Diagnostic Imaging

Question 1

Giant cell tumor

Answer 1

Typically seen in the 2nd, 3rd, and 4th decades of life
Diaphyseal bone, but can cross over the metaphysis
Can penetrate the growth plate
“Soap bubble” appearance on radiographs
Can metastasize
In rare cases, can be associated with over activity of parathyroid glands - “hyperparathyroidism”

Question 2

Peroneus longus/brevis

Answer 2

T2 MRI (water image) is best to visualize tendinosis, partial/complete rupture, inflammatory changes (tenosynovitis)
Brevis originates medial (deep) to peroneus longus muscle, from the lateral surface of the fibula and intermuscular septa in the distal 2/3 of the lower leg 
Longus originates from the proximal fibula, lateral tibial condyle and intermuscular septa
At the level of the ankle, both peroneus longus and brevis share a common synovial sheath which is held in place by a fibrous tunnel
In the fibular groove, the peroneus brevis tendon is adjacent to the bone, anterior and medial to the peroneus longus tendon (PB is deep and in front of PL)
PB in transverse sections is flat or mildly crescentic (moon shaped) whereas PL is rounded

Question 3

Friberg’s infarction

Answer 3

Osteochondrosis of a metatarsal head, most commonly the 2nd but can occur in the 3rd up to 25% of the time, less common in the 4th met head
Commonly presents in adolescence, more common in female
Decreased T2 signal intensity is noted at the site of injury
Stage 2 of disease, met head flattens because of central bone resorption
The cartilage of the plantar articular surface is healthier and there is increased T2 signal intensity noted at the site of injury which decrease as the bone becomes sclerotic

Question 4

Morton’s neuroma on US

Answer 4

Appears hyperechoic proximal to metatarsal head
Pressure is applied to the interspace on opposite side of foot as the transducer to splay the interspace and improve visualization

Question 5

Appearance of injection on US

Answer 5

During a normal US guided injection, there should be obvious displacement of the tissue by the injection that is visibly hypoechoic (black)

Question 6

Calcaneal inclination angle

Answer 6

Formed from a line that runs from the inferior portion of the calcaneal tuberosity to the distal/inferior point of the CC joint
Normal range is 20-25 degrees (decreased → pes planus, increased → pes cavus)

Question 7

Tzank test

Answer 7

An itchy rash with small, fluid filled blisters is a common presentation of chicken pox (varicella) 
Prior to routine vaccination, most children in a family would have symptoms at the same time 
Tzank test (skin scraping) is used to identify chicken pox and herpes

Question 8

Osteosarcoma metastases

Answer 8

Most common area that osteosarcoma metastasizes to is the lungs
Metastatic osteosarcoma can also spread to other bones, brain or other organs but MOST COMMON is the LUNGS

Question 9

Washout phenomenon

Answer 9

A ceretec scan can be used to differentiate Charcot arthropathy from osteomyelitis
Technetium labeled WBC scan (Ceretec)
Both Charcot and osteomyelitis show increased uptake after 4 hours of imaging
In the absence of infection, abnormal uptake with have subsequent “washout phenomenon” indicating Charcot
This is due to the development of active bone marrow due to fracture repair in Charcot pathology
When there is an accompanying infection, would not expect to see the washout phenomenon, but an area of persistent increased intensity )depicting cell activity and infection found in delayed imaging

Question 10

EMG in tarsal tunnel

Answer 10

Prolonged posterior tibial latency to the abductor hallucis and delayed nerve conduction velocity
Prolonged posterior tibial latency to the abductor hallucis and delayed nerve conduction velocities are expected EMG/NCB findings. Motor nerve latencies through the tarsal tunnel in normal adult subjects: standard determinations corrected for temperature and distance.

