Musculoskeletal Radiology Practice Questions

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

DISH. ***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.

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

Ground glass density. ***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.

Q: What is depicted in the X-ray of the skull? (Refer to the provided image)

Pepper pot skull. ***Pepper pot skull*** - This X-ray appearance is characterized by **numerous small lytic lesions** scattered throughout the skull, resembling a "pepper pot." - It is a classic radiographic finding in **hyperparathyroidism**, indicative of subperiosteal bone resorption. *Artifacts* - Artifacts are **extraneous marks** or structures on an image caused by technical issues during image acquisition or processing. - The observed pattern is a consistent pathological finding, not random defects due to technical issues. *Silver-beaten appearance* - A **silver-beaten (or beaten copper) skull** appearance refers to prominent convolutional markings on the inner table of the skull, often seen in conditions with **increased intracranial pressure**. - This appearance is characterized by broad, irregular indentations, which is distinct from the fine, punctate lytic lesions seen in a pepper pot skull. *Gunshot injury with retained pellets* - This option refers to **traumatic gunshot injury** with metallic pellets scattered within the soft tissues or bone of the head. - The image displays a diffuse bone pathology rather than foreign metallic fragments from a traumatic event.

Q: Onion-peel appearance is seen in:

Ewing's sarcoma. ***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.

Q: The earliest radiological change to appear in a case of acute osteomyelitis is:

Loss of plane between soft tissue and muscle. ***Loss of plane between soft tissue and muscle*** - This finding, often seen as **soft tissue swelling** and effacement of fat planes on radiographs, is the **earliest detectable radiographic sign** in acute osteomyelitis, typically appearing within 24-48 hours. - It reflects the initial inflammatory changes and **edema** in the soft tissues surrounding the infected bone. *Periosteal reaction* - This occurs later than soft tissue changes, usually appearing after **7-10 days** of infection, as the periosteum is lifted and new bone formation begins. - It is a sign of bone irritation and can be seen as linear or lamellated **new bone growth** parallel to the cortex. *Sequestrum formation* - A sequestrum is a piece of **devitalized (necrotic) bone** that separates from the healthy bone, a much later complication of osteomyelitis. - It typically appears several weeks into the disease course, indicating established bone necrosis and usually requiring surgical intervention. *Bony sclerosis* - **Bony sclerosis**, or increased bone density, is a sign of chronic inflammation and new bone formation in response to persistent infection. - This change is usually observed in the **later stages of osteomyelitis** or in chronic forms, not in the acute phase.

Q: In scurvy, all of the following radiological signs are seen except:

Soap bubble appearance. ***Soap bubble appearance*** - This radiological sign is typically associated with **fibrous dysplasia** or certain types of **bone tumors**, such as **aneurysmal bone cysts** or **giant cell tumors**, indicating a lytic lesion with trabeculae. - It does not characterize the bone changes seen in **scurvy**, which primarily involves impaired collagen synthesis leading to weakened bone structure. *Pelken spur* - This refers to a **lateral metaphyseal spur** or projection, which is a classic radiographic finding in **scurvy**. - It results from the **subperiosteal hemorrhage** and subsequent callus formation, alongside weakening of the cortex at the metaphysis. *Zone of demarcation near epiphysis* - This describes the **Trümmerfeld zone**, a rarefaction (lucent line) in the metaphysis, immediately adjacent to the epiphysis. - It signifies the impaired osteoid formation and **demineralization** of the provisional calcification zone due to vitamin C deficiency. *Frenkel's line* - Also known as the **white line of Frenkel**, this is a dense, sclerotic line at the metaphysis adjacent to the epiphyseal plate. - It represents the dense, calcified but un-osteoidized cartilage that forms due to normal calcification of cartilage but **defective osteoblastic activity** in scurvy.

Q: Which of the following is least useful for diagnosing spondylolisthesis?

X-ray spine AP view. ***X-ray spine AP view*** - An **AP (Anterior-Posterior) view** of the spine is least useful for diagnosing spondylolisthesis because it does not adequately demonstrate the **forward slippage** of one vertebra over another. - This view primarily visualizes the spine in the **coronal plane**, making it difficult to assess the **sagittal displacement** characteristic of spondylolisthesis. *X-ray spine lateral view* - A **lateral view** of the spine is highly useful as it directly shows the **sagittal alignment** and can clearly demonstrate the **anterior displacement** of a vertebral body. - It is often the **initial imaging modality** for suspecting and classifying spondylolisthesis severity. *MRI* - **MRI** is excellent for evaluating **soft tissue structures**, such as the spinal cord, nerve roots, and intervertebral discs, which can be compressed or damaged by spondylolisthesis. - While it can visualize the slippage, it is usually reserved for assessing **neurological compromise** or if surgical planning requires detailed soft tissue information. *CT scan* - **CT scans** provide detailed **bony anatomy** and are highly effective in visualizing the pars interarticularis defects (spondylolysis) often associated with spondylolisthesis. - It offers superior detail compared to plain X-rays for assessing the **extent of bone displacement** and associated degenerative changes.

Q: What is the radiological feature characteristic of osteosarcoma?

