Neuroradiology Practice Questions

Q: Sphenoid wing dysplasia is seen in which of the following conditions?

Neurofibromatosis. **Explanation:** **Sphenoid wing dysplasia** is a characteristic skeletal manifestation of **Neurofibromatosis Type 1 (NF-1)**. It involves the partial or complete absence of the greater wing of the sphenoid bone. This defect leads to an expansion of the superior orbital fissure, resulting in a communication between the orbit and the middle cranial fossa. Radiologically, this produces the classic **"Bare Orbit Sign"** on a frontal skull X-ray or CT scan. Clinically, it may present as pulsating exophthalmos due to the transmission of cerebrospinal fluid (CSF) pulsations to the orbital contents. **Analysis of Incorrect Options:** * **A. Von Hippel Lindau (VHL):** A phakomatosis characterized by hemangioblastomas (cerebellum/retina), renal cell carcinoma, and pheochromocytoma. It does not involve sphenoid bone defects. * **C. Sturge-Weber Syndrome:** Characterized by a facial port-wine stain (trigeminal distribution) and leptomeningeal angiomatosis. Classic imaging finding is **"tram-track" cortical calcifications**, not bone dysplasia. * **D. Bournville’s Disease (Tuberous Sclerosis):** Features include cortical tubers, subependymal nodules (SEN), and subependymal giant cell astrocytomas (SEGA). Skeletal findings usually involve sclerotic bone islands, not dysplasia of the sphenoid. **High-Yield Clinical Pearls for NF-1:** * **Diagnostic Criteria (NIH):** Café-au-lait spots (≥6), Lisch nodules (iris hamartomas), Axillary/Inguinal freckling (Crowe sign), Optic nerve gliomas, and Neurofibromas. * **Skeletal Findings:** Sphenoid wing dysplasia, pseudoarthrosis of the tibia, and severe kyphoscoliosis. * **Imaging:** "Bare orbit sign" is a favorite NEET-PG image-based question.

Q: What is the investigation of choice for acute subarachnoid hemorrhage?

CT scan. ### Explanation **Correct Answer: C. CT scan** **Why CT scan is the investigation of choice:** Non-contrast Computed Tomography (NCCT) of the head is the **gold standard initial investigation** for acute subarachnoid hemorrhage (SAH). It is highly sensitive (nearly 98-100% within the first 6-12 hours) because fresh blood appears **hyperdense** (bright white) against the brain parenchyma. Blood typically collects in the basal cisterns, sylvian fissures, and sulci, often forming a characteristic "star-shaped" pattern in the suprasellar cistern. Its widespread availability, speed, and superior ability to detect acute hemorrhage make it the first-line choice in emergency settings. **Why other options are incorrect:** * **A. Digital Subtraction Angiography (DSA):** While DSA is the **gold standard for identifying the cause** of SAH (e.g., detecting the specific site and morphology of a ruptured aneurysm), it is an invasive procedure and not the initial diagnostic tool to confirm the presence of blood. * **B. X-ray:** Plain radiographs have no role in diagnosing intracranial hemorrhage. * **C. MRI:** While highly sensitive, MRI (specifically FLAIR sequences) is generally reserved for **subacute or chronic SAH** where CT sensitivity drops. It is time-consuming and less practical in an acute emergency. **High-Yield Clinical Pearls for NEET-PG:** 1. **Sensitivity Trend:** CT sensitivity for SAH decreases over time (100% at <6 hrs, ~93% at 24 hrs, and <50% after one week). 2. **Next Step:** If CT is negative but clinical suspicion (e.g., "thunderclap headache") remains high, the next gold standard step is a **Lumbar Puncture** to look for xanthochromia. 3. **Grading:** The **Fisher Scale** is used to grade SAH based on CT appearance to predict the risk of cerebral vasospasm. 4. **Common Cause:** The most common cause of spontaneous SAH is a ruptured **Berry aneurysm** (usually at the junction of the Anterior Communicating Artery).

Q: Stereotactic surgery is used for the treatment of which of the following conditions?

