Neuroradiology Practice Questions

Q: Which of the following conditions is least likely to cause posterior scalloping of the vertebrae?

Aortic aneurysm. ***Aortic aneurysm*** - An **aortic aneurysm** is located **anterior to the vertebral column** and primarily affects the anterior aspect of the vertebral bodies, causing **anterior scalloping** due to chronic pulsatile erosion, not posterior scalloping. - Posterior scalloping requires intraspinal pathology that expands the spinal canal from within; an aortic aneurysm is extraspinal and anterior, making it the **least likely** cause of posterior scalloping. *Neurofibromatosis* - **Neurofibromatosis** commonly causes posterior vertebral scalloping due to **dural ectasia** (widening of the dural sac) and pressure erosion from expanding neurofibromas within the spinal canal. - This condition is also associated with paraspinal masses, posterior vertebral body erosion, and scoliosis. *Astrocytoma* - An **intramedullary astrocytoma** within the spinal cord can lead to expansion of the cord that causes chronic pressure on the posterior vertebral bodies from within the spinal canal. - This slow-growing intraspinal tumor gradually remodels the bone, causing posterior scalloping. *Ependymoma* - Similar to astrocytoma, an **intramedullary ependymoma** (the most common primary intramedullary tumor in adults) can enlarge the spinal cord, leading to pressure erosion on the posterior vertebral bodies. - This is a characteristic feature of slowly growing intraspinal masses, which cause remodeling of the bony spinal canal.

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: 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 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: In which of the following diseases is the NAA peak seen?

Canavan disease. ***Canavan disease*** - **Canavan disease** is a **leukodystrophy** characterized by a deficiency of the enzyme **aspartoacylase**. - This deficiency leads to an accumulation of **N-acetylaspartate (NAA)** in the brain, resulting in a significantly elevated NAA peak on **magnetic resonance spectroscopy (MRS)**. *Tuberculoma* - **Tuberculomas** are granulomatous lesions that typically show reduced or absent NAA, an elevated lipid peak, and sometimes an elevated **lactate peak** on MRS. - The metabolic profile reflects inflammation, necrosis, and cellular destruction rather than elevated NAA. *Glioblastoma* - **Glioblastoma**, a high-grade glioma, is characterized by a significantly elevated **choline** peak (reflecting increased cell membrane turnover) and often an elevated **lipid/lactate peak** (due to necrosis and anaerobic metabolism) on MRS. - The NAA peak is typically decreased or absent due to neuronal destruction and loss. *Meningioma* - **Meningiomas** are extra-axial tumors that originate from the meninges. On MRS, they typically show an elevated **alanine peak**, and sometimes elevated choline, but lack an elevated NAA peak. - Reduced or absent NAA is expected as these tumors are not composed of neuronal cells.

Q: On MRI, which of the following shows diffusion restriction?

Medulloblastoma. ***Medulloblastoma*** - **Medulloblastomas** are highly cellular tumors, leading to **restricted diffusion** on MRI due to the dense packing of cells and reduced extracellular space. - This feature helps distinguish them from other posterior fossa tumors like ependymomas and pilocytic astrocytomas. - They are the **most common malignant posterior fossa tumor in children** and show bright signal on DWI with low ADC values. *Ependymoma* - **Ependymomas** typically show **facilitated diffusion** or no significant diffusion restriction on MRI due to their less cellular nature and higher water content. - They often arise from the ependyma lining the ventricles and can have heterogeneous signal characteristics. - Variable ADC values are seen, generally higher than medulloblastomas. *Meningioma* - **Meningiomas** usually do not show significant **diffusion restriction**; instead, they have an appearance reflecting their fibrous and vascular nature. - They tend to be extra-axial, dural-based tumors that enhance homogenously. - ADC values are typically elevated compared to highly cellular tumors. *Germinoma* - **Germinomas** are also highly cellular tumors and **do show diffusion restriction** similar to medulloblastomas. - However, they are typically located in the **pineal or suprasellar regions**, not the posterior fossa. - In this context, **medulloblastoma** is the best answer as the classic example of a diffusion-restricting posterior fossa tumor commonly tested in examinations.

Q: Which of the following conditions is known to cause intracranial calcification visible on a skull X-ray?

Cysticercosis. ***Cysticercosis*** - **Cysticercosis**, caused by the larval stage of the **tapeworm *Taenia solium***, frequently leads to multiple parenchymal or subarachnoid cysts in the brain that often calcify after the larval death. - These calcified lesions are readily visible on skull X-rays and are a hallmark of chronic neurocysticercosis. *Pineal calcification (benign physiological process)* - **Pineal gland calcification** is a very common, often incidental finding that is considered a **normal physiological process** related to aging. - While visible on skull X-rays, it is typically of no clinical significance and not indicative of a disease state. *Dural calcification (associated with metabolic disorders)* - While **dural calcifications** can occur, they are generally rare and not a common or prominent cause of intracranial calcification visible on a skull X-ray in the context of a broadly asked question about conditions causing such findings. - When present, particularly extensive dural calcification, it can be associated with certain **metabolic disorders** (e.g., hyperparathyroidism) or genetic syndromes, but it is less frequently assessed via skull X-ray compared to other imaging modalities. *Tuberculosis (CNS involvement)* - **CNS tuberculosis** can lead to various manifestations, including **tuberculomas** and **tuberculous meningitis**. - While tuberculomas can rarely calcify, it is not as common or characteristic a feature on a skull X-ray as the calcifications seen in cysticercosis, and often requires more advanced imaging like CT or MRI for detailed visualization.

