Random_2 Flashcards
DDx for terminal ileal tumor
- carcinoid tumor (top differential)
- lymphoma
- adenocarcinoma
- GIST
- metastatic disease
Carcinoid tumor
- most common small bowel neoplasm
- small mass in the small bowel, but with large mesenteric mass that demonstrates desmoplastic reactions and calcifications
- when mets to the liver - carcinoid syndrome
- carcinoid liver mets are hypervascular - need biphasic liver CT (enhances avidly during arterial phase)
Buzz word for small bowel lymphoma
- involves long segment of the sb
- aneurysmal dilatation
- no obstruction!
NOTE: adenocarcinoma of the sb often causes obstruction!
When you see a large mass in the abdomen that you don’t know where it is arising from
- soft tissue sarcoma (NOS)
- GIST
- lymphoma
- desmoid tumor
Groove pancreatitis
- ectopic pancreatic tissue/ducts trapped in the duodenal wall
- can manifest as duodenitis/pancreatitis
- involves the medial duodenal wall +/- pancreatic head
- MR - T2 hyperintense cystic structures within the duodenal wall
Dx for proximal stomach fold thickening?
Menetrier’s disease
- hypersecretory gastritis
- mostly middle aged men
- thickened rugae in the proximal stomach - fundus and prixmal body
- epigastric pain, hypoalbuminemia secondary to loss of albumin into the stomach lumen, and protein losing enteropathy; peripheral edema
Thorotrast
- used as contrast agent in the 1930 - 1950s
- alpha-emitter - biological half life is 400 years
- colloidal thorium dioxide deposits in the liver, spleen, lymph nodes –> metal density of liver and spleen; splenic infarction
- hepatic dose in 20 years is 1000-3000 rads, can lead to angiosarcomas (hemangioendotheliomas) of the liver, cholangiocarcinoma, HCC
DDx for splenic auto-infarction
- sickle cell disease
- Thorotrast
Splenic/hepatic calcifications
- curvilinear - aneurysm, calcified cyst
- multi-nodular - phleboliths, hemangiomata, TB, histo, PCP
- solitary, large - healed infarct, old hematoma, PCP, abscess
- shrunken spleen - sickle cell disease, Thorotrast
Space of Retzius
- retropubic space
- extraperitoneal space
Urachus
- urachus is a fibrous remnant of the allantois, a canal that drains the fetal urinary bladder that joins and runs within the umbilical cord
- normally regress, becomes “median umbilical ligament”
- within the space of Retzius
- spectrum of urachal remnants
- cyst
- sinus
- fistula
- diverticulum
- neoplasm - adenocarcinoma*, teratoma, lipoma
Giant fibroepithelial esophageal polyp
- giant polyp
- connected on a long thin stalk
- may regurgitate into the mouth, and may cause massive hemorrhage, aspiration and sudden death if bit on
- DDx
- leiomyoma
- lipoma
- pseudosarcoma
Appearance of sclerosing cholangitis
- “pruning” appearance
- beaded appearance, areas of stricturing
- causes of sclerosing cholangitis
- primary sclerosing cholangitis - most pts with PSC will have IBD, but only a small portion of IBD pts will have PSC
- post liver transplant - hepatic artery stenosis and thrombosis, chronic rejection
- sequelae of TACE
- HIV cholangiopathy
Blood supply to the bile ducts
Bile ducts solely rely on hepatic arteris
Primary biliary cirrhosis
PBC
- centered at tiny cholangioles
- present as cirrhosis
- pathologic diagnosis
- not seen on radiologic studies
- unlike PSC - radiologic dx
Appearance of hepatic abscess
usually has ill-defined margins with perilesional edema
Biliary cystadenoma
- middle aged women
- cystic neoplasms that may be unilocular or multilocular
- calcifications of septa or cyst wall may be seen
- low malignant potential
How to confirm gossypiboma?
