Neuroradiology Practice Questions

Q: A 6-year-old boy presented with complex seizures per day in spite of an adequate 4-drug antiepileptic regimen. He had a history of repeated high-grade fever in childhood. MRI for epilepsy protocol revealed a normal brain scan. Which of the following will not be helpful for functional imaging of the brain?

MDCT. **Explanation:** The clinical presentation of a 6-year-old with drug-resistant epilepsy (DRE) and a normal structural MRI (non-lesional epilepsy) necessitates **functional neuroimaging** to localize the epileptogenic focus for potential surgical intervention. **Why MDCT is the correct answer:** Multi-Detector Computed Tomography (MDCT) is a **structural** imaging modality. While excellent for detecting acute hemorrhage, calcifications, or bony abnormalities, it lacks the physiological sensitivity to map brain metabolism or blood flow changes associated with seizure activity. Therefore, it has no role in the functional evaluation of epilepsy. **Analysis of functional imaging options:** * **Interictal 18F-FDG PET:** This measures glucose metabolism. In the interictal state (between seizures), the epileptogenic focus typically appears as an area of **hypometabolism**. * **Ictal SPECT (99mTc-HMPAO):** This measures regional cerebral blood flow (rCBF). During a seizure (ictal state), the focus shows **hyperperfusion**. Comparing ictal SPECT with interictal SPECT (SISCOM) is a highly sensitive method for localization. * **Video EEG:** This is the gold standard for correlating electrical activity with clinical semiology, providing essential functional data. **Clinical Pearls for NEET-PG:** * **Drug-Resistant Epilepsy (DRE):** Defined as failure of adequate trials of two tolerated, appropriately chosen, and used antiepileptic drug schedules. * **PET vs. SPECT:** Remember, PET shows **interictal hypometabolism**, whereas SPECT shows **ictal hyperperfusion**. * **MRI Protocol:** The "Epilepsy Protocol" includes thin-slice coronal FLAIR and T2 sequences perpendicular to the long axis of the hippocampus to rule out Mesial Temporal Sclerosis (MTS).

Q: MRI is the investigation of choice in all of the following except:

Skull bone tumors. **Explanation:** The core principle of neuroimaging is that **MRI** is superior for soft tissues and posterior fossa structures, while **CT** is superior for cortical bone and acute hemorrhage. **Why Skull Bone Tumors is the correct answer:** MRI has poor signal intensity for cortical bone because bone contains very few mobile hydrogen protons. For evaluating **skull bone tumors** (like osteomas or fibrous dysplasia) and bony destruction, **Computed Tomography (CT)** is the investigation of choice. CT provides excellent spatial resolution and contrast for mineralized tissues, allowing for the precise assessment of cortical integrity and trabecular patterns. **Why the other options are incorrect:** * **Syringomyelia:** MRI is the gold standard as it can clearly visualize the syrinx (fluid-filled cavity) within the spinal cord and identify associated causes like Chiari malformations. * **Brain stem tumors:** The brain stem is located in the posterior fossa. CT often suffers from "bone hardening artifacts" in this region due to the surrounding dense petrous bones. MRI provides superior contrast resolution and multiplanar imaging, making it the choice for brain stem lesions. * **Multiple Sclerosis (MS):** MRI is the most sensitive modality for detecting demyelinating plaques. It is essential for demonstrating "dissemination in space and time" (McDonald Criteria). **High-Yield Clinical Pearls for NEET-PG:** * **IOC for Acute Stroke:** Non-contrast CT (to rule out hemorrhage); however, **Diffusion-Weighted MRI (DWI)** is the most sensitive for early ischemic changes (within minutes). * **IOC for Head Trauma:** Non-contrast CT (to detect fractures and acute bleeds). * **IOC for Posterior Fossa lesions:** MRI. * **Calcification:** CT is more sensitive than MRI for detecting intracranial calcification.

Q: What is the investigation of choice for subdural hemorrhage?

