Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology Indian Medical PG Practice Questions and MCQs

Question 351: What is the main diagnostic feature of osteoarthritis on X-ray imaging?

A. Subchondral sclerosis
B. Periarticular osteopenia
C. Joint ankylosis
D. Joint space narrowing (Correct Answer)

Explanation: ***Joint space narrowing*** - This is the **primary and most consistent radiographic feature** of **osteoarthritis (OA)**, reflecting progressive **cartilage loss** over time. - It is the earliest radiographic change and forms the basis of radiological grading systems for OA severity. - Joint space narrowing is caused by **articular cartilage degradation**, allowing the bone ends to move closer together. - Along with **osteophytes**, it constitutes the cardinal radiographic sign of OA. *Subchondral sclerosis* - While a characteristic feature of OA, **subchondral sclerosis** represents a secondary change occurring as bone remodeling in response to cartilage loss. - It reflects hardening and thickening of bone beneath the articular surface but typically appears later in disease progression. - It is a hallmark feature but not the primary diagnostic criterion. *Periarticular osteopenia* - This refers to decreased bone density around the joint and is characteristic of **inflammatory arthropathies** like **rheumatoid arthritis**, not osteoarthritis. - OA typically shows **increased bone density** (sclerosis) rather than osteopenia. - It suggests active inflammation and bone resorption, which is distinct from the degenerative changes in OA. *Joint ankylosis* - **Joint ankylosis** is complete bony fusion of a joint, seen in severe inflammatory conditions like **ankylosing spondylitis** or advanced rheumatoid arthritis. - It is not a feature of osteoarthritis, which maintains joint mobility despite cartilage loss and remodeling. - OA is characterized by **degeneration**, not fusion.

Question 352: Which investigation is least effective in diagnosing acute osteomyelitis?

A. X-ray (Correct Answer)
B. Bone scan
C. MRI
D. CT scan

Explanation: ***X-ray*** - **Plain radiographs** are often normal in the early stages of acute osteomyelitis, as bony changes take time to develop. - Changes like **periosteal elevation** or **bony destruction** typically become visible only after 10-14 days following infection onset. *Bone scan* - A **three-phase bone scan** (technetium-99m) is highly sensitive for detecting early osteomyelitis by showing increased blood flow and uptake in the affected area. - It can detect changes within 24-48 hours of infection, making it useful when plain radiographs are normal. *MRI* - **Magnetic Resonance Imaging (MRI)** is considered the most sensitive and specific imaging modality for diagnosing acute osteomyelitis. - It provides excellent soft tissue contrast, allowing early detection of **marrow edema**, **abscess formation**, and **cortical disruption**. *CT scan* - **Computed Tomography (CT) scans** are useful for visualizing cortical bone changes, **sequestra**, and defining the extent of bone involvement, especially helpful for surgical planning. - While more sensitive than X-rays, it is typically less sensitive than MRI in detecting early marrow changes in acute osteomyelitis.

Question 353: Shenton's line is seen in X-ray of -

A. Antero-posterior pelvis with both hips (Correct Answer)
B. Antero-posterior shoulder
C. Lateral cervical spine
D. Lateral lumbosacral spine

Explanation: ***Antero-posterior pelvis with both hips*** - Shenton's line is a curved line that can be drawn along the inferior border of the **femoral neck** and continuous with the inferior border of the **superior pubic ramus** (obturator foramen). - It is best visualized on an **antero-posterior X-ray of the pelvis** including both hips and is commonly assessed for hip dislocations or fractures. *Antero-posterior shoulder* - This view is primarily used to assess the **glenohumeral joint**, clavicle, and scapula. - Shenton's line specifically relates to the hip joint anatomy and is not relevant to the shoulder. *Lateral cervical spine* - A lateral cervical spine view focuses on the alignment of the **vertebral bodies**, intervertebral discs, and neural foramina in the neck. - It is used for assessing conditions like cervical fractures, dislocations, or degenerative changes, not hip pathology. *Lateral lumbosacral spine* - This view is used to evaluate the **lumbar vertebrae** and sacrum, looking for disc herniations, spondylolisthesis, or spinal alignment issues. - Shenton's line is not a landmark assessed on a lateral lumbosacral spine X-ray.

Question 354: X-ray appearance of sequestrum?