Q: Which primary brain parenchymal tumor is most commonly associated with calcifications seen on imaging studies?

Oligodendroglioma. ***Oligodendroglioma*** - **Oligodendrogliomas** are highly associated with **calcifications**, which are observed in **70-90% of cases** on imaging studies like CT scans. - The calcifications appear as **coarse, punctate, or nodular** and are typically located in the **cerebral hemispheres** (frontal and temporal lobes most common). - This is the **classic imaging finding** that helps differentiate oligodendrogliomas from other glial tumors. *Astrocytoma* - While some astrocytomas can calcify, especially low-grade forms, they are **not as consistently calcified** as oligodendrogliomas. - Calcifications occur in only **20-30% of cases** and are typically less prominent. *Medulloblastoma* - **Medulloblastomas** are most commonly found in the **cerebellum** (posterior fossa) and primarily affect children. - Calcifications are **infrequent**, occurring in approximately **10-20% of cases**, and are usually small and inconspicuous. *Craniopharyngioma* - **Craniopharyngiomas** are benign tumors arising from Rathke's pouch remnants, located in the **suprasellar region**. - While they do frequently calcify (especially in children), they are **extra-axial tumors**, not primary brain parenchymal tumors. - This question specifically asks about parenchymal brain tumors, making oligodendroglioma the correct answer among glial neoplasms.

Q: Primary investigation of choice in a patient with suspected subarachnoid hemorrhage should be:

Non-contrast computed tomography. ***Non-contrast computed tomography*** - **Non-contrast CT** of the head is the primary imaging modality for suspected subarachnoid hemorrhage due to its **rapid availability** and **high sensitivity** in detecting acute blood. - It effectively visualizes blood in the **subarachnoid space** as hyperdense areas, especially within the first 6-12 hours after symptom onset. *Magnetic resonance imaging (MRI)* - While MRI can detect subarachnoid hemorrhage, it is **less readily available** and takes longer to perform than CT in emergency settings. - MRI may be used in cases where CT is negative but suspicion remains high, especially for hemorrhage in the **posterior fossa** or older bleeds. *Contrast-enhanced computed tomography* - **Contrast-enhanced CT** is generally not the initial imaging choice for subarachnoid hemorrhage because fresh blood is highly visible on unenhanced scans. - Contrast administration can obscure the visualization of acute blood in the subarachnoid space and is typically reserved for **CT angiography** to identify the source of bleeding. *Lumbar puncture* - **Lumbar puncture** is performed if a non-contrast CT is negative for subarachnoid hemorrhage but clinical suspicion remains high. - Its purpose is to detect **xanthochromia** (yellow discoloration due to bilirubin from red blood cell breakdown) or an elevated red blood cell count, confirming the presence of blood in the cerebrospinal fluid.

Question 1

Which of the following conditions is least likely to cause posterior scalloping of the vertebrae?

Accepted Answer

Aortic aneurysm

Answer

Astrocytoma

Answer

Neurofibromatosis

Answer

Ependymoma

Question 2

Investigation of choice for multiple sclerosis

Accepted Answer

MRI

Answer

CT

Answer

USG

Answer

PET

Question 3

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 4

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 5

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 6

In which of the following diseases is the NAA peak seen?

Accepted Answer

Canavan disease

Answer

Tuberculoma

Answer

Meningioma

Answer

Glioblastoma

Question 7

On MRI, which of the following shows diffusion restriction?

Accepted Answer

Medulloblastoma

Answer

Ependymoma

Answer

Meningioma

Answer

Germinoma

Question 8

Which of the following conditions is known to cause intracranial calcification visible on a skull X-ray?

Accepted Answer

Cysticercosis

Answer

Dural calcification (associated with metabolic disorders)

Answer

Pineal calcification (benign physiological process)

Answer

Tuberculosis (CNS involvement)

Question 9

Which primary brain parenchymal tumor is most commonly associated with calcifications seen on imaging studies?

Accepted Answer

Oligodendroglioma

Answer

Astrocytoma

Answer

Medulloblastoma

Answer

Craniopharyngioma

Question 10

Primary investigation of choice in a patient with suspected subarachnoid hemorrhage should be:

Accepted Answer

Non-contrast computed tomography

Answer

Magnetic resonance imaging (MRI)

Answer

Contrast-enhanced computed tomography

Answer

Lumbar puncture

Neuroradiology — MCQs

Neuroradiology — MCQs

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