mnemonics Flashcards
A mnemonic for causes of nasopharyngeal masses is:
SAIL
S: squamous cell carcinoma
A: antrochoanal polyp (extending from sinonasal cavity)
I: inverted papilloma (extending from sinonasal cavity)
L: lymphoma
Acro-osteolysis
PINCHFO
For band acro-osteolysis its backwards
P - Psoriasis/pyknodystosis
I - injury - frostbite, thermal burn
N - neuropathy - diabetes
C - collagen vascular disease - scleroderma/raynauds
H - hyperparathyroidism
F - familial - Hajdu-Cheney syndrome
O -`Other - polyvinyl exposure
Eccentric bone lesions
GCT
Chondroblastoma
ABC
NOF
Chondromyxoid fibroma
Central bone lesions
SBC
enchondroma
FD
Bone forming lesions
Enostosis (BONE ISLAND) - osteopoikilosis = autosomal dominant syndrome with multiple bone islands and keloid formation
osteoma - Gardner syndrome = autosomal dominant multiple osteomas, intestinal polyposis and st dermoids
Melorheostosis - non neoplastic proliferation of thickened and irregular cortex with a typical candle wax appearance
(intense uptake on bone scan). Clinically presents with pain, decreased ROM, Leg bowing and leg length discrepancy
osteoid osteoma - nidus, surrounded by reactive bone sclerosis
osteoblastoma - same as above but >2cm
osteosarcoma - conventional, telangiectatic, parosteal (cauliflower like exophytic lesion) and periosteal
Cartilage forming lesions
Synovial chondromatosis - intra-articular lobulated cartilaginous nodules
Enchondroma - rings and arcs calcification - ddx = medullary bone infarct
Osteochondroma - continuity with cortex and communication with medullary cavity, arises from metaphysis and grows away from epiphysis. Cartilage cap >2cm suggests malignant transformation
Chrondroblastoma - eccentric in the epiphysis
Chondormyxoid fibroma - eccentric tibial or femoral metaphysis around the knee. Sclerotic margins on xray and high signal on T2
Chondrosarcoma - conventional (intramedullary) is most common, typically expansile in medullary bone, ring and arc chondroid matrix, thickening and endosteal scalloping of the cortex. associated soft tissue mass.
Fibrous origin lesions
NOF - aka fibroxanthoma. NOF and fibrous cortical defect = same lesion. NOF usually larger and symptomatic
lucent lesion with narrow zone of transition, sclerotic margin and no matrix calcification. CT or MRI may show cortical disruption or thinning representing replacement of cortex by fibrous tissue.
Malignant fibrous histiocytoma (MFH) aka undifferentiated pleomorphic sarcoma not otherwise specified.
Fibrous dysplasia - can be mono or polyostotic. long bones - central and metaphyseal. most common complication = pathologic fracture (femoral neck)
in ribs/long bones matrix is indistinct and ground glass
pelvic bones = cystic
skull base - expansile looks like pagets
Lesions of vascular origin
Hemangioma - trabecullar thickening
corduroy striations or polka dot sign
Angiosarcoma - looks and acts aggressively
GCT - epiphyseal lucent lesion, eccentric, and articular. Arises from the metaphysis but crosses the closed epihyseal plate to involve the epiphysis.
Eosinophilic granuloma - LCH - abnormal proliferation of histiocytes. children 5-10 yrs. skull - bevelled edge
mandible/maxilla - floating tooth from reabsorption of alveolar bone. spine - vertebra plana. Long bones - destructive radiolucent lesion with aggressive periosteal (lamellated) reaction, may look like lymphoma or ewing sarcoma
Ewing sarcoma - small round cell tumour in children/adolescents, male predominance. Aggressive lesion with aggressive periosteal reaction and soft tissue mass
Multiple myeloma/plasmacytoma - multiple lytic lesions. Negative on bone scan. Solitary tumour = plasmacytoma.
Lymphoma - aggressive lytic lesion or ivory/sclerotic vertebral body. often has adjacent soft tissue mass
Fat (lipo-) lesions
Lipoma - intraosseous - most common sites are calcaneus, subtrochanteric region of femur, distal tibie/fibula and metatarsals.
Liposarcoma - large size, thick septations, globular or nodular soft tissue, or composition containing <75% fat.
Notochord lesions
Chordoma - spheno-occipital, body of C2 or sacrococcygeal. Highly destructive with irregular scalloped borders. May have calcs, due to necrosis
Lesions of unknown cell origin
SBC aka unicameral bone cyst. hollow or fluid filled and typically found in proximal diaphysis of humerus or femur. no periosteal rxn. fallen fragment sign. always central
fluid fluid level. trtment injection with methylprednisolone
ABC - expansile multicystic lesion. composed of blood filled sinusoids and solid fibrous elements. can be central or eccentric. can occur in posterior elements of spine.
Adamantinoma - low grade malignant tumour, tibia, soap bubble appearance - ddx FD
Lesions that have fluid fluid levels ?
SBC
ABC
GCT
Telangiectatic osteosarcoma
Osseous mets
lytic lesions (5)
Blastic lesions (5)
Lytic
- lung
- breast (can be both)
- Thyroid
- Kidney
- stomach/colon (can be both)
Blastic
- breast (can be both)
- prostate, seminoma
- TCC
- mucinous tumors
- carcinoid
Hyperparathyroidism - imaging hallmarks
Skull: Salt and pepper
Hands: subperiosteal reabsorption radial aspect of 2nd and 3rd middle phalanges
Clavicle: subperiosteal reaction of distal clavicle
Knee: subperiosteal bone resorption medial proximal tibia metaphysis.
Teeth: loss of lamina dura
Anywhere: brown tumours
everywhere: diffuse osteopenia
Hypothyroidism findings
delay in skeletal and dental maturity
bullet shaped vertebral bodies and wormian bones in the skull
SUFE
Hypoparathyroidism
metastatic deposit of calcium
subcutanoues tissues and basal ganglia
Pseudohypoparathyroidism
CLASSIC - short MC of either the 4th or 5th digit or the thumb.
Osteopetrosis
deficiency in osteoclastic carbonic anhydrase - leads to inability of osteoclasts to resorb bone
Diffuse marked sclerosis of the entire skeleton
Gauchers disease
autosomal recessive
defect in glucocerebrosidase leading to abdnormal deposition of cerebroside in macropahges called gaucher cells
Gaucher cells cause bone infarcts, medullary expansion and hepatosplenomegaly
Erlenmeyer flask deformity
H-shaped vertebral bodies
Sickle cell
autosomal recessive
beta chain hemoglobin
sickle shaped rbc causing microvascular occlusion
bone infarcts, increased risk of osteomyelitis, marrow expansion/hyperplasia
Thalassemia
autosomal recessive
alpha or beta hemoglobin
bone infarcts, marrow hyperplasia, infection.
hair on end striations
widening and squaring of the phalanges and metacarpals
erlenmyer flask deformity
Myelofibrosis
progressive fibrosis of BM in older patients
splenomegaly
diffusely sclerotic bones
Mastocytosis
abnormal proliferation of mast cells
diffuse osteoporosis or sclerosis
Lucent epiphyseal lesion - includes patella, carpal bones, calcaneus
GEIChA
GCT
Eosiniphilic granuloma
Infection
Chondroblastoma
ABC
Expansile lytic rib lesion
FAMEB
FD
ABC
Mets, myleoma, Plasmacytoma
Enchondroma
Brown tumour
Kohler disease (children)
Mueller-Weiss (adults)
Osteonecrosis of the navicular
Freiberg’s infraction
AVN of the 2nd MT head
Bucket handle meniscal tear
more common in medial meniscus
absent bow tie sign
if fragment flips anteriorly = double delta sign (either meniscus)
if fragment flips posterior = double PCL sign (medial meniscus only)
Discoid meniscus
more common laterally
PVNS
benign hyperplastic proliferation of the synovium within the joint
Bakers cyst is located between ?
SemiMembranousus and Medial head of gastrocnemius
Baker’s M&M
classic location for stress fracture in femur
fractures due to bisphosphonate use
Inferomedial neck
lateral femoral diaphyseal and transverse diaphyseal fractures.
Spondylolysis
fracture of the pars interarticularis - leads to spondylolisthesis
Basion dental interval =
Atlanto-dental interval =
<12 mm
< 2.5 mm in adults
< 5 mm in children
SLAP
GLAD
Superior labrum anterior posterior tear - centered at the attachement of the bicepos tendon - anterior-posterior of the superior labrum
Glenoid labral articular disruption - superficial tear of the anterior-inferior labrum
suprascapular nerve entrapment at the suprascapular notch causes atrophy of ?
Suprascapular nerve entrapment at the spinoglenoid nothc causes atrophy of ?
