Neuroradiology Practice Questions

Q: Bony clival erosion with intracranial calcification is seen in which of the following?

Sella chordoma. **Explanation:** **Chordomas** are rare, slow-growing, but locally aggressive malignant tumors arising from the remnants of the **primitive notochord**. In the skull base, they typically occur at the **clivus** (spheno-occipital synchondrosis). 1. **Why Chordoma is Correct:** * **Bony Erosion:** Because they arise from bone, chordomas are characterized by extensive, irregular **bone destruction/erosion** of the clivus. * **Calcification:** Intracranial calcification is seen in approximately 50–90% of cases. This is often "sequestra" (fragments of destroyed bone) rather than true intratumoral calcification. On MRI, they show a characteristic "honeycomb" appearance with high T2 signal. 2. **Why Other Options are Incorrect:** * **Craniopharyngioma:** While these frequently show calcification (especially the adamantinomatous type in children), they are suprasellar tumors that cause **sellar enlargement** or pressure erosion of the dorsum sellae, not primary clival destruction. * **Medulloblastoma:** This is a posterior fossa tumor arising from the roof of the 4th ventricle. It typically presents as a solid midline mass in children and does not cause clival erosion. * **Papilloma of the Choroid Plexus:** These are intraventricular tumors (lateral ventricles in children, 4th ventricle in adults). They present with hydrocephalus due to CSF overproduction, not bony destruction of the skull base. **High-Yield Pearls for NEET-PG:** * **Most common site for Chordoma:** Sacrococcygeal region (50%), followed by Spheno-occipital/Clival (35%). * **Radiological Sign:** "Thumb sign" (the tumor deforms the pons posteriorly). * **Differential Diagnosis:** Chondrosarcoma (often located off-midline at the petro-occipital fissure, whereas Chordoma is strictly midline). * **Histology:** Characterized by **Physaliphorous cells** (large cells with vacuolated, bubbly cytoplasm).

Q: Which of the following is represented by an MRI of the skull?

Vein of Galen. ***Vein of Galen*** - MRI shows a characteristic **large midline flow void** or **vascular structure** near the **quadrigeminal plate**, representing the dilated Vein of Galen malformation (VOGM). - Associated with **neonatal heart failure** and **hydrocephalus** due to high-flow arteriovenous shunting through the malformed vein. *Dandy-Walker Syndrome* - MRI would show **cerebellar vermis hypoplasia** with **cystic dilatation** of the fourth ventricle and **enlarged posterior fossa**. - Characterized by **absent or incomplete cerebellar vermis** rather than vascular malformation. *Pneumocephalus* - MRI would demonstrate **intracranial air** appearing as **hypointense signal** on T1 and T2 sequences. - Often occurs post-operatively or after **trauma** with **skull base fractures**, not showing vascular structures. *Crouzon syndrome* - MRI would show features of **craniosynostosis** with **premature fusion** of cranial sutures and **shallow orbits**. - Associated with **characteristic facial dysmorphism** and **increased intracranial pressure**, not vascular malformations.

Q: Which leukodystrophy characteristically presents with bilateral occipital lobe involvement?

Adrenoleukodystrophy. **Explanation:** **X-linked Adrenoleukodystrophy (X-ALD)** is a peroxisomal disorder caused by a mutation in the *ABCD1* gene, leading to the accumulation of **Very Long Chain Fatty Acids (VLCFA)**. In the childhood cerebral form, the hallmark radiological finding is **symmetrical demyelination of the posterior white matter**, specifically involving the **occipital and parietal lobes**. This often spreads anteriorly and involves the splenium of the corpus callosum. A characteristic feature on contrast-enhanced MRI is the "zonal" enhancement at the leading edge of the lesion, representing active neuroinflammation. **Analysis of Incorrect Options:** * **MELAS (Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes):** While it frequently involves the occipital lobes, the lesions are "stroke-like" (cortical/subcortical) and do not follow vascular territories. It is a mitochondrial cytopathy, not a primary leukodystrophy. * **Canavan Disease:** Characterized by **diffuse** white matter involvement with a predilection for the **subcortical U-fibers** and involvement of the thalami and globus pallidus. A key finding is elevated **N-acetylaspartate (NAA)** on MR spectroscopy. * **Alexander Disease:** Classically presents with **frontal lobe** predominance (anterior-to-posterior gradient) and macrocephaly. **High-Yield Pearls for NEET-PG:** * **Adrenoleukodystrophy:** Posterior (Occipital) involvement + VLCFA elevation. * **Alexander Disease:** Anterior (Frontal) involvement + Rosenthal fibers on biopsy. * **Metachromatic Leukodystrophy:** "Butterfly" or "Tigroid" pattern of demyelination; spares subcortical U-fibers. * **Canavan Disease:** Spongiform degeneration + Diffuse involvement (including U-fibers) + High NAA peak. * **Krabbe Disease:** Thalamic hyperdensity on CT; involvement of posterior limb of internal capsule.

