Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology Indian Medical PG Practice Questions and MCQs

Question 371: "Sunray appearance" on X-rays is suggestive of:

A. A metastatic tumour in the bone
B. An Osteogenic sarcoma (Correct Answer)
C. An Ewing's sarcoma
D. A type of bone cancer that can show various radiographic appearances

Explanation: ***An Osteogenic sarcoma*** - The **"sunray appearance" (or sunburst)** on X-rays is a classic radiographic finding pathognomonic for **osteosarcoma**, especially in adults and adolescents. - This appearance is due to the **periosteal new bone formation** that grows perpendicular to the bone surface, creating a radiating spicule pattern. *A type of bone cancer that can show various radiographic appearances* - While true that bone cancers can show various appearances, the "sunray appearance" is specific enough to strongly point to a particular type, rather than just a general category. - This option is too broad and does not provide the most precise diagnosis indicated by the specific radiographic sign. *A metastatic tumour in the bone* - Metastatic bone lesions typically present with **lytic (bone destruction)** or **blastic (bone formation)** patterns, or a mixed pattern, but rarely produce the periosteal "sunray" appearance. - The characteristic radiographic finding for metastasis would often involve multiple lesions and different periosteal reactions, such as an **onion skin appearance** in some aggressive cases, but not typically sunray. *An Ewing's sarcoma* - Ewing's sarcoma commonly presents with an **"onion skin" periosteal reaction** due to multiple layers of new bone formation. - While both are primary bone tumors, the radiographic findings are distinctly different, allowing for differentiation.

Question 372: Which one of the following is a recognized X-ray feature of rheumatoid arthritis?

A. Bamboo spine
B. Bone erosions (Correct Answer)
C. Peri-articular calcification
D. Juxta-articular osteosclerosis

Explanation: ***Bone erosions*** - **Bone erosions** are a hallmark feature of **rheumatoid arthritis (RA)**, representing irreversible joint damage caused by synovial inflammation and pannus formation. - They typically appear early in the disease course and contribute to functional impairment. *Juxta-articular osteosclerosis* - **Osteosclerosis** (increased bone density) near the joints is more characteristic of **osteoarthritis**, where new bone formation occurs in response to cartilage loss. - In rheumatoid arthritis, **juxta-articular osteopenia** (decreased bone density) due to inflammation and disuse is more common. *Bamboo spine* - **Bamboo spine** is a characteristic radiographic finding in **ankylosing spondylitis**, due to syndesmophyte formation and fusion of vertebral bodies. - It is not associated with rheumatoid arthritis. *Peri-articular calcification* - **Peri-articular calcification** is seen in conditions like **calcium pyrophosphate deposition disease (CPPD)**, also known as pseudogout. - While calcification can occur in some rheumatic conditions, it is not a primary or characteristic feature of rheumatoid arthritis.

Question 373: What is the gold standard for the diagnosis of osteoporosis?

A. Dual energy X-ray absorptiometry (Correct Answer)
B. Single energy X-ray absorptiometry
C. Ultrasound
D. Quantitative computed tomography

Explanation: ***Dual energy X-ray absorptiometry*** - **DXA** is the current **gold standard** for diagnosing osteoporosis and assessing fracture risk due to its high precision and accuracy in measuring **bone mineral density (BMD)**. - It measures BMD at clinically relevant sites such as the **lumbar spine** and **hip**, providing T-scores and Z-scores for comparison. *Single energy X-ray absorptiometry* - **SXA** measures BMD at peripheral sites but is **less accurate** and comprehensive than DXA for diagnosing osteoporosis. - It has **limited utility** as a diagnostic tool for osteoporosis at the hip or spine, which are critical sites for fracture risk. *Ultrasound* - **Quantitative ultrasound (QUS)** can assess bone quality but is primarily used for **screening** and is not accurate enough for definitive diagnosis or treatment monitoring of osteoporosis. - It does **not provide direct bone mineral density measurements** comparable to DXA for diagnostic purposes. *Quantitative computed tomography* - **QCT** can measure volumetric bone density and is useful for assessing **trabecular bone**, but involves higher radiation exposure than DXA. - It is **more expensive** and less readily available than DXA, making it a secondary option for osteoporosis diagnosis.

