Neuroradiology Flashcards
Enlarged perivascular (virchow robin) spaces?
- Cryptococcus (gelatinous pseudocyts, do not enhance) - Mucopolysaccharidoses (hunters, Hurlers) - Atrophy VR don’t contain CSF
Myelination pattern?
Progression: inferior to superior, posterior to anterior, central to peripheral Subcortical white matter is last to myelinate Brainstem and posterior limb of internal capsule are myelinated at 36 weeks
Corpus Callosum Development?
Front to back (but the rostrum is last)
Immature Myelin Appearance?
Higher water content- brighter on T2 and darker on T1 Mature myelin- bright on T1 and T2 dark T1 (1 yo) changes proceed T2 changes (2yo)
Paranasal sinus formation?
Maxillary -> Ethmoid -> Sphenoid ->Frontal
Foramen Ovale
CN V3, accessory meningeal artery
Foramen Rotundum
CNV2 (R2V2)
Superior Orbital Fissure
CN 3,4, V1, and CN 6
Inferior orbital fissure
CN V2
Foramen Spinosum
Middle meningeal artery (spine contains meninges)
Jugular foramen
Jugular vein, CN 9, CN 10, CN 11
Hypoglossal canal
CN12
Optic canal
CN 2 and opthalmic artery
What runs in the cavernous sinus
CN 3, 4, V1, V2, CN 6 (CN 2 and CN V3- do not run in)
What nerve is adjacent to the carotid artery in the cavernous sinus and is not within the wall?
CN6
Branches of external carotid?
Some administrators like fucking over poor medical students Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior Auricular Maxillary Superficial temporal
Internal Carotid Artery Branches?
C2- petrous C3 - Lacerum C4- Cavernous (site of CC fistulas) C5- Clinoid ( aneurysm can compress the optic nerve at this level) C6-Ophthalmic (origin at the dural ring- intrdural) C7- Communicating terminal (aneurysm can cause CN III palsy)
Fetal PCA?
PCOM is as large or bigger then the P1 segment PCOM is superior and lateral to CN 3 (as opposed to superior and medial in normal anatomy)
Deep Cerebral Veins
Basal Vein of Rosenthal Vein of Galen Inferior Petrosal Sinus
Superficial Cerebral Veins
Vein of Trolard (drains into superior sagittal sinus) Vein of Labbe (drains into the transverse sinus) Superficial Middle Cerebral Veins Superior Cerebral Veins
CN III Palsy
Terminal Aneurysm Aneurysm of the PComm Artery
CN 6 palsy
Increased intracranial pressure
Intacranial hypotension
Sagging of midbrain meningeal enhancement distension of dural venous sinuses
Intracranial Hypertension
Empty Sella Optic Hydrops Papilledema
Vasogenic Edema
Extracellular
Cytotoxic edema
Intracellular Na/K pump
Hydrocephalus
Obstructive: Non-communicating- involves the ventricular system Communicating-Involves the villi/arachnodi granulations Non-obstructive: Increased production of CSF- choroid plexus papilloma
Transtentorial Herniation
Effaces ipsilateral suprasellar cistern first Duret hemorrhage from basilar artery perforators
Multiple Sclerosis
- Relapsing and remitting is most common type - Acute plaques should restrict diffusion - Tumefactive- incomplete ring enhancement Marburg- childhood variant, fulminant, rapid demise
ADEM
Post-viral/vaccination T2 bright lesions, which enhance in a nodular/ring like fashion Typically don’t involve the collosal septal interface
Hurst Disease/ Acute Hemorrhagic Leukoencephalitis?
Fulminant from of ADEM, hemorrhage on seen on autopsy
Wenick’e Encephlopathy
Enhancing mammillary bodies Edema in the medial thalami and periaqueductal gray matter
Carbon monoxide
T2 bright globus palladi
Marchiafava-Bigmani
Demylination and Necrosis of the CC- T2 hyperintense signal in the corpus callosum, which starts in the central CC Associated with alcoholism and chronic nutritional deficiencies
What is preserved on FDG-PET in dementia?
