MSK Flashcards
MRI parameter that would result in decreased metallic susceptibility artifact:
Increasing the receiver bandwidth*** by restricting geometric distortion what would do the opposite Increasing field strength, increased voxel size, and increased slice thickness
Mixture contrast for arthrogram ratio : iodinated contrast with saline and/or anesthetic … ?:?
1:1
contraindications for arthrography
Anticoagulation and infection at the joint
Placing an MRI receiver coil farther than normal from the area of interest will result in
lower signal, lower SNR, noise is constant
What percentage of bone mineralization must be lost to be detected by radiographs?
30% to 40% . Radiographs are insensitive in detecting early bone loss.
preferred location for needle placement in the direct vertical approach for hip arthro
superior lateral head–neck junction of the femur.
Appropriate mixture for MR arthrogram
0.1 to 0.2 mL gadolinium per 20 mL of iodinated contrast, saline, and/or anesthetic Gad is therefore diluted to a 1/100–1/200 concentration
CT over MRI arthrography in…
-large or obese patients -postop evaluation of labral tears to avoid the metallic artifact - and in patients who cannot undergo MRI evaluation.
How to fix aliasing artifact on MRI?
Double the image oversampling in the phase-encoded direction. [it was not to double the FOV]
Structures with long T2 relaxation time Structures with short T1 relaxation time
bright on T2 (water) bright on T1 (blood - some)
What will achieve high-resolution imaging of small MSK structures
thin slices; however, when you use thin slices in a 2D acquisition, the signal-to-noise tends to decrease too much for the images to be useful. This decrease can be overcome using 3D, which achieves thin slices but regains SNR through averaging.
What radial imaging techniques on MRI can tolerate more movement and why?
BLADE (MRI acronym, Siemens) and PROPELLOR (MRI acronym, GE) sample the center of k-space more frequently
also known as ringing artifact, has the appearance of multiple, regularly spaced bands that are parallel to one another. why does it happen?
Gibbs caused by insufficient sampling of high frequencies, which may occur at sharp boundaries (discontinuities in signal)
What parameter can be altered without changing the total scan time
Number of frequency encoding steps
Total scan time is directly proportional to
time of repetition (TR) number of excitations (NEX) # of phase-encoding steps.
Total scan time is inversely proportional to
echo train length (ETL)
The number of frequency-encoding steps does not alter
acquisition time
What change in parameter would cause a lower signal-to-noise ratio on a T2-weighted image
Increase the bandwidth
Concerns for tattoos in MRI
Heating of the tattoo by radio waves
The presence of the metal induces substantial ______ in the magnetic field.
inhomogeneity
_______ are particularly sensitive to magnetic field inhomogeneities because they do not have a 180-degree pulse to refocus the magnetization.
GRE This effect is exacerbated with longer echo times.
Correct dose of epinephrine
1 to 3 mL of 1/10,000 dilution IV or 0.3 mL of 1/1,000 dilution IM.
Needle size for FNA for core bx
22G 14-18G
Bx for _____ lesions should be performed with CT > US.
intramedullary
medulla definition
inner region of an organ or tissue, especially when it is distinguishable from the outer region
the most appropriate position to place the needle for a hip aspiration or injection under ultrasound guidance.
anterior recess of the femoral head neck junction
the ability to differentiate between two high-contrast objects
Spatial resolution
the ability to detect differences in intensities in adjacent regions on an image.
Contrast resolution
Modality that offers the best spatial resolution for evaluation of superficial structures such as many ligaments and tendons. Frequencies used?
US 7.5 to 20 MHz
a normal bone mineral density has a T-score
≥ − 1.0
T score for osteopenia
−1.0 and −2.5
T score for osteoporosis
≤−2.5
When diagnosing osteoporosis, what T score is used?
the lower of the T-scores between the PA spine and the hip
When evaluating the hip for fracture risk, what T score should be used?
the lower of the T-scores of the hip.
Potential uses for FDG PET in malignant soft tissue tumors
primary staging, metastatic evaluation, and evaluation of tumor response to treatment.