Question 374: Scotty dog sign is seen in:

A. Spondylolysis (Correct Answer)
B. Fracture femur
C. Sarcoidosis
D. Osteosarcoma

Explanation: ***Spondylolysis*** - The **Scotty dog sign** is a classic radiographic finding on an **oblique lumbar spine X-ray** indicating a defect in the pars interarticularis. - This defect, known as **spondylolysis**, causes the "neck" of the Scotty dog to appear broken or wearing a collar. *Fracture femur* - **Femur fractures** are typically identified by discontinuity of the cortical bone and soft tissue swelling, often visualized on **AP and lateral views of the thigh/hip**. - No specific "Scotty dog" appearance is associated with femur fractures, as this sign relates to the **lumbar spine**. *Sarcoidosis* - **Sarcoidosis** is a multi-system inflammatory disease primarily affecting the lungs and lymph nodes, with characteristic **non-caseating granulomas**. - Radiological findings typically include **hilar lymphadenopathy** and pulmonary infiltrates, not a bony defect like the Scotty dog sign. *Osteosarcoma* - **Osteosarcoma** is a primary malignant bone tumor often presenting with a **sunburst pattern** or **Codman triangle** on X-ray. - It primarily affects the metaphysis of long bones and does not produce the specific bony defect seen in the pars interarticularis.

Question 375: Striated vertebrae are seen in which of the following conditions?

A. TB spine
B. Hemangioma (Correct Answer)
C. Chordoma
D. Metastasis

Explanation: ***Hemangioma*** - **Striated vertebrae**, also known as **corduroy cloth sign** or **vertical striations**, are characteristic radiological findings of vertebral hemangiomas. - This appearance is due to the **thickened vertical trabeculae** within the vertebral body, resulting from the overgrowth of vascular tissue. *TB spine* - **Tuberculosis of the spine (Pott's disease)** typically presents with destructive lesions, **vertebral collapse**, and potentially paravertebral abscesses. - It does not typically cause the striated appearance seen in hemangiomas. *Chordoma* - Chordomas are rare, slow-growing malignant tumors often found in the **sacrococcygeal region** or clivus, less commonly affecting the mobile spine. - They tend to cause **lytic or sclerotic lesions** with soft tissue involvement and do not typically produce a striated vertebral body. *Metastasis* - **Vertebral metastases** can be lytic, blastic, or mixed, leading to bone destruction, sclerosis, or both. - While they can cause spinal pain and bone abnormalities, they do not classically result in the **corduroy cloth appearance** of striated vertebrae.

Question 376: Sclerotic lesions in the bone are seen in all except:

A. Melorheostosis
B. Caffey's disease
C. Osteopetrosis
D. Osteitis fibrosa (Correct Answer)

Explanation: ***Osteitis fibrosa*** - This condition is associated with **hyperparathyroidism**, leading to excessive bone resorption and replacement by fibrous tissue, which is characterized by **osteopenia and cystic changes**, not sclerotic lesions. - Classic features include **brown tumors** and **subperiosteal bone resorption**. *Osteopetrosis* - Characterized by abnormally **dense bones** due to a defect in **osteoclast function**, resulting in impaired bone resorption. - This leads to diffusely **sclerotic bones** on imaging, increasing bone mass and fragility. *Melorheostosis* - A rare, non-hereditary mesenchymal dysplasia characterized by **flowing hyperostosis** of cortical bone, resembling "flowing candle wax." - This results in localized or regional areas of **sclerosis and bone thickening**. *Caffey's disease* - Also known as **infantile cortical hyperostosis**, it is characterized by areas of **sclerotic periosteal new bone formation** and proliferation, mainly in infants. - It typically affects the diaphysis of long bones, mandible, and ribs, presenting as **tender swelling** and cortical thickening.

Question 377: Flowing wax appearance on the anterior and posterior borders of the vertebrae is seen in?

A. Ankylosing spondylitis
B. DISH (Correct Answer)
C. Psoriatic arthropathy
D. Rheumatoid arthritis

Explanation: ***DISH*** - The "flowing wax" or "melting candle wax" appearance on the anterior and posterior borders of the vertebrae is a classic radiographic finding in **Diffuse Idiopathic Skeletal Hyperostosis (DISH)**, also known as Forestier's disease. - This appearance is due to the **calcification and ossification of ligaments and entheses**, particularly the anterior longitudinal ligament. *Ankylosing spondylitis* - Characterized by ascending **sacroiliitis** and subsequent fusion of vertebral bodies, leading to a "bamboo spine" appearance, which is distinct from "flowing wax." - Involves **inflammatory changes** at entheses, but the pattern of ossification differs from DISH. *Psoriatic arthropathy* - Can affect the spine, but it typically causes **non-marginal syndesmophytes** and erosion, rather than the extensive ligamentous ossification seen in DISH. - Often associated with distinctive **peripheral arthritis** and **skin lesions**. *Rheumatoid arthritis* - Primarily affects the **synovial joints**, with spinal involvement mainly seen in the **cervical spine** leading to instability or subluxation. - Does not typically cause diffuse ligamentous ossification or a "flowing wax" appearance in the thoracolumbar spine.