Motor strip
Mimics of vascular dementia?
Lyme disease, HIV, Vasculitis
First sign of alzheimer’s?
Hippocampal atrophy (temporal atrophy > 3 mm is suggestive)
Crossed Cerebellar Diaschisis
contralateral cerebellum has decreased uptake
Binswangers
Small vessel vascular dementia spares subcortical U-fibers
TORCH- CMV
Most Common TORCH infection - Periventricular calcifications - Highest association with polymicrogyria
TORCH- Toxoplasmosis
Associated with hydrocephalus Basal ganglia calcifications
TORCH- HSV
HSV-type 2 Thrombus and hemorrhagic infarctions
HIV- Intrauterine
Atrophy of the frontal lobes
PML
JC virus Involves the subcortical U fibers CD4 count typically less than 50 T2 lesions out of proportion to mass effect
Toxoplasmosis
Most common opportunistic infection in HIV T2 bright, ring enhancing lesion, lots of edema, NO RESTRICTION Cold on thallium (lymphoma is hot on thallium)
Hydrocephalus and nodular enhancement of the basilar meninges?
TB (sarcoid generally does not cause hydrocephalus)
HSV infection- Adults
HSV 1 First sign is restricted diffusion May have hemorrhage
Limbic Encephalitis
Paraneoplastic syndrome (ex: small cell carcinoma of the lung) No enhancement
CJD
Diffusion restriction-cortical ribboning, hockey stick sign (medial thalamus)
Stages of Neurocysticercosis
- Vesicular- thin walled cyst, no edema 2. Colloid- Hyperdense cyst with edema 3. Granular- cyst shrinks, wall thickens (less edema) 4. Nodular- calcified lesion, no edema
Cortically Based Tumors?
Dysembryoplastic Neuroepithelial Tumor (DNET) Oligodendroglioma Ganglioglioma
NF1
Optic gliomas/Astrocytomas Plexiform neurofibromas Iris Hamartomas
NF2
Multiple schwannomas Meningiomas Ependymomas
Tuberous Sclerosis Tumors
Subependymal tubors Giant Cell astrocytomas
VHL
hemangioblastomas (cerebellar) Others: Pheochromocytomas Retinal angiomas Choriod plexus papilloma Endolymphatic sac tumor Pancreatic cyst, islet cell tumor, adenocarcinoma RCC- clear cell Renal AML, cysts Liver cysts Cysts of the epididymis
What low grade tumors can enhance?
JPA, gangliogliomas
Restricting lesion in the CP angle?
Epidermoid
Calcified cortically based mass?
Oligodendroglioma 1p/19q deletion have a better prognosis
Hemorrhagic Mets?
RCC Thyroid Melanoma Choriocarcinoma
What is associated with GBM?
Turcot Syndrome- medulloblastoma, intestinal polyposis
Hemangioblastoma?
Associated with VHL Can cause polycythemia (increased epo levels) Cyst with enhancing mural nodule, can have prominent flow voids
Benign choroid plexus mass that restricts diffusion?
xanthogranuloma Do not touch lesion
Most common type of functional pituitary adenoma?
prolactinoma
Pituitary apoplexy is assocaited with?
Bromocriptine use Sheehan Syndrome- post-partum necrosis
Craniopharyngioma?
Calcifications Can have papillary- Solid and capsule (adult) or Adamantinomatous type, cysts which can have protein and hemorrhage (peds)
Meningiomas can be hot on what nuclear medicine studies?
Tc-MDP octreotide
Which CPA mass invades to internal auditory canal?
Schwannoma- widen porus acousticus Meningiomas typically don’t widen IAC
What differentiates ana arachnoid cyst from epidermoid?
Epidermoid restricts diffusion and are mildly bright on FLAIR, both lesions follow CSF signal
Most common dural metastases?