Q: What is the imaging modality of choice in the setting of head trauma?

Helical CT scan without IV contrast. **Explanation:** In the acute setting of head trauma, **Non-Contrast Computed Tomography (NCCT) of the head** is the gold standard and the initial imaging modality of choice. **Why Option A is correct:** 1. **Speed and Accessibility:** Helical (spiral) CT is rapid, which is critical for unstable trauma patients. 2. **Acute Hemorrhage:** It is highly sensitive for detecting acute intracranial hemorrhage (which appears hyperdense/white). 3. **Bony Injuries:** It provides excellent visualization of skull fractures. 4. **No Contrast Needed:** IV contrast is avoided initially because it can extravasate or mimic the appearance of acute blood, making it difficult to differentiate a bleed from enhancement. **Why other options are incorrect:** * **Option B:** Contrast is generally avoided in trauma as it obscures acute blood and adds unnecessary time and risk of nephropathy/anaphylaxis. * **Option C:** While MRI is more sensitive for Diffuse Axonal Injury (DAI) and subacute changes, it is time-consuming, expensive, and difficult to monitor unstable patients inside the magnet. * **Option D:** Skull X-rays have a low sensitivity for intracranial pathology; a "normal" X-ray does not rule out a life-threatening intracranial bleed. **High-Yield Clinical Pearls for NEET-PG:** * **Epidural Hematoma (EDH):** Biconvex/Lens-shaped, does not cross sutures, usually involves the Middle Meningeal Artery. * **Subdural Hematoma (SDH):** Crescent-shaped, crosses sutures, involves tearing of cortical bridging veins. * **GCS Threshold:** Imaging is generally indicated if GCS <15 two hours after injury. * **Windowing:** Always evaluate the "Bone Window" to look for subtle fractures and the "Blood Window" to identify small hemorrhages.

Q: Which area of the thalamus is involved in Wernicke's encephalopathy?

Dorsomedial Nucleus. **Explanation:** Wernicke’s Encephalopathy (WE) is an acute neurological emergency caused by **Thiamine (Vitamin B1) deficiency**, most commonly seen in chronic alcoholism. Thiamine is a co-factor for key enzymes in glucose metabolism; its deficiency leads to metabolic failure and characteristic cytotoxic/vasogenic edema in specific vulnerable brain regions. **Why the Dorsomedial Nucleus is Correct:** The **Dorsomedial (DM) nucleus** of the thalamus is one of the most frequently involved structures in WE. On MRI, this manifests as symmetrical T2/FLAIR hyperintensities. Involvement of the DM nucleus and the pulvinar is highly specific for the diagnosis. Damage to these thalamic nuclei, along with the mammillary bodies, contributes to the profound anterograde and retrograde amnesia seen if the condition progresses to Korsakoff Syndrome. **Analysis of Incorrect Options:** * **A. Mammillary Bodies:** While these are classic sites of involvement in WE (often showing atrophy or enhancement), they are **not** part of the thalamus itself; they are part of the hypothalamus/limbic system. * **C. Ventral Posterolateral (VPL) Nucleus:** This is the sensory relay station for the body (spinothalamic and medial lemniscus). It is typically spared in WE. * **D. Anterior Nucleus:** While involved in the Circuit of Papez, it is less characteristically or consistently affected in WE compared to the DM nucleus. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad:** Encephalopathy (confusion), Ataxia, and Ophthalmoplegia (6th nerve palsy/nystagmus). * **MRI Findings:** Symmetrical T2/FLAIR hyperintensities in the **periaqueductal gray matter**, **dorsomedial thalami**, **tectal plate**, and **mammillary bodies**. * **Treatment:** Immediate IV Thiamine **before** glucose administration to prevent worsening of the metabolic crisis.

Q: A 45-year-old female presents with headache, vomiting, and deterioration of consciousness, two years after resection of a parietal lobe brain tumor. What is the most appropriate investigation to perform now?

