Musculoskeletal Radiology Practice Questions

Q: Which imaging modality is best for evaluating retinoblastoma?

CT scan and MRI. **Explanation:** Retinoblastoma is the most common primary intraocular malignancy in children. The diagnosis and staging require a multi-modal imaging approach, making **CT scan and MRI** the combined gold standard. * **Why CT and MRI are both essential:** * **CT Scan:** It is the most sensitive modality for detecting **intraocular calcification**, which is the hallmark of retinoblastoma (seen in >90% of cases). CT is crucial for confirming the diagnosis when clinical findings are ambiguous. * **MRI:** It is the modality of choice for **staging**. MRI provides superior soft-tissue contrast to evaluate for optic nerve invasion, extraocular extension, and intracranial involvement (such as trilateral retinoblastoma involving the pineal gland). Crucially, MRI avoids ionizing radiation, which is vital in these patients who often have a genetic predisposition to secondary malignancies (RB1 mutation). **Analysis of Incorrect Options:** * **A. Ultrasonography:** While useful for initial screening and detecting calcified masses (showing high reflectivity with acoustic shadowing), it is operator-dependent and cannot assess posterior extension or intracranial spread. * **B & D. CT or MRI alone:** While both are powerful, neither is sufficient on its own for a complete evaluation. CT excels at identifying pathognomonic calcification, while MRI is mandatory for assessing the extent of the disease and planning management. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Presentation:** Leukocoria (white pupillary reflex) in a child under 3 years. * **Trilateral Retinoblastoma:** Bilateral retinoblastoma associated with a pineal gland tumor (Pineoblastoma). * **Imaging Sign:** "Cloud-like" or "clumpy" calcification on CT. * **Management Tip:** Avoid biopsy (fine-needle aspiration) due to the high risk of tumor seeding along the needle track. Diagnosis is based on clinical exam and imaging.

Q: Calcification around the joint is seen in which of the following conditions?

Pseudogout. **Explanation:** The presence of calcification within or around a joint is a hallmark of **Pseudogout**, also known as **Calcium Pyrophosphate Deposition Disease (CPPD)**. In this condition, calcium pyrophosphate dihydrate crystals deposit in the hyaline cartilage and fibrocartilage, a radiological finding termed **chondrocalcinosis**. It most commonly affects the knees (meniscus), wrists (triangular fibrocartilage complex), and symphysis pubis. **Analysis of Options:** * **Pseudogout (Correct):** Characterized by linear or punctate calcifications within the joint space. Under polarized microscopy, these crystals are weakly positively birefringent and rhomboid-shaped. * **Hyperparathyroidism:** While it can cause metastatic calcification and is associated with an increased incidence of CPPD, the primary radiological features are subperiosteal bone resorption (classically on the radial aspect of middle phalanges) and "salt and pepper" skull. * **Rheumatoid Arthritis:** This is an inflammatory, non-crystal arthropathy. Key radiological features include periarticular osteopenia, uniform joint space narrowing, and marginal erosions. Calcification is not a feature. * **Gout:** Caused by Monosodium Urate (MSU) crystals. These crystals are radiolucent; therefore, gout typically presents with "punched-out" erosions with overhanging edges (Martel’s sign) and soft tissue tophi, but not joint calcification. **High-Yield Clinical Pearls for NEET-PG:** * **Chondrocalcinosis "Big Three" locations:** Knee (Meniscus), Wrist (TFCC), and Pelvis (Symphysis Pubis). * **Milwaukee Shoulder:** A severe destructive arthropathy associated with Basic Calcium Phosphate (Hydroxyapatite) deposition. * **Polarized Microscopy:** * Gout: Needle-shaped, Strongly Negative birefringent. * Pseudogout: Rhomboid-shaped, Weakly Positive birefringent.

Q: Superior rib notching is caused by which of the following?