Question 11

Sesamoid axial

Answer 11

Sesamoid axial projection is useful in evaluating the metatarsal sesamoid articulation
Shows the relationship of the sesamoids to the cristae

Question 12

Proximal articular set angle

Answer 12

The angulation between a line perpendicular to the 1st metatarsal articular cartilage and the longitudinal axis of the first metatarsal
Normal = 0 to 8 degrees

Question 13

Distal articular set angle

Answer 13

The angulation between a line perpendicular to the proximal articular surface and longitudinal bisection of the hallux proximal phalanx
Normal = 0-8 degrees

Question 14

Hallux abductus angle

Answer 14

The angle between the longitudinal bisection of the hallux proximal phalanx and the longitudinal bisection of the first metatarsal
Normal = 15 degrees or less (parallel to the second)

Question 15

Psoriatic arthritis

Answer 15

Asymmetric arthritis involving the distal interphalangeal joints (DIPJ) is a characteristic feature of psoriatic arthritis
These joints are generally red and warm to the touch
“Asymmetrical oligoarthritis” = inflammation affecting two to four joints during the first 6 months of disease → 70% of cases
15% of cases arthritis is symmetrical
Overall sites that are affected: PIPJ, DIPJ, MCPJ, wrist

Question 16

Bohler’s angle

Answer 16

Normal: 25-40 degrees
Measured on the lateral view
Formed by two lines that are drawn tangent to the anterior and posterior aspects of the superior calcaneus.
A value less than 20° can be seen in calcaneal fracture.

Question 17

3 phase Technetium 99

Answer 17

Stress fracture would have increased signal in all 3 phases
Technetium-99m phosphate analogues are most commonly used because they are taken up at sites of turnover of bone. The stress fracture will show up in all three phases as a focally intense fusiform area of cortical uptake. The sensitivity of the bone scan is compromised by the lack of specificity

Question 18

US plantar fascia

Answer 18

Normal thickness of plantar fascia is 4 mm
Increased thickness of the PF measuring more than 4–5 mm within 5 mm of its calcaneal attachment is evident on lateral plain radiographs of individuals with plantar fasciitis

Question 19

Harris Beath

Answer 19

Best radiograph to visualize a talocalcaneal coalition - axial view of the hindfoot and heel

Question 20

Plantar fibromatosis

Answer 20

Slowly growing plantar mass
Characterized by disordered fibrous tissue proliferation and the subsequent formation of nodules
MRI showed low signal intensity, well defined, lobulated aponeurotic lesion
First line treatment includes steroids that can shrink the nodule and relief pain. Surgical treatment is reserved for symptomatic nodules not responsive to conservative management

Question 21

Ewing’s sarcoma

Answer 21

Malignant neoplasm of bone develops in the diaphysis or metaphysis of long bones, especially the femur/tibia/humerus. Also the pelvis and ribs
Most common in childhood, most patients younger than 20 and boys more than girls
10-20 is the most common time of radiographic diagnosis

Question 22

Chondromyxoid fibroma

Answer 22

More common in males
Rare tumor
Radiographic findings include a lytic lesion with a scalloped and sclerotic rim
Treatment is intralesional curettage and bone grafting

Question 23

Plantar plate rupture

Answer 23

Arthrogram can diagnose an isolated plantar plate rupture
Only the plantar plate separates the MTPJ from the flexor tendon sheath. The medial and lateral collateral ligaments and the extraarticular, deep transverse metatarsal ligament are contiguous with the plantar plate.
Contrast opacification of the flexor tendon sheath is indicative of plantar plate rupture

Question 24

Radiography

Answer 24

Patient dose is determined at skin level

Question 25

Osteomyelitis on MRI

Answer 25

Decreased on TI, increase on T2 T1- weighted low signal intensity medullary space T2 weighted high signal intensity surrounding inflammatory process, edema

Question 26

Sarcoidosis

Answer 26

Kveim test showed high sensitivity in the diagnosis of sarcoidosis

Question 27

Pencil in cup deformity

Answer 27

Pencil-in-cup deformity is most recognized in psoriatic arthritis, but may also appear in rheumatoid arthritis, reactive arthritis and scleroderma. The pencil in cup appearance emerges from the periarticular erosion and bone resorption

Question 28

Tissue calcinosis of renal failure

Answer 28

Presents with ESRD on HD, multiple painless plantar lumps, amorphous, multilobulated “cloud like” calcifications on x-ray Management of tumoral calcinosis is often difficult and involves dietary phosphate restriction, noncalcemic phosphate binders and intensification of dialysis treatment using a low-calcium dialysate, parathyroidectomy in patients with high PTH levels due to tertiary hyperparathyroidism. Surgical excision is an option for persistent symptomatic lesions

