Neuroradiology Practice Questions

Q: Which imaging modality is most appropriate for evaluating a suspected acoustic neuroma?

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is the gold standard for diagnosing acoustic neuromas due to its superior soft tissue contrast and ability to visualize the **internal auditory canal** and **cerebellopontine angle**. - MRI with **gadolinium contrast** can detect even small acoustic neuromas, which appear as enhancing lesions. *CT scan* - While CT can show larger tumors indirectly by revealing **bone erosion** or **widening of the internal auditory canal**, it has poor soft tissue resolution for early detection of acoustic neuromas. - CT scans expose the patient to **ionizing radiation**, and its primary role is usually limited to evaluating bone structures or for patients who cannot undergo MRI. *X-ray* - **Plain X-rays** (e.g., skull films) are not effective for diagnosing acoustic neuromas as they only show bone and cannot visualize soft tissue tumors in this region. - They lack the necessary detail and sensitivity to detect such a tumor, especially in its early stages. *Ultrasound* - **Ultrasound** is not suitable for evaluating intracranial structures like acoustic neuromas because the **skull bone** obstructs the transmission of sound waves. - Its utility is primarily in visualizing superficial soft tissue structures or organs in the abdomen and neck.

Q: A 35-year-old female presents with a history of seizures and headaches. An MRI shows a well-defined cystic lesion with an enhancing mural nodule in the temporal lobe. What is the most likely diagnosis?

Low-grade astrocytoma. ***Low-grade astrocytoma*** - The **cyst with enhancing mural nodule** appearance in the temporal lobe of a young adult with seizures is highly characteristic of **pleomorphic xanthoastrocytoma (PXA)**, a subtype of low-grade astrocytoma (WHO Grade II). - PXA typically presents as a **superficial, cortically-based cystic mass** with a solid enhancing nodule, often with **dural involvement** ("dural tail" sign). - The patient's age (35-year-old female) and presenting symptoms of **seizures** and **headaches** are consistent with the slow-growing nature of these tumors, which often irritate cortical structures. - PXA has a **favorable prognosis** compared to other astrocytomas and commonly occurs in the **temporal lobe**. *Glioblastoma multiforme* - **Glioblastoma multiforme (GBM)** is a highly aggressive WHO Grade IV tumor that typically presents with **thick irregular ring enhancement**, **central necrosis**, and **extensive surrounding vasogenic edema**. - GBM shows rapid clinical progression and would not typically present as a well-defined cyst with mural nodule. - The imaging appearance described is more consistent with a low-grade tumor. *Meningioma* - **Meningiomas** are **extra-axial (dural-based) tumors** that demonstrate **uniform, homogeneous enhancement** with a characteristic **dural tail** sign. - They are typically **solid masses** (not cystic) that compress rather than infiltrate brain parenchyma. - The described cystic lesion with mural nodule is more consistent with an intra-axial tumor like PXA. *Oligodendroglioma* - **Oligodendrogliomas** characteristically show **calcifications** (present in 70-90% of cases) and are commonly located in the **frontal lobes**. - They typically appear as **heterogeneous, infiltrative masses** rather than well-defined cystic lesions with mural nodules. - While they can cause seizures, the imaging appearance described is not typical for oligodendroglioma.

Q: Identify the condition based on the provided image.

Callosal dysgenesis. ***Callosal dysgenesis*** - This condition is characterized by the **partial or complete absence of the corpus callosum**, which connects the two cerebral hemispheres. - Imaging typically shows widely separated and parallel lateral ventricles, sometimes described as a "bat wing" or "moose horn" configuration, and a high-riding third ventricle. *Dandy-Walker malformation* - This malformation involves the **cerebellum and fourth ventricle**, characterized by agenesis or hypoplasia of the cerebellar vermis and cystic dilation of the fourth ventricle. - It results in an enlarged posterior fossa, which is not depicted in this image. *Aicardi syndrome* - Aicardi syndrome is a rare genetic disorder characterized by the triad of **infantile spasms**, **chorioretinal lacunae**, and **agenesis of the corpus callosum**. - While agenesis of the corpus callosum is present, Aicardi syndrome is a broader diagnosis that also includes specific ocular and seizure findings, which cannot be solely determined from an isolated image showing callosal dysgenesis. *Septo-optic dysplasia* - This condition involves the **hypoplasia of the optic nerves** and **absence or hypoplasia of the septum pellucidum**, along with hypothalamic-pituitary dysfunction. - While the septum pellucidum is absent, the characteristic optic nerve hypoplasia and endocrine dysfunction are essential diagnostic features that cannot be inferred from this image alone.

Q: What is the most likely finding in the CT image of the left maxillary sinus in a patient with a history of allergic rhinitis?

