Musculoskeletal Radiology Practice Questions

Q: Investigation of choice for soft tissue sarcoma is -

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the investigation of choice for soft tissue sarcomas due to its superior **soft tissue contrast resolution**, allowing for detailed assessment of tumor size, location, and extent within muscle, fat, and neurovascular structures. - MRI is crucial for **surgical planning**, helping to define tumor margins and evaluate involvement of adjacent critical structures. *CT* - While CT scans can identify masses, they have **limited soft tissue contrast resolution** compared to MRI, making it less effective for precise delineation of soft tissue sarcomas. - CT is often used for **staging to detect metastatic disease**, particularly in the lungs, rather than for primary tumor characterization. *Ultrasound* - **Ultrasound** is a good initial screening tool for soft tissue masses due to its accessibility and lack of radiation, but it is **operator-dependent** and has limitations in assessing deep or large lesions. - It can help differentiate cystic from solid lesions and guide biopsies but **lacks the comprehensive detail** of MRI for definitive diagnosis and staging. *X-ray* - **X-rays** are primarily used to visualize **bone abnormalities** and are generally not effective for evaluating soft tissue masses unless there is associated calcification or bone erosion. - They provide **minimal information** regarding the internal structure or extent of a soft tissue sarcoma.

Q: What does the fallen fragment sign indicate in radiology?

Indicates a simple bone cyst. ***Indicates a simple bone cyst*** - The **fallen fragment sign** is a classic radiographic finding seen in **simple bone cysts** (unicameral bone cysts), particularly after a pathological fracture. - It occurs when a **fractured piece of bone** falls through the fluid-filled cyst cavity due to gravity, creating a characteristic appearance that indicates a benign, fluid-filled lesion. - This sign is considered **pathognomonic** for simple bone cysts. *Indicates osteosarcoma* - Osteosarcoma is a **malignant bone tumor** characterized by aggressive bone destruction and **osteoid formation**. - It typically does not demonstrate a fallen fragment sign; instead, it often shows a **Codman triangle** or **sunburst periosteal reaction**. - The aggressive nature and solid tumor composition make this sign incompatible with osteosarcoma. *Indicates an aneurysmal bone cyst* - An aneurysmal bone cyst (ABC) is a **benign, vascular bone lesion** that is usually multiloculated and blood-filled. - While it can cause bone expansion and pathological fractures, the fallen fragment sign is **not characteristic** of ABCs, which are typically hemorrhagic and contain blood-filled septa rather than clear fluid. - ABCs show a characteristic **fluid-fluid level** on imaging, not a fallen fragment. *Indicates adamantinoma* - Adamantinoma is a **rare, low-grade malignant bone tumor** most commonly found in the tibia. - This tumor does not exhibit a fallen fragment sign; its radiographic features often include **lobulated osteolytic lesions** with a sclerotic rim. - It is a solid tumor without the fluid-filled cavity necessary for this sign.

Q: What type of lesions in the skull bones can be identified on this X-ray?

Paget's disease. ***Paget's disease*** - An X-ray of the skull in Paget's disease typically shows **thickening of the skull vault** and areas of both **osteolysis** and **osteosclerosis**, leading to a characteristic "cotton wool" appearance. - The disease involves abnormal bone remodeling, leading to enlarged and weakened bones susceptible to deformity and fracture. *Multiple myeloma* - On a skull X-ray, multiple myeloma usually presents as multiple, sharply-defined, **"punched-out" lytic lesions** without a sclerotic border. - These lesions reflect areas where malignant plasma cells have destroyed bone, which is distinct from the mixed lytic and sclerotic changes of Paget's disease. *Osteosarcoma* - Osteosarcoma is a **primary bone malignancy** that typically presents as a solitary lesion with a mixture of lytic and sclerotic areas, often with a **sunburst or Codman's triangle** periosteal reaction. - It most commonly affects long bones in younger individuals and is a much less common presentation in the skull compared to other bone conditions. *Osteomyelitis* - Osteomyelitis is an **infection of the bone** that would appear on an X-ray as areas of bone destruction (lysis) and new bone formation (sclerosis), often with **sequestrum** (dead bone) and **involucrum** (new bone formation around the infection). - While it can affect the skull, its imaging features would typically be localized signs of infection rather than the widespread, generalized changes seen in Paget's disease.

Q: What is the condition characterized by a 'dripping candle wax' appearance on the spine?