Both supraspinatus and infraspinatus
infraspinatus muscle only
Essex-Lopresti fracture-dislocation involves?
Monteggia
Galeazzi
1) radial head fracture and tearing of the interosseous membrane with ulnar dislocation at the distal radioulnar joint.
2) Mid diaphyseal ulnar fracture and radial head dislocation
3) radial diaphyseal fracture and distal ulnar dislocation,
Kienboch disease = ?
AVN of the lunate
Neurofibramatosis 1
CAFE SPOT
chromosome 17 - (17 letters in neurofibramatosis)
1:3000
autosomal dominant
Cafe au lait spots
axillary or inguinal freckling
fibromas - (neurofibroma) plexiform
eye harmartoma - lisch nodules - pigmented nodules of the iris
skeletal abnormalities - sphenoid wing dysplasia
postive family history
optic tumour - gliomas of the optic nerve
peripheral nerve sheath tumour - plexiform neurofibroma
pheochromocytoma
sphenoid wing dysplasia, posterior vertebral scalloping, rib notching, tibial bowing
Brain neoplasms -
Optic nerve glioma
juvenile pilocytic astrocytoma
brainstem glioma
Also associated with multiple extra-cranial neoplasms
Wilms tumour, Rhabdomyosarcoma, AML, leiomyosarcoma
Neurofibromatosis 2
MISME
22 letters for NF type 2
chromosome 22
Multiple inherited schwannomas
meningioma
ependymoma
Paeds thoracic tumours
pleuropulmonary blastoma - 3 types - cystic, mixed cystic solid and purely solid
Inflammatory myofibroblastic tumour
Mesenchymal hamartoma -
MEN 1
Pit para panc
pituitary adenoma
parathyroid proliferative disease
pancreatic endocrine tumours
MEN 2 A
PMP
Pheochromocytoma
Medullary thyroid ca
Parathyroid hyperplasia
MEN 2 B
PMMM
Pheochromocytoma
Medullary thyroid ca
Mucosal neuroma
Marfinoid habitus
Carney Complex
MEN syndrome
Cardiac myxoma
Skin pigmentation
Carney Triad
3 tumours
Extra-adrenal paraganglioma
GIST
Pulmonary chondroma
Pheochromocytoma
medullary
MR -Variable T1/T2 signal due to hemorrhage, cystic degeneration, and necrosis
Traditional classic imaging feature: T2 (“light bulb”) hyperintensity
Hypervascular solid components
assoc autosomal dominant familial syndromes
von Hippel-Lindau, multiple endocrine neoplasia 2, neurofibromatosis type 1
Classic teaching: Rule of 10s (or 10% tumor)
10% extraadrenal (paraganglioma) 10% bilateral 10% malignant 10% extraabdominal 10% familial 10% pediatric 10% silent 10% autosomal dominant transmission
DDX - adrenal adenoma
adrenal carcinoma
adrenal mets and lymphoma
Ewing sarcoma
aggressive permeative lesion in diaphysis of a child
second most common malignant primary bone tumors of childhood after osteosarcoma, typically arising from the medullary cavity with the invasion of the Haversian system. Ewing sarcomas usually present as moth-eaten, destructive, and permeative lucent lesions in the shaft of long bones, with a large soft tissue component and typical onion skin periostitis. These tumors may also involve flat bones and can appear sclerotic in up to 30% of cases.
Wilms tumour
Wilms tumor, also known as nephroblastoma, is a malignant pediatric renal tumor.
x-linked Adrenoleukodystrophy
Lack of oxidation of long chain fatty acids that results in a severe inflammatory demyelination
spares subcortical u-fibres
Involves symmetric occipital white matter and splenium of corpus callosum
Metachromatic leukodystrophy
autosomal recessive lysosomal storage disorder
white matter diffusely affected
Bilateral symmetric periventricular change - butterfly pattern
spares u-fibres
Alexander disease (fibrinoid leukodystrophy)
Rosenthal fibres
Involves subcortical u-fibres, basal ganglia and enhances
involves frontal white matter
Starts in frontal region and extends posteriorly.
Involves u-fibers early in disease
Canavan disease (spongiform degeneration of white matter)
CaNAAvan
Prevelant in Jewish
Autosomal recessive due to gene mutation leading to deficiency of N-acetylasparta and accumulation of NAA in brain, CSF and plasma and urine
Bilateral diffuse symmetrical white matter involvement
involves subcortical u-fibres, basal ganglia, thalamus
Spares CC, caudate and internal capsule
No enhancment
diffuse white matter involvement
5 Congenital heart defects associated with cyanosis
T’s (right –> left shunt)
Tetralogy of fallot
transposition of the great arteries - 90% NOT associated with a syndrome. Common in diabetic mother
truncus arteriosus
total anomalous pulmonary venous return (TAPVR - pulmonary and systemic veins all drain into the right atrium)
tricuspid valve abnormalities
Egg on a string XR
Boot shaped heart
Snowman
Figure 3
Box shaped
TGA
TOF - VSD, Obstruction of right ventricle outflow, aorta overides VSD, right ventricular hypertrophy
TAPVR
Co-arctation
Ebstein
Giant cell arteritis
Medium vessel vasculitis
Small vessel vasculitis
Temporal arteritis
Takayasu - granulomatous vasculitis of medium + large art (aortic arch)
Polyarteritis nodosa - kidneys (spares lungs)
p-ANCA
Kawasaki - Self-limited small and medium vessel vasculitis in young children that can lead to coronary artery aneurysms
Churg-Strauss syndrome - small vessel necrotizing vasculitis in patients with asthma and eosinophilia - ANCA + 40%
Bechet - small to medium neutrophilic vasculitis - Chronic, idiopathic, relapsing-remitting, multisystem vascular-inflammatory disease characterized by recurrent orogenital ulcerations and uveitis
Left to right shunt - acyanotic congenital heart defects
ASD - 90% secundum
VSD - 90% in membranous intraventricular septum
PDA
TREVOR disease
osteochondroma that points towards the joint
Causes of rugger jersey spine ?
pictures frame vertebrae
sandwich vertebrae
Renal osteodystrophy
hyperparathyroidism
Pagets
ostepetrosis
Pepper pot skull
Raindrop skull
Hyperparathyroid
Multiple myeloma
Renal artery stenosis causes
Atherosclerosis
NF1 - ostium
FMD - distal artery
vasculitis
TS
TSC1 and TSC2
cortical and subcortical tubers
SEGA
Renal AML
Cardiac rhabdomyomas
LAM - rare
VHL
Numerous benign and malignant tumours
RCC
Pheochromocytoma
Pancreatic cysts
CNS - hemangioblastoma
Anterior mediastinal mass (5 T’s)
Thymoma
Teratoma
Thyroid
Terrible lymphoma
Thoracic aorta
VACTERL
Vertebral anomalies
Anal atresia
Cardiovascular anomalies
Tracheo-esophageal fistula
Renal/radial anomalies
Limb defects
Lucent metaphyseal bands
LINE
Leukaemia
Infection (TORCH)
Neuroblastoma mets
Endocrine - Ricket’s ,scurvy
Lucent/lytic bone lesions
FEGNOMASHIC
FD
Enchondroma
GCT
NOF
Osteoblastoma
Mets/myeloma
ABC
SBC
Hyperparathyroidism (brown tumour)
Infection
Chondroblastoma or chondromyxoid fibroma
CAVITY - lung
Cancer - squamous
Autoimmune (wegners, rheum)
Vascular - septic emboli
Infection - TB
Trauma - pneumatocele
Young - Congenital (CCAM, sequestration)
Bleeding mets
MR CT
Melanoma
Renal
carcinoid/cholangioncarcinoma
thyroid
Cortical based tumours
Pl-DOG
Pleomorphic xanthroastrocytoma
DNET - dysembryonic neuroepithelial tumour
Oligodendroglioma
ganglioglioma
TORCH
toxoplasmosis
Other - syphilis, varicella, parvovirus B19
Rubella
CMV
HSV
GOUT mimickers
American Roetengen Ray Society Hooray
Amyloid
RA (cystic)
Reticular histocytosis
Sarcoid
Hyperlipidaemia
Medullary Nephrocalcinosis
HAM HOP
Hyperparathyroidism
Acidosis - renal tubular
Medullary sponge kidney
Hypercalacaemia
Oxalosis
Papillary necrosis
Calcified intracranial masses
CA COME
Chraniopharyngioma
Astrocytoma, aneurysm
Choroid plexus tumour
oligodendroglioma
Meningioma
Ependymoma
Ring enhancing lesion
MAGIC DR
Mets
abscess
glioma
infarct
contusion
demyelination
radiation
Posterior fossa tumours
GAME
Glioma - brainstem
Astrocytoma - pilocytic
medulloblastoma
ependymoma
CPA angle masses
SAME
Schwannoma - enhance
Arachnoid cyst
Meningioma - enchance
Epidermoid cyst - RD
Suprasellar masses
SATCHMO
Sarcoidosis
Adenoma/aneurysm
Teratoma/germinoma, TB
Chraniopharyngioma, Ranthke’s Cleft cyst
Hypothalamic hamartoma, histiocytosis
Meningioma, mets
Optic pathway glioma
Renal papillary necrosis
POSTCARDS
Pyelonephritis (infection)
Obstruction
Sickle cell disease
TB
Cirrhosis
Analgesic abuse
renal vein thrombosis
DM
Systemic vasculitis
Dense bone
3Ms PROOF
Malignancy
Myelofibrosis
Mastocytosis
Sickle cell disease
Pagets
Renal osteodystrophy
Osteopetrosis
Other
Fluorosis
Hepatic lymphoma
What is Post transplant lymphoproliferative disorder
looks like mets - single or multiple masses
is a type of lymphoma caused by ebstein barr virus after solid organ or BM transplant. renal transplant patients most at risk.