Ground-glass opacity. ***Ground-glass opacity*** - This image shows diffuse opacification of the left maxillary sinus with a characteristic **ground-glass appearance**, which is often associated with allergic fungal rhinosinusitis (AFRS), a condition that can complicate allergic rhinitis. - The patient's history of **allergic rhinitis** makes AFRS a strong consideration, and the CT finding of ground-glass opacity within the sinus lumen is a classic imaging feature of this condition, representing fungal elements and mucin. *Honeycomb appearance* - A **honeycomb appearance** on CT is typically seen in the lungs and indicates **pulmonary fibrosis**, characterized by clustered cystic airspaces with thickened walls. - This finding is not associated with paranasal sinus pathology, especially not with allergic rhinitis or its common complications. *Onion peel appearance* - The **onion peel appearance** on imaging refers to periosteal reaction with multiple concentric layers of new bone formation. - This is a hallmark feature of conditions like **Ewing sarcoma** and chronic osteomyelitis, primarily affecting bone, not the soft tissue or mucosal lining of a sinus in the context of allergic rhinitis. *Double density* - **Double density** is a term primarily used in echocardiography to describe specific findings related to left atrial enlargement, or occasionally in chest radiography where it might represent superimposed densities. - This term does not describe a finding relevant to paranasal sinus pathology on CT imaging.

Q: Identify the condition in the image below?

Lacunar infarct. ***Lacunar infarct*** - The image shows a small, deep infarction, typical of a **lacunar infarct**, which results from occlusion of a single penetrating artery. - These infarcts are often associated with **chronic hypertension** and affect subcortical structures like the basal ganglia, internal capsule, or brainstem. *Embolic infarct* - An **embolic infarct** typically appears as a larger, wedge-shaped lesion at the cortex, reflecting occlusion of a larger cerebral artery by an embolus. - It would not typically present as the small, deep lesion seen in the image. *Thrombotic infarct* - A **thrombotic infarct** usually results from *in situ* thrombosis of a larger vessel due to atherosclerosis, appearing as a larger lesion, often involving cortical or subcortical areas supplied by that vessel. - The lesion in the image is too small and deep to be a typical thrombotic infarct of a major artery. *Intracerebral hemorrhage* - **Intracerebral hemorrhage** would appear as a high-density (bright) area on CT scans, indicating extravasated blood, which is not what is shown in the image. - The image depicts an area of tissue loss (dark on CT, bright on flair/DWI MRI), consistent with an infarct, not a hemorrhage.

Q: What condition is shown in the MR angiogram of the skull?

Vein of Galen malformation. ***Vein of Galen malformation*** - The image provided is an **MR angiogram (MRA)**, which clearly shows a **large, dilated vein of Galen**. This is the characteristic appearance of a Vein of Galen malformation. - This congenital vascular malformation involves a direct artery-to-vein shunt, leading to the characteristic aneurysmal dilatation of the vein. *Dandy-Walker malformation* - This is a congenital brain malformation characterized by **agenesis or hypoplasia of the cerebellar vermis** and cystic dilation of the fourth ventricle. - While it affects brain structures, it does not involve the type of vascular abnormality seen in the image. *Pneumocephalus* - **Pneumocephalus** refers to the presence of **air within the intracranial cavity**, often due to trauma or surgery. - It would appear as dark areas on imaging, representing air, not the bright, dilated vascular structures seen here. *Crouzon syndrome* - **Crouzon syndrome** is a genetic disorder characterized by **craniosynostosis**, which is the premature fusion of skull sutures. - This condition primarily affects bone growth and skull shape, with no direct involvement of the cerebral vasculature as depicted in the MRA.

Q: What type of lesions in the skull calvarium can be identified on this X-ray?

Brain metastases. ***Brain metastases (Skull metastases)*** - The image shows multiple **lytic lesions** in the skull calvarium, which are characteristic of metastatic disease that has spread to bone - Metastases from primary cancers (lung, breast, kidney, thyroid, prostate) commonly involve the skull and appear as **punched-out or moth-eaten lytic lesions** - While plain X-rays cannot visualize brain parenchyma, they can detect **bony destruction** caused by metastatic deposits in the skull - These appear as well-defined osteolytic lesions without sclerotic margins *Multiple myeloma* - Multiple myeloma typically presents with **multiple punched-out lytic lesions** in the skull that can appear very similar to metastases - However, multiple myeloma is a **primary bone marrow malignancy** rather than metastatic disease - Key differentiator: myeloma lesions are usually more uniform in size and distribution - Clinical context (monoclonal protein, anemia, renal dysfunction) helps distinguish from metastases *Osteosarcoma* - Osteosarcoma is a **primary bone tumor** that usually causes a mixture of lytic and blastic (bone-forming) lesions - Typically presents with **sunburst or spiculated periosteal reaction** and soft tissue mass - Usually occurs as a **solitary aggressive lesion** in younger patients, not multiple scattered lesions - Rarely occurs in the skull compared to long bones *Osteomyelitis* - Osteomyelitis is an **infection of the bone** that causes bone destruction and reactive new bone formation - Shows features of **bone destruction, periosteal reaction**, and possibly sequestra (dead bone fragments) - Typically presents as a **focal process** with surrounding inflammatory changes - Does not produce the multiple discrete lytic lesions pattern seen in metastatic disease

