Musculoskeletal Radiology Practice Questions

Q: An MRI pelvis shows 'bow tie' sign in the sacrum. Which additional finding would best support sacral insufficiency fracture?

H-pattern on bone scan. ***H-pattern on bone scan*** - The "bow tie" sign on MRI, indicating **sacral insufficiency fracture**, is often accompanied by an **H-pattern** (or Honda sign) on a **technetium-99m bone scan**. - This characteristic H-pattern reflects increased radionuclide uptake in the **sacral ala** and across the **sacral body**, following the fracture lines. *Cortical destruction* - **Cortical destruction** is typically associated with **malignant processes** or severe infections, which are not characteristic of insufficiency fractures. - While fractures can disrupt bone architecture, complete cortical destruction is a more aggressive sign than usually seen in insufficiency fractures. *Soft tissue mass* - The presence of a **soft tissue mass** usually suggests a **tumor** (benign or malignant) or an **abscess**, which are distinct pathologies from an insufficiency fracture. - Sacral insufficiency fractures are stress-related injuries with no associated soft tissue component. *Periosteal reaction* - **Periosteal reaction** indicates an active process of **bone formation** or destruction involving the periosteum, often seen in infections, tumors, or traumatic fractures with significant periosteal stripping. - While bone healing can show some new bone formation, a distinct periosteal reaction is not a primary or specific feature for diagnosing sacral insufficiency fractures.

Q: An MRI spine shows 'pancake vertebra' appearance. Which additional finding would best support osteoporotic compression fracture?

Posterior wall buckling. **Posterior wall buckling** - Posterior wall buckling on MRI is a strong indicator of an **osteoporotic compression fracture**, as it represents the posterior cortex of the vertebral body being pushed posteriorly. - This finding helps distinguish osteoporotic fractures from pathological fractures which are less likely to exhibit uniform vertebral body collapse. *Paraspinal mass* - A paraspinal mass is more suggestive of a **destructive lesion**, such as malignancy or infection, rather than an osteoporotic fracture. - It indicates potential involvement of soft tissues beyond the vertebral body itself, which is not typical for uncomplicated osteoporotic fractures. *Pedicle involvement* - Pedicle involvement is highly indicative of a **malignant process** or severe trauma rather than a purely osteoporotic compression fracture. - Osteoporotic fractures primarily affect the vertebral body, typically sparing the posterior elements like the pedicles. *Normal signal on STIR* - A normal signal on **STIR (Short Tau Inversion Recovery)** sequence indicates the absence of acute edema or inflammation, which would suggest a chronic or old fracture. - An acute osteoporotic compression fracture typically shows **high signal intensity on STIR** due to bone marrow edema, reflecting recent trauma.

Q: An abdominal CT shows 'champagne glass' appearance of pelvic bones. Which additional finding would best support Paget's disease?

Cotton wool skull. ***Cotton wool skull*** - The **champagne glass appearance** of the pelvic bones is a characteristic radiological finding in **Paget's disease**, indicating bone remodeling with cortical thickening and expansion of the iliac bones. - The presence of a **cotton wool skull**, characterized by patchy areas of sclerosis and lucency on skull radiographs, is another highly specific and common finding in advanced Paget's disease, further supporting this diagnosis. *Bamboo spine* - **Bamboo spine** is a characteristic radiographic finding in **ankylosing spondylitis**, representing calcification of the spinal ligaments and fusion of vertebrae. - This finding is not associated with Paget's disease of bone. *Ivory vertebra* - An **ivory vertebra** refers to a homogeneously dense and sclerotic vertebral body, which is a classic radiographic sign seen in **Paget's disease**, **metastatic prostate cancer**, and occasionally in **lymphoma**. - While ivory vertebra can occur in Paget's disease, the **cotton wool skull** in conjunction with the champagne glass pelvis provides a more specific diagnostic pattern, as cotton wool appearance is almost pathognomonic for Paget's disease. *Bone islands* - **Bone islands** (enostoses) are common, benign focal areas of cortical bone within the cancellous bone, usually seen as uniformly dense, well-circumscribed lesions on imaging. - They are typically asymptomatic and unrelated to Paget's disease, which involves widespread disorganized bone remodeling.

Q: An MRI shows 'salt and pepper' appearance of skull. Which bone scan finding would best support Paget's disease?

