Musculoskeletal Radiology Practice Questions

Q: All the following are seen in Hyperparathyroidism except:

Calvarial thickening. ***Calvarial thickening*** - **Calvarial thickening** is typically associated with conditions like **Paget's disease** of bone or certain anemias, which increase bone deposition, whereas hyperparathyroidism leads to bone resorption. - In hyperparathyroidism, the primary skeletal manifestation is **osteoclastic bone resorption**, leading to thinning of cortical bone and loss of bone density, not thickening. *Pepper-pot skull* - This describes the radiographic appearance of the skull due to **resorption of trabecular bone** and formation of numerous small lucencies, giving it a "pepper-pot" or "salt-and-pepper" appearance. - It's a classic sign of **hyperparathyroidism**, indicating diffuse bone demineralization in the skull. *Loss of lamina dura* - The **lamina dura** is the dense bone lining the tooth socket, which appears as a radiopaque line around the tooth root on radiographs. - Its **loss or absence** is a characteristic sign of hyperparathyroidism due to generalized bone demineralization, as it is one of the first cortical bone structures to undergo resorption. *Subperiosteal erosion of bone* - This is considered the **pathognomonic radiographic sign** of hyperparathyroidism, particularly seen in the phalanges of the hand. - It results from excessive **osteoclastic activity** leading to resorption of bone directly beneath the periosteum.

Q: Spine MRI shows 'pencil-sharpened' vertebral bodies and 'H-shaped' vertebrae on T1-weighted images. Most likely diagnosis?

Sickle cell disease. ***Sickle cell disease*** - **'Pencil-sharpened' vertebral bodies** and **'H-shaped' vertebrae** are characteristic findings in sickle cell disease due to chronic **ischemic necrosis** of the vertebral endplates. - This vertebral deformity arises from the collapse of the central portion of the vertebral body, often associated with episodes of **vaso-occlusion**. *Paget's disease* - Characterized by abnormal bone remodeling, leading to **bone enlargement** and thickening, not vertebral notching or collapse. - Common radiological findings include **cotton wool appearance** of the skull and **sclerosis** of the vertebrae, distinct from the described MRI findings. *Thalassemia* - Causes significant **bone marrow expansion** due to ineffective erythropoiesis, leading to cortical thinning and widened medullary spaces. - While it can affect bone morphology, it typically does not produce the specific 'H-shaped' or 'pencil-sharpened' vertebral body deformities. *Osteopetrosis* - Known as **'marble bone disease'**, characterized by abnormally dense bones due to defective osteoclast function. - Radiologically, it presents with **generalized increased bone density** and obliterated marrow spaces, which is opposite to the changes seen in sickle cell disease.

Q: STIR sequence in MRI is most useful for

Bone marrow lesions. ***Bone marrow lesions*** - **STIR (Short Tau Inversion Recovery)** sequences are excellent for suppressing fat signals, making them highly sensitive for detecting **edema** and **fluid-rich lesions** within the **bone marrow**. - This characteristic makes it ideal for identifying conditions like **bone bruises**, **stress fractures**, **osteomyelitis**, and **marrow infiltration** by tumors. *Liver masses* - While STIR can show some features of liver lesions, other sequences like **T1-weighted fat-saturated** and **dynamic contrast-enhanced imaging** are typically more specific for characterizing liver masses. - The primary strength of STIR is fat suppression, which is less critical for distinguishing most liver mass types from the surrounding parenchyma. *Brain tumors* - **Fluid-attenuated inversion recovery (FLAIR)** sequences are generally preferred for evaluating brain tumors, as they suppress CSF signal effectively, making peritumoral edema and lesions visible. - While STIR can be used, its strong fat suppression isn't as critical in the brain as it is for musculoskeletal imaging, and FLAIR offers better grey/white matter contrast. *Kidney stones* - **CT scans**, especially **non-contrast helical CT**, are the gold standard for detecting and characterizing kidney stones due to their high spatial resolution and sensitivity to calcifications. - MRI, including STIR, has limited utility for identifying kidney stones as most stones are too small to be clearly visualized and do not typically exhibit features enhanced by fat suppression.

Q: Most sensitive imaging modality for detecting early osteomyelitis

MRI. **MRI** - **MRI** is the most sensitive imaging modality for detecting **early osteomyelitis** due to its superior ability to visualize **bone marrow edema** and soft tissue changes, which are the earliest signs of infection. - It can differentiate between **bone infection** and other processes like inflammation or tumor, even before cortical bone changes are evident. *Nuclear bone scan* - **Nuclear bone scans** (e.g., technetium-99m) are highly sensitive for detecting **increased bone turnover** but lack specificity for infection. - They can identify areas of **inflammation** or injury but cannot reliably distinguish between osteomyelitis and other conditions like **fractures** or **tumors**. *CT scan* - **CT scans** are excellent for visualizing **cortical bone destruction**, **sequestra**, and **involucrum** in later stages of osteomyelitis. - However, **CT scans** are not as sensitive as MRI for detecting early bone marrow changes and soft tissue involvement, making them less ideal for **early diagnosis**. *Plain radiograph* - **Plain radiographs** are often the first imaging study for suspected osteomyelitis but have **low sensitivity** in the early stages, with changes typically not visible until 10-14 days after infection onset. - Early findings may include **periosteal elevation** or soft tissue swelling, but **bone destruction** or new bone formation is usually required for a definitive diagnosis.