Brain tumor. **Explanation:** **Stereotactic surgery** (or stereotactic radiosurgery/biopsy) is a minimally invasive technique that uses a three-dimensional coordinate system to locate small targets inside the body and perform actions such as biopsies, injections, or radiation delivery with high precision. **Why Option A is Correct:** The skull provides a fixed, rigid frame of reference, making the **brain** the ideal organ for stereotactic procedures. By using a stereotactic frame (like the Lexsell frame) or frameless neuronavigation based on CT/MRI scans, neurosurgeons can reach deep-seated brain tumors with millimeter precision, minimizing damage to surrounding eloquent brain tissue. It is the gold standard for brain biopsies and Gamma Knife surgery. **Why Other Options are Incorrect:** * **Options B, C, and D (Lungs, Cervix, Renal):** These organs are located in the thorax and abdomen/pelvis. Unlike the brain, these organs are not encased in a rigid bony structure and are subject to **physiological motion** (respiration, peristalsis, and bladder filling). While "Stereotactic Body Radiotherapy" (SBRT) exists for these areas, the term "Stereotactic Surgery" classically refers to intracranial procedures where a fixed spatial coordinate system is applied to a stationary target. **Clinical Pearls for NEET-PG:** * **Gamma Knife:** A form of stereotactic radiosurgery (SRS) specifically used for intracranial lesions (e.g., Acoustic Neuroma, AVMs, Trigeminal Neuralgia). * **Key Components:** Requires a stereotactic frame, an imaging modality (CT/MRI), and a mathematical target localization software. * **Advantages:** Reduced hospital stay, ability to reach "inoperable" deep-seated lesions, and avoidance of large craniotomies.

Q: A 56-year-old man with a history of poorly controlled hypertension presents to the accident and emergency department with sudden onset weakness on the left side. What initial investigation would you request?

CT head. **Explanation:** The clinical presentation of sudden-onset focal neurological deficits (left-sided weakness) in a patient with hypertension is highly suggestive of an **acute stroke**. In the emergency setting, the primary goal is to differentiate between an **ischemic stroke** and a **hemorrhagic stroke**, as the management for each is diametrically opposed. **Why CT Head is the correct answer:** A **Non-Contrast Computed Tomography (NCCT) Head** is the gold standard initial investigation for suspected stroke. Its primary utility lies in its **high sensitivity for detecting acute intracranial hemorrhage**, which appears hyperdense (white). It is fast, widely available, and essential to rule out a bleed before initiating thrombolytic therapy (like tPA) or anticoagulation. **Why other options are incorrect:** * **MRI:** While Diffusion-Weighted Imaging (DWI) MRI is more sensitive for detecting early ischemic changes (within minutes), it is time-consuming, less available, and more expensive. In the "Time is Brain" window, CT is preferred for its speed. * **X-Ray:** Conventional skull X-rays have no role in the evaluation of acute stroke as they cannot visualize brain parenchyma or hemorrhage. * **D-dimer assay:** This is used to rule out venous thromboembolism (PE/DVT) and has no diagnostic value in the acute management of a stroke. **High-Yield Clinical Pearls for NEET-PG:** * **NCCT Findings:** In acute ischemia, the CT may appear normal for the first 6–12 hours. Early signs include the **"Hyperdense MCA sign"** (thrombus in the vessel) and loss of insular ribbon. * **Hemorrhage:** Appears **hyperdense** (60–80 HU) on CT. * **Ischemia:** Appears **hypodense** (dark) on CT as edema develops. * **Door-to-CT time:** Ideally should be within **20 minutes** of arrival.

Q: Which of the following conditions can cause a "bare orbit"?

Metastasis. The **"Bare Orbit" sign** is a classic radiological finding on a frontal skull X-ray or CT scan characterized by the **absence of the innominate line** (the greater wing of the sphenoid bone). This occurs due to the destruction or hypoplasia of the sphenoid wing, leading to an empty-appearing orbit. ### Why Metastasis is Correct **Metastasis** (particularly from neuroblastoma in children or lung/breast cancer in adults) is a common cause of aggressive bony destruction. When the greater wing of the sphenoid is destroyed by a neoplastic process, the normal bony landmarks disappear, resulting in the "bare orbit" appearance. ### Why Other Options are Incorrect * **Pseudotumor cerebri:** This involves idiopathic intracranial hypertension. While it may cause an empty sella or slit-like ventricles, it does not cause bony destruction of the sphenoid wing. * **Optic nerve glioma:** This typically causes **enlargement of the optic canal** rather than generalized destruction of the sphenoid wing. * **Osteomyelitis:** While it can cause bone erosion, it is a rare cause of a classic "bare orbit" compared to neoplastic or congenital conditions. ### High-Yield Pearls for NEET-PG * **Most Common Cause:** The most classic association for "bare orbit" in radiology exams is **Neurofibromatosis Type 1 (NF1)**, due to congenital sphenoid wing dysplasia. * **Differential Diagnosis for Bare Orbit:** 1. Neurofibromatosis Type 1 (Sphenoid dysplasia) 2. Langerhans Cell Histiocytosis (LCH) 3. Metastatic disease (Neuroblastoma) 4. Post-surgical changes (Craniotomy) * **Clinical Correlation:** In NF1, this finding is often associated with **pulsatile exophthalmos** because the brain pulsations are transmitted directly to the orbit through the bony defect.