Cortical nephrocalcinosis
COAG
Cortical necrosis (acute)
Oxaluria (hyper)
Alport syndrome
(chronic) glomerulonephritis
Echogenic renal mass
AML
Malignant neoplasm
renal calculus
intrarenal gas
milk of calcium
sloughed papilla
Carotid artery blood flow
Normal PSV = 60 - 100 cm/sec
>125 cm/sec >50% stenosis
>230 cm/sec >70% stenosis
Waveform - before the stenosis will be high resistance with spectral broadening
After stenosis - low resistance with tardus parvus waveform
Hashimoto thyroiditis
Graves
HYPOthyroid
increased right of thyroid lymphoma
diffusely nodular or coarsened gland on USS
HYPERthyroid
thyrotoxicosis
enlarged gland with coarse echotexture
thyroid inferno - increased blood flow
SUBACUTE THYROIDITIS - de Quervain thyroiditis
viral
gland is tender with adjacent cervical adenopathy
heterogenous gland with patchy areas of decreased echogenicity
Anencephaly
Encephalocele
Holoprosenchephaly (trisomy 13)
Agenesis of CC (trisomy 13 and 18)
Absence of cavum septum pellucidum
complete lack of brain above the orbits
protrusion of brain and meninges outside the calvarium
Failure of midline cleavage - fused thalami, no falx
Looksfor cavum septum pellucidum (formed together).
Septo-optic dysplasia and absent CC
Meckel-Gruber
Encephalocele
Renal dysplasia - echogenic kidneys
Polydactyly
Beckwith-Wiedemann
increased risk of Wilms tumour\
hemihypertrophy, organomegaly
macroglossia
omphalocele
perinatal hypoglycaemia
What does CADASIL stand for and what is it ?
cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
Hereditary small-vessel disease due to mutations in NOTCH3 gene on chromosome 19, which causes stroke in young to middle-aged adults
FINDINGS:
Diffuse white matter hyperintensities = leukoaraiosis, early finding
Multiple lacunar infarcts
Anterior temporal pole, external capsule, and paramedian superior frontal lobe highly sensitive and specific locations
Diffusion restriction in acute lacunar infarcts
Carcinoid tumour
Recommend In-111 octreotide scan / I-123 labelled MIBG scan.
Correlate with chromogranin A and 5HIAA levels
5-HIAA (5-hydroxyindoleacetic acid): usually suggests a functioning carcinoid tumor
chromogranin A (CgA): considered a valuable tool in the diagnosis of neuroendocrine neoplasia in general
Parathyroid adenoma
CAPLAN syndrome
Caplan syndrome, also known as rheumatoid pneumoconiosis, is the combination of seropositive rheumatoid arthritis and a characteristic pattern of fibrosis.
CHARGE syndrome
Coloboma
Heart anomaly
Atresia choanae
Restricted growth and development: Mental and somatic development
Genital hypoplasia
Ear abnormalities
Malignant mesothelioma
primary malignant tumour arising from either the visceral or parietal pleura
1000x increased risk in asbestos workers
80% are asbestos related
Smoking has NO association or synergistic effect
3 types
Epithelial type (60%)
Sarcomartoid type (20%) - worst prognosis
Mixed type
TB
Mycobacterium tuberculosis
caseating granulomatous inflammation
Type IV hypersensitivity reaction: cell mediated immunity (by T helper lymphocytes)
PRIMARY TB - Ghon complex - 1cm subpleural lesion in midzone with caseous centre (Ghon focus) + ipsilateral caseous tracheobronchial nodes
SECONDARY (reactivation) TB
PROGRESSIVE TB
subtypes - cavitatory, miliary, tb bronchopneumonia, empyema
Hypersensitivity pneumonitis
immunologically mediated mixed alveolar and predominently interstitial lung disorders caused by prolonged exposure to inhaled organic dusts acting as antigen.
Sarcoid
Non caseating granulomas
Small vessel vasculitis - 3
Wegener’s granulomatosis. C-ANCA
Churg-Strauss syndrome P-ANCA
Systemic Lupus Erythematosus (SLE)
Pulmonary alveolar proteinosis (PAP)
Rare disease of unknown aetiology characterised by airspace consolidation due to accumulation of an amorphous protein - lipid (PAS positive) granular precipitate within alveoli
Pulmonary collagen vascular disease
Scleroderma
SLE
RA
Drug induced lung disease
bronchospasm - 2
HSP - 2
Pneumonitis-fibrosis - 2
aspirin and beta agonists
methotraxate and nitrofurantoin
bleomycin and amiodarone
Viruses abd corresponding neoplasms
EBV
Hep B
HPV
HTLV-1
Burkitt’s lymophoma
Nasopharyngeal carcinoma
Other B-cell lymohomas
HCC
Cervical ca and other skin ca
T-cell leukaemia/lymphoma
Tumour markers and Tumour
AFP
HCG
Acid phosphatase
CEA
Hormones
HCC and germ cell
Trophoblastic tumour
prostatic carcinoma
GI tract neoplasia
Endocrine tumour
Nuc medicine
Kaposi sarcoma
TB
Lymphoma
KaT - kaposi is Thallium avid
TuG - TB is gallium avid
Lymphoma likes both (thallium and gallium)
Mucopolysaccharidoses
group of lysosomal disorders including Hurler’s, Morquio and Hunters
imaging findings: ant vertebral body beaking, thickened ribs and undertubulated bones
Madelung deformity of the wrist
thickened calvarium with J-shaped sella
Hurler’s - ant beaking of vertebral bodies, primarily inferiorly
Morquio - middle of vertebral body
;.
Syphilis
Treponema Pallidum
Wimberger sign - destructive erosion at the medial aspect of the proximal tibia
symmetric periosteal reaction in a child
DDH
alpha angle < 60 degrees and < 50% coverage of the femoral head.
Blount disease
osteochondrosis of the proximal tibia metaphysis causing tibia varus and internal rotation which leads to progressive deformity, gair deviations and leg lenght discrepancy
(sloping of the medial portions of the proximal tibia metaphysis)
Panner disease
osteochondrosis of the capitellum
Periosteal reaction in child
physiological 1-4 months - lateral or medial aspect of long bones
prostoglandin therapy -
infectious
neoplastic
trauma
metabolic - ricket’s, scurvy
syndromic - Caffey disease (infantile cortical hyperostosis) rare inflammatory disease causing periostitis of the mandible, scapula and clavicle
Polymicrogyria
causes
in utero infection
in utero ischaemia
genetic
Lissencephaly
absent or decreased cortical convolutions causing smooth, thickened cortical surface
Schizencephaly
full thickness cleft of the cerebal hemisphere lined by dysplastic grey matter
associated with septo-optic dysplasia which is characterised by agenesis of the septum pellucidum and optic never hypoplasia
Holoprosencephaly
forebrain does not divide into two hemispheres
Alobar, semilobar and lobar
Chiari I malformation
displacement of the cerebellar tonsils beyond the foramen magnum
syrinx
Chiari II
herniation of the vermis, cerebelalr tonsils, and medulla into the foramen magnum with resultant beaking of the tectum
Dandy Walker
enlarged posterior fossa
Sturge Weber
Vascular disorder
facial port wine stain
ocular abnormalities
failure of normal cortical venous development
underlying vascular anomaly leads to chronic ischaemia, cortical atrophy, and cortical calcification
Joubert syndrome
midbrain malformation
molar tooth
Autosomal recessive genetic disorders with impaired ciliary function
molar tooth sign on MR, intellectual impairment, hypotonia
Mnemonic for associations of Madelung deformity
HIT DOC
Hurler syndrome
Infection
Trauma
Dyschondrosteosis
Osteochondroma
Congenital - Turners
Ivory vertebrae
M. PHIL
Mets (osteoblastic) - breast and prostate
Pagets
Haemangioma
Infection - TB spondylitis
Lymphoma (hodgkins)
Bony sequestrum
E-FILM
Eosinophilic granuloma (LCH)
Fibrosarcoma
Infection (Brodie’s abscess)
Lymphoma
Mets - breast ca
Wormian Bones
<10 = idiopathic
>10 think Osteogenisis imperfecta first
>10 + absent clavicle = Cleidocranial Dystosis
PORK CHOP
Pyknodysostosis
Osteogenesis imperfecta
Rickets
Kinky hair syndrome
Cleidocranial dysostosis
Hypothyroidism/Hypophosphatasia
One too many chromosomes (21) downs
Primary acro-osteolysis (Hadju-Cheney)
Subglottic hemangioma
assymetric narrowing of the subglottic region
Croup - symmetric narrowing
associated with PHACES syndrome (7%)
P - posterior fossa (dandy walker)
H - Hemangiomas
A - arterial anomalies
C- coarctation of aorta and cardiac defects
E - eye abnormalities
S - subglottic hemangiomas
Rhabdomyosarcoma
most common mass in the masticator space of a kid!