All of the above. **Explanation:** Rib notching is a classic radiological sign characterized by cortical erosion along the rib margins. While **inferior rib notching** is most commonly associated with Coarctation of the Aorta (due to dilated intercostal arteries), **superior rib notching** is typically caused by conditions that affect bone resorption, connective tissue integrity, or chronic pressure from muscle atrophy. **Why "All of the Above" is Correct:** 1. **Hyperparathyroidism (Option A):** This is the most common cause of superior rib notching. Increased parathyroid hormone leads to subperiosteal bone resorption, which frequently occurs along the superior borders of the ribs. 2. **Poliomyelitis (Option B):** Chronic paralysis and muscle atrophy lead to a loss of the normal mechanical stress on the bone and decreased vascular supply. The resulting localized pressure and trophic changes cause thinning and notching of the superior rib margins. 3. **Marfan Syndrome (Option C):** This connective tissue disorder results in weakened periosteal attachments and abnormal bone remodeling, leading to superior rib erosions. **High-Yield Clinical Pearls for NEET-PG:** * **Inferior Rib Notching (Roesler’s Sign):** Classically involves the 3rd to 9th ribs. It is a hallmark of **Coarctation of the Aorta** (post-ductal). It is *not* seen in the 1st and 2nd ribs because they are supplied by the costocervical trunk, not the intercostal arteries. * **Other causes of Superior Notching:** Osteogenesis Imperfecta, Rheumatoid Arthritis, and Systemic Lupus Erythematosus (SLE). * **Unilateral Rib Notching:** Suggests a Blalock-Taussig shunt or subclavian artery stenosis.

Q: The "Beheaded Scottish Terrier sign" is characteristic of which of the following conditions?

Spondylolisthesis. ### Explanation The **"Beheaded Scottish Terrier"** sign is a classic radiological finding seen on **oblique radiographs** of the lumbar spine. It indicates **Spondylolisthesis** resulting from **Spondylolysis** (a defect in the pars interarticularis). #### 1. Why Spondylolisthesis is Correct In a normal oblique lumbar X-ray, the posterior elements form the shape of a "Scotty Dog": * **Ear:** Superior articular process * **Nose:** Transverse process * **Eye:** Pedicle * **Neck:** Pars interarticularis * **Front Leg:** Inferior articular process When there is a fracture or defect in the **pars interarticularis** (Spondylolysis), it appears as a "collar" around the dog's neck. If the vertebrae then slide forward (**Spondylolisthesis**), the "neck" is severed, leading to the **"Beheaded"** appearance. #### 2. Why Other Options are Incorrect * **Spondylosis:** This refers to degenerative changes (osteophytes, disc space narrowing). While common, it does not involve the pars defect required to "behead" the dog. * **Lumbar Canal Stenosis:** This is the narrowing of the spinal canal, often diagnosed via MRI. It does not have a specific "Scotty Dog" correlation on X-ray. * **Slipped Disc (PivD):** This involves the herniation of the nucleus pulposus. It is a soft tissue pathology best visualized on MRI, not a bony defect of the pars. #### 3. Clinical Pearls for NEET-PG * **Best View:** The Scotty Dog is only seen on the **Oblique View**. * **Most Common Site:** L5-S1 is the most frequent level for spondylolisthesis. * **Meyerding Classification:** Used to grade the severity of slippage (Grade I to V). * **Inverted Napoleon Hat Sign:** Seen on **Frontal (AP) view** in severe cases (Grade III or IV) of spondylolisthesis.

Q: Spoke wheel calcification in an osteolytic lesion is seen in which of the following conditions?

Hemangioma. **Explanation:** **Vertebral Hemangiomas** are the most common benign primary tumors of the spine. The characteristic **"Spoke-wheel"** appearance (also known as the **"Polka-dot"** or **"Salt and pepper"** sign on axial imaging) occurs due to the resorption of horizontal trabeculae and the compensatory thickening of vertical trabeculae. On a lateral X-ray, this presents as vertical striations called the **"Corduroy cloth"** or **"Jail-bar"** appearance. **Analysis of Options:** * **Hemangioma (Correct):** The "Spoke-wheel" pattern refers specifically to the radiating trabecular pattern seen in flat bones (like the skull) or the axial cross-section of a vertebral body affected by hemangioma. * **Secondaries (Incorrect):** Skeletal metastases typically present as purely lytic (e.g., RCC, Thyroid), blastic (e.g., Prostate), or mixed lesions. They usually cause irregular bone destruction without the organized trabecular thickening seen in hemangiomas. * **Plasmacytoma (Incorrect):** While it presents as a "punched-out" osteolytic lesion or a "soap-bubble" appearance (in the expansile form), it does not show the classic spoke-wheel calcification. * **Hydatid Disease (Incorrect):** In the bone, *Echinococcus* causes multiloculated, "bunch of grapes" osteolytic lesions. Calcification, if present, is usually in the cyst wall (pericyst), not in a spoke-wheel trabecular pattern. **High-Yield Pearls for NEET-PG:** * **Corduroy Cloth Sign:** Vertical trabeculations in the spine (Hemangioma). * **Sunburst Appearance:** Malignant periosteal reaction (Osteosarcoma). * **Soap Bubble Appearance:** Giant Cell Tumor (GCT). * **Onion Skin Appearance:** Ewing’s Sarcoma. * **Most common site for Hemangioma:** Thoracic and Lumbar spine.