If In-111 WBC uptake exceeds Tc-99m sulfur colloid uptake in a knee prosthesis…
Diagnostic for infxn.
No grids are used when imaging extremities because
Grids are used to removed scatter and small body parts generate low scatter radiation (scatter depends on size of the imaging area and the pts size)
Increased SID will do what to focal spot blurring?
Decrease… no entendi esto
What happens to attenuation with increasing XR energy?
always decreases the attenuation difference between material will also decrease
Increasing reconstruction slice thickness does what to metal artifact?
Reduce (the artifact pattern will remain the same, just look less intense, vs. when using a metal artifact software where the pattern will change)
With the heel effect, The difference in radiation intensity across the useful beam of an x-ray field can vary by as much as ____
45%.
Physiologic bowing is often seen in the setting of
Neg ulnar variance
Periosteal desmoid (has many other names, including avulsive cortical irregularity, distal metaphyseal femoral defect, cortical desmoid, and medial supracondylar defect of the femur) is often seen where? management?
posteromedial cortex of the distal end of the femur, adjacent to the medial femoral condyle. located at the insertion of the adductor magnus aponeurosis or the origin of the medial head of the gastrocnemius tendon. Benign finding. No further imaging is needed.
The most common accessory muscle seen in the lateral ankle
peroneus quartus.
three accessory muscles, which can be seen in the medial ankle:
- accessory flexor digitorum longus 2. accessory soleus (only one located superficial to the flexor retinaculum) 3. peroneocalcaneus internus.
What is the most common accessory muscle of the ankle?
the peroneus quartus, occurring in up to 10% to 22% of the population. -Posterior to peroneus brevis and longus tendonds (lateral ankle)
order of ossification of the elbow
CRITOE 1,3,4,8,10
_____ tendons originate at the medial epicondyle ____ tendons at the lateral epicondyle
flexors, extensors
osteochondrosis of the navicular of the foot with a sclerotic, flattened, and fragmented navicular. Symp?
Köhler disease ( M>F) pain and swelling
osteochondrosis of the second metatarsal head
Freiberg infraction Pain increased by weight bearing
What is the most common carpal coalition?
Lunotriquetral
Madelung deformity is often idiopathic but can also be seen in the setting of
- prior trauma - Turner disease, or - skeletal dysplasias such as MHE
shortened distal radius, which demonstrates abnormal ulnar tilt of its distal articular surface. Dx?
Madelung deformity
pattern of wrist malalignment characterized by widening of the scapholunate interval, midcarpal collapse, proximal migration of the capitate, and radioscaphoid degenerative changes
SLAC wrist
Common causes of SLAC wrist
prior trauma or CPPD arthropathy
MC presenting symptomp of bipartite patella
anterior knee pain
MC locaation for bipartite patella
superolateral
MC MRI finding with bipartite patella?
Hyperintense T2 signal within the bipartite fragment (66%)
Nail-patella syndrome tetrad
iliac horns w abnormalities of nail (MC), patella and elbow.
iliac horns pathog for?
Nail patella Syndrome (AD) A Neil Patel se las pegan…. :/
Congenital etiologies for acroosteolysis
pycnodysostosis, HajduCheney syndrome, and Lesch-Nyhan syndrome
MC initial site of briding ossification in fibrodysplasia ossificans progressiva?
- SCM 2. shoulder
nerve territory oriented macrodactyly, and neural fibrolipoma with macrodactyly. In the hand, the second and third digits are most commonly affected. Dx?
Macrodystrophia lipomatosa
Primary hypertrophic osteoarthropathy is also known as
pachydermoperiostosis
The most common cause of secondary hypertrophic osteoarthropathy
malignancy (90% of cases)
Involvement of the tufts is not common in either primary or secondary cases; however, when it does occur, acroosteolysis is more commonly associated with ____ hypertrophic osteoarthropathy while tuft hypertrophy is more commonly associated with ___ hypertrophic osteoarthropathy.
primary; secondary
decreased disc space heights, increased AP diameter of the involved vertebral bodies, anterior wedging of at least 5 degrees involving three or more consecutive vertebral bodies, and Schmorl nodes.