Order an X-ray to confirm
Involucrum
Sequestrum
Cloacae formation
- Involucrum - cloak of laminated / spiculated periosteal reaction; layer of living bone that has formed around dead bone / sequestrum
- Sequestrum - detached necrotic cortical bone
- Cloacae formation - space in which the dead bone resides; opening in the involucrum or cortex which sequestrum or granulation tissue may be discharged
Brodie abscess
A Brodie abscess is a subacute osteomyelitis, which may persist for years before converting to a frank osteomyelitis. Classically, this may present after conversion as a draining abscess extending from the tibia out through the shin.
Last place for bone marrow conversion from red marrow to yellow marrow in the tibia?
Proximal metaphysis
What is most important history to get when reporting MSK MR, besides patient’s presenting symptoms?
Previous surgery or not?
To quality meniscal tear
- linear or globular areas of increased signal
- extends to the articular surface
- on at least 2 consecutive images
Grading system for meniscal tear
- Grade 1 - small lobular areas of increased signal within the central portion of the meniscus as demonstrated on sagittal or coronal portion PD or T1WI - no clinical signifiance
- Grade 2 - signal abnormalities represent linear or globular increased signal in the central portion of the meniscus, which does not reach an articular surface - low association with meniscal tear
- Grade 3 - increased signal within the eniscus that comes in contact with either the superior or inferior articular surface on at least 2 consecutive images - direct MR evidence of tear. NOTE: meniscal tears may be inapparent on T2WI unless there is a fluid-like signal within the linear defects. Also NOTE: normal finding of a linear transverse intermediate signal line in the peripheral third of the meniscus that extends to the peripheral margin - tenuous meniscal blood supply - child and young adults
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Liver anatomy
- Functional division of the functional right and left lobes is by the middle hepatic vein (same plane as the IVC and gallbladder); devision between segments IVa/IVb and segments V/VIII.
- Anatomic division of the anatomic right and left lobes is by the falciform ligament; division between segments II/III and segments IVa/IVb.
Pleural malignancy
- most common malignancy that affects the pleura is metastatic disease
- lung - 40%
- breast - 20%
- lymphoma - 10%
When to suspect pleural malignancy/metastatic dz
- circumferential or nodular pleural thickening
- involvment of the mediastinal pleura
- pleural thickening greater than 1cm
Key finding of calyceal diverticulum
- Contrast fills calyceal diverticulum on CT and IVP
- CT demonstrates a low attenuating corticomedullary cystic lesion with layering contrast on delayed imaging. Milk of calcium may or may not be present.
- Ultrasound demonstrates a round, thin walled, anechoic lesion with increased through transmission. Echogenic material may layer dependently, if present.
- A peripelvic cyst appears similar except it will not fill with contrast at any time during imaging.
Components of the lateral collateral ligament complex
- iliotibial band
- fibular collateral ligament
- biceps femoris tendon
Deep fibers of the MCL blends into the medial meniscus
4 signs of ACL/PCL tear
- swelling
- increased signal
- fiber discontinuity
- change in expected course of the ligament
- normal orientation of the ACL is more vertical than the femoral intercondylar notch roof
- a line drawn tangent to the posterior margin of the descending limb intersects the distal tibia - if not, ACL tear (due to anterior tibial translation)
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Natalizumab
(Tysabri)
- monoclonal ab therapy as Rx for refractory MS and Crohn’s disease
- immunosuppressive therapy puts patient has increased risk of developing progressive multifocal leukoencephalopathy/PML - JC virus
- PML - an area of confluent T2 hyperintensity in the supratentorial white matter WITHOUT associated mass effect or enhancement
Immune reconstitution inflammatory syndrome
IRIS
Inflammatory PML
- HIV pts who undergo immune reconstitution after commencing HAART; or MS pts who discontinue natalizumab/Tysabri
- aggressive and often destruction immune response that affects many organ systems
- in the setting of MS pts who were on Tysabri, who developed PML
- PML –> inflammatory PML
- imaging characteristics differ from classic PML
- mass effective
- vasogenic edema
- enhancement
Facetious
Treating serious issues with deliberately inappropriate humor; flippant.
Pitfalls involving the posterior horn of the lateral meniscus
- meniscofemoral ligament insertion
- pulsation of the popliteal artery
- magic angle effect
- popliteus tendon
Nebulous
Adjective
In the form of a cloud or haze; hazy.
(of an idea) Unclear, vague, or ill-defined.