Melorheostosis. ***Melorheostosis*** - This rare sclerosing bone dysplasia is characterized by **unilateral, linear periosteal bone thickening** that gives the appearance of **"dripping candle wax"** on imaging studies. - The distinctive radiographic finding is due to an overgrowth of cortical bone, often affecting a single limb. *Metastasis* - **Bone metastases** typically present as multifocal lytic or blastic lesions, depending on the primary tumor, rather than a linear, thick "dripping candle wax" pattern. - While they can involve the spine, the radiographic morphology is distinct from the **cortical thickening** seen in melorheostosis. *TB spine* - Tuberculosis of the spine, or **Pott's disease**, primarily causes **vertebral body destruction**, kyphosis, and *paravertebral abscess formation*. - It does not produce the characteristic **"dripping candle wax" appearance** of cortical hyperostosis. *Osteopetrosis* - **Osteopetrosis** (marble bone disease) is characterized by a generalized increase in **bone density** due to defective osteoclast function. - This condition results in uniformly dense and thickened bones, often referred to as **"bone within a bone"** or a **"sandwich vertebrae"** appearance, which differs from the localized, flowing hyperostosis of melorheostosis.

Q: Which condition is associated with the pencil in cup deformity?

Psoriatic arthritis. ***Psoriatic arthritis*** - The **pencil-in-cup deformity** is a classic radiographic finding in advanced psoriatic arthritis, occurring due to **periarticular bone erosion** and phalangeal telescoping. - This specific deformity is characterized by the proximal phalanx eroding and fitting into the expanded distal phalanx, resembling a "pencil in a cup." *Rheumatoid arthritis* - While rheumatoid arthritis causes significant joint destruction, it typically presents with **periarticular erosions** and **joint space narrowing**, but not the characteristic pencil-in-cup morphology. - Common deformities include **swan-neck** and **boutonnière** deformities, and ulnar deviation. *Ankylosing spondylitis* - This condition primarily affects the **axial skeleton**, leading to spinal fusion and **sacroiliitis**. - Peripheral joint involvement is less common and typically does not result in the pencil-in-cup deformity; instead, it can cause **syndesmophytes**. *Avascular necrosis* - **Avascular necrosis** (AVN) involves the death of bone tissue due to lack of blood supply, primarily affecting the femoral head or other major joints. - Radiographic findings include **subchondral collapse**, crescent sign, and eventual joint destruction, but not the specific deformities seen in inflammatory arthritis like pencil-in-cup.

Q: In which condition is the 'Picture frame vertebra' seen?

Paget disease. ***Paget disease*** - The "picture frame vertebra" sign is a classic radiographic finding in **Paget disease**, characterized by **cortical thickening** and sclerosis around the vertebral body circumference, resembling a picture frame. - This appearance is due to the disordered bone remodeling processes (increased osteoclastic bone resorption followed by disorganized osteoblastic new bone formation) characteristic of Paget disease. *Osteopetrosis (marble bone disease)* - Osteopetrosis is characterized by **increased bone density** due to defective osteoclast function, leading to bones that are dense but brittle. - It does not typically present with the specific "picture frame" appearance of individual vertebrae, but rather with diffuse sclerosis of bones. *Ankylosing spondylitis (AS)* - Ankylosing spondylitis primarily affects the **axial skeleton**, causing inflammation and eventual fusion of the vertebrae (leading to a "bamboo spine" appearance). - While it involves the spine, it does not produce the "picture frame" vertebral sign seen in Paget disease. *Osteoporosis* - Osteoporosis is characterized by **reduced bone mass** and microstructural deterioration of bone tissue, leading to increased bone fragility and fracture risk. - Radiographically, it shows **decreased bone density** and possible vertebral compression fractures, which is the opposite of the increased bone density and cortical thickening seen in the "picture frame" sign.

Q: Which condition is characterized by a 'moth-eaten' appearance of the bones?

Multiple myeloma. ***Multiple myeloma*** [1][2] - Characterized by **punched-out lytic lesions** in bones, often described as **moth-eaten** appearance on imaging [1]. - Associated with **elevated serum proteins** and **Bence Jones proteins** in urine, confirming the diagnosis [2]. *Eosinophilic granuloma* - Usually presents with **solitary bone lesions** and is linked to **Langerhans cell histiocytosis** rather than the moth-eaten pattern. - Does not typically cause generalized **lytic bone lesions** seen in cases of multiple myeloma. *Chondromyxoid fibroma* - Generally appears as a **well-defined cortical lesion** and is not associated with a moth-eaten appearance. - It predominantly affects the **metaphysis** of long bones and shows a characteristic **cartilaginous matrix**. *Osteoid osteoma* - Presents with a **nidus** of osteoid formation, leading to localized bone pain, and does not exhibit a moth-eaten consistency. - Tends to cause **cortical bone thickening** rather than the diffuse lytic lesions associated with multiple myeloma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 608. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 616-617.

