Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology Indian Medical PG Practice Questions and MCQs

Question 51: Sunburst appearance of skull is not seen in which of the following conditions?

A. Paget's disease (Correct Answer)
B. Osteosarcoma
C. Metastasis due to neuroblastoma
D. Hemangioma

Explanation: The **"Sunburst appearance"** (also known as the hair-on-end appearance) in the skull is a radiological sign caused by a periosteal reaction. It occurs when the periosteum is displaced by an underlying process (tumor or marrow expansion), leading to the formation of new bone along the radiating Sharpey’s fibers perpendicular to the bone surface. ### **Explanation of Options:** * **Paget’s Disease (Correct Answer):** Paget’s disease is characterized by disordered bone remodeling. In the skull, the classic early finding is **Osteoporosis Circumscripta** (well-defined lytic lesions). In later stages, it presents as **"Cotton Wool spots"** due to thickened, sclerotic patches. It does *not* typically produce a sunburst periosteal reaction. * **Osteosarcoma:** This is a primary bone malignancy that frequently causes a sunburst periosteal reaction due to rapid, aggressive osteoid production. * **Metastasis due to Neuroblastoma:** In children, neuroblastoma is a common cause of "hair-on-end" skull changes. The tumor cells infiltrate the sutures and subperiosteal space, triggering vertical bone formation. * **Hemangioma:** While often presenting with a "honeycomb" or "soap-bubble" appearance, cavernous hemangiomas of the skull can occasionally show a classic sunburst pattern of radiating spicules from a central point. ### **High-Yield Clinical Pearls for NEET-PG:** 1. **Hair-on-end appearance** is most classically associated with chronic hemolytic anemias like **Thalassemia Major** and Sickle Cell Anemia (due to extramedullary hematopoiesis). 2. **Paget’s Disease Key Signs:** Cotton wool skull, Picture frame vertebra, Ivory vertebra, and Blade of grass sign (long bones). 3. **Meningioma** is another important differential for the sunburst appearance in the skull due to reactive bone formation. 4. **Codman’s Triangle** is another periosteal reaction seen in Osteosarcoma, but it represents the elevation of the periosteum at the tumor edge rather than radiating spicules.

Question 52: The "flowing wax" appearance on the anterior and posterior borders of vertebrae, with normal intervertebral disc spaces, occurring due to ligament calcification, is seen in which condition?

A. Ankylosing spondylitis
B. Diffuse idiopathic skeletal hyperostosis (Correct Answer)
C. Psoriatic spondyloarthropathy
D. Rheumatoid arthritis

Explanation: ### Explanation **Correct Answer: B. Diffuse Idiopathic Skeletal Hyperostosis (DISH)** **Why it is correct:** Diffuse Idiopathic Skeletal Hyperostosis (DISH), also known as **Forestier’s disease**, is a non-inflammatory systemic condition characterized by the ossification of spinal ligaments, most commonly the **Anterior Longitudinal Ligament (ALL)**. The classic radiographic hallmark is the **"flowing wax"** or "dripping candle wax" appearance, where thick, exuberant calcifications occur along the ventrolateral aspect of at least four contiguous vertebral bodies. Crucially, in DISH, the **intervertebral disc spaces are preserved**, and the sacroiliac (SI) joints remain normal, which distinguishes it from inflammatory spondyloarthropathies. **Why incorrect options are wrong:** * **Ankylosing Spondylitis (AS):** Characterized by thin, vertical **syndesmophytes** (Bamboo spine), bilateral symmetrical **sacroiliitis**, and disc space narrowing/squaring of vertebrae. It is an inflammatory condition (HLA-B27 positive). * **Psoriatic Spondyloarthropathy:** Features **bulky, asymmetric paramarginal syndesmophytes** and often involves the SI joints (usually asymmetric). * **Rheumatoid Arthritis:** Primarily affects the **cervical spine** (atlantoaxial subluxation) and small joints of hands; it does not cause "flowing wax" ligamentous calcification in the thoracolumbar spine. **High-Yield Clinical Pearls for NEET-PG:** * **Resnick’s Criteria for DISH:** 1) Flowing calcification over $\geq$ 4 contiguous vertebrae. 2) Preservation of disc height. 3) Absence of SI joint ankylosis or erosion. * **Clinical Association:** Strongly associated with **Diabetes Mellitus** and obesity. * **Most Common Site:** Thoracic spine (specifically the right side, as the pulsating aorta on the left inhibits calcification). * **Symptom:** Patients often present with stiffness and, occasionally, **dysphagia** if large osteophytes involve the cervical spine.

Question 53: A 40-year-old male gymnast presents with right shoulder pain for 20 days. What does the arrow indicate?