3 types of carpal coalition
e.g. lunotriquetral coaltion
- osseous - most common
- fibrous
- cartilaginous
3 different fat pads in the knee
- Hoffa’s fat pad (infrapatellar fat pad)
- suprapatellar fat pad
- prefemoral fat pad
DDx for well corticated erosions in the joint
- PVNS
- amyloid
- gout
Penchant
Noun
A strong or habitual liking for something or tendency to do something.
Synonyms
inclination - tendency - leaning - liking - propensity
Lytic lesions that cross a joint space
- inflammation
- infection
- trauma
- malignancy
Maligancies that cross a joint space
- lymphoma
- chondrosarcoma
- chordoma
- multiple myeloma
- metastasis
What blood test can you do to diagnose carcinoid syndrome?
5-HIAA test
5-Hydroxyindoleacetic Acid
DDx for intra-articular masses
- non-infectious synovial proliferative process
- lipoma arborescens
- synovial osteochondromatosis
- PVNS
- RA
- infectious granulomatous disease
- TB
- cocci
- deposition disorders
- gout
- amyloid
- vascular malformations
- synovial hemangioma
- AVM
- malignancies
- synovial chondrosarcoma
- synovial sarcoma
- synovial metastases
- miscellaneous
- cyclops lesion
Airway manifestation of warfarin toxicity
Warfarin-induced tracheobronchial calcification
Warfarin alters vitamin K metabolism, which is crucial in preventing calcification of cartilage and connective tissue
e.g., warfarin in newborns - punctate foci of ossifications in the noncalcified cartilage
How to differentiate warfarin-induced tracheobronchial calcification from other causes of tracheobronchial calcification?
- Warfarin induced tracheobronchial calcification - distal cartilaginous rings
- Other causes - proximal cartilaginous rings
- elderly patients (senile calcificiation)
- TB infection
- congenital syndromes and cardiovascular anomalies
- adrenogenital syndrome
- chondrodysplasia punctata
- other bone dysplasias
Classic imaging findings of NF-1
von Recklinghausen disease
- plexiform neurofibromas
- dural ectasia
- sphenoid bone dysplasia
- thoracic scoliosis
- subcutaneous neurofibromas
How to differentiate periportal edema from intrahepatic biliary duct dilatation?
- Periportal edema - periportal lymphatic usually surround either side of the portal triad
- Intrahepatic biliary duct dilatation - bile duct lies on one side of the portal vein
Causes of periportal edema
- aggressive fluid resuscitation
- intrahepatic congestion - may be due to cardiac failure
- acute hepatitis
- ascending cholangitis
- liver transplantation
- hepatic metastasis/lymphoma
Causes of pneumomediastinum in the setting of blunt trauma
- alveolar rupture (Macklin effect - alveolar rupture - air dissecting along the bronchovascular bundles into the mediastinum)
- pneumothorax
- trachobronchial injury
- air dissecting from above - fracture of the paranasal sinuses
- air dissecting from below - intraperitoneal and extraperitoneal air
Hamate fracture
- rare
- fracture fragment projecting over the distal carpal row on lateral image
- v.s. triquetral fracture - fragment projecting over the proximal carpal row
- 2 types
- type I - hook fracture
- type II - body fracture
Hamate fracture
Pneumomediastinum
Hanged vs Hung
Hanged, as a past tense and a past participle of hang, is used in the sense of “to put to death by hanging,” as in Frontier courts hanged many a prisoner after a summary trial. A majority of the Usage Panel objects to hung used in this sense.
In all other senses of the word, hung is the preferred form as past tense and past participle, as in I hung my child’s picture above my desk.
Xray appearance of congenital heart disease
- boot heart - tetralogy of fallot
- box heart - ebstein malformation
- egg on a string - transposition of great vessels
- goose neck - endocardial cushion defect
Fallen fragment sign
Unicameral bone cyst
UBC
Bone-in-bone appearance
- osteopotrosis
- Thorotrast injection in childhood
Hide-bound appearance of the bowel folds
Hide-bound appearance of bowel folds depsite adequate distention
seen in scleroderma
lHow to describe an ICA aneurysm
- infra-clinoid
- para-clinoid
- supra-clinoid
- distal ICA
- ICA terminus - call it an ICA terminus aneurysm ONLY if it is right at the bifurcation of the ICA into the ACA and MCA!