Q: Radiological sign in case of Perthes disease?

Flattening of femoral head. ***Flattening of femoral head*** - **Flattening** and **fragmentation** of the femoral head are characteristic radiological findings in **early-stage** Perthes disease. - This flattening is a direct consequence of the **avascular necrosis** and subsequent **remodeling** of the femoral epiphysis. *Fragmentation of femoral head epiphysis* - While **fragmentation** is a key feature of Perthes disease, it's typically observed **after** the initial flattening and sclerosis in the avascular stage. - It represents the process of **resorption** and **revascularization** as the bone attempts to heal. *Lateral femoral head displacement* - **Lateral displacement** of the femoral head is a more common finding in conditions like **slipped capital femoral epiphysis (SCFE)**, where the epiphysis slips from the metaphysis. - In Perthes disease, the primary issue is the **necrosis and collapse** of the femoral head itself, rather than displacement from the neck. *Limited hip abduction* - **Limited hip abduction** is a clinical sign, not a radiological sign, and it is a common symptom in Perthes disease due to pain, inflammation, and deformity of the femoral head. - Radiological signs are visual abnormalities observed on imaging studies like X-rays.

Q: "Sunray appearance" on X-rays is suggestive of:

An Osteogenic sarcoma. ***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.

Q: What is seen on x-ray with posterior elbow dislocation

Coronoid process appears posterior to humerus. ***Coronoid process appears posterior to humerus*** - In a **posterior elbow dislocation**, the ulna and radius (including the coronoid process) are displaced **posteriorly** relative to the distal humerus. - This posterior displacement means the coronoid process, which normally articulates with the trochlea of the humerus, will be located behind the humerus on a lateral X-ray view. *Coronoid process appears anterior to humerus* - This position would typically be seen in an **anterior elbow dislocation**, which is rare. - In a normal elbow, the coronoid process is anterior to the elbow joint's axis but maintains articulation with the trochlea. *Coronoid process appears below humerus* - The term "below" is imprecise in this context and does not accurately describe the characteristic displacement in a posterior dislocation. - Displacement in dislocations is typically described in relation to the main bone involved (humerus) in an anterior-posterior or medial-lateral plane. *No visible coronoid process* - The coronoid process is an integral part of the ulna and is almost always visible on plain X-rays, even in dislocations. - Its presence is key to identifying the ulna's position relative to the humerus.

Question 1

Investigation of choice for soft tissue sarcoma is -

Accepted Answer

MRI

Answer

CT

Answer

Ultrasound

Answer

X-ray

Question 2

What does the fallen fragment sign indicate in radiology?

Accepted Answer

Indicates a simple bone cyst

Answer

Indicates osteosarcoma

Answer

Indicates an aneurysmal bone cyst

Answer

Indicates adamantinoma

Question 3

What type of lesions in the skull bones can be identified on this X-ray?

Accepted Answer

Paget's disease

Answer

Multiple myeloma

Answer

Osteosarcoma

Answer

Osteomyelitis

Question 4

What is the condition characterized by a 'dripping candle wax' appearance on the spine?

Accepted Answer

Melorheostosis

Answer

Metastasis

Answer

TB spine

Answer

Osteopetrosis

Question 5

Which condition is associated with the pencil in cup deformity?

Accepted Answer

Psoriatic arthritis

Answer

Rheumatoid arthritis

Answer

Ankylosing spondylitis

Answer

Avascular necrosis

Question 6

In which condition is the 'Picture frame vertebra' seen?

Accepted Answer

Paget disease

Answer

Osteopetrosis (marble bone disease)

Answer

Ankylosing spondylitis (AS)

Answer

Osteoporosis

Question 7

Which condition is characterized by a 'moth-eaten' appearance of the bones?

Accepted Answer

Multiple myeloma

Answer

Osteoid osteoma

Answer

Eosinophilic granuloma

Answer

Chondromyxoid fibroma

Question 8

Radiological sign in case of Perthes disease?

Accepted Answer

Flattening of femoral head

Answer

Fragmentation of femoral head epiphysis

Answer

Lateral femoral head displacement

Answer

Limited hip abduction

Question 9

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

Accepted Answer

An Osteogenic sarcoma

Answer

A metastatic tumour in the bone

Answer

An Ewing's sarcoma

Answer

A type of bone cancer that can show various radiographic appearances

Question 10

What is seen on x-ray with posterior elbow dislocation

Accepted Answer

Coronoid process appears posterior to humerus

Answer

Coronoid process appears anterior to humerus

Answer

Coronoid process appears below humerus

Answer

No visible coronoid process

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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