Sunray appearance. ***Sunray appearance*** - The **sunburst** or **sunray appearance** is a characteristic radiological feature of osteosarcoma, representing rapidly growing tumor spicules extending perpendicularly from the bone cortex. - This pattern is formed by **calcified tumor osteoid** radiating from the periosteum. *Periosteal new bone formation* - While osteosarcoma does involve periosteal new bone formation, this term is **too general** and can describe various bone conditions and tumors. - The specific pattern of new bone formation in osteosarcoma is better described by terms like "sunray" or "Codman's triangle", which are more diagnostic. *Cotton wool spots* - **Cotton wool spots** are seen in **Paget's disease of bone**, representing areas of sclerotic bone. - This appearance is not characteristic of osteosarcoma, which typically presents with destructive and proliferative bone changes. *Osteoid formation* - **Osteoid formation** is a histological hallmark of osteosarcoma, as it is a bone-forming tumor. - However, on radiology, the presence alone of osteoid is not a specific diagnostic feature; rather, it's the **pattern of osteoid mineralization** that defines the radiological appearance.

Q: Fallen fragment sign is a feature of what?

Simple bone cyst. ***Simple bone cyst*** - The **fallen fragment sign** is pathognomonic for a **simple bone cyst (SBC)**, occurring when a fragment of cortical bone breaks off and falls to the dependent portion of the cyst cavity. - This sign is visible on **radiographs** and indicates a **fluid-filled cavity**, as bone fragments would not fall in a solid tumor. *Aneurysmal bone cyst* - While also a **benign osteolytic lesion**, an aneurysmal bone cyst (ABC) is characterized by **blood-filled spaces** and does not typically exhibit the fallen fragment sign. - ABCs are often **expansile** and may show **fluid-fluid levels** on MRI, but not free-floating bone fragments. *Giant cell tumor* - This is an **aggressive, often benign** bone tumor characterized by **multinucleated giant cells** and typically affects the **epiphysis** of long bones in young adults. - Giant cell tumors are **solid lesions** and do not contain fluid-filled cavities where bone fragments could fall. *Fibrous dysplasia* - Fibrous dysplasia is a **developmental anomaly** where normal bone is replaced by **fibrous tissue and immature bone**. - Radiographically, it often presents with a **"ground-glass" appearance** and cortical thinning, but it is a solid lesion and does not feature the fallen fragment sign.

Q: Aggressive bone production with a characteristic "sunray" appearance on x-ray is diagnostic of osteosarcoma in this child because of:

Periosteal reaction. ***Periosteal reaction*** - The characteristic "sunray" or "sunburst" appearance in osteosarcoma is a type of **aggressive periosteal reaction**, where tumor spicules grow perpendicular to the bone surface lifting the periosteum. - This pattern is highly suggestive of a rapidly growing malignant bone tumor like **osteosarcoma**, especially in a child. *Calcification along the periosteum* - While there is calcification associated with the periosteum, simply calcification along the periosteum is a **general term** and does not specifically describe the pattern seen in a "sunray" appearance. - Many conditions can cause periosteal calcification, and it does not always indicate the **aggressive, spiculated growth** characteristic of osteosarcoma. *Calcification along the blood vessels* - **Vascular calcification** refers to calcification within blood vessel walls, which is a separate pathological process. - This is not directly related to the **bone tumor's growth pattern** or the "sunray" appearance on an X-ray. *Soft tissue invasion* - While osteosarcoma often **invades surrounding soft tissues**, this invasion itself doesn't directly cause the "sunray" appearance. - The "sunray" pattern specifically refers to the **periosteal new bone formation** and not the mere presence of tumor cells in soft tissue.

Question 1

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

Accepted Answer

DISH

Answer

Ankylosing spondylitis

Answer

Psoriatic arthropathy

Answer

Rheumatoid arthritis

Question 2

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

Accepted Answer

Ground glass density

Answer

Calcifications

Answer

Cortical thickening

Answer

Bony expansion

Question 3

What is depicted in the X-ray of the skull? (Refer to the provided image)

Accepted Answer

Pepper pot skull

Answer

Artifacts

Answer

Silver-beaten appearance

Answer

Gunshot injury with retained pellets

Question 4

Onion-peel appearance is seen in:

Accepted Answer

Ewing's sarcoma

Answer

Osteoma

Answer

Osteoclastoma

Answer

Osteosarcoma

Question 5

The earliest radiological change to appear in a case of acute osteomyelitis is:

Accepted Answer

Loss of plane between soft tissue and muscle

Answer

Periosteal reaction

Answer

Sequestrum formation

Answer

Bony sclerosis

Question 6

In scurvy, all of the following radiological signs are seen except:

Accepted Answer

Soap bubble appearance

Answer

Zone of demarcation near epiphysis

Answer

Frenkel's line

Answer

Pelken spur

Question 7

Which of the following is least useful for diagnosing spondylolisthesis?

Accepted Answer

X-ray spine AP view

Answer

X-ray spine lateral view

Answer

MRI

Answer

CT scan

Question 8

What is the radiological feature characteristic of osteosarcoma?

Accepted Answer

Sunray appearance

Answer

Osteoid formation

Answer

Periosteal new bone formation

Answer

Cotton wool spots

Question 9

Fallen fragment sign is a feature of what?

Accepted Answer

Simple bone cyst

Answer

Aneurysmal bone cyst

Answer

Giant cell tumor

Answer

Fibrous dysplasia

Question 10

Aggressive bone production with a characteristic "sunray" appearance on x-ray is diagnostic of osteosarcoma in this child because of:

Accepted Answer

Periosteal reaction

Answer

Calcification along the periosteum

Answer

Calcification along the blood vessels

Answer

Soft tissue invasion

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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