Q: In acute quadriceps tendon rupture, which radiographic finding is most specific?

Patella Alta. ***Patella Alta*** - **Patella alta**, or a high-riding patella, is a classic radiographic sign of acute quadriceps tendon rupture because the **patella** is no longer tethered inferiorly by the intact quadriceps tendon. - The unopposed pull of the patellar tendon elevates the patella, making this a highly **specific finding**. *Joint Space Narrowing* - **Joint space narrowing** is indicative of cartilage loss and is commonly seen in degenerative conditions like **osteoarthritis**. - It does not directly reflect soft tissue injury such as a quadriceps tendon rupture. *Osteophytes* - **Osteophytes**, or bone spurs, are a sign of **degenerative joint disease** and chronic stress on joints, often seen in osteoarthritis. - They are not specific to acute traumatic injuries like tendon ruptures. *Patella Baja* - **Patella baja**, or a low-riding patella, is typically associated with **patellar tendon rupture**, not quadriceps tendon rupture. - In a patellar tendon rupture, the patella *drops* due to the loss of its inferior anchor, which is the opposite of a quadriceps rupture.

Q: What is the most reliable radiological sign of early osteonecrosis of femoral head?

Double Line Sign on MRI. ***Double Line Sign on MRI*** - The **double line sign on MRI** is considered the most reliable and earliest radiological sign of **osteonecrosis of the femoral head**. - It represents the reactive interface between the necrotic and viable bone, characterized by a **low-signal intensity rim** (fibrosis/sclerosis) and an **inner high-signal intensity line** (granulation tissue). *Osteopenia* - **Osteopenia** is a general sign of bone demineralization and can be seen in many conditions, not specific to early osteonecrosis. - It is a less sensitive and specific indicator for initial changes related to compromised blood supply in the femoral head. *Crescent Sign* - The **crescent sign** is indicative of a **subchondral collapse** and is a later finding in osteonecrosis, suggesting disease progression rather than early onset. - It appears on plain radiographs as a thin, radiolucent line parallel to the articular surface. *Joint Space Narrowing* - **Joint space narrowing** is a feature of **osteoarthritis** and other forms of degenerative joint disease, indicating cartilage loss. - It is not typically an early or specific sign of osteonecrosis, which primarily affects the bone itself.

Q: Which MRI finding is suggestive of a torn meniscus in the knee?

Increased signal intensity in the meniscus. ***Increased signal intensity in the meniscus*** A torn meniscus on MRI typically shows **increased signal intensity** within the meniscal substance that **extends to at least one articular surface**, which is the key diagnostic criterion. This high signal indicates **fluid within the tear** or degenerative changes. The signal must reach the surface to differentiate a true tear from intrasubstance degeneration, which shows signal that does not reach the surface. *Loss of cartilage* **Cartilage loss** is characteristic of **osteoarthritis** or chronic degenerative joint disease, not specifically an acute meniscal tear. While it can coexist with meniscal tears as part of degenerative joint disease, it is not a direct indicator of a tear within the meniscus itself. *Effusion* A **knee effusion** (fluid within the joint) is a general sign of joint irritation or injury and can be present with various conditions, including meniscal tears, ligament injuries, and arthritis. However, it is a **non-specific finding** and does not directly confirm a meniscal tear. *Bone marrow edema* **Bone marrow edema** is often seen with **bone bruises**, stress fractures, or osteonecrosis. It indicates stress or injury to the bone rather than soft tissue injury, and is not directly indicative of a meniscal tear.

Q: Which condition is associated with a 'sunburst' pattern on X-ray?

Osteosarcoma. ***Osteosarcoma*** - This highly aggressive primary bone tumor is characterized by **malignant osteoid formation** and often presents with a **'sunburst' or 'spiculated' periosteal reaction** on X-ray. - The sunburst pattern represents **new bone formation perpendicular to the cortical surface**, indicating rapid tumor growth. *Ewing's sarcoma* - Ewing's sarcoma commonly presents with an **'onion skin' appearance** (lamellated periosteal reaction) on X-ray due to layers of reactive bone. - It is typically a **small round blue cell tumor** found in the diaphysis of long bones. *Giant cell tumor* - This tumor is characterized by a **soap bubble appearance** or **lytic, expansile lesions** on X-ray, typically located in the epiphysis of long bones. - It does not usually exhibit a periosteal reaction like a 'sunburst' pattern. *Chondrosarcoma* - Chondrosarcoma is characterized by a **calcified matrix** with a **'rings and arcs' or 'popcorn' calcification pattern** on X-ray. - While it is a primary bone tumor, its radiographic features differ significantly from the 'sunburst' pattern.

