Musculoskeletal Radiology Practice Questions

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

Supraspinatus tendon calcification. ***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.

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

No radiographic signs. ### 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).

Q: Cotton wool skull is seen in which condition?

Paget's disease. **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).

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

Vertebral hemangioma. **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.

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

Driven-snow appearance. **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.

Q: 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?

MRI. **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.

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

Kidney. **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.

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

Active scurvy. 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).

Question 1

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

Accepted Answer

Paget's disease

Answer

Osteosarcoma

Answer

Metastasis due to neuroblastoma

Answer

Hemangioma

Question 2

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?

Accepted Answer

Diffuse idiopathic skeletal hyperostosis

Answer

Ankylosing spondylitis

Answer

Psoriatic spondyloarthropathy

Answer

Rheumatoid arthritis

Question 3

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

Accepted Answer

Supraspinatus tendon calcification

Answer

Calcific Biceps tendinitis

Answer

Coracoacromial ligament calcification

Answer

Avulsion fracture of greater tuberosity

Question 4

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

Accepted Answer

No radiographic signs

Answer

Punched-out bone lesions

Answer

Hair-on-end appearance of the skull

Answer

Step-ladder appearance of vertebral bodies

Question 5

Cotton wool skull is seen in which condition?

Accepted Answer

Paget's disease

Answer

Rickets

Answer

Congenital syphilis

Answer

Hydrocephalus

Question 6

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

Accepted Answer

Vertebral hemangioma

Answer

Ewing's sarcoma

Answer

Osteosarcoma

Answer

Eosinophilic granuloma

Question 7

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

Accepted Answer

Driven-snow appearance

Answer

Onion-peel appearance

Answer

Sunburst appearance

Answer

Cherry-blossom appearance

Question 8

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?

Accepted Answer

MRI

Answer

CT scan

Answer

Bone scan

Answer

Plain x-ray

Question 9

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

Accepted Answer

Kidney

Answer

Bronchus

Answer

Breast

Answer

Prostate

Question 10

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

Accepted Answer

Active scurvy

Answer

Neonates

Answer

Acromegaly

Answer

Osteopetrosis

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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