Breast Cancer
Hemangiopericytoma
-Aggressive sarcoma that invades skull, can mimic an aggressive meningioma -Don’t Calcify
Rapidly increasing head circumference in child
Desmoplastic infantile ganglioglioma/ Astrocytoma Typically supratentorial, cystic masses
Most common location of Choroid Plexus Papilloma?
Adults- 4th ventricle Kids- Lateral ventricle (usually trigone)
Where does neuroblastoma like to involve?
Calvarium Dura Postero-lateral aspect of orbits
Dysembryoplastic Neuroepithelial Tumor Characteristic?
Temporal Lobe T2 Bubbly appearance Frequently presents as drug resistant seizures
Pleomorphic Xanthroastrocytoma
Temporal lobe involvement Cyst with nodule
What lesion is in the tuber cinereum and assocaited with gelastic seizures?
Hypothalamic Hamartoma (most common presenting sign is actually precocious puberty)
Medulloblastoma?
Typically arise from vermis and project into 4th ventricle Restrict diffusion, enhance homogenously Drop mets are common Associated with basal nevus syndrome and turcots
What is gorlin syndrome?
Medulloblastoma + dural calcifications + basal cell skin cancers + odontogenic cysts
Pineal mass containing fat and calcifications?
Germinoma- engulf the pineal gland (pineocytoma and pineoblastoma expand the pineal gland) Most commonly seen in boys in the pineal region and girls in the suprasellar region
What can germinomas secrete?
HCG- precocious puberty
What is associated with pineoblastoma?
retinoblastoma (3rd place of retiunoblastoma)
Lhermitte-Duclos is associated with?
Cowden Syndrome
Most sensitive sequence for subarachnoid hemorrhage?
FLAIR
Le Forte 1
lateral nasal aperture
LeFort 2
Inferior orbital rim and floor
LeFort 3
Zygomatic Arch and lateral orbital rim/wall
ZMC fracture
involves the zygoma, inferior and lateral orbit
Longitudinal Temporal Bone Fracture
Comes from lateral Ossicular dislocation, conductive hearing loss
Transverse Temporal Bone Fracture
Sensorineuronal hearing loss Facial nerve damage
Acute
1-3 days Deoxyhemoglobin
Early Subacute
>3 days Intracellular methemoglobin
Late subacute
>7 days Extracellular methemoglobin
Chronic
>14 days Hemosiderin
Symptoms of superficial siderosis
sensorineural hearing loss and ataxia
Watershed infarcts in child, most common cause?
Moyamoya
How long is diffusion restriction positive for in CVA
30 minutes- 2 weeks If FLAIR is not hyperintense, think less than 6 hours
When does stroke enhance?
3 days-3 months
Sequela of Venous Sinus thrombosis
Dural AVF Increased CSF pressure
Most common site of aneurysm?
Anterior Communicating Aneurysm
Pedicle Aneurysm?
Aneurysm on the feeding artery of the AVM
Most common site of mycotic aneurysms?
Distal MCA
Increased risk of AVM hemorrhage
3% per year Small size of AVM (increased pressure) Single draining vein Aneurysm associated with nidus Basal Ganglia, thalamic, periventricular location
Classic symptoms of dural venous fistula?
Pulsatile tinnitus if involving the superior sagittal sinus, assocaited with venous thrombosis May be occult and require angio
DVA associated with?
cavernous malformation (cavernoma)
Cavernoma?
No normal intervening brain matter Angio occult, low flow lesion
Capillary Teleangectasia?
NO increased risk of hemorrhage, “brush like” Does have normal intervening brain parenchyma Can develop as complication of radiation therapy
When does vasospasm associated with subarachnodi hemorrhage happen?
4-14 days after Other causes of vasospasm- Meningitis, PRES, MIgraine
What systemic vasculitis involves the intracranial arteries?