Question 29

Iselin’s disease

Answer 29

Apophysitis of the 5th metatarsal base An overuse osteochondrosis seen in growing children Although amenable to treatment, it is a self-limiting disorder, disappearing spontaneously with completion of growth

Question 30

Sesamoid axial

Answer 30

An axial projection uncovers the relationship of the sesamoids to the cristae

Question 31

Codman triangle

Answer 31

Defined as the lifting of the periosteum due to new subperiosteal bone formation, resulting from an underlying tumor Codman triangle is the diagnostic finding in the osteosarcoma which is the most common primary tumor of the long bones of the lower extremities Most commonly found in the distal femur and proximal tibia Codman triangle along with sun rising appearance, radial, patchy aggressive periosteal reactions, osteoid matrix in the areas of bone destruction and a soft-tissue mass - are common findings on radiograph

Question 32

Bone scan nonunion

Answer 32

The presence of new bone callus on xray or increased tracer uptake on bone scan indicates that biologic activity is present. Uptake in bone scintigraphy indicates blood flow and new bone formation and increased chance of success with bone stimulation. An atrophic or avascular nonunion would likely have little to no improvement with bone stimulation alone. Surgical treatment must be considered for an atrophic nonunion

Question 33

Cellulitis on bone scan

Answer 33

Technetium negative, gallium positive A useful breakdown on how bone scans will differentiate infections: Tc-99: If positive in Phase 3, Indicative of OM, If Negative in Phase 3, excludes osteo Ga-67: Diffuse uptake: Soft tissue infection In-111: Acute OM: Positive, Chronic OM: Negative Yet another break down: Acute OM: Positive Tc-99, Positive Gallium /// Septic Arthritis: Positive Tc-99, Positive Gallium /// Chronic Osteomyelitis: Positive Tc-99, Negative Gallium /// Cellulitis: Negative Tc-99, Positive Gallium ///

Question 34

Hypertrophic nonunion

Answer 34

An “elephant foot,” nonunion is a subdivision of a hypervascular nonunion. They are hypertrophic, rich in callus formation, and provide the best chance at healing

Question 35

Osteochondroma

Answer 35

Osteochondromas are stalked lesions that point to the diaphysis and away from the growth plate, typically they point away from the joint within the digits. When the tumor is palpable, it may feel much larger than it is apparent on radiographs

Question 36

Vertical talus

Answer 36

Vertical talus presents with a rigid rocker bottom deformity with fixed hindfoot valgus, a rigid dorsiflexed midfoot and forefoot that is abducted and dorsiflexed. Kite’s angle (talocalcaneal on AP) increases in pronation, and decreases with supination

Question 37

Stress fracture

Answer 37

Radiographic evidence after 2 weeks

Question 38

Eckert and Davis Classification for Peroneal Subluxation

Answer 38

Grade I: retinaculum detaches from fibrocartilage ridge Grade II: elevation of retinaculum and fibrocartilage ridge from lateral malleolus Grade III: avulsion of bone fragment with retinaculum and fibrocartilage ridge from lateral malleolus - “Fleck sign” Grade IV (Ogden modification): rupture of retinaculum posterior to insertion

Question 39

Tetracycline for diagnosis of osteoid osteoma

Answer 39

Using tetracycline dosed 4 times daily for 2 days pre-operatively will cause the nidus of osteoid osteoma to exhibit a golden yellow fluorescence This simple technique permits quick, easy, economical and sure verification that the nidus ahs been excised

Question 40

Ceretec scan

Answer 40

Need at least 2000 cells/μL to safely perform ceretec scan WBC scan completed over 2 appointments Indium labelled WBC scan detects abscesses or infections using radioactive material, however requires least 2000 cells/μL

Question 41

What lights up on bone scan

Answer 41

Increased uptake of radioactivity in the facial area, sternum, tips of the scapulae, spine, and sacroiliac joints Scans of children's bones also show increased uptake in active epiphyseal bone-growth centers such as knees, ankles, elbows Kidneys and bladder are visualized because of the renal excretions

