Neuroradiology Practice Questions

Q: A polytrauma patient's CT brain shows a crescent-shaped extra-axial collection with a concave inner margin. What is the most likely diagnosis?

SDH. ***SDH*** - The image shows a **crescent-shaped collection** of hemorrhage with a concave inner margin, consistent with a **subdural hematoma** (SDH). - SDHs result from the tearing of **bridging veins** and typically conform to the brain's surface, crossing suture lines but not limited by bony sutures. *EDH* - An **epidural hematoma (EDH)** characteristically appears as a **lenticular** or **biconvex** shape on CT, not crescent-shaped. - EDHs are typically caused by arterial bleeding, often from the **middle meningeal artery**, and are limited by cranial sutures. *Contusion* - A **contusion** is brain tissue bruising that appears as **heterogeneous areas** of hemorrhage and edema within the brain parenchyma itself. - It would not manifest as a distinct extra-axial collection with a smooth, concave margin. *Diffuse axonal injury* - **Diffuse axonal injury (DAI)** involves widespread microscopic damage to axons, often at the gray-white matter junction. - It may appear as *punctate hemorrhages* or **small lesions** at these junctions on CT, but often the CT can be normal, and it would not present as a large extra-axial collection.

Q: Investigation of choice for intramedullary SOL is -

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the investigation of choice for intramedullary lesions due to its superior **soft tissue contrast** and ability to visualize the **spinal cord** parenchyma. - It provides detailed information on lesion size, location, and internal characteristics, which is crucial for diagnosis and surgical planning. *USG* - **Ultrasound (USG)** has limited utility for intramedullary lesions as a primary diagnostic tool because **bone impedes sound waves**, making it difficult to visualize structures within the spinal canal. - It might be used for neonatal spinal screening or intraoperative guidance, but not for definitive diagnosis of intramedullary lesions in adults. *CT* - **Computed Tomography (CT)** excels at visualizing **bone structures** and calcifications, but it provides less detailed information about soft tissue elements like the spinal cord compared to MRI. - While it can identify bony changes associated with intramedullary lesions, it is not the preferred initial imaging modality for characterizing the lesion itself. *X-ray* - **X-rays** provide basic imaging of bone but offer essentially **no visualization of soft tissues** such as the spinal cord or intramedullary lesions. - They are primarily used to identify gross bony abnormalities like fractures or severe degenerative changes, not for subtle intraspinal pathologies.

Q: Investigation of choice for multiple sclerosis

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the investigation of choice for **multiple sclerosis** due to its superior ability to visualize **demyelinating plaques** in the brain and spinal cord. - It can detect both **new and old lesions**, crucial for diagnosis and monitoring disease progression, according to the **McDonald criteria**. *CT* - **Computed Tomography (CT) scans** are generally less sensitive than MRI in detecting the subtle **demyelinating lesions** characteristic of multiple sclerosis. - While it can sometimes show larger lesions, it often misses smaller or early-stage plaques, making it less suitable for initial diagnosis. *USG* - **Ultrasound (USG)** is primarily used for visualizing soft tissues and vascular structures, not for detailed imaging of the brain or spinal cord parenchyma. - It has no role in the diagnosis or monitoring of **multiple sclerosis**. *PET* - **Positron Emission Tomography (PET) scans** are used to assess metabolic activity and perfusion, often in oncology or certain neurological disorders like Alzheimer's or Parkinson's disease. - It is not routinely used for the diagnosis of **multiple sclerosis**, as it does not clearly visualize the **demyelinating lesions**.

Q: Which condition is characterized by the 'Eye of the Tiger' sign on MRI?

Pantothenate Kinase-Associated Neurodegeneration (PKAN). ***Pantothenate Kinase-Associated Neurodegeneration (PKAN)*** - The **'Eye of the Tiger' sign** is a classic MRI finding in PKAN, characterized by a central area of high signal intensity (pallidal necrosis and gliosis) with a surrounding rim of low signal intensity (iron deposition) in the **globus pallidus**. - This sign is highly specific for PKAN, which is caused by a mutation in the *PANK2* gene leading to **iron accumulation** in the brain, particularly the basal ganglia. *Wilsons disease* - Wilson's disease is characterized by **copper accumulation** in various organs, including the brain. - MRI findings may include **basal ganglia lesions** but typically do not exhibit the specific 'Eye of the Tiger' pattern. *Alzheimer's* - Alzheimer's disease is a neurodegenerative disorder primarily characterized by **amyloid plaques** and **neurofibrillary tangles**. - MRI typically shows **cortical atrophy**, particularly in the hippocampus and temporal lobes, but not basal ganglia iron accumulation. *Neurodegeneration with brain iron accumulation (NBIA), excluding PKAN* - While other forms of NBIA (e.g., neuroferritinopathy) involve iron accumulation, the **'Eye of the Tiger' sign** is pathognomonic for **PKAN** and not typically seen in other NBIA subtypes. - The specific pattern of pallidal necrosis and iron rim is unique to PKAN due to its distinct underlying genetic and biochemical pathology.