A. Radiodense bone fragments (Correct Answer)
B. Osteopenic fragment
C. Fragment with honeycomb loculated appearance
D. Radiolucent area with speckled calcification

Explanation: ***Radiodense bone fragments*** - A **sequestrum** refers to a piece of dead bone that has become detached from the surrounding healthy bone, typically due to **osteomyelitis**. - On X-ray, this necrotic bone often appears **denser** (radiodense) than the surrounding viable bone because it has lost its blood supply and can undergo sclerosis, or it simply stands out within the less dense inflammatory exudate. *Osteopenic fragment* - An **osteopenic fragment** would indicate a piece of bone with reduced density, often associated with bone loss or demineralization, which is not characteristic of a sequestrum. - While surrounding bone might appear osteopenic due to infection, the sequestrum itself is typically **denser**. *Fragment with honeycomb loculated appearance* - A **honeycomb or loculated appearance** is typically associated with conditions like fibrous dysplasia, aneurysmal bone cysts, or certain tumors, which involve bone remodeling or cystic changes, not necrotic bone. - This appearance suggests architectural changes within the bone rather than a detached piece of dead bone. *Radiolucent area with speckled calcification* - A **radiolucent area** implies an area of decreased bone density, and when combined with speckled calcifications, it might suggest entities like cartilage tumors (e.g., enchondroma) or certain types of malignant bone tumors. - This description does not fit the characteristic appearance of a **sequestrum**, which is a **dense** bone fragment within a radiolucent area of pus and granulation tissue.

Question 355: First radiological sign for active tubercular arthritis is?

A. Sclerosis
B. Localized osteoporosis (Correct Answer)
C. Joint space reduction
D. Osteophytes

Explanation: ***Localized osteoporosis*** - **Localized osteoporosis** in the juxta-articular region is often the earliest detectable radiological sign in active tubercular arthritis due to **inflammation-induced bone resorption**. - This finding reflects the initial bone changes in response to the **Mycobacterium tuberculosis** infection. *Sclerosis* - **Sclerosis** (increased bone density) in the subchondral bone is typically a feature of chronic or healing arthritis, indicating bone repair and remodeling, which occurs much later than initial inflammation. - It is not an early sign of active disease but rather a response to long-standing stress or infection. *Joint space reduction* - **Joint space reduction** occurs as cartilage is destroyed, which is a relatively later stage in tubercular arthritis, as initial inflammation primarily affects the synovium and juxta-articular bone. - While it is a common radiological finding in many forms of arthritis, it usually follows significant cartilage degradation, thus not being the first sign. *Osteophytes* - **Osteophytes** (bone spurs) are characteristic of degenerative joint disease (osteoarthritis) and represent the body's attempt to stabilize the joint in response to chronic wear and tear or instability. - They are not typically associated with the acute inflammatory process of active tubercular arthritis.

Question 356: Which of the following is not a typical radiological finding in rheumatoid arthritis?

A. Subchondral sclerosis (Correct Answer)
B. Marginal erosion
C. Symmetrical involvement
D. Juxta-articular osteopenia

Explanation: ***Subchondral sclerosis*** - **Subchondral sclerosis** is a hallmark of **osteoarthritis**, representing bone hardening beneath damaged cartilage, which is not characteristic of rheumatoid arthritis. - In rheumatoid arthritis, the primary pathology involves **synovial inflammation** leading to bone erosion rather than bone thickening. *Symmetrical involvement* - **Symmetrical polyarthritis** is a defining feature of rheumatoid arthritis, often affecting the same joints on both sides of the body. - This pattern helps differentiate it from other inflammatory arthropathies that might exhibit asymmetrical joint involvement. *Marginal erosion* - **Marginal erosions** are a classic early radiological sign of rheumatoid arthritis, caused by the inflammatory pannus invading the bare areas of bone. - These erosions typically appear at the edges of the joint, where the synovial membrane attaches. *Juxta-articular osteopenia* - **Juxta-articular osteopenia** (localized bone thinning near the joint) is an early and common radiological finding in rheumatoid arthritis. - It results from local inflammatory mediators and disuse around the affected joints.

Question 357: Cotton wool skull is a radiological feature of which condition?