extra-occular orbital malignancy - painless proptosis and no signs of infection
Cystic lesions in the neck
lateral - think - 2nd branchial cleft cyst
lymphatic malformation - septa enhance
vascular malformation (phleboliths) - cystic spaces enhance
Posterior element bone lesions
ABC
Osteosarcoma
Osteoblastoma
Osteochondroma
chondromsarcoma
osteoid osteoma
ewings
Glomus tympanicum paraganglioma
Glomus tympanicum paraganglioma arises from glomus bodies situated on the cochlear promontory. Larger lesions may cause erosion of the walls of the middle ear or ossicles. As with other paragangliomas, intense enhancement is the rule.
Subdural effusion
Most subdural effusions occur after meningitis and are more common in children than adults. They consist of a plasma exudate, NOT cerebrospinal fluid, and do NOT contain blood. They don’t enhance nor do they restrict on DWI. This distinguishes them clearly from other subdural collections such as chronic hematomas, empyemas, and hygromas
Wegners vs sarcoid
Wegener granulomatosis (granulomatosis with polyangiitis, GPA) involves the sinonasal cavities in over 75% of patients. Orbital extension of sinonasal disease is a characteristic feature of GPA. Because GPA is a systemic necrotizing vasculitis, the majority of patients have involvement beyond the upper respiratory tract, including the lower respiratory tract, kidneys, skin, and joints.
Sarcoidosis is an idiopathic granulomatous inflammatory disease that involves the sinonasal cavities in about 20% of patients. Nasal septal perforation is a characteristic feature and does not imply secondary malignancy.
Both GPA and sarcoidosis have a similar imaging appearance, with a predilection for the nasal cavity, production of nodular soft tissue lesions, bone destruction, and nasal septal perforation
Low-grade diffusely infiltrating astrocytoma
Low-grade diffusely infiltrating astrocytoma does not enhance. Infection (e.g., ventriculitis) and neoplasm (e.g., medulloblastoma and ependymoma in children, lymphoma and glioblastoma multiforme in adults) can both cause ependymal enhancement. Much of the cerebral white matter of the corona radiata drains centrally into subependymal veins. These normally enhance with contrast and should not be mistaken for pathology. Normal enhancing subependymal veins are usually thin and linear, not fat and nodular. A “rind” of ependymal thickening and enhancement is not a normal finding.
FMD
Fibromuscular dysplasia (FMD) is an arteriopathy of unknown etiology that affects medium and large arteries. The carotid arteries are involved in about a 3rd of all cases, with the vertebral artery involved in about 10%. Bilateral carotid artery lesions are found in about 2/3 of all cases. The “string of beads” appearance is most common (85% of cases) and is caused by medial fibroplasia. Long tubular stenosis is caused by intimal fibroplasia and accounts for 10% of cephalocervical FMD cases. A rare variant is periadventitial fibroplasia, where there is an asymmetric outpouching that involves 1 side of the artery. FMD carries increased risk of vascular complications including dissection, transient ischemic attacks, and subarachnoid hemorrhage from saccular aneurysm.
secondary laryngocele
Laryngopyocele
A small cyst in the right paraglottic space is consistent with an internal laryngocele secondary to an enhancing glottic squamous cell carcinoma (SCCa) with nodularity anteriorly (Fig. 2). The term secondary laryngocele is used when a glottic level lesion obstructs the laryngeal ventricle and creates a laryngocele superiorly.
Laryngopyocele shows inflammatory findings of a thickened wall and inflammatory stranding in surrounding soft tissues. Thyroglossal duct cyst may extend into the preepiglottic space in the anterior midline but not in the more lateral paraglottic space. This is not a hypopharyngeal diverticulum, as it does not communicate with the hypopharyngeal airway.
Larynx - divisions
Remember the larynx can be divided into 3 major pieces, the supraglottis, glottis and, subglottis. The supraglottic larynx is further divided into three subsites, the epiglottis, aryepiglottic folds, and the false cords.
Cranial nerves exit points
CN 9
The glossopharyngeal nerve (CN9) exits the skull base through the pars nervosa (along with the inferior petrosal sinus). The vagus and accessory nerves (10 and 11) exit through the pars vascularis of the jugular foramen. The hypoglossal nerve (12) exits through the hypoglossal canal , which lies just under the jugular tubercle
Heterotopic grey matter
Heterotopic gray matter has a spectrum of appearances. Most commonly seen as subependymal nodules, it can also appear as bands of gray matter signal deep to the cortex (“band heterotopia”) or as a nodule in a subcortical location, often adjacent to abnormal sulcation/gyration. It is important to recognize it as a cause of seizures and not to mistake it for a neoplasm.
Ankylosing spondylitis
Sagittal STIR MR image of the spine demonstrates Romanus lesions . Romanus lesions consist of edema and less often seen erosions involving the anterior edges of the vertebral endplates. These lesions occur at the site of attachment of the annulus fibrosus to the vertebral endplate. Such a junction of bone and ligamentous structure is an enthesis and, therefore, a Romanus lesion or spondylitis can be regarded as an enthesitis. Chronically, these lesions can sclerose, giving the classical plain film appearance of “shiny corners”.
Spinal lipoma
Spinal lipoma is intimately associated with the dorsal spinal cord (intradural) or distal cord/filum insertion (terminal). It is a hyperintense (T1WI) intradural mass. Use frequency selective fat suppression if unsure of the composition of the hyperintense mass.
Germinoma
Germ cell tumors are the most common pineal gland tumor, and germinomas are the most common type of germ cell tumor. Synchronous occurrence in the pineal gland and suprasellar cistern is a classic presentation with the suprasellar component representing a “drop metastasis” from the pineal germinoma. An adolescent male presenting with a solid tumor in both locations is pathognomonic of this type of tumor.
Myxopapillary ependymoma
A well-demarcated lobular mass extending from the conus is typical appearance of myxopapillary ependymoma. Lack of dural attachment excludes meningioma as a possible diagnosis. Lack of multiplicity makes intradural metastases less likely, but a solitary metastases is possible. Cauda equina schwannoma may be indistinguishable from a small ependymoma, as in this case.
Sturge-Weber
The constellation of findings seen in Sturge-Weber syndrome (also known as encephalotrigeminal angiomatosis) is due to a failed development of normal cortical veins. The brain findings are a manifestation of the resulting chronic venous ischemia, while the pial angiomatosis, facial port-wine stain (a capillary malformation classically in the trigeminal nerve first branch distribution), globe choroidal angioma, and choroid plexus enlargement are all due to attempted collateral drainage pathways. Buphthalmos (“ox eye”) is enlargement of the globe that develops in patients less than 3 years of age due to increased intraocular pressure; in these patients it is likely related to impaired aqueous humor drainage due to the choroidal angioma. Bilateral intracranial involvement is seen in up to 20% of cases. Clinical manifestations are typically related to seizures, hemiplegia, mental retardation, and cosmetic issues from the port-wine stain. Seizures may require hemispherectomy for treatment. Laser therapy may improve cosmetic appearance.
Chordoma
Chordomas are locally aggressive tumors of notochordal origin, found along the neural axis from the sella to the coccyx. Intracranial chordomas constitute 1/3 of lesions, usually within the vicinity of the clivus. Chordomas have peak prevalence in the 4th decade but can occur at any age. This example shows classic features of a bulky destructive mass, midline location, “thumbing” of the pons, T2 hyperintensity, and heterogeneous enhancement
Most common head and neck cancer
Squamous cell carcinoma (SCCa) is the most common sinonasal malignancy, 70% of which arise in the maxillary antrum. Although adenocarcinomas may originate in the paranasal sinuses, they have a predilection for the ethmoid sinuses and are rare in comparison with SCCa, accounting for < 20% of sinonasal neoplasms. Sinonasal lymphoma and melanoma are much less common than SCCa, and both have a predilection for originating in the nasal cavity rather than in the paranasal sinuses.