Q: In ankylosing spondylitis, which of the following is commonly seen on MRI?

Sacroiliitis. ***Sacroiliitis*** - **Sacroiliitis**, inflammation of the **sacroiliac joints**, is the hallmark and earliest radiological finding in **ankylosing spondylitis** and is readily visualized on MRI. - MRI is highly sensitive for detecting both **bone marrow edema** (indicating active inflammation) and **erosions** in the sacroiliac joints, even before changes are visible on conventional X-rays. *Schmorl's nodes* - **Schmorl's nodes** are **vertebral endplate infarctions** where the intervertebral disc herniates into the vertebral body, typically due to degeneration or trauma. - While they can be seen in various spinal conditions, they are **not specifically diagnostic** or characteristic of **ankylosing spondylitis**. *Intervertebral disc prolapse* - An **intervertebral disc prolapse**, commonly known as a **slipped disc**, involves the bulging or rupture of a disc, often causing nerve root compression. - This is a common cause of back pain in the general population but is **not a primary feature** or direct consequence of the inflammatory process in **ankylosing spondylitis**. *Bamboo spine* - **Bamboo spine** refers to the **fusion of vertebral bodies** due to syndesmophyte formation, leading to a rigid spine. - This is a **late-stage radiological change** seen on plain X-rays, representing chronic, irreversible damage, whereas MRI is used for early detection of active inflammation like sacroiliitis.

Q: Which radiological feature is a hallmark of adolescent idiopathic scoliosis?

Rotational deformity of the vertebrae. ***Rotational deformity of the vertebrae*** - **Adolescent idiopathic scoliosis** is characterized by a 3D spinal deformity, and an axial **rotational deformity of the vertebrae** is a hallmark finding on imaging. - This rotation contributes to the rib hump seen on physical examination and is crucial for measuring the severity of the scoliosis curve using methods like the **Cobb angle**. *Lytic lesions* - **Lytic lesions** indicate areas of bone destruction, often associated with tumors, infections like osteomyelitis, or metabolic bone diseases. - They are not characteristic findings in **idiopathic scoliosis**, which is a structural deformity rather than a destructive process. *Vertebral collapse* - **Vertebral collapse** (or compression fractures) is typically caused by trauma, osteoporosis, or metastatic disease, leading to a reduction in vertebral body height. - This is not a feature of **adolescent idiopathic scoliosis**, where the vertebral bodies generally maintain their structural integrity, albeit with rotation. *Sclerotic lesions* - **Sclerotic lesions** refer to areas of increased bone density, which can be seen in conditions like osteoblastic metastases, Paget's disease, or chronic stress responses. - They are not a characteristic radiological finding in **adolescent idiopathic scoliosis**, where the primary issue is spinal curvature and vertebral rotation.

Question 1

All the following are seen in Hyperparathyroidism except:

Accepted Answer

Calvarial thickening

Answer

Pepper - pot skull

Answer

Loss of lamina dura

Answer

Subperiosteal erosion of bone

Question 2

Spine MRI shows 'pencil-sharpened' vertebral bodies and 'H-shaped' vertebrae on T1-weighted images. Most likely diagnosis?

Accepted Answer

Sickle cell disease

Answer

Paget's disease

Answer

Thalassemia

Answer

Osteopetrosis

Question 3

STIR sequence in MRI is most useful for

Accepted Answer

Bone marrow lesions

Answer

Liver masses

Answer

Brain tumors

Answer

Kidney stones

Question 4

Most sensitive imaging modality for detecting early osteomyelitis

Accepted Answer

MRI

Answer

Nuclear bone scan

Answer

CT scan

Answer

Plain radiograph

Question 5

In acute quadriceps tendon rupture, which radiographic finding is most specific?

Accepted Answer

Patella Alta

Answer

Joint Space Narrowing

Answer

Osteophytes

Answer

Patella Baja

Question 6

What is the most reliable radiological sign of early osteonecrosis of femoral head?

Accepted Answer

Double Line Sign on MRI

Answer

Osteopenia

Answer

Crescent Sign

Answer

Joint Space Narrowing

Question 7

Which MRI finding is suggestive of a torn meniscus in the knee?

Accepted Answer

Increased signal intensity in the meniscus

Answer

Loss of cartilage

Answer

Effusion

Answer

Bone marrow edema

Question 8

Which condition is associated with a 'sunburst' pattern on X-ray?

Accepted Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Giant cell tumor

Answer

Chondrosarcoma

Question 9

In ankylosing spondylitis, which of the following is commonly seen on MRI?

Accepted Answer

Sacroiliitis

Answer

Schmorl's nodes

Answer

Intervertebral disc prolapse

Answer

Bamboo spine

Question 10

Which radiological feature is a hallmark of adolescent idiopathic scoliosis?

Accepted Answer

Rotational deformity of the vertebrae

Answer

Lytic lesions

Answer

Vertebral collapse

Answer

Sclerotic lesions

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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