Musculoskeletal Radiology Practice Questions

Q: A 12-year-old patient presents with a painless, slowly enlarging swelling of the left posterior mandible for the past 6 months. Clinical examination reveals a firm, non-tender expansion of the mandible, and the adjacent mandibular left second molar is carious with a periapical abscess. Radiographically, the lesion shown in the image could be:

Garre's osteomyelitis. ***Garre's osteomyelitis*** - The radiographs show **periosteal new bone formation** resembling an **"onion skin"** appearance, which is characteristic of **Garre's osteomyelitis** (chronic osteomyelitis with proliferative periostitis). - This condition is typically a **reaction to low-grade chronic infection** or irritation, often seen in the periosteum of the mandible. *Cherubism* - Cherubism is a **fibro-osseous lesion** characterized by bilateral, symmetric enlargement of the jaws, giving a "cherubic" appearance. - Radiographically, it presents as **multilocular radiolucencies** with well-defined borders, usually in children. *Fibrous dysplasia* - Fibrous dysplasia is a developmental anomaly where normal bone is replaced by **fibrous tissue and immature bone**. - Radiographically, it often has a **"ground glass" appearance** or a "peau d'orange" texture, differentiating it from the periosteal reaction seen in the image. *Osteosarcoma* - Osteosarcoma is a **malignant bone tumor** that typically shows a mix of osteolytic and osteoblastic areas, often with a **"sunburst" or "spiculated" periosteal reaction**. - While it involves periosteal reaction, the pattern and typical aggressive nature differ from the more layered and milder appearance of Garre's osteomyelitis.

Q: What is the investigation of choice for diagnosing a stress fracture?

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the most sensitive and specific imaging modality for diagnosing **stress fractures**, especially in their early stages. - It can detect **bone marrow edema** and **periosteal reactions** indicative of stress injury before cortical changes are visible on plain radiographs. *X-ray* - **X-rays** are often the initial investigation, but they have low sensitivity for **stress fractures** in the early stages as bone changes may not be apparent for several weeks. - A positive X-ray for stress fracture typically shows a **sclerotic line** or **periosteal reaction**, but this indicates a more advanced injury. *CT scan* - **CT scans** provide excellent detail of **cortical bone** and can detect subtle fractures not seen on X-rays. - While more sensitive than X-rays, CT has **higher radiation exposure** and is generally less sensitive than MRI for early detection of **bone marrow edema** associated with stress injuries. *Bone scan* - **Bone scans** (scintigraphy) are highly sensitive for detecting increased **osteoblastic activity** associated with stress fractures. - However, they are **less specific** as various conditions can cause increased uptake, and they do not provide detailed anatomical information, making MRI superior for definitive diagnosis and staging.

Q: X-ray features of hypoparathyroidism are the following except:

Subperiosteal resorption. ***Subperiosteal resorption*** - This is a classic radiographic feature of **hyperparathyroidism**, characterized by the breakdown of bone beneath the periosteum, commonly seen in the phalanges. - In **hypoparathyroidism**, bone resorption is *decreased*, leading to increased bone density or **osteosclerosis**, not resorption. *Calvarial thickening* - **Calvarial thickening** can be observed in hypoparathyroidism due to altered bone remodeling processes resulting from chronic low parathyroid hormone (PTH) levels. - The absence of PTH leads to **decreased osteoclastic activity**, promoting bone accumulation. *Subcutaneous calcification* - **Subcutaneous calcification** occurs in hypoparathyroidism due to chronic **hyperphosphatemia** and **hypocalcemia**. - This imbalance can lead to the precipitation of **calcium phosphate crystals** in soft tissues. *Osteosclerosis* - **Osteosclerosis** is a direct consequence of chronic hypoparathyroidism, as the low PTH levels lead to **reduced bone turnover** and decreased osteoclast activity. - This results in an **increase in bone density**, making the bones appear denser on X-ray.

Q: All of the following have the same radiographic features except:

Odontoma. ***Odontoma*** - This is the **correct answer** as it is the exception among the listed lesions. - Odontoma is a **benign odontogenic tumor** composed of mature enamel, dentin, cementum, and pulp tissue, which radiographically appears as a **radiopaque mass** (tooth-like structure) often associated with an impacted tooth. - Unlike the other three options which are all **radiolucent**, odontoma's distinct **radiopacity** differentiates it from the predominantly radiolucent cystic and tumoral lesions. *Keratocyst* - This lesion typically presents as a **well-defined, unilocular or multilocular radiolucency** with a smooth, corticated margin. - It does not contain radiopaque calcifications or tooth-like structures. - **Radiographically radiolucent** - similar to the other incorrect options. *Dentigerous cyst* - This cyst is classically seen as a **well-defined, unilocular radiolucency** surrounding the crown of an unerupted or impacted tooth. - Like other cysts, it is predominantly **radiolucent** and lacks internal radiopacities. *Ameloblastoma* - This is a **benign but locally invasive odontogenic tumor** that radiographically appears as a **multilocular ("soap bubble" or "honeycomb") or unilocular radiolucency**. - It is distinctively **radiolucent** and does not exhibit the radiopaque features of tooth-forming lesions.