When talking about submandibular sialadenitis
Always comment on the presence of an abscess
Optic nerve will never have a schwannoma
- since optic nerve is not covered by schwann cells
- but schwanna can involve CN III/IV/V1/VI
Otosclerosis
- anterior to the oval window
- lucent –> sclerotic over time
Types of mastoidectomy
- canal wall up - preserves the posterior wall of the external auditory wall
- canal wall down - posterior wall of the external auditory wall out, allowing for clnical exam
If you see enlarged extraocular muscle
DDx?
- grave’s ophthalmopathogy
- spares the tedoninous insertion
- involves the muscle belly only
- IMSLO
- oribital inflammatory pseudotumor
- can involve any structure
- can look like anything
- idiopathic orbital inflammation
- eye PAIN, proptosis, injection, chemosis, ophthalmoplegia
- may involve
- EOM
- trochlea
- lacrimal gland
- entire orbit
- unilateral or bilateral
- orbital bx often required
Morel-Lavellee lesion
- a closed degloving injury
- presents as a hemolymphatic mass
- occur as a result of a shearing of subcutaneous tissues away from underlying fascia
- may spontaneously resolve, may become encapsulated and persistent
- classic locatoin - greater trochanter of the femur
- imaging
- small thin slivers of fluid
- thickly encapsulated lesions
- when chronic - oval or fusiform in shape adherent to the underlying fascia
Morel-Lavelle lesion
Definition of a true locked knee
unable to fully extend the knee
most commonly caused by a bucket handle tear with the fragment in the intercondylar notch
sprain
vs
strain
- sprain - same as a “partial tear”; can be used for tendon or ligament
- strain - only applies to a muscle
How do you differentiate medial from lateral femoral condyles on a lateral knee radiograph?
- lateral condyle - the sulcus terminalis is more posterior
- medial condyle - the sulcus terminalis is more anterior
Deep sulcus sign
- >2mm deep on lateral femoral condyle sulcus terminalis
- associated with osteochondral injury
- pivot-shift mechanism
- associated with ACL
Physaliferous cells
- associated with chordoma
*
Good wording
Very articulate
“Well-defined, T1 iso, STIR/T2 hyperintensie lesion centered along the physeal scar in the medial femoral condyle anteriorly, favored to represent a chondroid lesion.”
“This may represent an enchondroma, however, its eccentric location is atypical. No definite aggressive imaging features are identified.”
“Recommend reassessment with MRI in … time to document stability.”
Operculum
Operculum (Latin, meaning “little lid”) is the part of the cerebral cortex that covers the insula.
Neuroscience divides the operculum into frontal, parietal and temporal regions, after the lobes they form a part of.
Cavernous sinus anatomy
What if you see fat density in the brain?
Fat embolism
Ruptured dermoid
Classic triad of symptoms at presentation of air embolism from an atrioesophageal fistula?
Acute neurologic symptoms,
hematemesis, and
chronic dysphagia
Most effective Rx for cerebral air embolism?
Hyperbaric oxygen within 30 hours of insult has decreased the mortality of air embolism from 90% to as low as 7%.
How to you get cerebral air embolism?
- directly into the arterial system
- esophageal-left atrial fistula
- through the venous system
- large amount of air overwhelming the pulmonary capillary system
- PFO
- pulmonary AVM
DWI
b values
ADC
When performing DWI cancer studies, images are typically acquired using different b-values (typically 0–1000 s mm−2). The images obtained at different b-values allow the calculation of the apparent diffusion coefficient (ADC; unit mm2 s−1), which is usually presented as a quantitative parametric map.
The degree of diffusion-weighting applied is indicated by the b-value (measured in s mm−2), which indicates the magnitude and duration of the applied gradients and time between the paired gradients. By varying the amplitudes, lengths and intervals between the diffusion gradients, the sensitivity to the degree of diffusion motion can be altered and the data processed to provide information about actual diffusion distances. Hence, DWI using a larger b-value (e.g. b = 500 s mm−2) is more sensitive to the slower motion of water molecules and smaller diffusion distances, whereas the converse is true with a smaller b-value (e.g. b = 50 s mm−2).