Scheuermann disease
most commonly results from intraosseous disc herniation through a weakened vertebral endplate
Schmorl node
Klippel-Feil syndrome def
failure of cervical segmentation at multiple levels. This is often associated with a short neck and a low hairline.. These patients have limited cervical motion as well as an increased risk for renal; spinal cord; and inner-, middle-, and outer-ear abnormalities.
Tethering of the scapula to the cervical spine by a fibrous band, resulting in a high position of the scapula. Occurs in 1/3 of pts with Klippel-Fail.
Sprengel deformity
How is congenital dislocation of the radial head distinguished from a prior traumatic radial head dislocation?
The radial head is overgrown and dysplastic in congenital dislocation of the radial head, +/- dysplastic configuration of the capitellum.
OI types
I: Least severe II: Most severe, lethal at birth III: Most severe and alive IV: Like type one but with basilar skull impression (Odontoid process precess into brainstem)
[BW] dripping candle wax
Melorheostosis
MC location for melorheostosis
lower extremities. MC spares the skull and facial bones.
The os odontoideum is fixed to the arch of ____ and moves with it on flexion and extension views.
the atlas, C1
primary etiology leading to Osteopetrosis
Abnormal osteoClast function, leading to an imbalance between bone resoprtion and formation.
bones are diffusely and uniformly dense with loss of the normal corticomedullary differentiation
Osteopetrosis
acute kyphosis seen in association with Pott disease
Gibbus deformity
It is seen on a lateral radiograph as a triangular ossicle, most commonly located at the anterior–superior border of the vertebral body.
Limbus vertebra
thin vertical ossifications in the annulus fibrosis at the discovertebral junction
Syndesmophytes seen with AS
The most common cause of scoliosis is
idiopathic (85% of cases)
broadened femoral head with a short and wide femoral neck represents _____ seen with ____.
Coxa Magna; DDH
DDH is bilateral in ___% of cases
20
To make the diagnosis of a discoid meniscus, the bow tie appearance should be present on at least ____ consecutive sagittal images, assuming 5-mm-thick sagittal sections.
Three
Chronic osteomyelitis has been associated with development of ______ within sinus tracts in 0.2% to 1.6% of patients
squamous cell carcinoma
Chronic OM changes?
increased osseous destruction, sclerosis, and thickening of the remaining cortex. Other findings: periosteal new bone formation, sequestrum and involucrum formation, cloaca formation, and sinus tracts to the skin surface.
80 - 90 % of pts with Ewing Sarcoma are what age?
< 20yoa
Possible clinical hx of a sequestrum associated with osteomyelitis
recent IV drug use
necrotic bone surrounded by purulent material or granulation tissue. What am I?
Sequestrum
The sequestrum and purulent material are typically surrounded by a bone shell called the
involucrum
a cortical and periosteal defect that allows pus to drain from the infected medullary cavity into the adjacent surrounded tissues
cloaca
MC site of foot OM in DM pts?
- first and fifth metatarsal heads - the phalanges - and the calcaneus. At site of increased pressure.
MC infectious etiology in subperiosteal abscess
S. aureus.
Earliest radiographic finding of septic arthritis?
joint effusion Later findings include periarticular osteoporosis, cartilage destruction seen as joint space narrowing, indistinctness of the cortical bone, marginal erosions, osteomyelitis, sclerosis, and eventually ankylosis.
enhancement of the deep fascia would suggest
nec fasc
intramuscular abscess with an enhancing peripheral rim. What am I?
pyomyositis
Which T1-weighted signal pattern is most reliable in diagnosing osteomyelitis of the foot?
low T1 signal in a geographic medullary distribution with corresponding high signal on T2FS.
Characteristics of abscess on MRI
Central low T1 high T2 signal with a thick enhancing rim corresponding to the fibrous capsule. ?
classic CT finding of necrotizing fasciitis is …
soft tissue gas associated with fluid collections within the deep fascial planes.