Superscan pattern. ***Superscan pattern*** - A **superscan** on a bone scintigraphy signifies widespread, increased radionuclide uptake in the skeleton, often seen in the disseminated form of **Paget's disease**, particularly involving multiple bones. - While "salt and pepper" skull refers to **osteoporosis circumscripta** in Paget's, the superscan on bone scan indicates diffuse metabolic activity consistent with the overall disease process. *Mickey mouse sign* - This sign is typically associated with **fibrous dysplasia** of the skull, not Paget's disease. - It describes a characteristic appearance on scintigraphy due to asymmetric uptake in the skull base, distinct from Paget's. *Photopenic lesions* - **Photopenic** or "cold" lesions on bone scan indicate areas of decreased metabolic activity or bone destruction, such as in some metastases or avascular necrosis. - Paget's disease is characterized by markedly **increased bone turnover**, resulting in areas of increased uptake, not photopenia. *Doughnut sign* - The **doughnut sign** can be seen in various conditions like benign bone cysts or fibrous dysplasia through bone scintigraphy, but it is not characteristic of Paget's disease. - It represents a central area of decreased uptake surrounded by a rim of increased uptake, which differs from the diffuse uptake pattern in Paget's.

Q: An MRI shows 'pencil-in-cup' deformity of interphalangeal joints. Which radiological finding would best support psoriatic arthritis?

Periosteal reaction. ***Periosteal reaction*** - **Periosteal reaction (new bone formation)** is a characteristic feature of **psoriatic arthritis**, particularly in the small bones of the hands and feet. - Psoriatic arthritis shows a distinctive **combination of erosive and proliferative changes**: the "pencil-in-cup" deformity represents bone erosion, while periosteal reaction represents new bone formation. - This mixed pattern of bone destruction and formation helps distinguish psoriatic arthritis from other inflammatory arthropathies. *Bamboo spine* - **Bamboo spine** is a radiological hallmark of **ankylosing spondylitis**, resulting from syndesmophyte formation and fusion of vertebrae. - It is not typically seen in psoriatic arthritis, which primarily affects peripheral joints and entheses. While psoriatic arthritis can cause axial involvement, it more commonly presents with asymmetric syndesmophytes rather than the classic bamboo spine appearance. *Juxta-articular osteopenia* - **Juxta-articular osteopenia** is a common early finding in **rheumatoid arthritis** due to chronic inflammation and hyperemia causing bone resorption near affected joints. - In contrast, psoriatic arthritis typically shows **preserved or increased bone density** in periarticular regions due to new bone formation, making this a key differentiating feature. *Soft tissue swelling* - **Soft tissue swelling** is a nonspecific sign of inflammation present in many arthritic conditions, including psoriatic arthritis. - It is a **non-discriminatory finding** and does not help distinguish psoriatic arthritis from other types of inflammatory arthritis such as rheumatoid arthritis or reactive arthritis.

Q: Initial radiological finding seen in knee TB

Increase in joint space. ***Increase in joint space*** - Early **tuberculous synovitis** leads to synovial hypertrophy and effusion, causing an **increase in joint space** due to fluid accumulation on imaging. - This is the **initial radiological finding** before significant cartilage destruction or bone erosion occurs. - Part of **Phemister's triad** (juxta-articular osteoporosis, peripheral erosions, and gradual joint space reduction in later stages). *Reduction of joint space* - **Joint space narrowing** typically occurs later in the disease as the **cartilage is destroyed**. - This finding is more characteristic of advanced tuberculous arthritis, not the initial stages of knee TB. *Bone resorption* - **Bone resorption (osteolysis)** is a later manifestation of knee TB, often seen with **caseous necrosis** and subchondral bone involvement. - It does not represent the very initial radiological changes, which are primarily synovial-based. *Degeneration of cartilage* - While cartilage is eventually affected by knee TB, **cartilage degeneration** leading to significant changes visualized on imaging is a later event. - The initial presentation is more about synovial inflammation and fluid buildup causing increased joint space.

Q: All are radiological signs of Vitamin C deficiency except:

Widening of epiphysis. ***Widening of epiphysis*** - This is **NOT a radiological sign of Vitamin C deficiency (scurvy)**. - In scurvy, **epiphyseal-metaphyseal separation** or **slipped epiphyses** can occur due to weakened growth plates and subperiosteal hemorrhage, but the epiphysis itself does not show widening. - Scurvy is characterized by impaired collagen synthesis leading to fragility at the growth plate zone, resulting in displacement or separation, not widening. *White line of Fränkel* - This refers to a dense, **calcified metaphyseal line** seen on radiographs, characteristic of scurvy. - It represents the zone of provisional calcification, which appears prominent due to impaired endochondral ossification in **Vitamin C deficiency**. *Wimberger line (Wimberger's sign)* - Also known as Wimberger's ring sign, this describes a **sclerotic ring of increased density** around the **epiphyseal ossification centers**. - It is caused by **subperiosteal hemorrhage** and subsequent calcification, a classic radiological sign of scurvy. *Osteoporosis of bone* - **Generalized osteopenia** (ground-glass osteoporosis) is seen in scurvy due to impaired osteoid formation and defective collagen synthesis. - This leads to decreased bone density and increased skeletal fragility, making bones more susceptible to fractures.