A. Osteopetrosis
B. Eosinophilic granuloma
C. Fibrous dysplasia
D. Paget's disease (Correct Answer)

Explanation: ***Paget's disease*** - The "cotton wool skull" appearance is a **classic radiological finding** in **Paget's disease of bone**, particularly in the **sclerotic phase** - This appearance results from patchy areas of **osteosclerosis** (increased bone density) interspersed with areas of **osteolysis** (bone destruction) - The mixed lytic-sclerotic pattern creates the characteristic fluffy, cotton wool-like appearance on skull radiographs *Eosinophilic granuloma* - Presents as **well-demarcated lytic (punched-out) lesions** in the skull - Does not cause the mixed osteolytic and osteosclerotic changes characteristic of cotton wool appearance - Typically affects children and young adults *Fibrous dysplasia* - Appears as **ground-glass opacity** or lytic lesion with sclerotic rim on radiographs - Shows homogeneous expansion of bone rather than patchy changes - Does not produce the cotton wool pattern seen in Paget's disease *Osteopetrosis* - Characterized by abnormally **dense, uniformly sclerotic bones** throughout the skeleton - Results from defective osteoclast function (Albers-Schönberg disease) - Presents with diffuse increased density rather than the patchy cotton wool pattern

Question 358: Based on the X-ray image, which condition is indicated by a sunray appearance?

A. Osteochondroma
B. Osteoclastoma
C. Chondroblastoma
D. Osteosarcoma (Correct Answer)

Explanation: ***Osteosarcoma*** - A **sunray or sunburst appearance** on X-ray is a classic radiologic sign of osteosarcoma, representing new bone formation perpendicular to the bone cortex. - This aggressive primary bone tumor often presents with a combination of **osteoblastic (bone-forming)** and osteolytic (bone-destroying) features. *Osteochondroma* - Osteochondromas appear as **bony outgrowths** from the surface of bones, covered by a cartilage cap. - They are typically benign and do not exhibit the aggressive periosteal reaction seen in a sunray appearance. *Osteoclastoma* - Also known as a **giant cell tumor of bone**, osteoclastomas are typically **lytic lesions** that cause bone destruction. - They do not form new bone in a sunray pattern. *Chondroblastoma* - Chondroblastomas are rare, benign cartilaginous tumors usually found in the **epiphysis** of long bones. - They are typically **well-circumscribed lytic lesions** with fine, punctate calcifications, not a sunray pattern.

Question 359: The given image is an x-ray of a 22-year-old female. What is the probable diagnosis based on the x-ray?

A. Chondroblastoma
B. Osteochondroma
C. Giant cell tumor (Correct Answer)
D. Aneurysmal bone cyst

Explanation: ***Giant cell tumor*** - The X-ray shows a **lytic lesion** in the **distal humeral metaphysis extending into the epiphysis**, which is characteristic of a giant cell tumor. - Giant cell tumors typically occur in **young adults (20-40 years old)**, are often **eccentric with no sclerotic rim**, and can be aggressive, resembling the presented image in a 22-year-old female. *Chondroblastoma* - This typically presents as an **epiphyseal lesion** with a sclerotic rim in patients with **open physes**, usually younger than 20 years. - The lesion in the image appears to extend beyond the epiphysis, and the patient's age (22) makes chondroblastoma less likely as the physes are generally closed. *Osteochondroma* - This is an **exophytic lesion** typically growing away from the joint, characterized by a cartilage cap and continuity of the cortex and medullary cavity with the parent bone. - The image shows an **intraosseous lytic lesion**, not an exophytic bony projection. *Aneurysmal bone cyst* - This lesion often presents as an **expansile, lytic lesion** with internal septations and fluid-fluid levels, more common in the **metaphysis of long bones** in individuals younger than 20. - While aneurysmal bone cysts can be expansile, they typically show a "soap bubble" appearance with prominent internal septations, unlike the more solid-appearing lesion characteristic of giant cell tumor in this patient.

Question 360: What is the angle shown in the image known as?

A. Cobb angle (Correct Answer)
B. Bohler angle
C. Ferguson angle
D. Baumann angle

Explanation: ***Correct Option: Cobb angle*** - The image displays a method for measuring the angle of a spinal curvature, which is known as the **Cobb angle** - This measurement is routinely used to assess the severity of **scoliosis** by drawing lines parallel to the vertebral endplates at the extreme ends of the curve and then determining the angle between these lines - The Cobb angle is the **gold standard** for quantifying scoliosis and monitoring curve progression *Incorrect Option: Bohler angle* - The **Bohler angle** is a measurement used in the assessment of **calcaneal fractures** - It is formed by two lines drawn on a lateral foot X-ray and is not relevant to spinal deformities *Incorrect Option: Ferguson angle* - The **Ferguson angle**, also known as the lumbosacral angle, measures the angle of the sacral base relative to the horizontal - It describes the degree of **lordosis** and is not used to quantify scoliosis as depicted in the image *Incorrect Option: Baumann angle* - The **Baumann angle** is an important measurement used in pediatric orthopedics to assess the alignment of the **distal humerus** after a supracondylar fracture - It is irrelevant to spinal imaging and curvature assessment

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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