A. Calcific Biceps tendinitis
B. Coracoacromial ligament calcification
C. Avulsion fracture of greater tuberosity
D. Supraspinatus tendon calcification (Correct Answer)

Explanation: ***Supraspinatus tendon calcification*** - The arrow points to a **fluffy, cloud-like opacity** located above the **greater tuberosity**, which is characteristic of **calcific tendinitis** of the supraspinatus tendon. - This condition commonly affects **active adults** aged 30-50, particularly athletes like gymnasts, presenting with **shoulder pain** and impingement symptoms. *Calcific Biceps tendinitis* - Calcification would appear in the **bicipital groove** (intertubercular groove), not above the greater tuberosity. - **Biceps tendon** calcification is less common and would be located more **medially** on the humeral head. *Coracoacromial ligament calcification* - This would appear as calcification **superior to the humeral head**, extending toward the **coracoid process**. - The **coracoacromial arch** calcification typically presents as a **linear** rather than **fluffy** opacity. *Avulsion fracture of greater tuberosity* - Would show a **discrete bony fragment** separated from the **greater tuberosity** with clear **cortical disruption**. - Avulsion fractures appear as **well-defined bone fragments**, not the **cloud-like calcific deposits** seen in this image.

Question 54: In early cases, multiple myeloma most commonly presents with which of the following radiographic findings?

A. No radiographic signs (Correct Answer)
B. Punched-out bone lesions
C. Hair-on-end appearance of the skull
D. Step-ladder appearance of vertebral bodies

Explanation: ### Explanation **1. Why "No radiographic signs" is correct:** In the early stages of Multiple Myeloma (MM), conventional radiography (X-ray) often appears normal. This is because bone destruction is only visible on a plain radiograph once **30% to 50% of the bone mineral density has been lost**. MM is characterized by the proliferation of plasma cells in the bone marrow, which initially causes diffuse osteopenia or marrow infiltration that is too subtle for X-rays to detect. Consequently, MRI is the most sensitive imaging modality for detecting early marrow involvement before cortical destruction occurs. **2. Analysis of Incorrect Options:** * **B. Punched-out bone lesions:** While this is the *classic* radiographic hallmark of MM (well-defined lytic lesions without sclerotic borders), it typically represents a more **established or advanced stage** of the disease rather than the earliest presentation. * **C. Hair-on-end appearance:** This is characteristic of marrow hyperplasia seen in chronic hemolytic anemias (like **Thalassemia major** or Sickle Cell Anemia), not MM. * **D. Step-ladder appearance:** This refers to the appearance of vertebral bodies in **Sickle Cell Disease** (due to central endplate infarction/Reynold’s sign), not MM. **3. High-Yield Clinical Pearls for NEET-PG:** * **Imaging Gold Standard:** Whole-body low-dose CT (WBLDCT) or MRI is now preferred over the traditional "Skeletal Survey" for initial staging because of higher sensitivity. * **Cold Bone Scan:** MM lesions are typically **"cold" on Technetium-99m bone scans** because there is minimal osteoblastic activity (bone scans detect bone formation, while MM is purely osteolytic). * **Vertebrae:** The most common site of involvement in MM is the vertebral column. * **Bence-Jones Proteins:** These are light chains found in urine; however, they do not show up on standard dipstick tests (requires sulfosalicylic acid test).

Question 55: Cotton wool skull is seen in which condition?

A. Rickets
B. Paget's disease (Correct Answer)
C. Congenital syphilis
D. Hydrocephalus

Explanation: **Explanation:** The **"Cotton Wool Skull"** is a classic radiological hallmark of **Paget’s disease (Osteitis Deformans)**. This appearance occurs during the late sclerotic (blastic) phase of the disease. It is characterized by thickened calvarium with disorganized, multifocal areas of opacification (sclerosis) superimposed on a background of radiolucent bone, resembling tufts of cotton wool. **Why Paget’s disease is correct:** Paget’s disease involves excessive and disorganized bone remodeling. It typically progresses through three stages: 1. **Lytic phase:** Characterized by *Osteoporosis Circumscripta* (well-defined lucent lesions). 2. **Mixed phase:** Both resorption and haphazard bone formation occur. 3. **Sclerotic phase:** Resulting in the thickened, "cotton wool" appearance. **Why other options are incorrect:** * **Rickets:** Characterized by a "Square skull" (Caput Quadratum) due to frontal bossing and delayed fontanelle closure, not focal sclerosis. * **Congenital Syphilis:** Associated with "Olympian brow" (frontal bossing) and "Hot cross bun skull," but lacks the cotton wool density. * **Hydrocephalus:** Shows "Copper beaten skull" (Luckenschadel) appearance due to increased intracranial pressure causing indentations on the inner table of the skull. **High-Yield Pearls for NEET-PG:** * **Biochemical marker:** Markedly elevated **Serum Alkaline Phosphatase (ALP)** with normal Calcium and Phosphate levels. * **Complications:** Hearing loss (due to CN VIII compression), high-output heart failure, and a 1% risk of transformation into **Osteosarcoma**. * **Other signs:** "Picture frame vertebra" and "Ivory vertebra." * **Treatment:** Bisphosphonates (Zoledronic acid is the drug of choice).