Question 378: Which of the following X-ray findings is characteristic of fibrous dysplasia?

A. Ground glass density (Correct Answer)
B. Calcifications
C. Cortical thickening
D. Bony expansion

Explanation: ***Ground glass density*** - The classic X-ray appearance of fibrous dysplasia is a **diffuse haziness** or ground glass density within the affected bone. - This appearance is due to the replacement of normal bone with **immature woven bone** and fibrous stroma. *Calcifications* - While some lesions might contain calcifications, it's not the **characteristic hallmark** feature of fibrous dysplasia itself, but rather a less common finding. - **Chondroid lesions** or those undergoing malignant transformation are more likely to exhibit significant calcification. *Cortical thickening* - Though fibrous dysplasia can lead to bone remodeling and some degree of cortical changes, prominent **cortical thickening** is not the primary diagnostic imaging feature. - **Paget's disease** or chronic osteomyelitis are more typically associated with significant cortical thickening. *Bony expansion* - Fibrous dysplasia often causes **bone expansion** and deformity, but this is a *result* of the underlying lesion rather than its specific radiographic *texture*. - Many bone lesions, both benign and malignant, can cause bony expansion, so it is not specific to fibrous dysplasia.

Question 379: What is the earliest X-ray sign observed in spinal tuberculosis?

A. Gibbus
B. Narrowing of disc space (Correct Answer)
C. Paravertebral shadow
D. Endplate erosion

Explanation: ***Narrowing of disc space*** - This is the **earliest radiographic finding** in spinal tuberculosis on plain X-ray, typically appearing within the first few weeks to months of infection. - Tuberculous spondylitis begins in the **anterior subchondral region** near the vertebral endplates, leading to early involvement of the intervertebral disc. - The infection spreads from the vertebral body to the adjacent disc, causing **disc space narrowing** along with endplate irregularities as initial manifestations. - Unlike pyogenic spondylitis, TB shows **relatively preserved** disc space initially, but narrowing is still the earliest visible change. *Endplate erosion* - **Endplate erosion** occurs concurrently with or shortly after disc space narrowing as the tuberculous infection destroys the subchondral bone. - Both findings appear early in the disease course and are often seen together on X-ray. - This represents active bone destruction at the vertebral margins. *Paravertebral shadow* - The **paravertebral abscess** is a characteristic and important finding in spinal tuberculosis, but it develops **later** in the disease course. - It forms as a secondary phenomenon when the infection spreads beyond the vertebral body, with caseous material and pus collecting along the paravertebral ligaments. - While highly suggestive of TB when present, it is not the earliest radiographic sign. *Gibbus* - A **gibbus deformity** is a **late complication** resulting from vertebral body collapse and subsequent angular kyphosis. - It indicates extensive vertebral destruction and significant structural compromise. - This is a clinical and radiographic sign of advanced disease, not an early finding.

Question 380: Onion-peel appearance is seen in:

A. Ewing's sarcoma (Correct Answer)
B. Osteoma
C. Osteoclastoma
D. Osteosarcoma

Explanation: ***Ewing's sarcoma*** - The **onion-peel appearance** refers to a characteristic **lamellated periosteal reaction** seen on X-rays, indicative of new bone formation in layers. - This pattern is a classic radiological sign of **Ewing's sarcoma**, a highly malignant primary bone tumor, as the tumor grows and stimulates cyclical new bone formation by the periosteum. *Osteoma* - An osteoma is a **benign tumor** characterized by a slow-growing, **dense, ossified lesion**, typically found on the surface of bones. - It does not exhibit an aggressive periosteal reaction or the layered "onion-peel" appearance, but rather a **dense, uniform sclerotic appearance**. *Osteoclastoma* - Also known as a **giant cell tumor of bone**, osteoclastomas are typically lytic lesions that appear as **expansile, soap-bubble-like** or cystic lesions on X-ray. - They are characterized by a lack of host bone formation and do not present with the layered periosteal reaction seen in Ewing's sarcoma. *Osteosarcoma* - Osteosarcoma is primarily characterized by the production of **osteoid (immature bone)** by malignant cells. - While it can exhibit various periosteal reactions (e.g., **Codman's triangle or sunburst pattern**), the classic "onion-peel" appearance is not its typical presentation.

Practice by Chapter

Radiographic Anatomy of Bones and Joints

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Imaging of Fractures and Dislocations

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Arthritides: Inflammatory and Degenerative

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Metabolic Bone Diseases

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Bone and Soft Tissue Tumors

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Congenital Skeletal Anomalies

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Spine Imaging

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Skeletal Infections

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Sports Medicine Imaging

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Imaging of Prostheses and Implants

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Musculoskeletal Ultrasound

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MSK Interventional Procedures

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