Q: A radiolucency in bone without periosteal bone reaction is seen in which of the following conditions?

Squamous cell carcinoma. **Explanation:** The presence or absence of a **periosteal reaction** is a critical diagnostic marker in bone radiology. It occurs when the periosteum is irritated by trauma, infection, or tumors, leading to new bone formation. **Why Squamous Cell Carcinoma (SCC) is correct:** When SCC (typically from the oral cavity or skin) invades underlying bone, it does so by **direct extension and pressure necrosis**. Because the tumor destroys the bone from the "outside-in" and often progresses rapidly without stimulating the osteoblastic activity of the periosteum, it typically presents as a **"punched-out" radiolucency** or an infiltrative lucent lesion **without periosteal reaction**. This is a classic radiological feature of secondary bone invasion by epithelial malignancies. **Why the other options are incorrect:** * **Garre’s Osteomyelitis:** Also known as proliferative periostitis, it is characterized by a prominent, "onion-skin" laminated periosteal reaction. It is a hallmark of chronic irritation in children/young adults. * **Osteosarcoma:** As a highly aggressive primary bone malignancy, it almost always presents with complex periosteal reactions, such as the **Codman’s triangle** or **Sunburst appearance**. * **Chronic Osteomyelitis:** This condition is defined by periosteal activity. The formation of an **Involucrum** (new bone sheath around the dead bone) is a classic example of a thick, exuberant periosteal reaction. **High-Yield Clinical Pearls for NEET-PG:** 1. **No Periosteal Reaction:** Seen in SCC invasion, Multiple Myeloma (punched-out lesions), and some slow-growing benign tumors. 2. **Onion-skin Reaction:** Ewing’s Sarcoma and Garre’s Osteomyelitis. 3. **Sunburst/Spiculated Reaction:** Osteosarcoma. 4. **Codman’s Triangle:** Indicates an aggressive process (Malignancy or Acute Osteomyelitis) lifting the periosteum.

Q: Which of the following is NOT a radiological feature of rheumatoid arthritis?

Osteophytes. ### Explanation The core distinction in musculoskeletal radiology for NEET-PG is differentiating between **Inflammatory Arthritis** (e.g., Rheumatoid Arthritis) and **Degenerative Arthritis** (e.g., Osteoarthritis). **Why Osteophytes is the correct answer:** Osteophytes (bony spurs) are the hallmark of **Osteoarthritis (OA)**. They represent a reparative response of the bone to mechanical stress and cartilage loss. In contrast, Rheumatoid Arthritis (RA) is a chronic inflammatory process characterized by synovial hypertrophy (pannus) that leads to bone **destruction** rather than bone formation. **Analysis of incorrect options:** * **Subchondral Osteopenia:** This is one of the earliest radiological signs of RA. Inflammatory cytokines and increased vascularity in the synovium lead to localized bone loss near the joint (juxta-articular osteopenia). * **Subchondral Cysts (Geodes):** In RA, synovial fluid is forced into the bone through marginal erosions under pressure, creating "pseudocysts" or geodes in the subchondral bone. * **Subchondral Swelling:** Early RA presents with soft tissue swelling around the joints (fusiform appearance) due to synovial inflammation and effusion. **Clinical Pearls for NEET-PG:** * **Classic RA Triad on X-ray:** Juxta-articular osteopenia, symmetrical joint space narrowing, and marginal erosions. * **Joints involved:** RA typically involves the MCP, PIP, and MTP joints, characteristically **sparing the DIP joints** (which are involved in OA and Psoriatic Arthritis). * **Deformities:** Look for "Rat-bite" erosions, ulnar deviation at MCP joints, and Swan-neck or Boutonniere deformities. * **Key Differentiator:** If you see **subchondral sclerosis** or **osteophytes**, think Osteoarthritis. If you see **osteopenia** and **erosions**, think Rheumatoid Arthritis.