Question 42

Metaphysis as origin of bone tumor

Answer 42

``` Osteosarcoma Fibrosarcoma Chondrosarcoma Osteoid osteoma Osteoblastoma Enchondroma Fibrous dysplasia Aneurysmal bone cyst Non-ossifying fibroma NOT Ewings sarcoma (diaphysis of long bones) ```

Question 43

Talar neck fracture

Answer 43

Most common complication of talar neck fracture is post traumatic arthritis

Question 44

Arterial calcifications

Answer 44

When you see arterial calcifications on x-ray, consider a treatment algorithm that includes arterial studies

Question 45

Hawkins sign

Answer 45

Subchondral radiolucent band in the talar dome that is indicative of viability at 6 to 8 weeks after a talus fracture. It is visible in the anterior-posterior view, but seldom appears on lateral radiographs

Question 46

Metformin

Answer 46

Renally excreted Can develop lactic acidosis with metformin use and administration of contrast angiography or procedures using contrast HIgh mortality in patients developing lactic acidosis Discontinue before procedure and 48 hrs after Restart when labs demonstrate normal renal function

Question 47

Giant cell tumor

Answer 47

Slow growing, large lytic mass at end of long bone (epiphysis) 30s-40s present Benign but can metastasize to lungs, chest

Question 48

Visualizing an anterior facet coalition

Answer 48

Although technically difficult to perform, of the views listed; isherwood provides the best view of the anterior facet of the calcaneus.

Question 49

Painful bone tumor

Answer 49

Osteoid osteoma is a benign bone tumour characterized by pain which is relieved by non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin

Question 50

Physeal closure of distal tibial physis

Answer 50

Skeletal growth typically continues until 16 years in males and 14 years in females. The distal tibia physis closes in a predictable manner: central, anteromedial, posteromedial, then lateral. The lateral aspect is most often injured in adolescents as it is last to close.

Question 51

Pigmented villonodular synovitis

Answer 51

Would show lipid laden macrophages and hemosiderin deposits

Question 52

Most common malignant bone or cartilage tumor in children?

Answer 52

Osteosarcoma

Question 53

Is cortical bone well visulaized on MRI?

Answer 53

NO - Cortical bone is NOT well evaluated on MRI. “X-ray imaging and CT scans enable the evaluation of bone destruction, periosteal reaction, sclerotic changes in lesions, condition of cortical bone, and ossification. MRI enables the assessment of tissue characteristics, tumor extent, and the reactive areas.”

Question 54

Lauge Hansen

Answer 54

Supination - Adduction (SA) Pronation - Abduction (PAb) Supination - External Rotation (SER) Pronation - External Rotation (PER)

Question 55

Supination - Adduction (SAd)

Answer 55

1. Talofibular sprain or distal fibular avulsion | 2. Vertical medial malleolus and impaction of anteromedial distal tibia

Question 56

Pronation - Abduction (PAb)

Answer 56

1. Medial malleolus transverse fracture or disruption of deltoid ligament 2. Anterior tibiofibular ligament sprain 3. Transverse comminuted fracture of the fibula above the level of the syndesmosis

Question 57

Supination - External Rotation (SER)

Answer 57

1. Anterior tibiofibular ligament sprain 2. Lateral short oblique fibula fracture (anteroinferior to posterosuperior) 3. Posterior tibiofibular ligament rupture or avulsion of posterior malleolus 4. Medial malleolus transverse fracture or disruption of deltoid ligament

Question 58

Pronation - External Rotation (PER)

Answer 58

1. Medial malleolus transverse fracture or disruption of deltoid ligament 2. Anterior tibiofibular ligament disruption 3. Lateral short oblique or spiral fracture of fibula (anterosuperior to posteroinferior) above the level of the joint 4. Posterior tibiofibular ligament rupture or avulsion of posterior malleolus.

Question 59

Talar dome lesions

Answer 59

Pictured below is a medial talar dome lesion. Anterolateral lesions are usually the result of an inversion injury and dorsiflexion forces, causing a shallow and wafer-shaped lesion. Medial talar dome lesions are usually deeper and cup-shaped. They are the result of plantarflexion, inversion and external rotation. DIAL - dorsiflexion inversion, anterior lateral PIMP - plantarflexion inversion external rotation, medial portion