystic w/ variable enhancement.
88
Pituitary apoplexy
_Presentation_
- headache, panhypopituitarism and visual disturbance.
- infarction with or without haemorrhage.
_Imaging_
- CT - sellar/suprasellar mass & hyperdensity is caused by the underlying haemorrhage if present.
- MRI - enlarged with T1 hyperintensity acutley, empty sellar chronically.
89
Pleomorphic xanthroastrocytoma (PXA)
1. Adult.
2. Cyst with a nodule
3. Supra tentoral (tempral lobe)
4. Dural tail (Invades the the meninges)
90
Pleomorphic adenoma
80% present in the parotid gland. 80% of those are in the superficial lobe. 80% are benign.
_Presentation_
- Slow growing painless lump.
_MRI_
- Low T1 and High T2 cystic lesion.
91
Posterior cranial fossa tumours in children
1. Medulloblastoma
* Cerebellar vermis
* CT Hyperdense; MR T1 dark T2 variable
2. Pilocytic astrocytoma
* Vermis or hemisphere
* Cystic with solitary enhancing nodule.
3. Ependymoma
* Fourth Ventrucle floor
* Heterogenous CT and MRI with calc and enhancement
4. Brain stem glioma
* Expansile brainstem.
* CT Iso/hypodense; MRI T1 dark T2 bright.
92
Potts puffy tumour
Frontal sinusitis complicated by osteomyelitis, with sub periosteal, epidural and subdural abscesses.
93
Primary CNS Lymphoma
* Present with confusion, lethargy and memory loss.
* Respond well to steroid therapy but rebound ++
* Small blue cells packed tightly together in pervascular spaces.
* Located adjacent to ventricles and leptomeninges
* Supratentoral (10% cerebellum)
* Subependymal spread
CT: Dense
MRI: T1 Dark with vasogenic oedema. Restrict diffusion.
94
Process of parenchymal abscess formation
1. Early cerebritis
* First few days of infection.
* Brain swollen and edematous.
* CT normal or focal areas of low denisity,
* MR low/iso T1 and high T2 and FLAIR.
* Mild mass effect with patchy enhancement - No ring enhacnement.
2. Late cerebritis
* 1-2 weeks
* coelescence of central necrosis. Vascular proliferation at the periphery of the lesion.
* CT shows irregular peripheral contrast enhancement with central low denisity.
* T1 low T2 and FLAIR high. Central restricted diffusion.
3. Early capsule.
* Walled of lesion with collogen and reticulin inflammatory vascular capsule formation. (thin)
* CT thin perhiperal enhancement and central hypodense.
* MR T2 hypo rim and hyper T2 central.
4. Later capsule.
* Thcker more well defined wall.
* Multiloculation.
* MR = Central restricted diffusion. Caspule is Iso/hyper T1 to WM and hypo T2 to WM.
95
Progressive Multifocal Leukoencephalopathy (PML)
AIDS patients
Reactivation of JC virus destroys oligodendrocytes - demyelinating disease
Asymmetric WM T2 hyperintensities that favour parieto-occipital regions. DOES NOT SPARE U FIBRES.
Lesions do not enhance.
96
Ranula
mucocele or mucus retention cyst originating in the sublingual space.
97
Retinoblastoma
Px = \<3 yo with leukokoria
Thickened, dense and calcified vitreous.
Occurs uni-, bi- or tri-laterally (pineal).
Assco w/ osteosarcoma. Can get get post radiation sarcoma also.
MR
* T1 iso to hyper comparared with normal vitreous
* T2 low
* T1+c Heterogenous enhancment.
98
Retrolental fibroplasia
Toxic retinopathy caused by oxygen therapy for hyaline membrane disease.
99
Sheehan's syndrome
A result of hypovolaemic shock and can be a consequence of delivery.
_Early_
- hyponatraemia, diabetes insipidus or hypothyroidism.
- Visual disturbance
- MRI - normal or pituitary **apoplexy** appearances of an enlarged pituitary with high T1 signal.
_Late_
- Panhypoituitarism
- MRI - Empty sella due to atrophy.
100
Sturge-Weber syndrome
Capillary venous angiomas
Px:
* Port-wine nevus in distribution of CN V
* Seizures
* Mental retardation
* Ipsilateral glaucoma
* Hemiparesis
Imaging:
* Tramtrack cortical calcifications
* Atrophic cortex (ipsilateral)
* Enlarged and enhancing ipsilateral choroid plexus
* Leptomeningeal venous angiomas.
* Skull thickening.
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Subacute sclerosing panecephalitis (SSPE)
Effects children witrh measles infection before the age of 2. Then presents after intervening period of 6-15 years.
Symptoms = progressinve dementia, seizures, myoclonus, paralysis and death.
NO CURE - Early Dx and interferon with antivirals can slow progession.