Non-contrast Computed Tomography (NCCT). **Explanation:** **Non-contrast Computed Tomography (NCCT) Head** is the investigation of choice (IOC) for acute subdural hemorrhage (SDH) because it is rapid, widely available, and highly sensitive to acute blood. In an emergency setting, NCCT is preferred over MRI to quickly differentiate between hemorrhagic and ischemic strokes or to identify life-threatening mass effects. * **Why NCCT is correct:** Acute blood appears **hyperdense (white)** on NCCT. A subdural hemorrhage typically presents as a **crescentic (concave)** collection that crosses suture lines but is limited by dural reflections (like the falx cerebri). * **Why others are incorrect:** * **Angiography:** Used to identify vascular malformations or aneurysms (e.g., in Subarachnoid Hemorrhage), but not for primary diagnosis of SDH. * **CECT:** Contrast can mimic the appearance of acute blood (extravasation) or mask small hemorrhages; it is generally avoided in the initial trauma/stroke protocol. * **MRI:** While more sensitive for chronic SDH or diffuse axonal injury, it is time-consuming and less accessible in acute trauma settings. **High-Yield Clinical Pearls for NEET-PG:** * **Shape:** SDH is **Crescentic/Concave** (vs. Epidural Hemorrhage which is Biconvex/Lens-shaped). * **Source of Bleed:** Tearing of **Bridging Veins** (vs. Middle Meningeal Artery in EDH). * **Density Evolution:** * *Acute:* Hyperdense (White) * *Subacute:* Isodense (Grey - may be difficult to see) * *Chronic:* Hypodense (Black) * **Risk Groups:** Elderly patients and alcoholics (due to brain atrophy stretching the bridging veins).

Q: Which condition is characterized by the following sign?

Medial medullary syndrome. ***Medial medullary syndrome*** - The image demonstrates **bilateral medial medullary infarction**, characterized by the **"heart sign"** on **MRI DWI** due to bilateral paramedian infarction of the medulla. In bilateral infarction, deficits may be bilateral or more extensive than in the unilateral form. - The classic **unilateral** presentation is the **Dejerine triad**: **ipsilateral CN XII palsy** (tongue deviation), **contralateral hemiparesis**, and **contralateral loss of proprioception**. This triad reflects a single-sided lesion and should be distinguished from the bilateral syndrome shown on this image. *Lateral medullary syndrome* - Also known as **Wallenberg syndrome**, caused by **PICA occlusion** affecting the lateral medulla. - Presents with **no motor weakness** but includes **dysphagia**, **vertigo**, and **crossed sensory loss** (ipsilateral face, contralateral body). *Benedict syndrome* - Affects the **midbrain** involving the **oculomotor nerve** and **red nucleus**. - Characterized by **ipsilateral CN III palsy** with **contralateral tremor** and **ataxia**, not medullary signs. *Millar Gubler syndrome* - Involves the **pons** affecting **CN VI and VII** with corticospinal tract involvement. - Presents with **ipsilateral CN VI and VII palsies** plus **contralateral hemiplegia**, distinct from medullary pathology.

Q: Geographic lytic lesions in the vault of the skull with bevelled edges are seen with which condition?

Eosinophilic granuloma. ### Explanation **1. Why Eosinophilic Granuloma is Correct:** Eosinophilic Granuloma (EG) is the most common and localized form of **Langerhans Cell Histiocytosis (LCH)**. The classic radiographic appearance in the skull is a "punched-out," geographic lytic lesion. The characteristic **"bevelled edge"** (or "hole-within-a-hole" appearance) occurs because the destruction of the inner table of the skull is more extensive than the outer table, creating slanted or overlapping margins. When a central density is seen within the lucency, it is termed a "sequestrum." **2. Why the Other Options are Incorrect:** * **Multiple Myeloma:** Presents as multiple, small, uniform, "punched-out" lytic lesions. Unlike EG, these lesions typically lack sclerotic margins and do not exhibit the classic bevelled edge. * **Hyperparathyroidism:** Characterized by a **"Salt and Pepper" skull** (mottled appearance) due to multiple tiny lucencies caused by trabecular resorption, rather than large geographic lytic lesions. * **Reticular Cell Carcinoma (Primary Lymphoma of Bone):** Usually presents as "moth-eaten" or permeative bone destruction with an associated soft tissue mass, rather than well-defined geographic lesions with bevelled edges. **3. NEET-PG High-Yield Pearls:** * **LCH Triad (Hand-Schüller-Christian disease):** Exophthalmos, Diabetes Insipidus, and lytic bone lesions. * **Vertebra Plana:** EG is the most common cause of a completely collapsed vertebral body (pancake vertebra) in children. * **Birbeck Granules:** On electron microscopy, LCH cells show "tennis racket-shaped" cytoplasmic inclusions. * **Immunohistochemistry:** LCH cells are typically positive for **S-100 and CD1a**.