CT scan. **Explanation:** The clinical presentation of headache, vomiting, and deteriorating consciousness in a patient with a history of brain tumor resection suggests an **acute increase in intracranial pressure (ICP)**. This is a neurosurgical emergency. **Why CT scan is the correct answer:** In an emergency setting, **Non-Contrast Computed Tomography (NCCT)** is the investigation of choice. It is preferred over MRI because: 1. **Speed:** It is significantly faster, allowing for rapid intervention. 2. **Sensitivity for Hemorrhage:** It is highly sensitive for detecting acute intracranial hemorrhage (a common cause of sudden deterioration post-resection). 3. **Hydrocephalus/Mass Effect:** It quickly identifies midline shift, ventricular enlargement (hydrocephalus), or brain herniation. 4. **Accessibility:** It is more readily available and easier to monitor unstable patients during the scan. **Why other options are incorrect:** * **MRI:** While MRI offers superior soft-tissue resolution and is better for detecting tumor recurrence, it is time-consuming and less practical in an acutely deteriorating patient. * **18 FDG-PET scan:** This is a functional imaging modality used primarily to differentiate between **radiation necrosis and tumor recurrence**. It has no role in the emergency management of raised ICP. * **HMPAO-SPECT scan:** This is used for assessing cerebral blood flow (e.g., in brain death or dementia) and is not indicated for acute neurological deterioration. **Clinical Pearls for NEET-PG:** * **Investigation of Choice (IOC) for Acute Head Injury/Stroke:** NCCT. * **IOC for Tumor Characterization:** MRI with Contrast (Gadolinium). * **Differentiating Radiation Necrosis vs. Recurrence:** PET scan (Recurrence shows high uptake; Necrosis shows low uptake). * **Cushing’s Triad (Sign of raised ICP):** Hypertension, Bradycardia, and Irregular Respiration.

Q: The given CT scan shows which brain lesion?

Medulloblastoma. ***Medulloblastoma*** - Appears as a **hyperdense, homogeneously enhancing mass** in the **cerebellar vermis** with compression of the **4th ventricle** and associated **obstructive hydrocephalus**. - Commonly presents as a **midline posterior fossa tumor** in children, often showing **calcifications** and **cystic components** on CT imaging. *Subdural hematoma (SDH)* - Appears as a **crescent-shaped collection** between the **dura and brain surface**, typically **hypodense** (chronic) or **hyperdense** (acute) on CT. - Located in the **supratentorial compartment** along the cerebral convexity, not in the **posterior fossa** or cerebellar region. *Brain abscess* - Characterized by a **ring-enhancing lesion** with a **hypodense necrotic center** and significant **perilesional edema** on contrast-enhanced CT. - Typically shows a **thin, smooth wall** with enhancement and may have **gas bubbles** within the lesion, unlike the solid appearance of medulloblastoma. *Oligodendroglioma* - Appears as a **well-demarcated, heterogeneous mass** with characteristic **"eggshell" calcifications** in the **cerebral hemispheres**, particularly **frontal and parietal lobes**. - Typically located in the **supratentorial compartment** rather than the **posterior fossa**, and shows less enhancement compared to medulloblastoma.

Q: The provided MRI of the spine denotes which of the following findings?

Syrinx. ***Syrinx*** - A **syrinx** (syringomyelia) appears as a **fluid-filled cystic cavity** within the spinal cord parenchyma on MRI, typically **hyperintense on T2-weighted images**. - It presents as a **central, longitudinal cavity** that expands the spinal cord, often associated with **Chiari malformation** or **spinal cord trauma**. *Cervical cord stenosis* - Shows **narrowing of the spinal canal** with **compression of the spinal cord** from external structures like ligaments or osteophytes. - The spinal cord appears **flattened** or **compressed** but maintains its solid structure without internal cavitation. *Meningocele* - Represents a **herniation of meninges** through a spinal defect, appearing as a **CSF-filled sac** **external to the spinal canal**. - The **spinal cord remains within the canal** and is not involved in the herniated sac, unlike myelomeningocele. *Myelomeningocele* - Shows **herniation of both spinal cord and meninges** through a spinal defect, with the **neural tissue visible within the herniated sac**. - Typically associated with **open spina bifida** and presents as an **external mass** containing both neural elements and CSF.

Q: What is the most definitive test for evaluating intracranial aneurysms?