Q: The 'Search lines' to detect fracture line on occipitomandibular radiographic view of midfacial skeleton fracture was described by:

McGrigor and Campbell. ***McGrigor and Campbell*** - **McGrigor and Campbell** described the "Search lines" concept for identifying fracture lines on **occipitomandibular radiographic views** of midfacial skeleton fractures. - Their work focused on systematic radiographic interpretation for diagnosing complex facial trauma. *Rowe and Williams* - **Rowe and Williams** are well-known for their classification of **mandibular fractures**, not specifically for "Search lines" on occipitomandibular views. - Their contributions are primarily in the surgical management and classification of various facial bone fractures. *Rene Le Fort and Guerin* - **Rene Le Fort** is renowned for defining the classical **Le Fort fracture patterns** of the midface, which are crucial for classifying maxillary trauma. - **Guerin** is associated with early descriptions of facial fractures, but neither described "Search lines" for specific radiographic views. *Andreason and Ravn* - **Andreason and Ravn** are recognized for their work on **dental traumatology**, particularly related to classification and management of tooth injuries. - Their primary focus is on **dentoalveolar trauma**, not the radiographic interpretation of midfacial bone fractures using "Search lines."

Q: "Hair on End" appearance is seen in:

Thalassemia. ***Thalassemia*** - The **"hair on end" appearance** on skull X-rays is caused by **extramedullary hematopoiesis** in the bone marrow, as the body tries to compensate for severe anemia. - This persistent, high-volume erythropoiesis leads to the **expansion** of the **bone marrow spaces**, especially in the skull, resulting in the characteristic radiating spicules. *Rickets* - Rickets is a disorder caused by **vitamin D deficiency**, leading to impaired bone mineralization. - It presents with **bowing of legs**, **rachitic rosary**, and **widening of growth plates**, not "hair on end" appearance. *Scurvy* - Scurvy is due to a **deficiency of vitamin C**, which is essential for collagen synthesis. - It manifests as **bleeding gums**, **perifollicular hemorrhages**, and **impaired wound healing**, not changes in skull bone marrow. *Hemochromatosis* - Hemochromatosis is characterized by **excessive iron accumulation** in various organs, leading to organ damage. - It can cause **liver cirrhosis**, **diabetes**, and **skin pigmentation**, but does not present with the "hair on end" skull manifestation.

Q: Not a radiological feature of Ankylosing spondylitis

Fish mouth vertebrae. **Fish mouth vertebrae** - **Fish mouth vertebrae**, characterized by concave vertebral bodies, are typically seen in conditions like **osteoporosis** or **sickle cell anemia**, resulting from vertebral compression or infarction. - This appearance is not a characteristic radiological feature of **ankylosing spondylitis**, which primarily involves fusion and ossification of spinal ligaments. *Romanus sign* - The **Romanus sign** refers to erosions at the anterior and posterior corners of the vertebral bodies, an early and characteristic radiological feature of **ankylosing spondylitis**. - These erosions eventually lead to squaring of the vertebrae. *Trolley track sign* - The **trolley track sign** is a classic late-stage radiological finding in **ankylosing spondylitis**, indicating ossification of the interspinous and supraspinous ligaments, and the facet joint capsules. - This results in three parallel lines visible on an anteroposterior spinal radiograph. *Dagger sign* - The **dagger sign** is another characteristic radiological feature of **ankylosing spondylitis**, representing ossification of the supraspinous and interspinous ligaments. - It appears as a single central radiopaque line on an anteroposterior spinal radiograph.

Q: Wimberger sign is seen in ?

Scurvy. ***Scurvy*** - Wimberger sign, characterized by a **dense band of calcified cartilage** at the metaphysis and a **rarefied zone beneath it**, is a classic radiographic sign of scurvy. - It reflects the impaired osteoid synthesis due to **vitamin C deficiency**, leading to weakened bone structure. *Osteoporosis* - Osteoporosis is characterized by **reduced bone mineral density** and increased bone porosity, leading to fragility fractures. - Radiographically, it appears as generalized **osteopenia** with thinning of cortical bone and prominent trabeculae, not specific metaphyseal changes like Wimberger sign. *Osteomalacia* - Osteomalacia is a condition of **defective bone mineralization** after epiphyseal closure, often due to **vitamin D deficiency**. - It presents with **Looser zones (pseudofractures)** and generalized radiolucency, distinct from the metaphyseal changes seen in Wimberger sign. *Rickets* - Rickets is a disorder of **impaired bone mineralization** in children, occurring before epiphyseal fusion, primarily due to **vitamin D deficiency**. - Radiographic features include **widened, cupped, and frayed metaphyses**, distinct from the dense and rarefied bands of Wimberger sign.