Q: Mount Fuji sign is a feature of which of the following conditions?

Tension pneumocephalus. **Explanation:** The **Mount Fuji sign** is a classic radiological hallmark of **Tension Pneumocephalus**. It is best visualized on a non-contrast CT scan of the head. 1. **Why Tension Pneumocephalus is correct:** This condition occurs when air enters the cranial cavity (usually post-trauma or surgery) but cannot escape, creating a "one-way valve" effect. The increasing pressure causes the air to compress the frontal lobes and separate them from the skull. Crucially, the air also separates the two frontal lobes at the midline, creating two peaked silhouettes that resemble the twin peaks of Mount Fuji. This indicates that the intracranial pressure is high enough to overcome the surface tension of the cerebrospinal fluid. 2. **Why the other options are incorrect:** * **Fahr’s Disease:** Characterized by bilateral, symmetrical **calcifications** of the basal ganglia and dentate nuclei, not air. * **Acute Bleed:** Appears as a **hyperdense** (white) area on CT (e.g., biconvex for extradural or crescentic for subdural hemorrhage). * **Chronic Bleed:** Typically appears **hypodense** (darker than brain tissue) as the blood liquefies over time, but it does not present with the specific "peaked" configuration of air. **High-Yield Pearls for NEET-PG:** * **Mount Fuji Sign vs. Air Bubble:** Simple pneumocephalus shows scattered air; the Mount Fuji sign specifically implies **tension** (a neurosurgical emergency). * **Pathophysiology:** Often described via the "Ball-valve mechanism." * **Treatment:** Requires urgent decompression (e.g., burr hole) to prevent brain herniation. * **Related Sign:** The **"Peaked Midline Sign"** is another term used to describe the compression of the frontal poles.

Q: A patient presents with severe headache. A CT scan of the brain reveals hyperdense areas in the right basal region, marked as 'X'. Which of the following is the most likely diagnosis?

Subarachnoid hemorrhage. ***Subarachnoid hemorrhage*** - The non-contrast CT scan shows **hyperdensity** (appears white) within the basal cisterns and Sylvian fissures (indicated by 'X'), which is the classic appearance of acute blood in the subarachnoid space. - This condition classically presents with a sudden, severe "**thunderclap headache**" and is most commonly caused by a ruptured **berry aneurysm**. *Meningococcal meningitis* - A non-contrast CT in meningitis is often normal. Key findings like **meningeal enhancement** would only be visible on a post-contrast CT scan, which is not the pattern seen here. - The clinical presentation typically involves a triad of **fever**, **nuchal rigidity**, and altered mental status, which are classic signs of meningeal irritation. *Brain abscess* - A brain abscess on a non-contrast CT typically appears as a **hypodense** (dark) or isodense mass within the brain parenchyma, often with surrounding vasogenic edema. - On a contrast-enhanced CT, it characteristically shows a **ring-enhancing lesion**, which is not depicted in this image. *Pneumocephalus* - Pneumocephalus refers to air within the cranial cavity, which appears as profoundly **hypodense** (black) on a CT scan. - The primary finding in the image is **hyperdensity** (blood), not the extreme hypodensity characteristic of air.