Q: Stenver's view is used for -

Internal auditory canal. ***Internal auditory canal*** - The **Stenvers position** (Stenvers view) is a specific radiographic projection designed to visualize the **petrous portion of the temporal bone**, with a clear profile of the internal auditory canal. - It is used to evaluate the **internal auditory canals** for abnormalities such as **acoustic neuromas** or other lesions affecting the vestibulocochlear nerve. *Inferior orbital foramen* - The inferior orbital foramen is typically visualized with standard facial bone views or specific orbital projections, not the Stenvers view. - It is a small opening on the floor of the orbit, transmitting the **infraorbital nerve and vessels**. *Sella turcica* - The sella turcica, which houses the pituitary gland, is best visualized using a **lateral skull view** or CT/MRI. - Stenvers view is not designed to provide optimal imaging of the sella turcica. *Superior orbital foramen* - The superior orbital foramen (more commonly referred to as the **superior orbital fissure**) is best seen on standard orbital or skull views. - It transmits cranial nerves III, IV, VI, and the ophthalmic division of V, and is not the primary focus of the Stenvers view.

Q: Which of the following provides excellent details about the chemodectomas?

MRI. ***MRI*** - **Magnetic Resonance Imaging (MRI)** is generally considered the best modality for evaluating **chemodectomas** due to its superior soft tissue contrast. - It can accurately delineate the tumor's extent, its relationship to surrounding structures, and detect any **vascular invasion** or **nerve involvement**. *Xray* - **X-rays** provide limited detail for soft tissue tumors like chemodectomas. - They primarily visualize bone structures and are not effective in characterizing small or non-calcified soft tissue masses. *Ultrasound* - **Ultrasound** can detect the presence of a mass and assess its vascularity, but its utility for chemodectomas is limited by its lower resolution and dependence on operator skill. - It may not provide sufficient detail for precise anatomical localization or differentiation from other neck masses. *CT angiography (can provide useful information regarding vascular involvement)* - **CT angiography** is excellent for visualizing the **vascular supply** to the tumor and assessing its relationship with critical blood vessels. - While useful for surgical planning, it typically offers less detailed soft tissue characterization compared to MRI for the primary tumor itself.

Question 1

Which imaging modality is most appropriate for evaluating a suspected acoustic neuroma?

Accepted Answer

MRI

Answer

CT scan

Answer

X-ray

Answer

Ultrasound

Question 2

A 35-year-old female presents with a history of seizures and headaches. An MRI shows a well-defined cystic lesion with an enhancing mural nodule in the temporal lobe. What is the most likely diagnosis?

Accepted Answer

Low-grade astrocytoma

Answer

Meningioma

Answer

Oligodendroglioma

Answer

Glioblastoma multiforme

Question 3

Identify the condition based on the provided image.

Accepted Answer

Callosal dysgenesis

Answer

Dandy-Walker malformation

Answer

Aicardi syndrome

Answer

Septo-optic dysplasia

Question 4

What is the most likely finding in the CT image of the left maxillary sinus in a patient with a history of allergic rhinitis?

Accepted Answer

Ground-glass opacity

Answer

Honeycomb appearance

Answer

Onion peel appearance

Answer

Double density

Question 5

Identify the condition in the image below?

Accepted Answer

Lacunar infarct

Answer

Embolic infarct

Answer

Thrombotic infarct

Answer

Intracerebral hemorrhage

Question 6

What condition is shown in the MR angiogram of the skull?

Accepted Answer

Vein of Galen malformation

Answer

Dandy-Walker malformation

Answer

Pneumocephalus

Answer

Crouzon syndrome

Question 7

What type of lesions in the skull calvarium can be identified on this X-ray?

Accepted Answer

Brain metastases

Answer

Multiple myeloma

Answer

Osteosarcoma

Answer

Osteomyelitis

Question 8

How does cerebrospinal fluid (CSF) appear on T1 and T2 weighted MRI images?

Accepted Answer

Hypointense on T1 weighted image and hyperintense on T2 weighted image

Answer

Hyperintense on T1 weighted image and hypointense on T2 weighted image

Answer

Hyperintense on both T1 and T2 weighted images

Answer

Hypointense on both T1 and T2 weighted images

Question 9

Stenver's view is used for -

Accepted Answer

Internal auditory canal

Answer

Sella turcica

Answer

Inferior orbital foramen

Answer

Superior orbital foramen

Question 10

Which of the following provides excellent details about the chemodectomas?

Accepted Answer

MRI

Answer

X-ray

Answer

Ultrasound

Answer

CT angiography

Neuroradiology — MCQs

Neuroradiology — MCQs

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