Q: Sunburst appearance found in:

Osteosarcoma. ***Osteosarcoma*** - A classic radiographic feature of **osteosarcoma** is the **sunburst appearance**, which represents new bone formation radiating outwards from the cortex. - This aggressive tumor typically occurs in the **metaphysis of long bones** (e.g., distal femur, proximal tibia). *Ewing sarcoma* - Characteristically presents with an **onion-skin appearance** (concentric layers of periosteal reaction) due to rapid bone destruction and new bone formation. - It often affects the **diaphysis of long bones** and flat bones, unlike the metaphyseal involvement of osteosarcoma. *Giant cell tumor* - Known for its characteristic **soap-bubble appearance** on imaging, indicating a lytic lesion with thin septations. - Typically found in the **epiphysis of long bones** in young adults. *Chondrosarcoma* - Radiographically, it often shows a **lobulated lesion** with **calcified cartilage matrix** (popcorn or ring-and-arc calcifications). - While it can be destructive, it does not typically exhibit the radiating pattern seen in a sunburst appearance, which is primarily an osteoblastic phenomenon.

Q: Radiological findings of scurvy are A/E:

Metaphyseal infarction. ***Metaphyseal infarction*** - **Metaphyseal infarction** (bone infarcts) is NOT a feature of scurvy and is typically associated with conditions like **sickle cell anemia**, **Gaucher disease**, or following trauma/infection. - Scurvy primarily affects collagen synthesis, leading to issues with bone matrix and subperiosteal hemorrhages rather than ischemic necrosis. *Pelkan spur* - **Pelkan spur** (also known as the "corner sign" or "spur formation") is a **characteristic radiological finding in scurvy**, not rickets. - It results from metaphyseal corner fractures due to subperiosteal hemorrhages and weakened bone matrix at the metaphyseal edges. *Epiphyseal widening* - This is not a classic or characteristic finding of scurvy. - While scurvy affects the growth plate with features like **Wimberger ring sign** (dense calcification around epiphysis) and **epiphyseal separation**, generalized epiphyseal widening is not typically described. *Metaphyseal porosis* - **Ground glass osteopenia/porosis** is a recognized feature of scurvy due to impaired osteoid formation. - This results from defective collagen synthesis leading to decreased bone density, particularly evident in the metaphyseal regions.

Question 1

A 12-year-old patient presents with a painless, slowly enlarging swelling of the left posterior mandible for the past 6 months. Clinical examination reveals a firm, non-tender expansion of the mandible, and the adjacent mandibular left second molar is carious with a periapical abscess. Radiographically, the lesion shown in the image could be:

Accepted Answer

Garre's osteomyelitis

Answer

Fibrous dysplasia

Answer

Osteosarcoma

Answer

Cherubism

Question 2

What is the investigation of choice for diagnosing a stress fracture?

Accepted Answer

MRI

Answer

X-ray

Answer

CT scan

Answer

Bone scan

Question 3

X-ray features of hypoparathyroidism are the following except:

Accepted Answer

Subperiosteal resorption

Answer

Calvarial thickening

Answer

Subcutaneous calcification

Answer

Osteosclerosis

Question 4

All of the following have the same radiographic features except:

Accepted Answer

Odontoma

Answer

Keratocyst

Answer

Dentigerous cyst

Answer

Ameloblastoma

Question 5

The 'Search lines' to detect fracture line on occipitomandibular radiographic view of midfacial skeleton fracture was described by:

Accepted Answer

McGrigor and Campbell

Answer

Rowe and Williams

Answer

Rene Le Fort and Guerin

Answer

Andreason and Ravn

Question 6

"Hair on End" appearance is seen in:

Accepted Answer

Thalassemia

Answer

Rickets

Answer

Scurvy

Answer

Hemochromatosis

Question 7

Not a radiological feature of Ankylosing spondylitis

Accepted Answer

Fish mouth vertebrae

Answer

Romanus sign

Answer

Trolley track sign

Answer

Dagger sign

Question 8

Wimberger sign is seen in ?

Accepted Answer

Scurvy

Answer

Osteoporosis

Answer

Osteomalacia

Answer

Rickets

Question 9

Sunburst appearance found in:

Accepted Answer

Osteosarcoma

Answer

Ewing sarcoma

Answer

Giant cell tumor

Answer

Chondrosarcoma

Question 10

Radiological findings of scurvy are A/E:

Accepted Answer

Metaphyseal infarction

Answer

Pelkan spur

Answer

Epiphyseal widening

Answer

Metaphyseal porosis

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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