Spinal ependymoma
Look for the hemosiderin “cap” sign at the cranial &/or caudal margins of the lesion, which can be seen in 20-64% of cord ependymomas. A small focus of hemosiderin is seen in this case. There are 4 subtypes of intramedullary ependymomas: cellular (most common), papillary, clear cell, and tanycytic. Cellular ependymomas are more commonly cervical in location and tend to be multisegmental, as in this case. Fifty to 90% may have syrinx or polar tumoral cysts, such as the large superior cystic component seen in this case.
vertebral artery segments
The V4 segments are entirely intracranial, extending from the foramen magnum to the junction with the basilar artery. The segment from the C1 transverse foramen to the foramen magnum is the V3 segment. V2 is the vertebral artery segment contained within the transverse foramens of C6 to C3. V1 is the most proximal vertebral artery (VA) segment, arising from the subclavian artery and extending to the transverse foramen of C6.
Intra-cranial mass extending across the midline
Intraaxial, bihemispheric masses which cross the corpus callosum are classically glioblastoma multiforme (GBM), lymphoma, or tumefactive multiple sclerosis. A patient’s age and past medical history as well as associated features narrow the differential. For example, if the patient is young and MR shows other demyelinating lesions, think multiple sclerosis; if the patient is older and with a necrotic mass and ependymal spread, think glioblastoma; if the patient is immunosuppressed and with lymphopoietic abnormalities on labs, think lymphoma. It is important to remember that in GBM tumor cells may extend beyond the area of MR signal abnormality. Prognosis is very poor in GBM, with death in 9-12 months. Treatment includes biopsy/debulking followed by radiation and chemotherapy.
Pituitary Macroadenoma
Pituitary macroadenoma is a sellar/suprasellar mass without a separable identifiable pituitary gland. These are > 10mm in diameter and > 4cm are called “giant” adenomas. Most pituitary adenomas enhance strongly but heterogeneously. Saccular aneurysm arises from the artery and is usually eccentric and the normal pituitary gland is visible separate from the mass. Meningioma is an extra-axial, strongly enhancing mass with the pituitary gland visible separate from the mass. In pituitary hyperplasia the gland is usually < 10mm in size.
Spinal cord infarct
The vascular supply to the spinal cord is supplied by the vertebral arteries and 10 medullary arteries that arise from segmental branches of the aorta. These medullary arteries join to form the anterior and posterior spinal arteries. Compromise to the spinal cord blood supply may result if any of the medullary arteries are obstructed or injured (during abdominal surgery, for example). The pattern of resulting neurological damage differs according to whether the supply to the posterior or anterior artery is interrupted. Loss of the posterior supply generally leads to loss of sensory functions, whereas loss of the anterior supply more often causes motor deficits.
Dermoid cyst appearance
Epidermoid cysts, arachnoid cysts, and racemose neurocysticercosis cysts in the subarachnoid cisterns all resemble cerebrospinal fluid (CSF) on NECT scans. Dermoid cysts are hypodense but are fat-like, not CSF-like.
Optic neuritis
Optic neuritis
Acute optic neuritis is most common in younger adult women and typically presents with sudden vision loss. MR is the best imaging tool and shows abnormal T2 hyperintensity, as well as enhancement with minimal enlargement of the nerve.
Meckels Cave
The Meckel cave is largely filled with cerebrospinal fluid (CSF). The trigeminal nerve (CN5) and ganglion occupy only a small fraction of the total volume of Meckel cave. On coronal T2WIs, fascicles of the trigeminal nerve appear as dot-like filling defects in the CSF-filled ovoid structure. The trigeminal ganglion sits at the bottom of the cave and is a thin, semilunar-shaped structure that is isointense to brain.
Cavernous Malformation association ?
Cavernous malformations are often associated with developmental venous anomaly (DVA). In fact when a cavernous malformation presents as an acute intracranial hemorrhage the presence of an associated DVA is an important clue to the diagnosis.
Hyperdense dural sinus
If the patient has a normal hematocrit, all dural venous sinuses normally appear slightly hyperdense compared to adjacent brain parenchyma (physiologic hyperdensity) on NECT scans. Polycythemia makes ALL the cranial vessels (dural sinuses as well as veins and arteries) appear similarly dense. Carefully examine the shape of a suspect dural venous sinus. Normally, its walls are flat or slightly concave. If they appear bulging and convex outward, a clot may be present. Contrast-enhanced CT (looking for an “empty delta” sign) or CTA/CTV usually resolves the issue. Lastly, beware the acute peritentorial subdural hematoma (SDH) that layers along the straight sinus and tentorium. A small, thin peritentorial SDH can mimic dural sinus thrombosis, but the clot is on the outside (not the inside) of the sinuses. Coronal reformatted images are very helpful in detecting peritentorial SDHs and distinguishing them from the normal, slightly hyperdense dura and venous sinuses on NECT scans.
Giant cell tumour
Giant cell tumor (GCT)
lytic, expansile lesion centered in the posterior elements can be a GCT. There is no associated soft tissue mass, marginal sclerosis, or matrix within the mass, which fits with GCT. Between 10-15% of GCTs also have an aneurysmal bone cyst component, which probably accounts for the fluid-fluid levels seen in this case. Elements of aneurysmal bone cyst (ABC) were found in the resected surgical specimen.
Teaching Point
Giant cell tumors (GCT) can coexist with and be indistinguishable from aneurysmal bone cysts (ABC). Histologically-mixed GCT/ABC is seen in 10-15% of cases. GCTs are locally aggressive tumors with a 12-50% recurrence rate. These lesions can undergo sarcomatous transformation, spontaneously or in response to radiation therapy. Pulmonary metastatic implants occur in 1-2% of cases.
A solitary lytic, expansile vertebral body mass in a young adult that lacks a definite sclerotic margin or bony matrix is most consistent with a giant cell tumor.
Choroid plexus
Choroid plexus in the 4th ventricle extends anteroinferiorly through both lateral recesses and the foramina of Luschka. Choroid plexus lacks a blood-brain barrier and therefore enhances following contrast administration. The lobulated curvilinear lines of enhancement indicated by the are the choroid plexi in the lateral recesses of the 4th ventricle. Sometimes, as seen in this case, prominent tufts of enhancing choroid plexus can be seen in the lower cerebellopontine angle cisterns and should not be mistaken for pathology.
thalamostriate veins
These are the thalamostriate veins (TSVs). The TSVs are lateral structures that run between the caudate nuclei and thalami, coursing toward the foramen of Monro. They typically unite with the septal veins, seen as faint linear hyperdensities running along the frontal horns of the lateral ventricles on this image in the midline, to form the internal cerebral veins (ICVs). The ICVs are also seen on this image as the enhancing “dots” that lie medial to the TSVs. The ICVs are seen as the tubular enhancing midline structures that course posteriorly between the thalami. The ICVs are contained in the velum interpositum, which is a cerebrospinal fluid (CSF)-filled subarachnoid space that lies just above the 3rd ventricle between the fornices.
nodal differentiated thyroid carcinoma
The calcified level II and heterogeneously enhancing level III (Fig. 2) nodes with solid enhancing and cystic foci in the right internal jugular nodal chain are typical findings of nodal differentiated thyroid carcinoma (DTCa). This patient had undergone prior thyroidectomy with central compartment nodal dissection but presented with recurrent adenopathy. The first consideration in patients with calcified or mixed solid-enhancing and cystic nodes should be metastatic DTCa.
Cystic (or necrotic) lymph nodes are encountered in both DTCa and squamous cell carcinoma (SCCa), however SCCa adenopathy is very rarely calcified. Lymphoma rarely shows nodal calcification after therapy, but the nodes are usually large and homogeneous. Reactive nodes are not calcified or inhomogeneous.
ADEM
Acute disseminated encephalomyelitis (ADEM) is typically a monophasic illness, usually occurring after a viral infection or immunization. It is an autoimmune-mediated disorder that is generally self-limited. Enhancement varies from none to punctate, linear, or ring-like (usually incomplete, with the “open” or nonenhancing part of the ring next to the cortex). There is a fulminant, often fatal, variant of ADEM called acute hemorrhagic leukoencephalopathy (AHLE or Weston-Hurst disease) that causes multifocal brain hemorrhages that may be seen only on T2* scans (SWI is better than GRE).
