Musculoskeletal Radiology Practice Questions

Q: In an adult patient, interpret the finding of a vertebral body that has lost almost its entire height anteriorly and posteriorly (pancake vertebra). Which of the following conditions is most likely associated with this finding?

Multiple myeloma. ***Multiple myeloma*** - **Multiple myeloma** causes diffuse **osteolytic lesions** throughout the vertebral body due to plasma cell infiltration, leading to uniform collapse and the characteristic **pancake vertebra** appearance. - In **adult patients**, multiple myeloma is the most common cause of **vertebra plana**, as the diffuse marrow replacement weakens the entire vertebral structure symmetrically. *Tuberculosis (Pott's disease)* - **Pott's disease** typically causes **anterior wedge collapse** with preservation of the posterior vertebral body, creating **kyphotic deformity** rather than complete flattening. - It commonly involves **disc space destruction** and **paraspinal abscess formation**, not the uniform pancake-like collapse seen in multiple myeloma. *Osteogenesis imperfecta* - This **genetic collagen disorder** causes **brittle bones** with frequent fractures, but vertebral involvement typically shows **anterior compression** with preserved posterior height. - The **wedge-shaped deformities** in osteogenesis imperfecta differ from the complete, uniform height loss characteristic of pancake vertebra. *Eosinophilic granuloma* - **Eosinophilic granuloma** can cause **vertebra plana** in **pediatric patients** as the most common cause, but it's less frequent in adults compared to multiple myeloma. - While it can produce complete vertebral collapse, it typically presents as a **solitary lesion** rather than the diffuse skeletal involvement seen in multiple myeloma.

Q: A 75-year-old female has chronic backache. X-ray of the spine is shown. What is the most likely diagnosis?

Osteoporosis. ***Osteoporosis*** - The X-ray shows diffuse **osteopenia** (reduced bone density) and **vertebral compression fractures**, particularly visible in the lateral view, which are characteristic findings in elderly patients with osteoporosis and chronic backache. - The vertebral bodies appear **demineralized** and some exhibit a loss of height, suggesting collapse due to weakened bone structure. *Spondylodiscitis* - This condition involves **inflammation of the vertebral body and adjacent intervertebral disc**, typically showing **erosions** of the vertebral endplates and **narrowing of the disc space** on X-ray, which are not clearly evident here as the primary issue. - While it can cause back pain, the dominant finding on this X-ray is widespread bone density loss and fractures, rather than localized infection-related changes. *Pott's spine* - Pott's spine (**tuberculous spondylitis**) is a form of osteomyelitis that causes **destruction of vertebral bodies** and adjacent discs, often leading to a **gibbus deformity** (sharp posterior angulation of the spine). - The X-ray does not show extensive vertebral destruction, paraspinal abscess formation, or typical kyphotic deformity associated with Pott's spine. *Spondylolisthesis* - Spondylolisthesis is characterized by the **forward slippage of one vertebral body over another**, often due to a defect in the pars interarticularis. - While there may be some degenerative changes, there is no clear evidence of significant anterior translation of a vertebral body on the lateral X-ray that would indicate spondylolisthesis.

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: Most sensitive modality for detecting bone metastases

MRI. ***MRI*** - **MRI**, especially **whole-body MRI (WB-MRI)**, has the **highest sensitivity (90-100%)** for detecting bone metastases among all imaging modalities. - It directly visualizes **bone marrow changes** before cortical bone destruction occurs, allowing for earlier detection than other modalities. - Excellent for detecting both **lytic and sclerotic lesions** and provides superior soft tissue contrast for assessing marrow involvement. - Particularly sensitive for **spine and pelvic metastases**, and whole-body protocols enable comprehensive skeletal assessment. *PET-CT* - **PET-CT with 18F-FDG** is highly sensitive for detecting metabolically active lesions and provides whole-body assessment with both metabolic and anatomical information. - However, its sensitivity varies by primary tumor type and is **limited for sclerotic/osteoblastic metastases** which may not be FDG-avid. - While excellent for many malignancies, it has **lower sensitivity than MRI** for pure bone metastases detection, particularly in low-metabolism lesions. *Bone scan* - **Bone scan (Tc-99m MDP)** detects increased osteoblastic activity and has been the traditional screening tool with good sensitivity (62-89%). - Effective for detecting osteoblastic lesions and provides whole-body skeletal survey at relatively low cost. - However, it is **less sensitive than MRI** and can miss purely lytic metastases or early marrow involvement before osteoblastic response occurs. *Plain radiograph* - **Plain radiographs** require significant bone mineral loss (30-50%) to visualize lesions, making them the **least sensitive modality** for bone metastases. - Useful for assessing established lesions and complications like pathological fractures, but inadequate for screening or early detection.