Q: A 30-year-old female patient involved in a road traffic accident had nausea and vomiting. She was brought unconscious to the emergency room. The NCCT brain reveals the following findings. What is the most likely diagnosis? ![img-49.jpeg](img-49.jpeg)

a. Extradural hemorrhage. ***Extradural hemorrhage*** - The NCCT image displays a classic **biconvex** or **lens-shaped** hyperdense collection of blood, which is the hallmark radiological feature of an extradural (epidural) hemorrhage. - This type of hemorrhage is most commonly caused by trauma leading to a skull fracture that tears the **middle meningeal artery**, and the hematoma is confined by suture lines where the dura is tightly attached to the skull. *Subdural hemorrhage* - A subdural hemorrhage typically appears as a **crescent-shaped** collection of blood on a CT scan, as it spreads along the contour of the cerebral hemisphere. - It is usually caused by the tearing of **bridging veins** and, unlike an extradural hemorrhage, it can cross suture lines but is limited by dural reflections. *Intra-parenchymal hemorrhage* - This refers to bleeding **within the brain tissue** itself, which would appear as a hyperdense lesion located inside the brain parenchyma, often with surrounding edema. - While it can be caused by trauma (contusion), it is frequently associated with non-traumatic causes like **hypertension** or **amyloid angiopathy**. *Subarachnoid hemorrhage* - A subarachnoid hemorrhage is characterized by blood in the **subarachnoid space**, appearing as hyperdensity within the cerebral **sulci**, **fissures**, and **basal cisterns** on a CT scan. - It is commonly caused by the rupture of a **berry aneurysm** or trauma, but its appearance is distinctly different from the localized, lens-shaped collection seen in the image.

Question 1

A 6-year-old boy presented with complex seizures per day in spite of an adequate 4-drug antiepileptic regimen. He had a history of repeated high-grade fever in childhood. MRI for epilepsy protocol revealed a normal brain scan. Which of the following will not be helpful for functional imaging of the brain?

Accepted Answer

MDCT

Answer

SPECT imaging

Answer

Interictal 18F-FDG PET

Answer

Video EEG with ictal 99mTc-HMPAO study of brain

Question 2

MRI is the investigation of choice in all of the following except:

Accepted Answer

Skull bone tumors

Answer

Syringomyelia

Answer

Brain stem tumors

Answer

Multiple sclerosis

Question 3

What is the investigation of choice for subdural hemorrhage?

Accepted Answer

Non-contrast Computed Tomography (NCCT)

Answer

Angiography

Answer

Contrast-Enhanced Computed Tomography (CECT)

Answer

Magnetic Resonance Imaging (MRI)

Question 4

Which condition is characterized by the following sign?

Accepted Answer

Medial medullary syndrome

Answer

Lateral medullary syndrome

Answer

Benedict syndrome

Answer

Millar Gubler syndrome

Question 5

Echoencephalography is most useful in detecting which of the following?

Accepted Answer

Ventricular dilatation

Answer

Midline shift

Answer

Epilepsy

Answer

Vascular lesions

Question 6

Geographic lytic lesions in the vault of the skull with bevelled edges are seen with which condition?

Accepted Answer

Eosinophilic granuloma

Answer

Multiple myeloma

Answer

Hyperparathyroidism

Answer

Reticular cell carcinoma

Question 7

Mount Fuji sign is a feature of which of the following conditions?

Accepted Answer

Tension pneumocephalus

Answer

Fahr's disease

Answer

Acute bleed

Answer

Chronic bleed

Question 8

What is the imaging tool of choice for evaluating a lacunar infarct?

Accepted Answer

Diffusion-weighted imaging (DWI) MRI with apparent diffusion coefficient (ADC) maps

Answer

HMPAO SPECT

Answer

MR Spectroscopy

Answer

PET

Question 9

A patient presents with severe headache. A CT scan of the brain reveals hyperdense areas in the right basal region, marked as 'X'. Which of the following is the most likely diagnosis?

Accepted Answer

Subarachnoid hemorrhage

Answer

Brain abscess

Answer

Pneumocephalus

Answer

Meningococcal meningitis

Question 10

A 30-year-old female patient involved in a road traffic accident had nausea and vomiting. She was brought unconscious to the emergency room. The NCCT brain reveals the following findings. What is the most likely diagnosis? ![img-49.jpeg](img-49.jpeg)

Accepted Answer

a. Extradural hemorrhage

Answer

b. Subdural hemorrhage

Answer

c. Intra-parenchymal hemorrhage

Answer

d. Subarachnoid hemorrhage

Neuroradiology — MCQs

Neuroradiology — MCQs

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