Rathke cleft cysts
Rathke cleft cysts (RCC) are benign, epithelium-lined intra-/suprasellar cysts that are believed to originate from remnants of the Rathke pouch. Most are incidental and asymptomatic, but patients can present with pituitary dysfunction, visual disturbances, and headaches. The most common approach in the treatment of RCC is trans-sphenoidal surgery in which the cyst is partially excised and drained.
Colloid cyst
A mass wedged into foramen of Monro with pillars of the fornix straddling and draped around it and the posterior part of frontal horns splayed laterally around it is characteristic of a colloid cyst. About a 3rd of colloid cysts are iso- or hypodense on NECT.
Medulloblastoma
Medulloblastomas are rare in adults, but this case illustrates a round, dense, highly cellular mass arising in the midline within the 4th ventricle (indicated by the ), all features typical of a medulloblastoma. Atypical teratoid/rhabdoid tumor can appear very similar on imaging but is most common in very young children (< 3 years of age). Hemangioblastoma usually occurs along the pial surface of the cerebellum and often has a cyst with an enhancing mural nodule. Subependymoma frequently occurs in the 4th ventricle, often in older patients, and enhancement would be unusual.
Subacute subdural hematomas
Subacute subdural hematomas are typically hyperintense on T1 MR in both early and late subacute stages due to the presence of methemoglobin. Contrast-enhanced CT or MR may show enhancing membranes. The presence of enhancing membranes suggests unstable subdural hematomas that are prone to rehemorrhage. On a noncontrast CT, subacute subdural hematoma is often of the same density as the underlying cortex. Cortical vessels in the subarachnoid space are displaced medially by any subdural collection.
CNS cryptococcal infection
CNS cryptococcal infection takes 3 main forms: Meningitis, gelatinous pseudocysts, and focal mass lesions called cryptococcomas. Cryptococcomas and meningitis are the most common forms in immunocompetent patients, whereas meningitis and gelatinous pseudocysts are the most common forms in HIV/AIDS patients. This patient has classic gelatinous pseudocysts, seen here as multiple nonenhancing cysts in the midbrain and basal ganglia.
pilocytic astrocytomas
A characteristic of neurofibromatosis type 1 (NF1) is development of gliomas, especially optic pathway gliomas (OPGs). Most OPGs are pilocytic astrocytomas, a World Health Organization (WHO) grade I neoplasm. Other gliomas may develop in the posterior fossa/brainstem, basal ganglia, and cerebral hemispheres. Less than 20% of gliomas in the setting of NF1 are frankly malignant, although they do occur. There is a variant of pilocytic astrocytoma (PA) called pilomyxoid astrocytoma that is histologically and biologically more aggressive. When a lesion such as this one that looks grossly like a PA hemorrhages or grows rapidly, especially if it is in very young patients (including infants), this variant should be suspected. The histologic diagnosis in this case was pilomyxoid variant of pilocytic astrocytoma.
Closed lip vs open lip schizencephaly
Gray matter-lined clefts are isointense to cortical gray matter on all MR sequences, although distinction of a gray matter-lined cleft can be difficult prior to myelination. “Closed-lip” schizencephaly contains an irregular tract of gray matter extending from the cortical surface to the ventricle, and the lining gray matter can appear dysplastic. “Open-lip” schizencephaly can be wide and wedge-shaped or with nearly parallel walls, and the gray matter-lined cleft may be harder to discern than in “closed-lip.” Developmental delay, paresis, microcephaly, and spasticity is more common with bilateral, whereas seizures are more common with unilateral.
Petrous apex cholesterol granuloma
Petrous apex cholesterol granuloma
Correct: T1 and T2 hyperintensity within an expansile lesion of the petrous apex is typical for cholesterol granuloma.
Teaching Point
The petrous apex lesion that is expansile with T1-T2 “high-high” signal is an imaging classic that tends to show up on radiology, as well as ears, nose, throat (ENT) certifying examinations.
Petrous apex cholesterol granuloma
Petrous apex cholesterol granuloma
Correct: T1 and T2 hyperintensity within an expansile lesion of the petrous apex is typical for cholesterol granuloma.
Teaching Point
The petrous apex lesion that is expansile with T1-T2 “high-high” signal is an imaging classic that tends to show up on radiology, as well as ears, nose, throat (ENT) certifying examinations.
classic developmental venous anomaly appearance
The large tubular enhancing structure with a “medusa head” appearance is a classic developmental venous anomaly (DVA). DVAs are often associated with cavernous malformations, and their detection is important prior to resection of cavernous malformations as they provide normal venous drainage to the surrounding tissue. GRE (Fig. 4) shows hemosiderin staining adjacent to the right aspect of the 4th ventricle, which relates to a site of old resection of a cavernous malformation.
Acute hypertensive encephalopathy, PRES
Acute hypertensive encephalopathy, PRES
The history and posterior circulation distribution of patchy cortical and subcortical hypodensity and MR FLAIR/T2 hyperintensity are classic for posterior reversible encephalopathy syndrome (PRES). Usually there is a supportive history, such as immunosuppressants (this case), pre-eclampsia, uremia, or drug toxicity, including recreational drugs like cocaine. PRES can almost look like anything, with a myriad of distributions (including deep gray matter), restricted diffusion, hemorrhage, and even enhancement. Keep it in the back of your differential pocket at all times. Also, remember that in children, blood pressure may be normal or only slightly elevated.
Teaching Point
Patchy bilateral low density foci in the occipital lobes may be the earliest manifestation of acute hypertensive encephalopathy (PRES), though it can manifest almost anywhere in the brain and have atypical features, such as ischemia on diffusion imaging or hemorrhage on gradient or susceptibility imaging. Ischemia is the major differential, but often history and distribution will support PRES.
Plexiform neurofibromas
Bilateral plexiform neurofibromas are present at almost every visualized spinal level with extramedullary tumors that enlarge the neural foramina. Plexiform neurofibromas are pathognomonic of neurofibromatosis type 1.
Chiari spells
This patient’s symptoms are suggestive of “Chiari spells” in which coughing or sneezing increases intrathecal pressure due to obstructed cerebrospinal fluid (CSF) flow and results in headaches or syncope. In Chiari 1 malformation, the cerebellar tonsils are pointed and extend >/= 5 mm below the foramen magnum . Chiari 1 malformation may be associated with syringohydromyelia, low/tethered cord; hence, imaging of the entire spine is indicated. Syringohydromyelia of the cervical cord is partially visualized on this sagittal image of the brain. Further imaging is needed as the inferior extent of the syrinx is not delineated by this brain MR alone.
Pars flaccida vs pars tensa cholesteatoma
As pars flaccida cholesteatoma enlarges, it most commonly spreads superiorly into the lateral epitympanic recess, gradually filling the superior mesotympanum and the epitympanum. As it does so, the cholesteatoma erodes the scutum and ossicles. With further enlargement, dehiscence of the lateral semicircular canal and tegmen tympani (roof of the middle ear) may be seen with or without erosion of the tympanic portion of the facial nerve canal as it passes under the lateral semicircular canal. The tympanic annulus , which is the site of attachment of the inferior margin of the tympanic membrane, is not affected by pars flaccida cholesteatoma.
The pars flaccida cholesteatoma originates in the Prussak space and usually extends posteriorly, while the pars tensa cholesteatoma originates in the posterior mesotympanum and tends to extend posteromedially.
Conventional non-contrast MR imaging with diffusion-weighted imaging is recommended in all patients with suspected cholesteatoma.
trigeminal nerve (CN5) emerges from
The cisternal segment of the trigeminal nerve (CN5) emerges from the lateral pons at the root entry zone (REZ). It courses anterosuperiorly through the prepontine cistern. It enters the middle cranial fossa by passing beneath tentorium at the apex of the petrous temporal bone. It then passes through an opening in the dura matter called porus trigeminus to enter Meckel cave.
Choroid plexus papilloma
Classic for a choroid plexus papilloma. Choroid plexus papilloma occurs in the lateral ventricle in young children (usually less than 5 years of age). Hydrocephalus is often present either due to obstruction or overproduction of cerebrospinal fluid.
Dandy-Walker malformation
Dandy-Walker malformation is considered a spectrum of malformation that ranges from “mega cisterna magna” (the mildest form) to a “classic” Dandy-Walker continuum in which cystic dilatation of the 4th ventricle communicates dorsally with a variably-sized posterior fossa cyst. The sinus confluence (“torcular Herophili”) and tentorium are markedly elevated and displaced above the lambdoid suture, a condition termed “lambdoid-torcular inversion.”
Causes for enlarged and enhancing optic nerve
The enhancement in this case corresponds precisely to a mildly enlarged optic nerve . Involvement of the nerve itself suggests an inflammatory process, such as idiopathic inflammation (pseudotumor) or acute optic neuritis related to multiple sclerosis; or possibly a neoplastic process, such as optic pathway glioma.