Q: Characteristic radiological feature of fibrous dysplasia is:

Ground glass appearance. ***Ground glass appearance*** - The "ground glass" appearance on **radiography** is a classic and highly characteristic feature of **fibrous dysplasia**, reflecting the immature, woven bone and fibrous tissue within the lesion. - This specific pattern results from the uniform, finely trabeculated osseous tissue that is less dense than normal bone, creating a hazy, frosted appearance. *Cortical erosion* - While significant **tumor growth** in any bone lesion can lead to cortical erosion, it is not a specific or characteristic primary feature of **fibrous dysplasia**. - **Cortical erosion** is more commonly associated with aggressive or rapidly expanding lesions, such as malignant tumors or infections. *Bone enlargement* - **Bone enlargement** can occur in fibrous dysplasia due to the expansion of the abnormal fibrous and osseous tissue, but it is a non-specific finding. - Many conditions, including various **benign** and **malignant tumors**, can cause bone enlargement, making it less diagnostic on its own. *Thickened bone matrix* - Fibrous dysplasia involves a disorganized and immature bone matrix, characterized by **woven bone**, not a thickened, well-organized normal bone matrix. - **Thickened bone matrix** may be seen in conditions like osteopetrosis or Paget's disease, which involve different pathological bone remodeling processes.

Q: Popcorn calcification is seen in

Chondrosarcoma. ***Chondrosarcoma*** - **Popcorn calcification** is a classic radiographic sign frequently observed in **chondrosarcoma**, representing calcified cartilage matrix. - This type of calcification is typically seen in tumors arising from **cartilaginous tissue**. *Adamantinoma* - Adamantinoma is a rare, malignant bone tumor characterized by **epithelial cell nests** within a fibrous stroma, primarily affecting the **tibia**. - It usually presents with **lytic lesions** and often contains areas of calcification, but not typically the "popcorn" pattern. *Osteosarcoma* - Osteosarcoma is characterized by the production of **osteoid** by malignant osteoblasts. - Radiographically, it often shows a **sunburst pattern** or **Codman's triangle**, indicative of aggressive periosteal reaction and calcified tumor matrix, distinct from popcorn calcification. *Multiple myeloma* - Multiple myeloma is a **hematologic malignancy** involving plasma cells, leading to widespread osteolytic lesions. - It typically presents as **punched-out lytic lesions** without calcification or osteoblastic activity.

Question 1

An MRI pelvis shows 'bow tie' sign in the sacrum. Which additional finding would best support sacral insufficiency fracture?

Accepted Answer

H-pattern on bone scan

Answer

Cortical destruction

Answer

Soft tissue mass

Answer

Periosteal reaction

Question 2

An MRI spine shows 'pancake vertebra' appearance. Which additional finding would best support osteoporotic compression fracture?

Accepted Answer

Posterior wall buckling

Answer

Paraspinal mass

Answer

Pedicle involvement

Answer

Normal signal on STIR

Question 3

An abdominal CT shows 'champagne glass' appearance of pelvic bones. Which additional finding would best support Paget's disease?

Accepted Answer

Cotton wool skull

Answer

Bamboo spine

Answer

Ivory vertebra

Answer

Bone islands

Question 4

An MRI shows 'salt and pepper' appearance of skull. Which bone scan finding would best support Paget's disease?

Accepted Answer

Superscan pattern

Answer

Mickey mouse sign

Answer

Photopenic lesions

Answer

Doughnut sign

Question 5

An MRI shows 'pencil-in-cup' deformity of interphalangeal joints. Which radiological finding would best support psoriatic arthritis?

Accepted Answer

Periosteal reaction

Answer

Bamboo spine

Answer

Juxta-articular osteopenia

Answer

Soft tissue swelling

Question 6

Initial radiological finding seen in knee TB

Accepted Answer

Increase in joint space

Answer

Reduction of joint space

Answer

Bone resorption

Answer

Degeneration of cartilage

Question 7

All are radiological signs of Vitamin C deficiency except:

Accepted Answer

Widening of epiphysis

Answer

White line of Fränkel

Answer

Wimberger line

Answer

Osteoporosis of bone

Question 8

Characteristic radiological feature of fibrous dysplasia is:

Accepted Answer

Ground glass appearance

Answer

Cortical erosion

Answer

Bone enlargement

Answer

Thickened bone matrix

Question 9

Popcorn calcification is seen in

Accepted Answer

Chondrosarcoma

Answer

Adamantinoma

Answer

Osteosarcoma

Answer

Multiple myeloma

Question 10

Which of the following represents important radiological differentiating features between psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis?

Accepted Answer

Radiological patterns and joint distribution

Answer

Laboratory markers and genetic associations

Answer

Clinical presentation and extra-articular features

Answer

Spinal involvement patterns

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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