Q: An elderly patient presented with sudden onset of headache and altered sensorium and is diagnosed to have Subarachnoid hemorrhage. What is the best investigation of choice in this case?

CT Scan. **Explanation:** The investigation of choice for an acute **Subarachnoid Hemorrhage (SAH)** is a **Non-Contrast Computed Tomography (NCCT) scan of the head**. **1. Why CT Scan is the Correct Answer:** * **Sensitivity:** NCCT is highly sensitive (up to 98-100%) in detecting acute blood within the first 6–24 hours of the event. * **Appearance:** Acute blood appears **hyperdense (white)** on CT, typically seen filling the basal cisterns, sulci, and the Sylvian fissure (often described as a "star-shaped" density). * **Speed and Accessibility:** It is fast, widely available, and superior at detecting acute bony injuries or calcifications compared to MRI. **2. Why Other Options are Incorrect:** * **B. MRI Scan:** While MRI (especially FLAIR sequences) is sensitive, it is time-consuming, less accessible in emergencies, and difficult to perform on unstable patients with altered sensorium. It is, however, more sensitive than CT for detecting *subacute* or *chronic* SAH. * **C. Roentgenogram (X-ray) of Skull:** X-rays cannot visualize intracranial soft tissues or hemorrhages. They are obsolete for diagnosing SAH. * **D. Carotid Angiogram:** While Digital Subtraction Angiography (DSA) is the **Gold Standard** for identifying the *source* of the bleed (e.g., a ruptured berry aneurysm), it is not the initial investigation to *diagnose* the presence of hemorrhage. **Clinical Pearls for NEET-PG:** * **Initial Step:** NCCT Head. * **Next Step if NCCT is negative but clinical suspicion is high:** Lumbar Puncture (to look for **Xanthochromia**). * **Gold Standard for etiology:** Digital Subtraction Angiography (DSA). * **Commonest Cause:** Trauma (Overall); Rupture of Saccular/Berry Aneurysm (Spontaneous). * **Classic Presentation:** "Thunderclap headache" or "Worst headache of my life."

Question 1

A 70-year-old hypertensive male presents complaining of a brief episode of slurred speech and left-sided weakness the previous evening. He gives a history of two transient episodes of sudden loss of vision in his right eye last month. His neurological examination is normal now. What is the most appropriate next diagnostic test?

Accepted Answer

Carotid Doppler

Answer

CT Scan

Answer

Diffusion-weighted MRI

Answer

Cerebral Angiography

Question 2

Sphenoid wing dysplasia is seen in which of the following conditions?

Accepted Answer

Neurofibromatosis

Answer

Von Hippel Lindau's disease

Answer

Sturge Weber syndrome

Answer

Bournville's disease

Question 3

What is the investigation of choice for acute subarachnoid hemorrhage?

Accepted Answer

CT scan

Answer

Digital Subtraction Angiography (DSA)

Answer

X-ray

Answer

MRI

Question 4

Stereotactic surgery is used for the treatment of which of the following conditions?

Accepted Answer

Brain tumor

Answer

Lungs carcinoma

Answer

Cervix cancer

Answer

Renal carcinoma

Question 5

Which of the following statements is false regarding a epidural hematoma?

Accepted Answer

Rupture of bridging or communicating veins is the primary cause.

Answer

A lucid interval is typically seen.

Answer

Fracture of the temporal bone is commonly present.

Answer

A fissure fracture is often seen.

Question 6

After head injury, a biconvex, lenticular shaped hematoma on CT scan is characteristic of which of the following?

Accepted Answer

Extradural haemorrhage

Answer

Subdural haemorrhage

Answer

Intracerebral hematoma

Answer

Diffuse axonal injury

Question 7

A 56-year-old man with a history of poorly controlled hypertension presents to the accident and emergency department with sudden onset weakness on the left side. What initial investigation would you request?

Accepted Answer

CT head

Answer

MRI

Answer

X-Ray

Answer

D-dimer assay

Question 8

Which of the following conditions can cause a "bare orbit"?

Accepted Answer

Metastasis

Answer

Pseudotumor cerebri

Answer

Optic nerve glioma

Answer

Osteomyelitis

Question 9

An elderly patient presented with sudden onset of headache and altered sensorium and is diagnosed to have Subarachnoid hemorrhage. What is the best investigation of choice in this case?

Accepted Answer

CT Scan

Answer

MRI Scan

Answer

Roentgenogram of Skull

Answer

Carotid Angiogram

Question 10

What are the common primary sites of metastasis to the brain?

Accepted Answer

Lung Carcinoma

Answer

Thyroid Carcinoma

Answer

Tongue Carcinoma

Answer

Breast Carcinoma

Neuroradiology — MCQs

Neuroradiology — MCQs

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