Earliest osseous radiographic sign of OM?
indistinctness of the cortex. No changes will be seen in the first two weeks of infxn. This is followed by permeative osseous destruction, endosteal scalloping, and periosteal reaction. Later changes include the formation of a sequestrum, an involucrum, or an abscess.
Most critical MRI finding in diagnosing gangrene of the foot?
Areas of nonenhancement
MRI findings seen in cellulitis but not in soft tissue edema assoc w diabetic vasculopathy?
intense soft tissue enhancement
Signs that suggest the presence of OM in a neuropathic joint
sinus tracts, replacement of the soft tissue fat, fluid collections, disappearance of subchondral cysts on sequential imaging, and extensive marrow abnormalities.
Signs that suggest osteomyelitis is not present in a neuropathic joint
thin rim enhancement of joint effusions, the presence of subchondral cysts, and the presence of intra-articular loose bodies.
non-hereditary dysplasia characterized by multiple enchondromas involving the metaphysis of long bones usually unilateral or asymmetric. Spares spine and skull.
Ollier Lesions usually regress or stabilize after skeletal maturation. The enchondromas can result in growth disturbance, bowing deformities, and increased risk of sarcomatous degeneration (due primarily to their multiplicity).
Ewing sarcoma characteristically occurs in which part of the bone?
Metadiaphysis
A type of benign fibroblastic and myofibroblastic tumor of the foot most commonly occuring at medial non weightbearing surface of the plantar fascia M>F Bilateral in 20-50% of cases Dx?
Plantar fibromatosis
Forestier disease is also known as
DISH
MC cause of heel pain characterized by thickening of the fascia, usually at the calcaneal margin, with variable degrees of soft tissue and osseous inflammation. Dx?
Plantar fasiitis
mass-like fibrosis of the plantar digital nerve, at the level of the metatarsal heads
Morton neuroma
Morton neuroma most commonly between
the 2nd and 3rd intermetatarsal spaces.
Features within a fatty soft tissue lesion that should raise suspicion for liposarcoma
- thick septations measuring >2 mm - lesion size larger than 10 cm - the presence of globular or nodular nonadipose areas.
What is the most frequent donor site for cancellous bone grafting?
The iliac bone - anterior iliac crest is the most easily assessed site for grafting.
well-defined, lytic lesion without a defined sclerotic margin, eccentric in location, and extending to the subarticular margin of the tibia in a 30 y/o
Giant cell tumor
Cause of increased T2 signal on intramuscular hemangioma
Slow flow
venign tumor with vascular changes, high T2, +CE, phleboliths on XR
hemangioma
appropriate indication for treatment of a NOF?
pathologic fracture; curettage and bone grafting may be indicated.
heterogeneous, multifocal areas of abnormal osseous uptake throughout the axial and appendicular skeleton, with decreased renal tracer uptake
superscan
Osseous bowing, osseous enlargement, and intracortical osteolysis with a characteristic sclerotic band are typically seen at the ant cortex of the tibial diaphysis in …?
Osteofibrous dysplasia
rare, exophytic growths from osseous cortical surfaces consisting of bone, cartilage, and fibrous tissue.
BPOP ~ Nora lesion Some studies suggest the etiology of this lesion to be related to a reparative process after periosteal injury, while others point to a benign neoplastic process as its cause.
Osteochondromas must demonstrate
corticomedullary contiguity.
Osteomas commonly involve the
skull, paranasal sinuses, and mandible
Osteomas can be seen in association with what syndrome?
Gardner syndrome
multiple enchondromas of the hand
Maffucci or Ollier
Pts w HME have (increased/decreased) risk of malignant degeneration to Chondrosarcoma when compared to pts w solitary osteochondromas
Increased. (Happens to 1-3% of pts)
An eccentrically positioned lesion in relation to the parent nerve suggests a
schwannoma
Sign assoc w multiple small ring-like structures with peripheral T2 hyperintensity hyperintensity?