Q: Best method of detection of a retained glass intraocular foreign body is

CT scan. ***CT scan*** - **CT scans** are highly sensitive and specific for detecting **retained glass intraocular foreign bodies** due to their excellent spatial resolution and ability to visualize foreign materials with different densities. - Unlike MRI, CT is safe with metallic foreign bodies and provides precise localization, aiding surgical planning. *Radiography* - While helpful for detecting radio-opaque foreign bodies like metal, **plain X-rays display limited soft tissue contrast** and may struggle to visualize small or less dense objects like glass effectively within the complex orbital structures. - **Glass foreign bodies can be difficult to discern** from surrounding bony structures or soft tissues on conventional radiographs, leading to false negatives. *USG* - **Ultrasound (USG)** is effective for imaging soft tissues and can detect some foreign bodies, but its utility is limited when the object is small, non-reflective, or located deep within the globe, especially behind structures like the lens or iris. - **Acoustic shadowing** and artifact creation can also obscure the foreign body or mimic its presence, reducing diagnostic accuracy for glass. *Tonometry* - **Tonometry measures intraocular pressure** and is primarily used to screen for or monitor glaucoma. - It provides no information about the presence or location of **intraocular foreign bodies**.

Q: What is the investigation of choice in a patient with traumatic paraplegia?

MRI scan. ***MRI scan*** - An **MRI scan** provides superior imaging of **soft tissues**, including the spinal cord, nerves, and ligaments, which are crucial for assessing damage in **traumatic paraplegia**. - It is essential for detecting **spinal cord compression**, hemorrhage, edema, and ligamentous injuries that may not be visible on other imaging modalities. *Plain X-ray* - A **plain X-ray** primarily visualizes bony structures and can detect major **fractures or dislocations** but offers limited information about the spinal cord or soft tissue damage. - It may miss subtle bony injuries and provides no information on **spinal cord integrity**, which is critical in paraplegia. *Myelography* - **Myelography** involves injecting contrast dye into the spinal canal and then performing X-rays or CT scans, which is an **invasive procedure** with potential risks. - While it can demonstrate **spinal cord compression** indirectly, it has largely been replaced by MRI due to its invasiveness and MRI's direct visualization capabilities. *CT scan* - A **CT scan** is excellent for evaluating **bony injuries**, such as vertebral fractures and alignment, with good detail. - However, it is less effective than MRI for directly visualizing the **spinal cord itself** and assessing soft tissue damage, which is paramount in paraplegia.

Q: Which of the following brain structures does not contribute to the Mickey Mouse sign on axial brain imaging?

Superior colliculus. ***Superior colliculus*** - The superior colliculus is located **dorsal to the cerebral peduncles** and substantia nigra, at a higher axial level, and therefore does not contribute to the "Mickey Mouse" appearance on axial imaging formed by the substantia nigra and red nucleus within the midbrain tegmentum. - The "Mickey Mouse" sign specifically refers to the configuration of structures visible on **axial T2-weighted MRI brain images** at the level of the midbrain, depicting the red nucleus and substantia nigra as the "ears" and the cerebral peduncles as the "face." *Cerebral peduncles* - The cerebral peduncles form the **"face" or main body** of the Mickey Mouse sign, evident on axial imaging due to their ventral position in the midbrain. - These are large bundles of nerve fibers descending from the cerebrum to the brainstem and spinal cord, creating a prominent structure in the anterior midbrain. *Interpeduncular cistern* - The interpeduncular cistern is the **CSF-filled space** located between the cerebral peduncles. - While it doesn't form part of Mickey's face or ears, its presence and surrounding structures help define the arrangement that creates the "Mickey Mouse" sign on imaging. *Substantia nigra* - The substantia nigra forms the **"ears" of the Mickey Mouse** sign on axial imaging, positioned dorsally to the cerebral peduncles. - Its high iron content causes it to be **hypointense on T2-weighted images**, contributing to its distinct appearance in this characteristic sign.

Q: Which of the following is not a sign of increased intracranial tension?

Ballooning of sella. ***Ballooning of sella*** - **Ballooning of the sella** is typically associated with a **pituitary adenoma** or other intrasellar mass, which directly expands the sella turcica. - While a large pituitary tumor can eventually cause increased intracranial pressure, ballooning itself is a sign of local tumor growth rather than generalized increased intracranial tension. *Erosion of dorsum sella* - **Erosion of the dorsum sella** and posterior clinoid processes are classic radiological signs of **chronically elevated intracranial pressure**. - The increased pressure causes remodeling and thinning of these bony structures over time. *Copper-beaten appearance* - The **copper-beaten appearance**, or **convolutional markings**, often seen on skull radiographs, is a sign of long-standing **increased intracranial pressure**. - It results from the cerebral convolutions indenting the inner table of the skull due to chronic pressure. *Sutural diastasis* - **Sutural diastasis**, or widening of the cranial sutures, is a sign of **increased intracranial tension** in infants and young children whose cranial sutures have not yet fused. - The sutures separate as the brain expands against the skull due to elevated pressure.

