Head & neck Flashcards
Bad signs of acute subdural haematoma
4
Heterogeneity
Convexity
Inc Mass effect
SAH
Features of isodense SDH
Further imaging
Unexplained mass effect
Effaced sulci
“thick’ cortex”
WM buckling
Do contrast
MR diagnostic
Traumatic brain haematoma - ring enhancing lesion
Diagnostic aids/clues
4
Bilateral
Orbitofrontal
Haemosiderin ring
Other injuries
Diffuse axonal injury
Grading - 3
Deeper lesions worse prognosis
1 : lobar WM. Lesions bloom
2: involves corpus callosum typically splenium
3: Dorsolateral midbrain
Worrying features of skull fractures
7
Overlies a dural sinus Overlies MMA Overlies eloquent cortex Depressed > table width Open/compound Traverses ICA canal Temporal bone # ( opacification of mastoid air cells) Skull base # ( blood in sphenoid sinus)
Carotico-cavernous fistula CT findings
5
Proptosis Enlarged extra ocular muscles Convex ipsilateral CS Enlarged superior opthalmic vein Retrobulbar fat stranding Check Brain - venous infarcts
Early NCCT signs of stroke
3
Penumbra on PWI : at risk area
DWI : infarct core
Loss of GW differentiation : insular ribbon sign, BG effacement (less delineation)
Dense artery sign (30%) - asymm, correlates c Sx
Hypodensity
Subacute : gyriform CE
Distal Carotid artery dissection features
mid to distal ICA below cavernous segment
Bulb spared
NO false lumen
Subintimal haematoma ( do MRI T1 FS - methaemaglobin in wall)
DSA may be normal!
Proximal carotid artery dissection features
Progression of aortic dissection CCA ICA extension uncommon False lumen May be asymptomatic
ICA dissection imaging signs
location unusual for atherosclerosis ( bulb spared) string sign aneurysmal dilatation occlusion intimal flap may be seen
Amyloid angiopathy
features
B-amyloid peptide deposition
Lobar haemorrhage in elderly (15% >60y, 50%>70y)
Subcortical microhaemorrhages, spares BG cf HTN
Non traumatic ICH
causes
Underlying lesion: tumour, AVM, cavernoma, aneurysm Amyloid angiopathy Dural sinus thrombosis Hypertension Coagulopathy
Hypertensive haemorrhage
locations & pattern
Putamen/EC - 60%
Thalamus - 15-25%
Pons/CBL - 10%
Lobar 5-15%
Acute focal haematoma
Subacute/ch microbleeds
CTA dot sign - active bleed
Cavernous malformation
features
Discrete collections of endothelial lined sinusoids
Vascular hamartoma
ICH risk - 0.15-1% annually
Sporadic- 75%, familial 10-30% ( fam cavernomatosis)
Angiographically occult
Associated DVA
COMPLETE haemosiderin rim
Variable SI locules
Popcorn appearance
Capillary telangiectasia in brain
Brainstem Ass with radiation No T2 abnormality Brush like Ca+ GRE blooming Do not touch
Spetzler-Martin Grading AVM
Size
Eloquence
Venous drainage
<3cm - 1
3-6cm -2
>6cm - 3
Eloquence 1 - 0
Venous drainage superficial/deep
RF for intracranial aneurysms
9
Smoking Cocaine Age > 50y Female > Male FMD Anatomic variants eg trigem artery Type IV Ehlers Danlos NF 1 ADPCKD
Trigeminal artery vs Persistent fetal PCA
Trigeminal originates from CAVERNOUS ICA to BA
persist fetal from supraclinoid ICA (above sella)
PseudoSAH
causes
4
Cellular material ( infection, carcinomatosis, granulomatous etc, clean ventricles)
Iodinated contrast (myelogram, leak due to RF etc)
CSF Hypotension
Anoxia
Pseudopseudo SAH
Global anoxia/hypoxia due to dense venous stasis (white cerebellum, indistinct BG, no hydrocephalus)
CSF hypotension : ?crowded normal blood vessels, SD collections and large dural sinuses
No hydrocephalus
Idiopathic intracranial hypertension
( BIH, pseudotumour cerebri)
Features
RF
Women 3rd decade Obese/weight gain May be drug induced(steroids) Papilloedema Headaches, visual obs, diplopia, pulsatile tinnitus
Look for secondary causes Empty sella Flat post globe Vert tortuous , distended ON sheath Slit like ventricles - rare Focal compression mid transverse sinuses (pseudostenosis)
Infarcts in young patients
4 main cause categories
Cardiovascular: CHD, valve disease, LA myxoma
Prothrombotic: SCD
Inherited: vascular - neurocut, CADASIL ; metabolic : MELAS, homocystinuria
Acquired : dissection, NAI, moya-moya, systemic angiitis, migraines, OCP, street drugs
Paediatric BG calcification
4 main
Fahr’s
Hypo/hyper parathyroidism
MELAS - stroke like cortical lesions that cross vascular territories, parieto-occipital, inc lactate on MRS ( in normal brain regions)
HIV
MELAS
mitochondrial myopathy/angiopathy
encephalopathy
lactic acidosis
stroke-like episodes
2nd decade
parieto-occipital
inc lactate in normal brain
progressive with periodic exacerbations
Pontine hyperintensity
causes
4 main
Ischaemia
Infection
Neoplasm - glioma
WM pathology: demyelination, myelinolysis, PML
Central pontine myelinolysis
( osmotic myelinolysis)
alcoholics, malnutrition, Tx, burn
spastic quadraparesis
pseudobulbar palsy
often rapidly progressive
non-inflammatory, non vascular
acute destruction of myelin
Symmetrical T2/FL hyper Diff + No post CE batwing contour Spares corticospinal and peripheral tracts
Can have symmetrical extrapontine lesions : BG, thalami, midbrain
Posterior reversible encephalopathy syndrome
clinical
CT
MRI - locations (5)
acute encephalopathy
WM hyperintensity
vasogenic oedema (no DWI unless non reversible component))
No CE
posterior fossa parietal occipital posterior frontal temporal
many associations!