Fasicular sign seen with tumors of neurogenic origin (neurofibroma, schwannoma, PNST)
Factors suggesting malignant transformation of an osteochondroma
- Growth in a skeletally MATURE pt 2. cartilage cap > 1.5cm 3. Interior focal destruction w lucent foci 4. irregular or indistinct surface Fluid at the overlying bursa is likely related to frictional forces and not malig degeneration
Benign disorder with multiple intra-articular nodules composed of hyaline cartilage (low T1, high T2) w/ +- erosion of adjacent bones (80%)
Synovial chondromatosis
MC location of Synovial chondromatosis
Knee (50% then elbow, hip and shoulder. But may arise anywhere there is synovium.
MC location for osteoid oseoma
Cortex of long bones
Preferred tx for osteoid osteoma
radio-frequency ablation
For successful tx of an osteoid osteoma, what needs to be resected for successful tx?
The lucent nidus
Typical location for a synovial sarcoma
Near a joint within a tendon sheath, less commonly within the joint.
centrally located, intramedullary, geographic lytic lesions, +/- endosteal scalloping and expansile remodeling. Dx?
SBC. Its a fluid filled cyst.
MC locations for SBC
prox humerus, prox femur & prox tibia in the pediatric pop
____ % of pts with an SBC present w a pathologic fx
50% fallen fragment sign
ideal approach for proximal humeral biopsies and why?
Traversing the deltoid musculature anteriorly just lateral to the deltopectoral interval - bc the deltoid is innervated post to ant.
Volar def?
Related to the palm of the hand or sole of the foot
Epiphyseal lesions
CIG Chondroblastoma infxn GCT
Metaphyseal lesions
UBC, Enchondromas, osteochondromas
MC location for lymphangiomas
H&N 75%
Chondroid matrix, endosteal scalloping, and pathologic fracture may be seen with both
enchondromas and chondrosarcomas
Features of chondrosarcoma not seen with enchondromas
- cortical destruction 2. soft tissue mas 3. Pain 4. + uptake on bone scan
benign fibro-osseous lesion comprised of a mixture of histologic elements with a predilection for the intertrochanteric region of the femur. Dx?
Liposclerosing myxofibrous tumor
vascular lesion of intermediate malignancy
Hemangiopericytoma
lytic lesion with +/- periosteal rxn, endosteal scalloping, cortical breakthrough, and no sclerotic margin.
LCH
Central or ring-like calcification/ossification in a lucent calcaneal lesion [P]
intraosseous lipoma
MC location for an intraosseous lipoma
Proximal femur
- Typical MR imaging feature of an intraosseous hemangioma?
Coarsened trabeculae Usually bright in T1 & T2 w/o enhancement
MC location of intraosseous hemangioma
VB
The risk of sarcomatous degeneration of pagetoid bone is approximately ___ in individuals with limited skeletal involvement.
1%
MC sarcoma assoc w Paget
Oseosarcoma
rings and arcs pattern with high T2 lobulated growth.
Chondrosarcoma
MC site of met from primary osteosarcoma
lung
MC site of origin of primary osteosarcoma
Innominate bone
aka the hip bone (formed by the fusion of the ilium, ischium and pubis)
Radiation dose MC assoc w sarcomas
5k-6k cGy
A permeative, destructive osseous lesion with soft tissue mass is characteristic for
Ewing Sarcoma
MC manifestation of extraosseus LCH
Skin
T1 low or iso, T2 bright lesion with hypointense septations and nodularity
Myxoma
Myxomas have a predilection for
muscle
intramuscular myxomas and fibrous dysplasia Syndrome
Mazabraud
Rare vascular disorder of lymphatic etiology characterized by spontaneous, progressive resorption of the bone +/- soft tissue changes adjacent to involved skeleton and splenic cysts Dx?
Gorham Syndrome = Vanishing bone syndrome
Imp bone lesion descriptors
margin, zone of transition, periosteal reaction, mineralization/matrix, size, number of lesions, and presence/absence of a soft tissue component and location
Rare benign cartilaginous tumor of the bone, with approximately 50% of lesions developing in the tibia or femur.
