Musculoskeletal Radiology Practice Questions

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: Which of the following is the most sensitive investigation for the condition shown in the following X-ray?

MRI. ***MRI*** - **Most sensitive investigation** for detecting **avascular necrosis (AVN)** of the femoral head, identifying early **marrow edema** and **ischemic changes** before radiographic abnormalities appear. - Superior **soft tissue contrast** allows visualization of **bone marrow signal changes** and **subchondral collapse** in early stages when X-rays may appear normal. *CT* - Less sensitive than MRI for **early AVN detection** as it primarily shows **bony architecture** rather than marrow changes. - More useful for assessing **subchondral fractures** and **joint collapse** in advanced stages, but misses early ischemic changes. *DEXA* - **Bone densitometry** scan used to measure **bone mineral density** for osteoporosis screening, not for AVN diagnosis. - Cannot detect **focal ischemic changes** or **structural abnormalities** specific to avascular necrosis of the femoral head. *PET* - **Functional imaging** that shows metabolic activity but has **limited spatial resolution** for detailed bone marrow assessment. - Not routinely used for AVN diagnosis due to **high cost** and **radiation exposure** compared to MRI's superior sensitivity.

Q: A lateral view X-ray of the wrist shows which of the following findings?

Perilunate dislocation. ***Perilunate dislocation*** - The **lunate maintains normal alignment** with the **radius** while the **capitate** and other carpal bones are displaced **dorsally**, creating the classic "spilled teacup" appearance. - Occurs following **high-energy wrist trauma** and represents the most severe form of **perilunate instability** without complete lunate dislocation. *Lunate dislocation* - The **lunate itself is displaced volarly** and loses alignment with the **radius**, appearing as a **triangular shape** on lateral view. - This represents progression beyond perilunate dislocation where the lunate has completely **rotated and dislocated** from its normal position. *Dorsal intercalated segment instability (DISI)* - Characterized by **dorsal angulation** of the lunate with **scapholunate angle >70°** due to **scapholunate ligament injury**. - The lunate appears **dorsally tilted** but remains in alignment with the radius, unlike the described findings. *Volar intercalated segment instability (VISI)* - Results from **lunotriquetral ligament injury** causing **volar angulation** of the lunate with **scapholunate angle <30°**. - The lunate appears **volarly tilted** and typically occurs with **ulnar-sided wrist injuries**, not high-energy dorsal dislocations.

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: What is the most specific but late radiographic feature of scurvy?

Trummerfeld zone at the metaphysis. **Explanation:** Scurvy (Vitamin C deficiency) leads to defective collagen synthesis, resulting in impaired osteoid formation. While bone resorption continues, the mineralization of the zone of provisional calcification remains intact, leading to characteristic radiographic signs. **Why Option D is Correct:** The **Trummerfeld zone** (Scorbutic zone) is a radiolucent band located in the metaphysis, just proximal to the zone of provisional calcification. It represents a "zone of debris" where weakened, fractured bone trabeculae have failed to form. It is considered the **most specific** radiographic feature of scurvy, but it appears **late** in the disease process as the structural integrity of the metaphysis collapses. **Analysis of Incorrect Options:** * **A. Ground glass appearance:** This refers to the generalized osteopenia of the shaft due to the loss of trabecular detail. It is an early, non-specific sign. * **B. Pencil outlining of the epiphysis (Wimberger sign):** This is a thin, sharp sclerotic margin surrounding a radiolucent epiphysis. While characteristic, it is not as specific as the Trummerfeld zone. * **C. White line of Frankel:** This is a dense, sclerotic line at the metaphysis representing the thickened zone of provisional calcification. It is one of the earliest signs, not a late one. **High-Yield Clinical Pearls for NEET-PG:** * **Pelkan Spur:** Lateral bony protrusions at the metaphysis caused by healing subperiosteal hemorrhages. * **Subperiosteal Hemorrhage:** The most characteristic clinical feature, though not visible on X-ray until healing/calcification begins. * **Key Mnemonic:** Scurvy involves "White lines" (Frankel) and "Black lines" (Trummerfeld). * **Differential:** Unlike Rickets (where the provisional zone of calcification is lost), in Scurvy, it is **widened and dense**.

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: What type of pelvic appearance is this?

Champagne glass pelvis. ***Champagne glass pelvis*** - Characterized by **squared iliac wings**, **narrow pelvic inlet**, and **small sciatic notches**, creating a wine glass appearance on AP radiographs. - Commonly seen in **achondroplasia** and other skeletal dysplasias, representing abnormal bone development. *Corkscrew pelvis* - This is **not a standard radiological classification** term used in pelvic anatomy or radiology. - The term does not correspond to any recognized **pelvic morphological pattern** in medical literature. *Gynecoid pelvis* - Refers to the **normal female pelvic shape** in the **Caldwell-Moloy classification** with rounded pelvic inlet. - Features include **wide pelvic inlet**, **curved sacrum**, and **wide pubic arch**, optimal for childbirth. *None of the above* - The **champagne glass pelvis** is a well-recognized radiological sign, making this option incorrect. - The characteristic appearance is pathognomonic for certain **skeletal dysplasias**, particularly achondroplasia.

Question 1

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 2

Which of the following is the most sensitive investigation for the condition shown in the following X-ray?

Accepted Answer

MRI

Answer

CT

Answer

DEXA

Answer

PET

Question 3

A lateral view X-ray of the wrist shows which of the following findings?

Accepted Answer

Perilunate dislocation

Answer

Lunate dislocation

Answer

Dorsal intercalated segment instability (DISI)

Answer

Volar intercalated segment instability (VISI)

Question 4

Cotton wool skull is seen in which condition?

Accepted Answer

Paget's disease

Answer

Rickets

Answer

Congenital syphilis

Answer

Hydrocephalus

Question 5

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 6

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 7

What is the most specific but late radiographic feature of scurvy?

Accepted Answer

Trummerfeld zone at the metaphysis

Answer

Ground glass appearance of the shaft of long bones

Answer

Pencil outlining of the epiphysis

Answer

White line of Frankel

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

What type of pelvic appearance is this?

Accepted Answer

Champagne glass pelvis

Answer

Corkscrew pelvis

Answer

Gynecoid pelvis

Answer

None of the above

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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