**_Imaging:_** Diffuse swelling and WM T2 high. No enhancement. Late stages show profound cortical atrophy.
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Subependymoma
1. Adults
2. Low grade (do not enhance)
3. Inferior aspect of the fourth ventricle.
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Suprasellar mass DDX (SATCHMO)
**_S_**upracellar extention of adenoma / Sarcoid
**_A_**neurism / Arachnoid cyst
**_T_**B / Teratoma (other germ cell tumours)
**_C_**raniopharyngioma
**_H_**ypothalamic glioma / Hamartoma
**_M_**eningioma / Mets - breast most common
**_O_**ptic chiasm glioma
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Thyroglossal cyst
Foramen cecum to thyroid
midline or paramedian
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Tornwaldt cyst
Benign nasopharyngeal midline mucosal cyst.
Between longus coli muscles
Present with halitosis due to constant leakage.
MR T1 mixed T2 hyper
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Toxoplasmosis
Most common oppertunistic CNS infection with AIDS.
Reactivation of previous infection.
can mimic subacute presentation of HIV encephalitis.
Imaging:
Multiple enhancing parenchymal lesionswith surrounding vasogenic oedema. 1-4cm.
* MR T1 hypointense.
* CT hypodense.
* Large elsions have ring enhancement.
Response to Abx differntiates between lymphoma.
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Treacher-Collins syndrome
Coloboma
Micrognathia
Microtia (underdeveloped pinna)
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Tuberculous meningitis
Affects young, elderly and immunocomprimised in 'at risk' poopulation.
Haematogenous spread. Commonly Mycobacterium Tuberculosis (but other myco can cause)
**Presentation:** Insideous onset of headache, malaise, apathy and focal neurological defecits.
**CSF:** LOW glucose, high protein, leukocytosis.
**Imaging:** Thickened meninges - along teh basal cisterns. Gelatenous exudate.
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Tuberous Sclerosis
1. Pyramid shaped cortical tubers (High T2)
2. Subependymal nodules/hamartomas (T2 dark kids and T2 bright adults)
3. Subependymal Gaint Cell Astrocytoma (SEGA)
4. AMLs in kidney
5. LAM (Thin walled pulmonary cysts)
6. Cardiac rabdomyomas / cardiomyopathy
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Turcot syndrome
CNS medulloblastoma or glioblastoma with multiple multiple colonic adenomas.
Can develop colorectal cancer.
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Tyhyroid opthalmopathy
Exophthalmos
Rectus muscle involvement spares tendonous insertions except in the acute phase.
Rectus muscle involvement - IM SLow
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VHL associations
1. Haemagioblastoma (brain, spine and retinal)
2. Endolymph sac tumour
3. Bilateral clear cell RCC + cysts
4. Pancreatic cysts / tumour
- serous cyst adenoma
- regular cysts
- islet cell tumour
5. Pheochromocytoma
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Vocal cord paralysis
injury to recurrent laryngeal nerve or vagus nerve anywhere alond its course.
Imaging:
* paramedian position of the affected true vocal cord
* widening of the ipsilateral laryngeal ventricle (sail sign)
* expansion of ipsilatera; pyriform sinus
* medial rotation and thickening of arytenoid cartilage
* cricoarytenoid atrophy
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Wernicke encephalopathy.
Cerebellar volume loss.
Marchiafava-Bignami = focal demyelination of the splenium of corpus collosum.
Acute: Hyperintensities in paraductal gray matter, mesial thalamus, parathird ventricle and mammiliary bodies.
Chronic: Mammilliary body volume loss.
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Differential for white matter mass crossing the midline.
1. GBM
2. Lymphoma
3. Tumofactive MS plaque
4. Radiation
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Which brain tumours calcify?
1. Oligodendroglioma
2. Ependymoma
3. Astrocytoma
4. GBM
5. PNET
(**O**ld **E**lephants **A**ge **G**racefully **P**eanuts)
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Which malignancies restrict diffusion?
1. Lymphoma
2. GBM
3. Meduloblastoma.
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Wilson's disease
* T2 hyper in putamen and thalami
* Midbrain - Red nuclei and SN are surrounded by high T2 signal = 'Panda sign'
* Gerneralised atrophy.
* Low density basal ganglia on CT
* Liver cirrhosis.
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Warthins tumour
Second most common benign tumour and only occurs in the parotid
Cystic.
15%bilateral
Assoc. w/ smoking
ONLY parotid tumour to take up pertechnetate.
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Methanol poisoning
* Optic nerve atrophy
* Subcortical white matter necrosis
* Hemorrhagic putaminal necrosis
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Haemqangiopericytoma
Rare fibrous dural lesion found in young adults.
Homogenous enhancment with a dural tail, erode adjacent bone and no calc. MR T1 and T2 Iso to brain.
Difficult to distinguish from meningioma.
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Carbon monoxide poisioning
T2 hyper basal ganglia - particularly GP, with restricted diffusion.
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