By contrast, optic nerve sheath meningioma, as the name suggests, involves the dural sheath, rather than the nerve itself. A meningioma would be distinquishable as enhancement surrounding the nerve, not within the nerve.
The superficial middle cerebral vein (SMCV)
The superficial middle cerebral vein (SMCV) is 1 of the 3 named anastomotic superficial cortical veins. It courses anteriorly and inferiorly from the lateral sylvian fissure, curving around the anterior temporal lobe and draining into the cavernous sinus. The SMCV is rarely occluded by venous thrombosis but can provide an important route for collateral venous drainage if multiple dural venous sinuses become occluded. The basal vein of Rosenthal curves around the midbrain (not the anterior temporal lobe) and the vein of Labbe courses posteriorly from the lateral cerebral (sylvian) fissure and terminates in the transverse sinus, not the cavernous sinus.
Tuberous sclerosis - findings?
Tuberous sclerosis is an inherited tumor disorder with multiorgan hamartomas. It commonly presents with the clinical triad of facial angiofibromas (90%), mental retardation (50-80%), and seizures (80-90%). Intracranial findings include calcified subependymal nodules, subependymal giant cell astrocytoma (typically located at foramen of Monro), cortical/subcortical tubers, and white matter radial migration lines. Associated systemic abnormalities can involve the kidneys (angiomyolipoma and cysts), heart (rhabdomyomas), lungs (cystic lymphangiomyomatosis/fibrosis), solid organs (adenomas, leiomyomas), skin (ash-leaf spots, facial angiofibromas, shagreen patches), and extremities (subungual fibromas, cystic bone lesions, undulating periosteal new bone formation).
Head and neck cancer in elderly
Squamous cell carcinoma (SCCa) is the most common sinonasal malignancy, 70% of which arise in the maxillary antrum. Although adenocarcinomas may originate in the paranasal sinuses, they have a predilection for the ethmoid sinuses and are rare in comparison with SCCa, accounting for < 20% of sinonasal neoplasms. Sinonasal lymphoma and melanoma are much less common than SCCa, and both have a predilection for originating in the nasal cavity rather than in the paranasal sinuses.
Acute optic neuritis (ANO)
Acute optic neuritis (ANO), as demonstrated on the left in this patient , is strongly associated with new onset demyelinating disease. Up to half of patients with ANO will develop multiple sclerosis; this risk is even higher in women. Acute vision loss with eye pain is the typical presentation of ANO. The majority of patients recover their vision spontaneously, although this recovery can be accelerated by the administration of steroids. Neuromyelitis optica (NMO) is an autoimmune demyelinating disease that is characterized by optic neuritis and spinal cord involvement; NMO is distinct from multiple sclerosis and is characterized by the presence of autoantibodies to the cellular water channel protein aquaporin-4. Orbital pain is common in ANO.
Mycetoma
The diagnosis in this case was mycetoma (fungus ball), a noninvasive form of fungal sinusitis. Mycetomas are typically indolent lesions presenting with few symptoms and are most often found in older adults. In this case, the maxillary sinus location, opacification of the sinus, wall thickening (chronic osteitis) , and the presence of calcifications are features suggestive of a mycetoma.
Nonfungal chronic rhinosinusitis could have a similar appearance; however, calcifications are much more often seen with mycetoma. The ossifying fibroma usually presents in the 20-40 age group, is expansile, and shows areas of dense ossification rather than punctate calcification. Inverted papillomas typically originate in the nasal cavity near the middle meatus and are more mass-like. Calcification is unusual in inverted papillomas, occurring in about 10% of lesions. Although esthesioneuroblastoma could occur in this age group, they characteristically arise in the superior nasal cavity near the cribriform plate and present with symptoms of nasal obstruction and bleeding.
Ameloblastoma
Ameloblastoma is the most common odontogenic tumor (35%). Its classic imaging description is a “bubbly,” multilocular, mixed cystic-solid mass in posterior mandibular ramus associated with unerupted 3rd molar tooth. Larger dentigerous cyst and keratocystic odontogenic tumor are most difficult to differentiate from ameloblastoma. The key imaging differential feature is the presence of nodular enhancement in ameloblastoma. Dentigerous cyst and keratocystic odontogenic tumor do not as a rule have nodular enhancing components.
Orbital lymphoma
Lymphoproliferative disease of the orbit includes a spectrum that ranges from polyclonal reactive disease to overt lymphoma, with mucosa-associated lymphoid tissue (MALT) representing a frequently seen extranodal marginal zone variant. Orbital lymphoma is characteristically very responsive to radiation; thus, surgical excision is usually not necessary, and only biopsy is needed to confirm the diagnosis. As with lymphoma elsewhere in the body, strong uniform enhancement is typical in the orbit. Lacrimal gland involvement is common in orbital lymphoma.
Pineal cysts
Pineal cysts are common incidental findings, seen in over half of all children and 25% of healthy adults on 3T MR. They are identified in 40% of autopsies. Density and signal intensity vary with cyst contents. Calcification is common. Enhancement is nonspecific as the pineal gland parenchyma lacks a blood-brain barrier and normally enhances following contrast administration. This multicystic pineal gland is a normal variant. Pineocytomas are very slow-growing, benign pineal parenchymal tumors that are often partially cystic and can increase in size over time. While pineocytomas and pineal cysts can appear identical on imaging studies, nonneoplastic pineal cysts are much more common than pineal neoplasms. Therefore, the most likely cause for the multiple pineal cysts seen in this case is normal variant.
Vein of Labbe
vein of Labbe, a named cortical vein that courses posterolaterally from the sylvian fissure to drain into the transverse sinus. When it is prominent, its drainage territory is large. Thrombosis of a transverse sinus that extends into the vein of Labbe can cause an extensive venous infarct of the posterior temporal lobe. The internal cerebral veins lie above the level of the vein of Labbe and are seen here as the sinusoidal veins that empty into the vein of Galen (which continues into the straight sinus).
Perimesencephalic nonaneurysmal subarachnoid hemorrhage
Perimesencephalic nonaneurysmal subarachnoid hemorrhage (pnSAH)
Correct: The concentration of blood in front of the pons and around the midbrain with relative sparing of the suprasellar cistern and lateral sylvian fissures is most consistent with this diagnosis.
Perimesencephalic nonaneurysmal subarachnoid hemorrhage (pnSAH) is very different from aneurysmal subarachnoid hemorrhage (aSAH). It is not caused by rupture of a saccular aneurysm and is thought to be secondary to a ruptured vein around the midbrain. These patients do not develop vasospasm and do not recur. Once a basilar tip aneurysm (which can rarely cause this type of perimesencephalic hemorrhage) has been ruled out (typically by CTA), the diagnosis of pnSAH can be established.
Optic nerve glioma vs optic nerve sheath meningioma
The presence of calcification, especially “tram-track” calcification, would be highly suggestive of an optic nerve sheath meningioma (ONSM); optic pathway glioma (OPG) does not calcify. Age and gender would also be useful discriminators, as OPG typically presents during childhood, whereas ONSM is usually seen in middle-aged and elderly women. Neurofibromatosis (NF), if present, would also be diagnostically useful: NF type 1 would favor OPG, whereas NF type 2 would point toward ONSM. Neither OPG nor ONSM typically presents with pain; rather, either may present with vision loss or mass effect. At surgery, this lesion was found to be meningioma.
Sickle cell disease findings
Sickle cell disease spine complications result from hyperplastic marrow, iron deposition, osteopenia, and bone ischemia. Both H-shaped vertebra and serpiginous hyperintensity in the vertebral bodies are features of bone ischemia. The hypointense marrow can relate to hyperplastic marrow or iron deposition. Posterior element ankylosis would be a feature of juvenile inflammatory arthritis.
HTN microheamorrhages vs Amyloid
Microhemorrhages are seen as small signal intensity loss on T2*-weighted gradient-echo images because of magnetic susceptibility effect. History and distribution help differentiate cerebral amyloid disease and chronic hypertension with hypertensive microhemorrhages, the latter predominantly in the deep gray matter, pons, and cerebellum. However, both amyloid and hypertensive-related microhemorrhages can coexist.
Retrotympanic mass differentials
The color and location of a retrotympanic mass on otoscopy is very helpful in its identification: an anteroinferior red mass is probably a glomus tympanicum; a red mass that crosses the tympanic membrane from posterior to anterior is likely an aberrant internal carotid artery (ICA); a blue mass posteriorly is probably a dehiscent jugular bulb; a white mass located inferiorly suggests congenital cholesteatoma; a white mass located superiorly is suspicious for a facial nerve schwannoma.
