Diagnostic Imaging EBM Exam Flashcards
What is the acronym for soft tissue tumors of the foot and ankle?
MaGiC SPELLS
What are your DDx for soft tissue tumors of the foot and ankle?
MaGiC SPELLS Malignant fibrous histiocytoma ganglion cyst clear cell sarcoma synovial chondromtosis pigmented villonodularsynovitis (PVNS) plantar fibromatosis epitheloid sarcoma ewing's sarcoma liposarcoma leiomyosarcoma synovial sarcoma
What is the classification system for stress fractures?
Wilson-Katz
What is the classification system for osteomyelitis?
Cierny-Mader
What radiographic finding are you evaluating on lateral view if you suspect Lisfranc injury?
normally, the plantar aspect of med cuneiform is dorsal to plantar aspect of 5th met (if it is reversed, this would suggest Lisfranc injury)
What are the 4 phases of bone scans?
1- blood flow
2- blood pool (tissue phase)
3- bone imaging
4- delayed phase
What does Tc-99 localize to?
hydroxyapatite crystals of bone (primarily osteoblasts)
Why is there a fourth phase to the bone scan?
for patients with poor circulation that need more time for the radionuclide to disperse
what is the lethal dose of radiation?
300 rad
How can you tell a medial oblique xray from a lateral oblique xray?
medial oblique demonstrates the lesser metatarsals and cuboid better than the lateral oblique (which shows the 1st and 2nd met-cuneiform columns better)
What is the “C-sign”?
radiographic finding seen in talocalcaneal coalition that represents coalition of sustentaculum tali and posteromedial process of the talus
What chemical is Tc-99 bound to during the 3 phase bone scan?
MDP (methylene diphosphate)
what is teh chemical in Ceretec scan?
HMPAO (hexamethylpropyleneamine oxime)
What does the Ceretec scan label?
leukocytes
What does rarefaction mean?
localized loss of bone density
What does gallium-67 localize to?
leukocytes
bacterial uptake by phagocytes
lactoferrin binding at the site of injection
What is a STIR image?
180 degree pulse followed by a 90 degree pulse; used to generate a T2 image where you want fat suppressed and want to maximize the brightness of the fluid
what radiographic findings do you look for on AP radiograph if you suspect a Lisfranc injury?
fleck sign
if 2nd met deviates laterally
M1-M2 asymmetry with widening > 1mm
what is the fleck sign?
avulsion fx (of lisfranc ligament) tears bone off the medial cuneiform or 2nd met
what radiographic finding do you look for on a medial oblique view if you suspect a Lisfranc injury?
alignment of lateral margins between Cu2-M2 and Cu3-M3 should be near perfect in a normal foot.
What radiographic finding do you look for on lateral view if you suspect a lisfranc injury?
plantar aspect of med cuneiform should be dorsal to plantar aspect of 5th met
-normal talometatarsal angle
What stress exams are used to evaluate a Lisfranc injury?
abduction and adduction stress test
What are you examining for on an abduction stress test for Lisfranc injury?
transverse instability (C2-M2 tarsometatarsal widening)
What are you examining for on an adduction stress test for Lisfranc injury?
longitudinal instability (C1-C2 intercuneiform widening )
Which soft tissue lesions have bony involvement?
PVNS
synovial sarcoma
synovial chondromatosis
Which soft tissue lesions have bony erosions on alternate sides of the joint?
PVNS
synovial chondromatosis
what contrast is used in MRI w/ contrast?
IV gadolinium
what adverse effect can result from gadolinium contrast used with MRI?
nephrogenic systemic fibrosis
what is teh magic angle effect?
on T1 images, when cartilage or tendon are oriented 55 degrees from the magnetic field, we see increased signal intensity, which represents a false artifact
what is the most common soft tissue sarcoma in the LE?
liposarcoma
what is the most common soft tissue sarcoma in the foot and ankle?
synovial sarcoma
what is the most common malignant soft tissue in the foot?
malignant melanoma
Which of the Magic spells mnemonic like to spread through the lymphatic system?
CARES acronym: clear cell sarcoma angiosarcoma (aka leiomyosarcoma) rhabdomyosarcoma epithelioid sarcoma synovial sarcoma
how do you stage soft tissue tumors?
GTNM (grade, tumor, nodal involvement, metastasis)
Stage this tumor using AJCC : moderately differentiated, tumor is 6cm, nodal involvement, metastasis.
(G2, T2, N1, M1)
Stage 4b
which soft tissue tumor looks like a “bag of bones” on MRI?
synovial chondromatosis
how does synovial chondromatosis appear on MRI?