Chondromyxoid fibroma
Characteristics of Chondromyxoid fibroma
eccentric, internal septations, thin sclerotic rim they can be elongated and expansile and erode through the cortex
benign subungual tumor (hamartoma) developing from the neuromyoarterial glomus bodies
Glomus tumor
Glomus tumor MRI and enhancement enhancement?
high T1 and high T2, +++ richly vascularized
Glomus tumor mx?
Surgical excision
combination of enchondromas and hemangiomas
Maffucci
Diffusely and avidly enhancing mass, with intimate association with the tendons of the thumb, and has associated underlying bony erosion Dx?
Giant cell tumor of the tendon sheath
The two MC soft tissue mass in the hand and wrist
Ganglion cyst and GCT of the tendon sheath
densely ossified juxtacortical mass that lies outside the cortex and occurs in the metaphyses which LACKS corticomedullary continuity between the tumor and the underlying medullary canal
Parosteal osteosarcoma
Periosteal osteosarcoma characteristics
Diaphysis, more lytic, cortical erosion and periosteal rxn.
Diff dx for multicystic mass w fluid fluid levels
ABC + Telangiectatic oseocarcoma
What effect does hemosiderin have on T2?
shorten
Extensive bone marrow edema surrounding an otherwise well-circumscribed epiphyseal lesion in a skeletally immature patient is highly characteristic of
chondroblastoma
In a young patient with a posterior spinal element mass, what would be the the most likely diagnosis? -Osteoblastoma -Chondroblastoma -Clear cell chondro -Osteosarcoma
Osteoblastoma
A 32 year old woman has history of Gaucher dx. What would be the most likely reason to obtain serial follow up MRI exams?
Treatment response Gaucher dx can be treated by enzyme replacement, and response to therapy can be monitored by MRI.
Best sequence and FOV size to visualize and measure the tendon gap in achilles Tendon Rupture
Large field of view w T2Fatsat (or STIR)
T score value cutoff for Osteopenia
Less than -1 (NOT -1)
What is the abnormality?
Torn TFC
chronic disorder of synovitis, acne, pustulosis and hyperostosis?
SAPHO syndrome
Best tx for Osteoid Osteoma
Radiofrequency Ablation
On ultrasound of full thickness rotator cuff tears, what is the most common finding?
hypo/anechoic defect
What is the best interpretation of the biceps tendon abnormality? Add MRI
Medial dislocation
What is the weakest and most frequently torn ankle ligament?
ATFL
Chronic, repetitive injury to the ATFL structure/region can lead to…
Anterolateral ankle impingement ( a soft tissue “mass” consisting of hypertrophic synovium and fibrotic tissue may develop within the lateral gutter of the ankle)
A typical field of view for a shoulder MRI on a 1.5 Tesla magnet is (cm):
16 cm
Dx?
Tumoral Calcinosis (Amorphous calcs in a periarticular distribution)
What type of arthropathy commonly results in joint deformation withOUT erosions?
Lupus
An epiphyseal geographic lesion with surrounding reactive edema in a skeletally immature patient is highly suggestive of
Chondroblastoma
Progressively decreasing interpedicular distance in the lumbar spine, flat acetabular roof, champagne glass pelvis with squared iliac bones, metaphyseal flaring of tubular bones and trident hand. Dx?
Achondroplasia
Fast spin echo sequence with a high receiver bandwidth is used to decrease what type of artifact?
Metallic
Lace like reticular pattern within the proximal phalanges without significant periosteal ran is seen with?
Sarcoidosis
Medication that is a risk factor for Achilles tendon rupture
Quinolones
MHE is assoc with the development of what malignancy?
Chondrosarcoma
What pattern of bruising of the knee bones suggests ACL tear?
ant femur, post tibia
A mass-like distention of the iliopsoas bursa that develops after total hip replacement?
Pseudotumor
What are the three complications of particle dx after THA that can be differentiated with MRI?
synovitis, osteolysis, and pseudotumor formation