“… follows the signal characteristics of …”
“… follows the signal characteristics of …”
Tarsal coaltion
- associated with pes planus and heel valgus
- male > female
- coaltion at birth can be 2 types - fibrous or cartilaginous; later ossify - symptoms more severe when ossify
- 2 types
- talocalcaneal - more common
- calcaneonavicular
- C-sign - talocalcaneal coalition
- Anteater nose sign - calcaneonavicular coalition
C sign
talonavicular coalition
Anteater sign
calcaneonavicular coaltion
Terminology for shrunk, non-functioning globe
Phthisis bulbi
Good descriptions
- Large amorphous calcific densities that surround the joint - tumoral calcinosis
- Endosteal scalloping and expansion of bone, with “rings-and-arcs” calcification - enchondroma
- Periarticular calcification with typical rings-and-arcs chondroid mineralization - synovial osteochondromatosis
- Circumferential calcification with a lucent center and a radiolucent cleft that separates the lesion from the cortex of the adjacent bone - myositis ossificans
Snow boarder’s fracture
Lateral process of the talus fracture
How to differentiate
apophysis of the 5th MT base
from
fracture of the 5th MT base
- Apophysis - vertically oriented
- Fracture - transversely oriented
How to differentiate Jone’s fracture from
other proximal 5th MT fracture?
- Jone’s fracture - more distal 5th MT diaphysis
- higher risk of non-union
- Proximal 5MT avulsion fracture - more proximal, at the base of the 5th MT
- avulsion injury associated with peroneus brevis
Unilateral sacroilitis
Infection/septic joint until prove otherwise!
DDx for complex cystic adnexal mass
- If fever, tubo-ovarian abscess
- If sudden onset of abdo pain, ovarian torsion
- ovarian neoplasm - primary vs metastatic
- polycystic ovarian disease (Stein Leventhal syndrome)
- If positive beta-HCG, ectopic pregnancy
Pitfall in US of the pancreas lesion
A microcystic lesio can appear solid
microcystic serous adenoma
Sclerosing mesenteritis
- Mesenteric lymph nodes - some may grow, others regress on followup imaing
- perivascular halo - mesenteric fat stranding sparing the perivascular fat
DDx for bulky pancreas and multiple renal lesions
- Lymphoma involving pancreas and kidneys
- Autoimmune pancreatitis
- IgG4 positive!
Tuberous sclerosis
clinical triad
- mental retardation
- seizure
- facial angiofibroma
Tuberous sclerosis
radiologic features
- CNS
- calcified subependymal nodules
- subependymal giant cell astrocytomas
- cortical/subcortical tubers
- cardiac
- rhabdomyomas
- lungs
- LAM/fibrosis
- renal
- AML or renal cysts
- solid organs
- adenomas, leiomyomas
- skin
- ash-leaf spots, facial/scalp angiofibromas
- ocular - giant drusen
- dental - enamel pits of permanent teeth
Liver MR signals
A liver lesion that is high on T1
The lesion contains hepatocytes
In and Out of phase MR of the liver
- Diffusely signal dropout on out-of-phase imaging - diffuse fatty infiltration of the liver
- Diffusely signal dropout on in-phase imaging - diffuse Fe deposition
- primary hemochromatosis
- secondary hemosiderosis
How to differentiate
primary hemochromatosis
vs
secondary hemosiderossis
- Primary hemochromatosis
- Pancreas
- liver
- myocardium
- thyroid
- Secondary hemosiderosis
- Spleen (reticuloendothelial system)
Pitfalls of adrenal adenoma imaging
- If HU > 130 –> worry about pheochromocytoma
- the lesion has to be < 3cm
- the lesion has to be homogeneous
Hindgut cyst
Hindgut cyst
Portal biliopathy
- portal vein thrombosis –>
- cavernous transformation –>
- mass effect and extrinsic compression on biliary ducts
- biliary stenosis
- upstream biliary dilatation
- biliary enhancement - “pseudocholangiocarcinoma”