10% have haemorrhage/infarcts
Mural nodule with cyst
intracranial
Juvenile pilocytic astrocytoma (CE wall)
Pleomorphic xanthoastrocytoma
Ganglioglioma
Haemangioblastoma ( non CE wall, PF)
Pleomorphic xanthoastrocytoma Demo location RF prognosis
rare astrocytoma subtype children and young adults superficial cortical location Temporal most common Cyst with mural nodule minimal oedema good prognosis
Oligodendrogliomas
low grade and anaplastic younger patients better prognosis cf astro frontal lobe most common Cortical expansion cortical involvement Ca 2+ > 80% Can appear aggressive Variable CE
Intracranial tumours with Ca
5
Oligodendroglioma Ependymoma Craniopharyngioma Choroid plexus tumour Meningioma
Intracranial chondrosarcoma
4 features
v. rare
Extra axial
very well defined
Do not have calcium
Intraparenchymal lesions with dural involvement
2
Metastases
Lymphoma
V. rare for glioblastoma
Subependymoma vs central neurocytoma
attached to septum pellucidum
Only neurocytoma enhances
Neurocytoma v. vascular!
Tumours with CSF Dissemination
5
PNET Medulloblastoma Pineoblastoma Ependymoma Choroid plexus Ca.
Mass lesions with diffusion restriction
4
Epidermoid
Abscess
Mucinous adenoca mets
Cellular tumours: lymphoma, PNET, meningioma
Tumour mimicking brain lesions
4
Radiation necrosis ( esp bilateral, non vascular)
Tumefactive demyelinating lesion
Pyogenic abscess
Toxoplasma encephalitis
CADASIL Cerebral Autosomal Dominant Arteriopathy with Sub-cortical Infarcts and Leukoencephalopathy
Demo
RF
hereditary Small vessel disease
causes stroke in young-middle adults
earlier age of stroke onset
inc frequency of migraine aura/hemiplegic migraine
variable pattern of ischaemic WM lesions on MR
involvement of temporal poles characteristic
Griesingers sign
Oedema of post auricular soft tissues due to thrombosis of mastoid emissary vein
Types of MS
5
Clinically isolated Xd ( 85%)
Relapsing-remitting
Secondary progressive MS
Benign MS ( 10-20%, relapsing ms with no long term disability)
Primary progressive ( 15%) - steady progression without clear cut relapses)
MS characteristic locations
Juxtacortical Periventricular ( Dawsons) Infratentorial ( dentate) Spinal cord < 2 segments Visual pathways
Paraganglioma of neck types based on location
4
Tympanic : glomus tympanicum
Jugular foramen : glomus jugulare
2cm below skull base (nodose ganglion): glomus vagale, does not enter jug foramen.
Carotid body tumour
Kallman Xd
M:F 5:1
Olfactory agenesis
Hypogonadotrophic hypogonadism
Intrinsic malignancy of olfactory tract
Esthesioneuroblastoma
… v rare
…PNET malignancy
…two peaks - paed , > 50yrs
Olfactory sulcus
depth to rule out congenital anosmia
8mm
Vestibular Schwannomas
arise in..
location..
Vestibular nerve only
At junction of neuroglial and schwann cells in IAC/porus 95% of time
Uncommon features of Vestibular Schwannoma
Almost totally cystic (larger tumours are solid/cystic)
Medial (5%) in CPA cistern
Associated peripheral arachnoid cyst
Pathognomonic feature of meningioma
focal enostosis ( bony spur) marks entrance of mengieal vascular pedicle
CSF like lesions in CPA
5
Epidermoid Arachnoid Cystic schwannoma Post op secondary arachnoid VS with peripheral arachnoid cyst
Extension pattern of glomus tumours
tympanicum : bone between hypotympanum and jugular foramen
Lateral : mastoid , salt/pepper appearance
anterior : filling up middle ear, pars petrosum towards apex
Intra/extra axial extension
Radiological features of glomus tumour
CT
MRI
Angio
Ddx
CT : enlargement of jugular foramen with bone erosion
MR : intratumoral vessels
Fixed extension patterns
Angio : very vascular
DDx : schwannoma, meningioma
H & N manifestations of Wegeners
Laryngeal involvement - usually subglottic stenosis ( circumferential thickening CE + non sp.) Sore throat Laryngitis OM, Sinusitis Saddle nose deformity
Sign of chronic VC denervation palsy on CT
posterior cricoarytenoid muscle atrophy
atrophy of muscles(fat replacement) adjacent to VC