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: A child with lymphoma shows 'ivory vertebra' sign. Best imaging modality for evaluation?

MRI spine. ***MRI spine*** - **MRI** is the **most sensitive and specific** imaging modality for evaluating bone marrow infiltration in lymphoma, especially detecting the **'ivory vertebra' sign** (diffuse uniform sclerotic density). - It provides excellent soft tissue contrast, allowing for detailed visualization of **vertebral body involvement**, **bone marrow infiltration**, and **spinal cord compression**, which are critical in managing lymphoma. - MRI superior for assessing **extent of marrow replacement** and detecting **soft tissue masses** associated with lymphomatous involvement. *Plain X-ray* - While a plain X-ray might show the **'ivory vertebra' sign** as increased homogeneous bone density, it has **limited sensitivity** for early or subtle bone marrow changes. - It is often insufficient for comprehensive staging or assessing the full extent of **vertebral and paravertebral soft tissue involvement** in lymphoma. *CT spine* - **CT scans** excel at evaluating **cortical bone involvement** and detecting sclerotic changes but are less sensitive than MRI for detecting subtle **marrow infiltration** and soft tissue components. - While it can clearly depict the sclerotic density of **'ivory vertebra'**, it exposes the patient to **ionizing radiation** and offers inferior soft tissue resolution for bone marrow changes and epidural extension compared to MRI. *Bone scan* - **Bone scans** are sensitive for detecting **increased osteoblastic activity** and skeletal involvement but are **non-specific**, meaning they can indicate bone abnormalities without precisely defining the cause or extent. - While it can identify areas of **increased uptake** in lymphomatous bone involvement, it doesn't provide the detailed anatomical resolution needed to characterize the vertebral changes or assess **spinal cord compression** as effectively as MRI.

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: 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.

Question 1

In an adult patient, interpret the finding of a vertebral body that has lost almost its entire height anteriorly and posteriorly (pancake vertebra). Which of the following conditions is most likely associated with this finding?

Accepted Answer

Multiple myeloma

Answer

Tuberculosis (Pott's disease)

Answer

Osteogenesis imperfecta

Answer

Eosinophilic granuloma

Question 2

A 75-year-old female has chronic backache. X-ray of the spine is shown. What is the most likely diagnosis?

Accepted Answer

Osteoporosis

Answer

Spondylodiscitis

Answer

Pott's spine

Answer

Spondylolisthesis

Question 3

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 4

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 5

Most sensitive modality for detecting bone metastases

Accepted Answer

MRI

Answer

Bone scan

Answer

PET-CT

Answer

Plain radiograph

Question 6

STIR sequence in MRI is most useful for

Accepted Answer

Bone marrow lesions

Answer

Liver masses

Answer

Brain tumors

Answer

Kidney stones

Question 7

A child with lymphoma shows 'ivory vertebra' sign. Best imaging modality for evaluation?

Accepted Answer

MRI spine

Answer

Plain X-ray

Answer

CT spine

Answer

Bone scan

Question 8

Most sensitive imaging modality for detecting early osteomyelitis

Accepted Answer

MRI

Answer

Nuclear bone scan

Answer

CT scan

Answer

Plain radiograph

Question 9

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 10

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

Musculoskeletal Radiology — MCQs

Musculoskeletal Radiology — MCQs

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