T1- homogenously black
T2- homogenously bright fluid + black calcifications in the middle
which soft tissue mass looks like a “blooming flower” on MRI?
PVNS
what are teh determinate lesions confirmed by MRI?
ganglion, lipoma, PVNS, aneurysmal bone cyst, hemangioma
Name the stages of Cierny-Mader classification of osteomyelitis.
Stage 1: Medullary
Stage 2: Superficial- infection of only superficial cortex
Stage 3: Localized- infection of only the cortex
Stage 4: Diffuse- infection of both cortex and medullary canal
what is the most common primary malignancy of bone in foot and ankle ?
chondrosarcoma
what is the most common primary malignancy tumor of bone in the body ?
multiple myeloma
what is the Most common benign bone tumor in foot and ankle and rest of the body ?
osteochondroma
A Well- defined lesion with a narrow margin is what type of lesion?
geographic lesion (the lesion is slow-growing and the bone has time to retreat and lay down new bone around the lesion)
What type of lesion is best represented by multiple myeloma?
moth-eaten lesion: represents several ill-defined areas of lucency
(“multiple punched-out lesions”
What does a lamellated or “onion-skin appearance” of the periosteum indicate about the lesion?
lesion exhibits on-and-off-growing
(periosteum has time to lay down thin shell of calcified new bone before the lesion starts another growth spurt –>leads to concentric shells of new bone over the lesion)
if a lesion grows rapidly, what are the 2 types of periosteal reactions that may be seen?
- sunburst or “hair-on-end”
OR 2. Codman’s triangle
What is the sunburts or hair-on-end periosteal reaction representative of?
periosteum has no time to lay down bone bc lesion is growing rapidly, but Sharpey’s fibers become calcified and stretched out perpendicular to the bone, and then ossify
What is the Codman’s triangle periosteal reaction representative of?
only the edges of the raised periosteum will ossify-this little bit of ossification forms a small angle with the surface of the bone, but not a complete triangle
a matrix derived from cartilage has what appearance?
speckled
a cloud matrix indicates what cell of origin?
bone (osteoblasts)
a “ground-glass matrix indicates what type of lesion?
fibrous, cystic (fluid-filled) lesion
“long lytic lesion in long bone”
fibrous dysplasia
“chicken-wire matrix”
chondroblastoma
“hurts like a b and tough to see”
“night pain relieved by NSAIDs”
osteoid osteoma
“mosaic glass on MRI”
is filled with blood and appears as many shades of gray on MRI
aneurysmal bone cyst
“end of bone with speckled tone”
enchondroma
metastasis to the foot/ankle usually involves what systems?
GI/GU tracts (esp colorectal cancer)
“at the end of a long fast, teens have a blast”
osteoblastoma
brown tumors are indicative of what disease?
hyperparathyroidism
most common tumor in teens that affects the ends of long bones
osteoblastoma
what is the “cousin of fibrous dysplasia”?
non-ossifying fibroma
“endosteal scalloping”
eosinophilic granuloma
“massive in metaphysis”
giant cell tumor of bone
where is the unicameral bone cyst most likely to be located?
calcaneus (middle facet)
“best bet is middle facet”
what malignant lucent bone lesion is likely to affect
neuroblastoma
what malignant lucent bone lesion is likely to affect a patient ages 1-10?
Ewing’s sarcoma
a patient aged 10-30 most likely has what bone tumor?
Ewing’s sarcoma, osteosarcoma
a patient aged 30-40 most likely has what bone tumor?
fibrosarcoma, lymphoma
a patient aged 40+ most likely has what bone tumor?
metastasis, myeloma, chondrosarcoma
what is the most common solitary sclerotic lesion of bone?
a benign bone island
How do you differentiate between osteochondroma and subungual exostosis?
- cap: osteochondroma has a hyaline cartilage cap while subungual exostosis has a fibrocartilage cap
- osteochondroma arises from the physeal plate and grows away from it (whereas subungual exostosis arises from soft tissue under the nail and grows inferiorly towards distal phaalnx)
What is Martel’s sign?
associated with gouty tophi that erodes bone, producing a characteristic overhanging C-shaped edge of bone; This overhanging margin of the new bone along the edge of erosion is called Martel’s sign
Classify this: radiolucent fx line that appears without evidence of endosteal callus or periosteal reaction?
Wilson-Katz type 1
How much Vitamin D supplement should you take daily?
800-2,000 IU Vit D
how much calcium supplement is recommended daily? what form of calcium is recommended?
citrate calcium- more readily absorbed compared to calcium carbonate
1200-1500mg Ca2+
Classify this: radiosclerotic area of cancellous bone; seen with endosteal callus.