Q: Tear drop sign on X-ray of the paranasal sinuses is seen in

Blow out fracture of the floor of the orbit. ***Blow out fracture of the floor of the orbit*** - The **tear drop sign** on X-ray is characteristic of a **blow-out fracture** of the orbital floor. It represents **herniation of orbital contents** (fat or inferior rectus muscle) into the maxillary sinus. - This sign appears as a **prolapsed soft tissue mass** hanging from the orbital floor into the maxillary antrum, resembling a tear drop. *Comminuted fracture of the maxilla* - A comminuted maxilla fracture involves **multiple bone fragments** and typically presents with significant facial deformity and instability, but not specifically a tear drop sign. - The **tear drop sign** is a specific radiological finding indicating orbital floor involvement, not a general maxillary fracture. *Fracture of the nasal bone* - Nasal bone fractures present with swelling, epistaxis, and deformity of the nose. - They do not typically affect the orbital contents or lead to signs in the paranasal sinuses like the **tear drop sign**. *Fracture of the mandible* - Mandible fractures involve the lower jaw and are associated with pain, malocclusion, and difficulty opening the mouth. - These fractures are anatomically distant from the orbit and paranasal sinuses, and therefore would not cause a **tear drop sign**.

Q: What is the most common cause of periventricular calcification?

Cytomegalic infection. ***Cytomegalic infection*** - **Periventricular calcification** is a classic finding in congenital Cytomegalovirus (CMV) infection due to the virus's predilection for the **subependymal germinal matrix**. - CMV is the **most common congenital infection** and the leading infectious cause of **sensorineural hearing loss** and neurodevelopmental delay, often presenting with such calcifications. *Toxoplasmosis* - Congenital toxoplasmosis typically causes **diffuse scattered intracranial calcifications** rather than the periventricular pattern seen with CMV. - While it is a significant cause of congenital neurological damage, its calcification pattern is usually **randomly distributed** throughout the brain parenchyma. *Congenital syphilis* - Congenital syphilis primarily affects the **bones, skin, liver, and eyes**, but typically does not cause intracranial calcifications. - Neurological manifestations in congenital syphilis are more commonly related to **meningitis** or **hydrocephalus**, without characteristic calcifications. *Tuberous sclerosis* - Tuberous sclerosis causes **subependymal nodules** that may calcify and can appear in a periventricular distribution. - However, these are **hamartomas** (non-infectious lesions) and are part of a broader neurocutaneous syndrome, distinguished from CMV by associated features like **cortical tubers**, **cardiac rhabdomyomas**, and **skin findings** (ash-leaf spots, shagreen patches).

Question 1

A polytrauma patient's CT brain shows a crescent-shaped extra-axial collection with a concave inner margin. What is the most likely diagnosis?

Accepted Answer

SDH

Answer

EDH

Answer

Contusion

Answer

Diffuse axonal injury

Question 2

Investigation of choice for intramedullary SOL is -

Accepted Answer

MRI

Answer

USG

Answer

CT

Answer

X-ray

Question 3

Investigation of choice for multiple sclerosis

Accepted Answer

MRI

Answer

CT

Answer

USG

Answer

PET

Question 4

Which condition is characterized by the 'Eye of the Tiger' sign on MRI?

Accepted Answer

Pantothenate Kinase-Associated Neurodegeneration (PKAN)

Answer

Wilson's disease

Answer

Alzheimer's

Answer

Neurodegeneration with brain iron accumulation (NBIA), excluding PKAN

Question 5

Best method of detection of a retained glass intraocular foreign body is

Accepted Answer

CT scan

Answer

USG

Answer

Radiography

Answer

Tonometry

Question 6

What is the investigation of choice in a patient with traumatic paraplegia?

Accepted Answer

MRI scan

Answer

Myelography

Answer

CT scan

Answer

Plain X-ray

Question 7

Which of the following brain structures does not contribute to the Mickey Mouse sign on axial brain imaging?

Accepted Answer

Superior colliculus

Answer

Interpeduncular cistern

Answer

Substantia nigra

Answer

Cerebral peduncles

Question 8

Which of the following is not a sign of increased intracranial tension?

Accepted Answer

Ballooning of sella

Answer

Erosion of dorsum sella

Answer

Copper-beaten appearance

Answer

Sutural diastasis

Question 9

Tear drop sign on X-ray of the paranasal sinuses is seen in

Accepted Answer

Blow out fracture of the floor of the orbit

Answer

Comminuted fracture of the maxilla

Answer

Fracture of the nasal bone

Answer

Fracture of the mandible

Question 10

What is the most common cause of periventricular calcification?

Accepted Answer

Cytomegalic infection

Answer

Toxoplasmosis

Answer

Congenital syphilis

Answer

Tuberous sclerosis

Neuroradiology — MCQs

Neuroradiology — MCQs

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