PAN Temporal arteritis, wegners, takayasu Other causes: cocain, RA/SLE, lyme
Moyamoya associations?
Sickle Cell, Neurofibromatosis, prior radiation, Down’s Syndrome
CARDASIL spares the ______ lobes?
Occipital lobes are spared Autosomal dominant- presents as headache and progresses to dementia -White matter chages- predominately in the temporal lobes
Formula for carotid artery stenosis?
1- A(maximal narrowing)/B (distal ICA) x 100
Colpocephaly?
Colpocephaly = Disproportionate dilation of the occipital horns –> corpus callosal agenesis –> CC agenesis is most common anomaly associated with other CNS malformations CC agenesis- Can also present as steer horn ventricles or parallel ventricles CC agenesis/dysgenesis is associated with Lipomas
Anencephaly Findings?
AFP is elevated, polyhydramnios
Iniencephaly
Deficit of the occipital bones, enlarged foramen magnum May have incomplete formation of cervico-thoracic vertebrae “star gazing fetus”-face turned upward, hyper-extended cervical spine
Molar Tooth Sign?
Joubert Syndrome -Superior cerebellar peduncles are thin and the vermis may be incomplete or absent
Joubert is associated with?
Retinal dysplasia, multicystic dysplastic kidney
Torcular-Lamboid Inversion?
Dandy-walker malformation - Absent vermis - Cyst communicates with the 4th ventricle
Blake Pouch
Cyst below or posterior to vermis (which is normal) Posterior fossa is not enlarged but the tentorium is elevated
Mega-Cisterna Magna
Retro-cerebellar CSF space > 10 mm Normal cerebellum
Lobar holoprosencephaly
Absent septum pellucidum Can have fusion of frontal lobes
Semi-lobar holoprosencephaly
Fusion of thalami Olefactory bulbs and tracts are absent
Alobar Holoprosencephaly
Single large ventricle with fusion of thalami and basal ganglia No falx or CC
Meckel- Gruber Syndrome
Trias: holoprosencephaly, renal cysts, polydactly
Big ventricle and cerebral hemisphere?
Hemimegalencephaly DDX: Rasmussen’s encephalitis- the smaller hemisphere has the big ventricle due to atrophy
What is associated with schizencephaly (open lip /close lip)?
Optic nerve hypoplasia absent septum pellucidum Epilepsy
Hydranencephaly will have?
Falx, due to in utero insult Cortical mantle is absent (severe hydrocepahlus will have a cortical mantle)
Klippel Fiel Syndrome is associated with?
Chiari I malformation
Scaphocephaly (dolichocephaly) is fusion of?
Sagittal sutures
Plagiocephaly is fusion of?
Unilateral coronal suture, Harlequin eye
Trigonocephaly is fusion of?
metropic suture (suture between frontal bones)
Brachcephaly is fusion of?
Coronal or Lambdoid sutures
Aperts syndrome?
Brachycephlay + fused fingers
Crouzons
Brachcephaly + First arch hypoplasia (maxilla, mandible)
Cleidocranial Dysostosis
Brachycepahly + Wormian bones + absent clavicles
Most common cranniosynostosis?
Sagittal- dolicocephaly
Turricephaly?
fusion of coronal and lambdoid sutures
What is associated with Piriform aperture stenosis (narrowing at opening of nose)?
hypothalamic-pituitary- adrenal axis dysfucntion
MELAS has what abnormalities on Spectroscopy?
increased lactate, decreased NAA
Canavans has elevated _____ on spectroscopy?
NAA Also have diffuse involvement of the bilateral subcortical U fibers
Alexanders Leukodystrophy is associated with?
Frontal white matter involvement
Metachromatic Leukodystrophy Findigns?
Most common leukodystrophy Dark spots in demylianted perventricular white matter, TRIGOID appearence
Adreno-Leukodystrophy presents with?
Symmetric involvement of the splenium and corpus callosum as well as occipital lobes Only occurs in boys
In spectroscopy, myoinositol is elevated with?