Q: What is the best radiographic view for a fracture of the C1-C2 vertebrae?

Odontoid view. ### Explanation The **Odontoid view** (also known as the **Open-mouth view**) is the gold standard radiographic projection for evaluating the C1 (Atlas) and C2 (Axis) vertebrae. **Why it is correct:** In a standard AP view, the mandible and the base of the skull superimpose over the upper cervical spine, obscuring the anatomy. By opening the mouth wide, these structures are moved out of the way, allowing a clear view of the **dens (odontoid process)**, the **lateral masses of C1**, and the **atlanto-axial joints**. This view is essential for diagnosing: * **Jefferson fractures** (burst fracture of C1): Look for lateral displacement of the C1 lateral masses relative to C2. * **Odontoid fractures** (C2): Specifically Type II and III fractures. **Why other options are incorrect:** * **AP View:** Useful for the lower cervical spine (C3-C7) but, as mentioned, the upper segments are hidden by the jaw. * **Lateral View:** While excellent for seeing the "Pre-vertebral soft tissue space" and the "Atlantodental interval (ADI)," it can miss non-displaced odontoid fractures or subtle lateral mass displacements. * **Oblique View:** Primarily used to visualize the **intervertebral foramina** and the facet joints, not the C1-C2 complex. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of Spence:** On an odontoid view, if the combined lateral displacement of C1 lateral masses over C2 is **>6.9 mm**, it indicates a rupture of the **Transverse Ligament**. * **Harris Lines:** Always check the four parallel lines on a lateral view to ensure spinal alignment. * **Pre-vertebral Space:** At C2, the soft tissue shadow should be **<7 mm**. Widening suggests a hidden fracture or hematoma. * **Gold Standard:** While the odontoid view is the best *radiographic* view, **Non-contrast CT** is the overall gold standard for diagnosing cervical spine fractures in trauma.

Question 1

Which imaging modality is best for evaluating retinoblastoma?

Accepted Answer

CT scan and MRI

Answer

Ultrasonography

Answer

CT scan

Answer

MRI

Question 2

Calcification around the joint is seen in which of the following conditions?

Accepted Answer

Pseudogout

Answer

Hyperparathyroidism

Answer

Rheumatoid arthritis

Answer

Gout

Question 3

A "cold spot" on bone scintigraphy is seen in all the following conditions except?

Accepted Answer

Eosinophilic granuloma

Answer

Fibrous cortical defect

Answer

Pseudarthrosis

Answer

Multiple myeloma

Question 4

Superior rib notching is caused by which of the following?

Accepted Answer

All of the above

Answer

Hyperparathyroidism

Answer

Poliomyelitis

Answer

Marfan syndrome

Question 5

The "Beheaded Scottish Terrier sign" is characteristic of which of the following conditions?

Accepted Answer

Spondylolisthesis

Answer

Spondylosis

Answer

Lumbar canal stenosis

Answer

Slipped disc

Question 6

Spoke wheel calcification in an osteolytic lesion is seen in which of the following conditions?

Accepted Answer

Hemangioma

Answer

Secondaries

Answer

Plasmacytosis

Answer

Hydatid disease

Question 7

A radiolucency in bone without periosteal bone reaction is seen in which of the following conditions?

Accepted Answer

Squamous cell carcinoma

Answer

Garre's osteomyelitis

Answer

Osteosarcoma

Answer

Chronic osteomyelitis

Question 8

Which of the following conditions show increased density in the skull vault?

Accepted Answer

Hyperparathyroidism, Multiple myeloma, Renal osteodystrophy

Answer

Hyperparathyroidism, Renal osteodystrophy

Answer

Multiple myeloma, Fluorosis

Answer

Multiple myeloma, Fluorosis, Renal osteodystrophy

Question 9

Which of the following is NOT a radiological feature of rheumatoid arthritis?

Accepted Answer

Osteophytes

Answer

Subchondral cysts

Answer

Subchondral osteopenia

Answer

Subchondral swelling

Question 10

What is the best radiographic view for a fracture of the C1-C2 vertebrae?

Accepted Answer

Odontoid view

Answer

AP view

Answer

Lateral view

Answer

Oblique view

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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