Pineocytoma appearance?
Pineocytomas are typically less than 3 cm, cystic change may be present, and avid enhancement is typical. Pineocytoma may be cystic and mimic pineal cyst. They are rarely invasive. Pineocytoma may compress adjacent structures, including the aqueduct that results in obstructive hydrocephalus. Most common signs/symptoms include headache and Parinaud syndrome (paralysis of upward gaze). Surgical excision or stereotactic biopsy may be performed if symptomatic or when diagnosis is in doubt.
Bilateral thalamic infarcts cause?
The artery of Percheron is a rare variant of the posterior cerebral circulation. It is a solitary arterial trunk arising from one of the P1 segments of either posterior cerebral artery and supplies the paramedian thalami and the rostral midbrain bilaterally. Recurrent artery of Huebner is a branch from the anterior cerebral artery typically from the proximal A2 segment or distal A1 segment and supplies the anteromedial caudate nucleus and the anterioinferior section of the internal capsule, as well as parts of the putamen.
Primary CNS lymphoma
Over 95% of primary CNS lymphoma (PCNSL) contact a CSF surface, either the ventricular ependyma or pia. Lesions are often deep-seated with a predilection for the periventricular white matter, especially the corpus callosum. In immunocompetent patients, PCNSL shows restricted diffusion and strong homogenous enhancement . Glioblastoma typically shows peripheral ring enhancement, necrosis, and hemorrhage. Abscesses typically show ring enhancement with a central cavity showing restricted diffusion. Metastasis are often multiple, heterogeneous, and have extensive surrounding edema.
The most common causes of multiple dural-based masses are meningioma and metastases. Neurosarcoid can involve virtually any intracranial structure, including the dura, where it can present as a solitary or multiple lesion. Extramedullary hematopoiesis is typically found in patients with chronic anemias or marrow depletion disorders. Langerhans cell histiocytosis (LCH) is a great mimicker in the brain and can look like virtually anything. The infundibular stalk is a common site, and LCH often has skull and scalp lesions associated with dural-based masses. Secondary (metastatic) lymphoma often involves the skull and dura, but primary CNS lymphoma, which is the correct answer to this question, rarely arises from the dura. Primary CNS lymphoma typically is a parenchymal disease. Basal ganglia and deep (periventricular) white matter are the most common sites.
Osteoblastoma
Osteoblastomas can occur at any age but most frequently occur in patients between 10-30 years old. Osteoblastoma is an expansile lytic lesion. There is a wide spectrum of internal calcification or ossification. It arises in the posterior elements and most commonly in the thoracic and lumbar spine. Painful scoliosis may be seen in patients with osteoblastoma.
Without radiographs or CT, this MR-only imaging is challenging. However, the patient’s age (15 years) and history (painful scoliosis) are very helpful. Osteoblastoma should always be considered in the differential diagnosis of a posterior element mass causing painful scoliosis. In this case, the lesion is larger than 1.5 cm, which by definition excludes the diagnosis of osteoid osteoma.
PRES
Thalamic involvement typically occurs in posterior reversible encephalopathy syndrome (PRES) patients who also have classic symmetrical parietooccipital T2 hyperintensity. Thalamic lesions are often bilateral but not necessarily symmetrical. Diffusion restriction and enhancement following contrast administration are atypical but occasional findings in PRES.
The brainstem and bi-thalamic involvement in this patient is more striking than the subtle occipital lesions. In a few cases, involvement of the brainstem and cerebellum may be the only manifestations of posterior reversible encephalopathy syndrome (PRES). In this case, the occipital involvement makes the diagnosis of PRES most likely. Phoning the emergency room (ER) and obtaining additional history (in this case, the patient was eclamptic) is helpful.
DNET
A dysembryoplastic neuroepithelial tumor (DNET) is classically a well-demarcated, micro- or macrolobular intracortical mass found in a young patient with longstanding partial seizures. It is commonly found in the temporal lobe and has minimal or no mass effect relative to its size. Atypical features, such as enhancement, may represent a predilection for recurrence or should suggest a possible alternative diagnosis.
Craniopharyngioma
Craniopharyngioma is a benign and often partially cystic sellar region tumor derived from Rathke pouch epithelium. There are 2 types: The adamantinomatous type occurs more frequently in children (peak at 5-15 years) and is typically cystic, whereas the papillary type occurs more commonly in adults (> 50 years) and is more solid. Remember the rule of 90%: 90% are cystic, 90% are calcified, and 90% enhance. Germinoma is primarily seen in young patients (90% of patients < 20 years). Epidermoid would show restricted diffusion and no enhancement.
Oligodendroglioma
Oligodendroglioma
The calcification, involvement of both cortex and subcortical white matter, patient age, and symptoms are most consistent with this diagnosis. About half of oligodendrogliomas show no enhancement.
Teaching Point
The most important criteria in assessing oligodendroglioma is not what it looks like on imaging or even histology, it’s the tumor genetics. If the tumor exhibits 1p19q deletion, the tumor is chemosensitive and the prognosis is relatively more favorable
glomus vagale paraganglioma
This lesion is located in the carotid space and has caused anteromedial internal carotid artery displacement . Intratumoral flow voids make the diagnosis of paraganglioma. There are also significant arterial flow voids seen just inferior to the mass . A paraganglioma centered just below the skull base but above the carotid bifurcation in the nasopharyngeal aspect of the carotid space is termed glomus vagale paraganglioma because it arises from glomus bodies in the vagal nodose ganglion.
Paragangliomas are named based on their anatomic location. Carotid body tumor is a paraganglioma centered in the carotid bifurcation. Glomus tympanicum paraganglioma is centered on the cochlear promontory in the middle ear. Glomus jugulare paraganglioma is centered in the jugular foramen of the skull base.
Guillain-Barre syndrome
Guillain-Barre syndrome (GBS) is an autoimmune post-infectious or post-vaccinial acute inflammatory demyelination of peripheral nerves, nerve roots, and cranial nerves. Intrathecal and extraforaminal nerve root enhancement can be seen in the acute and chronic polyneuropathies. GBS may actually be the 1st presentation of a chronic or hereditary disorder.
Arteriovenous malformation (AVM)
Correct: The CT angiogram appearance is classic for an AVM with a tangle of enlarged feeding vessels/nidus and an enlarged draining vein. In this case, no definite associated aneurysm is seen, but it may be too small to see and/or obliterated from acute blood, only to be seen on digital subtraction angiographic imaging. Even if a vascular malformation is not seen on CT or MR angiography in the setting of an intraparenchymal hematoma, it is still in the differential since it may be obscured by the hemorrhage.
Teaching Point
Fifteen percent of arteriovenous malformations (AVMs) are infratentorial. In a young patient, a spontaneous cerebellar hemorrhage is unlikely to be hypertensive and is most likely secondary to a vascular malformation. An AVM, cavernous malformation, or dural arteriovenous fistula with cortical venous drainage are the most common culprits.
Ewings vs Osteosarcoma
Ewing sarcoma may elicit reactive bone formation within the involved bone, which may appear similar to tumor osteoid. This bone formation may suggest the diagnosis of Ewing sarcoma versus osteosarcoma. However, it is important to remember that reactive bone formation does NOT occur in the soft tissues. If there is soft tissue mass containing amorphous bone formation, the diagnosis must be osteosarcoma.
ATFL
The structure is the anterior talofibular ligament (ATFL). The ATFL reportedly is the most commonly torn ligament in the human body and is usually injured in the setting of any significant ankle sprain. It is so often disrupted that it is unusual to see it this well. Of note: When the ATFL is in view, the lower portion of the talus, which is irregularly shaped as in the current case, will be present on the image. If the upper talus, which is square, is in view, then the ligament is usually the anterior inferior tibiofibular ligament.
Spine lesions
posterior elements vs vertebral body
When considering lesions arising in the osseous elements of the spine, it can be useful to divide lesions into those that predominantly involve the posterior elements (osteoblastoma, aneurysmal bone cyst, osteoid osteoma, myeloma, metastases) and those that predominantly involve the vertebral body (chordoma, giant cell tumor, Langerhans cell histiocytosis, Ewing sarcoma, lymphoma, metastases, myeloma). This can be a good starting point for discussion of the differential diagnosis.
Undifferentiated pleomorphic sarcoma
Undifferentiated pleomorphic sarcoma (formerly known as malignant fibrous histiocytoma) is a very common lesion in the adult population. With no specificity to its appearance, it should be considered in most cases of an aggressive soft tissue mass, though the most common site is in the deep soft tissues of the thigh.
Stroke findings
Core vs penumbra
CORE = increased MTT or TMax
Reduced CBF and CBV
PENUMBRA = Increased MTT or TMax
Reduced CBF
Normal or increased CBV due to vasodilation