Alzhemiers and low grade glioma
Alanine is elevated in?
Meningiomas
Radiation necrosis pattern?
Choline decreased, NAA down, Lactate up
What is elevated in hepatic encephalopathy?
Glutamine
Cholesterol Granuloma on MR?
At petrous apex typically T1 and T2 bright DDX: congenital cholesteotoma
Congenital cholesteotoma on MR?
Petrous apex T1 dark, T2 bright, RESTRICTS diffusion
Grandenigo Syndrome symptoms and involves?
Complication of apical petrositis when Dorello’s canal is involved (CN6) Lateral rectus palsy, otomastoiditis, and facial pain (trigeminal nerve involvement)
Endolymphatic sac tumors are assocaited with?
Von- Hippel-Lindau Tumors have amorphous calcifications, T2 bright, enhance
Paragangliomas of the jugular fossa most commonly present with?
Hoarseness- vagal nerve involvement Tumor- salt and pepper appearence, highly vascular
Large vestibular aqueduct syndrome?
Vestibular aqueduct connects vestibule to the endolymphatic sac Enlarges > 1.5 mm- associated with progressive sensorineural hearing loss Associated with absence of bony modiolus
Types of otosclerosis?
Fenestral- involves the fissula ante fenestram Retro-fenestral- demineralization around the cochlea, typically bilateral and symmetric Conductive hearing loss in female- typical presentation
Acquired Cholesteotoma will first errode? What is the most common ossicle to be erroded?
The scutum eroded first Long process of the incus is most common segment of ossicular chain to be eroded Cholesteotoma involves Prussak’s space Can have fistula to the lateral semicircular canal
Most common type of acquired cholesteotoma?
Pars flaccida (other is pars tensa)
Noise induced vertigo is associated with?
Dehiscence of the superior semicircular canal
Most common cause of necrotizing external otitis?
Diabetes with pseudomonas infection
Which portions of the facial nerve do not normally enhance?
cisternal, cannilicular, labyrinthine
What can cause abnormal cranial nerve VII enhancement?
Bell’s palsy, lymes, Ramsay Hunt, perineural tumor spread
What T-bone fracture is most likely to injure CNVII?
Transverse
Which is typically midline Chordoma or Chondrosarcoma?
Chordoma
What is the blood supply to the juvenile nasal angiofibroma?
Internal maxillary
Where is the JPA centered typically?
sphenopalantine foramen can expand the pterygopalantine foramen
Antrochoanal polyp arises in?
Maxillary sinus enlarges maxillary sinus ostium associated with nasal congestion and obstruction
Inverting papilloma arise from?
Lateral wall of the nasal cavity, frequently close to middle turbinate MRI- cerebriform pattern, look like mini-brain 10% harbor squamous cell carcinoma
Enthisioneuroblastoma originate?
Cribiform plate-> grow superiorly into the skull and down throught the sinus typically has cystic components, avid homogenous enhancement
What nasal tumor is positive on octreotide scan ?
Enthesioneuroblastoma
Most common site of squamous cell carcinoma?
Maxillary sinus
Epistaxis treatment?
IF posterior and compression does not work Embolize the sphenopalantine artery off the internal maxillary artery (evaluate for anastamosis between ECA and opthalamic)
Where does a rannula arise?
sublingual gland
Rannula is considered diving once it is below?
mylohyoid muscle
Sialolithiasis most commonly involves the?
Submandibular gland whartons duct
Spread of infection in the mouth is dictated by?
The mylohyoid muscle Above goes into the sublingual space Below goes into the submandibular space
What causes osteonecrosis of the mandible
prior radiation or bisphosphonate use
Causes of pulsatile exophthalmos?
CC fistula NF1 with sphenoid wind dysplasia
Dacrocysticits is?
Inflammation and dilation of the lacrimal sac
Most commonly affected extraoccular muscles in thyroid opthalmopathy?