Wilson-Katz type 2
Where are Wilson-Katz type 3 stress fractures seen?
diaphyseal area of metatarsals (which is made of cortical bone)
Where are Wilson-Katz type 2 stress fx seen usually?
cancellous bone- ex. calcaneus, tibial plafond, tarsal bones, met heads/bases
When should you consider initiating treatment given a FRAX score?
T-score of -1 to -2.5 (osteopenia) AND 10 year hip fx prob>3% or 10 year all major osteoporotic-related fx>20%
Classify this: medial displacement of 1st met
Hardcastle type B1
What is Hardcastle type A?
total displacement of Lisfranc’s joint (homolateral)
A1= lateral displacement
A2= dorsoplantar displacement
What is a lateral dislocation of the mets called?
Hardcastle type B2
What is Hardcastle type c?
divergent Lisfranc’s joint (1st met deviates medially while lesser metatarsals deviate laterally)
■ C1 = only some of the lesser mets deviate laterally
■ C2 = all lesser mets deviate laterally
which type of bone healing is stronger?
secondary bone healing ( stronger callus)
which type of bone healing occurs faster histologically?
primary bone healing
which type of bone healing appears first on radiograph?
secondary bone healing
Sammarco classification of plantar fibromas:
Grade 1
- focal disease
- no adherence to skin
- no deep extension to flexor sheath
Sammarco classification of plantar fibromas:
Grade 2
multifocal disease
no adherence to skin
no deep extension to flexor sheath
Sammarco classification of plantar fibromas:
Grade 3
multifocal disease
EITHER adherence to skin OR deep extension to flexor sheath
Sammarco classification of plantar fibromas:
Grade 4
multifocal disease
adherence to skin AND deep extension to flexor sheath
Which of the Magic spells soft tissue masses like to spread thru the lymphatic system?
*CARES mnmeonic* C- clear cell sarcoma A-angiosarcoma (aka leiomyosarcoma) R-rhabdomyosarcoma E-epithelioid sarcoma S-synovial sarcoma
Why is chemotherapy not used as often for? What are the 4 chemo drugs that are used?
no evidence for increased survival rate. Radiation is key
- ifosfamide
- doxorubicin
- methotrexate
- cyclophosphamide
what is the cell of origin for PVNS?
origin of synovium with proliferation of multi-nucleated giant cells and production of large quantities of hemosiderin
what is the cell of origin for ganglion cyst?
myxoid degeneration of periarticular CT
*DOES NOT connect to joints
What type of stress fx is usually seen in the calcaneus? metatarsals?
calcaneus- Wilson-Katz type 2 (cancellous bone)
metatarsals- Wilson-Katz type 3 (metatarsal shaft)
What is the TE and TR time for a T1 image?
short TR 100-1000ms
short TE 20-30ms
What is teh TE and TR time for a T2 image?
long TR 1600-3000ms
long TE 70-100ms
Where does Indium-111 localize to?
cytoplasmic component of WBC mb
*dependent on the chemotaxis of leukocytes
What does Tc-99 sulfur colloid localize to?
reticulocytes (macrophages) inside the bone marrow
What is the chemical that Tc-99 is bound to in a Ceretec scan?
HMPAO- hexamethylpropyleneamine oxime
What population gets Z-scores?
pre-menopausal women
children
men
Which medication is the only anabolic drug used to treat osteoporosis by rebuilding bone? How is this drug administered?
Teriparatide (Forteo) - 20 mcg SC daily injection
which bisphosphonate is administered intravenously?
Zolendronic acid (Reclast )- 5mg IV q12 months (for treatment) or 24 months (for prevention)
What is a normal Vit D3 serum level? What does this equate to in IU?
30ng/mL
(every 100 IU = 1ng/mL) So, 30 ng/mL = 3000 IU
what oxygen tension conditions favor bone formation?
low oxygen tension levels- this is because bone follows an anaerobic metabolic pathway
what pH level favors bone formation?
high pH
How are sarcomas different from carcinomas? What are their cell of origin?
sarcomas- arise from mesenchymal CT tissue such as bone, fat, or cartilage
carcinomas- arise from epithelial cells
How do sarcomas vs. carcinomas spread?
sarcomas spread hematogenously mostly while carcinomas spread thru the lymphatics
What malignancies are we concerned about for adults >40 y/o?
metastasis
myeloma
chondrosarcoma
what is the tissue of origin of synovial chondromatosis?
hyaline cartilage
what is the tissue of origin of plantar fibromas?
myofibroblasts of plantar fascia
which soft tissue masses tend to have bony involvement?
PVNS
synovial sarcoma
synovial chondromatosis