Question 56: Polka dot appearance on CT scan is characteristic of which of the following conditions?

A. Ewing's sarcoma
B. Osteosarcoma
C. Vertebral hemangioma (Correct Answer)
D. Eosinophilic granuloma

Explanation: **Explanation:** **Vertebral Hemangioma (Correct Answer):** Vertebral hemangiomas are the most common benign primary tumors of the spine. They are composed of thin-walled blood vessels interspersed among thickened vertical bony trabeculae. On a **CT scan (axial view)**, these thickened vertical trabeculae appear as small, dense white spots against a background of low-density fat and marrow, creating the classic **"Polka dot appearance."** On a lateral X-ray or sagittal CT, these same trabeculae appear as vertical linear streaks, known as the **"Jail-bar"** or **"Corduroy cloth"** appearance. **Incorrect Options:** * **Ewing’s Sarcoma:** Characterized by a "moth-eaten" pattern of bone destruction and a classic **"Onion-skin"** periosteal reaction on X-ray. * **Osteosarcoma:** Typically presents with a "cloud-like" osteoid matrix, a **"Sunburst"** appearance, or the formation of a **Codman’s triangle** due to aggressive periosteal elevation. * **Eosinophilic Granuloma:** Part of Langerhans Cell Histiocytosis (LCH). In the spine, it typically causes **Vertebra Plana** (pancake-like collapse of the vertebral body) rather than trabecular thickening. **High-Yield Pearls for NEET-PG:** * **MRI Appearance:** Hemangiomas show **high signal intensity** on both T1 and T2 weighted images due to the high fat content within the lesion. * **Most Common Site:** Thoracic spine (followed by lumbar). * **Management:** Most are asymptomatic and discovered incidentally; they do not require treatment unless they cause compressive myelopathy. * **Salt and Pepper Sign:** Another term sometimes used to describe the speckled appearance of hemangiomas on MRI.

Question 57: What is the characteristic radiographic appearance of Pindborg's tumor?

A. Onion-peel appearance
B. Sunburst appearance
C. Cherry-blossom appearance
D. Driven-snow appearance (Correct Answer)

Explanation: **Explanation:** **Pindborg’s Tumor**, medically known as the **Calcifying Epithelial Odontogenic Tumor (CEOT)**, is a rare, benign but locally aggressive odontogenic neoplasm. **1. Why "Driven-snow" is correct:** The characteristic radiographic hallmark of CEOT is the **"Driven-snow" appearance**. This occurs because the tumor often develops in association with an impacted tooth (most commonly the mandibular third molar). As the tumor matures, it produces radiopaque foci of calcification (Liesegang rings) within a radiolucent area. These scattered, white mineralized flecks against a dark background resemble falling snow on a radiograph. **2. Analysis of Incorrect Options:** * **A. Onion-peel appearance:** Characteristic of **Ewing’s Sarcoma** or Garre’s Osteomyelitis. It represents a laminated periosteal reaction. * **B. Sunburst appearance:** Classic for **Osteosarcoma**. It indicates aggressive periosteal bone formation perpendicular to the bone cortex. * **C. Cherry-blossom appearance:** Typically associated with **Sialography** in patients with **Sjögren’s syndrome**, representing punctate sialectasis. **3. High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most common in the **posterior mandible** (molar-ramus area). * **Association:** Frequently associated with an **unerupted/impacted tooth** (52% of cases). * **Histopathology:** Look for **Liesegang rings** (concentric calcifications) and **amyloid-like material** that stains with Congo Red and shows apple-green birefringence under polarized light. * **Age:** Most common in the 4th to 6th decades of life.

Question 58: A 40-year-old male patient on long-term steroid therapy presents with recent onset of severe pain in the right hip. What is the imaging modality of choice for this problem?

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

Explanation: **Explanation:** The clinical presentation of a patient on long-term steroid therapy with sudden hip pain is highly suggestive of **Avascular Necrosis (AVN)** of the femoral head. Steroids are a well-known risk factor for non-traumatic osteonecrosis. **Why MRI is the Correct Answer:** MRI is the **most sensitive (99%) and specific** imaging modality for the early detection of AVN. It can detect bone marrow edema and ischemic changes (the "double-line sign" on T2-weighted images) weeks or months before any abnormalities appear on a plain X-ray or CT scan. In the early stages (Stage 0 and I), when intervention is most effective, MRI is the gold standard. **Why Other Options are Incorrect:** * **Plain X-ray:** Often normal in the early stages of AVN. It only shows changes (like the "crescent sign" or joint space narrowing) once structural failure and subchondral collapse have occurred (Stage II/III). * **CT Scan:** While better than X-ray at detecting subtle cortical fractures or collapse, it lacks the sensitivity of MRI for early marrow changes and involves ionizing radiation. * **Bone Scan:** Though sensitive to increased bone turnover, it is less specific than MRI and cannot provide the detailed anatomical staging required for surgical planning. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for AVN:** Femoral head. * **Earliest sign on MRI:** Low signal intensity band on T1 (representing the reactive interface). * **Pathognomonic MRI sign:** **Double-line sign** on T2WI (inner bright line of granulation tissue and outer dark line of sclerotic bone). * **Staging System:** The **Ficat and Arlet** classification is commonly used to stage AVN based on imaging findings.