IMSLO - inferior rectus > medial >superior rectus > lateral rectus > Superior oblique Painless, does not involve the tendon
What divides the superficial and deep lobes of the parotid gland?
CN VII (retromandibular vein is medial to CN VII)
Most common salivary gland tumor?
Pleomorphic adenoma- T2 bright with rim of low signal small malignant potential
What are features of a warthin tumor?
Usually cystic Male smoker Bilateral Take up Pertechnetate
Mucoepidermoid Carcinoma
Most common malignant tumor of minot salivary glands associated with radiation
Which salivary gland tumor has increased propensity for perineural tumor spread?
Adenoid cystic carcinoma
Lymphoma of the parotid glands has a higher incidence in what population?
Sjogrens
Most common viral cause of parotitis?
Mumps
HIV patient with bilateral mixed cystic and solid parotid lesions?
Benign lymphoepithelial disease
“Honeycombed” parotid gland?
Sjogrens (associated with MALT lymphoma)
Carotid space contains?
Carotid artery, jugular nerve, CN IX, CN X, and CN XI
Paragangliomas take up what radiotracer?
octreotide
Most common paragangliomas?
Carotid Body- splays ECA/ICA Glomus Jugulare- jugular foramen Glomus Vagale- above carotid and below jugular foramen Glomus tympanicum- overlies cochlear promontory
Massicator Space Contains?
masticator, temporalis, medial and lateral ptyergoids, inferior alveolar nerve
Most common cause of massicator space mass?
odontogenic infection
Retropharyngeal space extends down to?
T3
Common causes of retropharyngeal lymph nodes?
SCC, papillary thyroid carcinoma, lymphoma
Bacterial cause of lemierre’s?
Fusobacterium Necrophorum
A mass in what location would displace the parapharyengeal fat medially?
parotid carotid mass- displace anterior Superficial Mucosa- displace laterally Massicator space mass would displace posteriorly
What separates 1A lymph nodes from 1B?
anterior belly of digastric
Separates 1B from 2A?
stylohyoid
Separates 2A from 2B?
Spinal accessory nerve
Separates level 2 from level 3?
inferior hyoid
separates level 3 from level 4?
lower border of cricoid
Fixation of the vocal cords and paraglottic space involvement indicate what level laryngeal cancer?
T3
What determines surgical resection candidacy for laryngeal conservation?
Invasion of the cricoid
Discontinuity of the posterior globe?
Coloboma
Coloboma is associated with which syndrome?
CHARGE
“martini glass globe”?
Persistent Hyperplastic primary vitreous can lead to retinal detachment
Coat’s disease
retinal teleangestasia with subretinal exudate (does not calcify like retinoblastoma)
Optic nerve glioma is associated with?
NF1 Global enlargement of the entire nerve WHO Grade I pilocytic astrocytomas
“tram track” calcifications of the optic nerve?
meningioma
Orbital Pseudotumor facts?
unilateral, painful, does not spare myotendinous junction most commonly involves lateral rectus
Inflammatory process in the cavernous sinus?
Tolosa Hunt
Lymphocytic hypophysitis?
Enlarged enhancing pituitary stalk and pituitary Can be T2 bright with dark surrounding rim Most common- 3rd trimester or post-partum
Most common location of occular dermoid?
Superior and lateral (arise from the frontozygomatic suture)
Appearance of metastatic breast cancer to the orbit?
desmoplastic reaction resulting in enophthalmos
Lymphoma of the orbit is associated with?
Chlamydia Psittaci Frequently involves the lacrimal gland
Most common intra-occular lesion in an adult?
Melanoma Invasion of Bruchs membrane- evaluate for
Quadrilateral Retinoblastoma?
both eyes, pineal, and suprasellar
Lymphangioma of the orbit?
Multi-spatial Fluid-fluid levels on MRI Do not increase with valsalve
Most common cause of spontaneous orbital hemorrhage?
varix, distend with provocative maneuvers