Question 59: Expansile type osseous metastases are characteristic of primary malignancy of which organ?

A. Kidney (Correct Answer)
B. Bronchus
C. Breast
D. Prostate

Explanation: **Explanation:** The correct answer is **Kidney (Renal Cell Carcinoma)**. **1. Why Kidney is Correct:** Expansile, osteolytic, and highly vascular (blow-out) metastases are a hallmark of **Renal Cell Carcinoma (RCC)** and **Thyroid Carcinoma**. The underlying mechanism involves rapid tumor growth and significant hypervascularity, which causes the bone to thinned out and "expand" rather than just being destroyed. On imaging, these appear as aggressive, lucent lesions that often bulge beyond the original bone cortex. **2. Why Other Options are Incorrect:** * **Bronchus (Lung):** Typically produces **purely osteolytic** lesions. While aggressive, they are usually not characterized by the "expansile/blow-out" appearance seen in RCC. * **Breast:** Most commonly produces **mixed** lesions (both osteolytic and osteoblastic). While it is the most common cause of bony metastasis in females, it is not the classic cause of expansile lesions. * **Prostate:** Characteristically produces **osteoblastic (sclerotic)** metastases. These appear as dense, white spots on X-ray/CT due to increased bone formation stimulated by the tumor cells. **3. NEET-PG High-Yield Pearls:** * **Expansile (Blow-out) Metastases:** Think **RCC** and **Thyroid** (Follicular variety). * **Osteoblastic Metastases:** Think **Prostate** (most common), Carcinoid, and Small Cell Lung Cancer. * **Purely Lytic Metastases:** Think **RCC, Thyroid, Kidney, and Multiple Myeloma**. * **Most common site for bone metastasis:** Spine (via Batson’s venous plexus). * **Clinical Tip:** If a patient presents with a pulsatile bone mass, the most likely primary is RCC or Thyroid carcinoma.

Question 60: The "bone in a bone" appearance is seen in all of the following conditions EXCEPT:

A. Neonates
B. Acromegaly
C. Osteopetrosis
D. Active scurvy (Correct Answer)

Explanation: The **"bone in a bone" appearance** (endobone) refers to a radiological phenomenon where a distinct, smaller replica of a bone is seen within the parent bone. This occurs due to a temporary cessation of growth followed by a sudden resumption, or due to a failure of osteoclasts to resorb primary spongiosa. ### **Why Active Scurvy is the Correct Answer** In **Active Scurvy** (Vitamin C deficiency), there is a failure of osteoid formation. The characteristic radiological findings include the **Wimberger ring sign** (sclerotic margin around an osteoporotic epiphysis), **Frankel’s line** (dense zone of provisional calcification), and **Pelkan spurs**. It does **not** produce a "bone in a bone" appearance. However, during the **healing phase** of scurvy, as new bone forms around the old calcified matrix, a "bone in a bone" appearance may transiently appear. ### **Explanation of Other Options** * **Neonates:** This is a physiological finding. A "fetal skeleton" appearance can be seen in the vertebrae of newborns due to the contrast between new neonatal bone and the denser prenatal bone. * **Acromegaly:** Excess growth hormone causes subperiosteal bone formation, particularly in the phalanges and vertebrae, which can create a double-contoured appearance. * **Osteopetrosis:** Also known as Marble Bone Disease, this is the classic cause. Defective osteoclasts fail to resorb old bone, leading to a dense "miniature" bone trapped inside the thickened cortex. ### **High-Yield Clinical Pearls for NEET-PG** * **Other causes of "Bone in a Bone":** Thorotrast injection, Sickle cell disease (post-infarction), Paget’s disease, and Lead poisoning. * **Vertebral "Bone in a Bone":** Most commonly associated with **Osteopetrosis** and **Thorotrast** exposure. * **Scurvy Mnemonic:** Remember the **"4 S's"** of Scurvy: **S**corbutic rosary, **S**ubperiosteal hemorrhage, **S**purring (Pelkan), and **S**clerotic rings (Wimberger).

Practice by Chapter

Radiographic Anatomy of Bones and Joints

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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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MSK Interventional Procedures

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