Angiography. **Explanation:** **Digital Subtraction Angiography (DSA)**, often referred to simply as angiography, remains the **gold standard** and most definitive test for evaluating intracranial aneurysms. Its superiority lies in its high spatial resolution and its ability to provide dynamic, real-time visualization of blood flow. It allows for the precise assessment of the aneurysm's neck, its relationship to parent vessels, and the detection of small aneurysms (less than 3mm) that might be missed by non-invasive modalities. Furthermore, it allows for immediate therapeutic intervention (endovascular coiling). **Analysis of Incorrect Options:** * **CT Scan (NCCT):** This is the investigation of choice for diagnosing an acute **Subarachnoid Hemorrhage (SAH)**, but it cannot definitively characterize the underlying aneurysm itself. CT Angiography (CTA) is excellent for screening but lacks the resolution of DSA. * **MRI Scan:** While MRA (Magnetic Resonance Angiography) is useful for screening and follow-up without radiation, it is prone to flow artifacts and lacks the sensitivity required for definitive surgical or endovascular planning. * **PET Scan:** This is a functional imaging modality used primarily for oncology or evaluating brain metabolism (e.g., epilepsy or dementia); it has no role in the structural evaluation of vascular aneurysms. **High-Yield Clinical Pearls for NEET-PG:** * **Best Initial Test for SAH:** Non-contrast CT (NCCT) Head (shows hyperdensity in basal cisterns). * **Gold Standard for Aneurysm:** Digital Subtraction Angiography (DSA). * **Most Common Site:** Junction of the Anterior Communicating Artery (A-com) and Anterior Cerebral Artery. * **Most Common Presentation:** "Worst headache of life" (Thunderclap headache). * **Complication Timing:** Vasospasm typically occurs 4–14 days post-rupture; Nimodipine is used for prophylaxis.

Q: J-Shaped sella turica is seen in which condition?

Hurler's disease. **Explanation:** The **J-shaped sella** (also known as the "omega sella") is a classic radiological sign where the sella turcica appears elongated horizontally with a flattened tuberculum sellae, resembling the letter 'J' or the Greek letter omega ($\Omega$). **1. Why Hurler’s Disease is Correct:** Hurler’s disease (Mucopolysaccharidosis Type I) is the prototypical cause of a J-shaped sella. The deformity occurs due to the deposition of glycosaminoglycans (GAGs) in the connective tissue of the skull base and the dura mater. This leads to a thickened, enlarged chiasmatic sulcus and an abnormal configuration of the sphenoid bone, creating the characteristic elongated appearance. **2. Why Other Options are Incorrect:** * **Multiple Myeloma:** This typically presents with "punched-out" lytic lesions in the calvarium. It does not specifically alter the structural shape of the sella turcica into a J-shape. * **Pinealoma:** These are tumors of the pineal gland located posterior to the third ventricle. While they can cause obstructive hydrocephalus and increased intracranial pressure (leading to "beaten silver" appearance or erosion of the clinoid processes), they do not cause a J-shaped sella. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **Differential Diagnosis for J-shaped Sella:** * **Mucopolysaccharidoses:** Hurler’s, Hunter’s, and Morquio syndrome. * **Achondroplasia:** Due to abnormal endochondral bone formation at the skull base. * **Optic Nerve Glioma:** A classic cause (especially in Neurofibromatosis Type 1) due to the enlargement of the optic chiasm. * **Chronic Hydrocephalus:** In children, due to pressure effects on the sphenoid bone. * **Radiology Tip:** Do not confuse J-shaped sella with **Empty Sella Syndrome**, where the sella is enlarged and filled with CSF, but the bony contours remain rounded.

Question 1

Bony clival erosion with intracranial calcification is seen in which of the following?

Accepted Answer

Sella chordoma

Answer

Craniopharyngioma

Answer

Medulloblastoma

Answer

Papilloma of the choroid plexus

Question 2

Which of the following is represented by an MRI of the skull?

Accepted Answer

Vein of Galen

Answer

Dandy-Walker Syndrome

Answer

Pneumocephalus

Answer

Crouzon syndrome

Question 3

Which leukodystrophy characteristically presents with bilateral occipital lobe involvement?

Accepted Answer

Adrenoleukodystrophy

Answer

MELAS

Answer

Canavan disease

Answer

Alexander disease

Question 4

What is the imaging modality of choice in the setting of head trauma?

Accepted Answer

Helical CT scan without IV contrast

Answer

Spiral CT scan with IV contrast

Answer

MRI

Answer

Digital skull radiographs

Question 5

Which area of the thalamus is involved in Wernicke's encephalopathy?

Accepted Answer

Dorsomedial Nucleus

Answer

Mammillary Bodies

Answer

Ventral Posterolateral Nucleus

Answer

Anterior Nucleus

Question 6

A 45-year-old female presents with headache, vomiting, and deterioration of consciousness, two years after resection of a parietal lobe brain tumor. What is the most appropriate investigation to perform now?

Accepted Answer

CT scan

Answer

MRI

Answer

18 FDG-PET scan

Answer

HMPAO-SPECT scan

Question 7

The given CT scan shows which brain lesion?

Accepted Answer

Medulloblastoma

Answer

Subdural hematoma (SDH)

Answer

Brain abscess

Answer

Oligodendroglioma

Question 8

The provided MRI of the spine denotes which of the following findings?

Accepted Answer

Syrinx

Answer

Cervical cord stenosis

Answer

Meningocele

Answer

Myelomeningocele

Question 9

What is the most definitive test for evaluating intracranial aneurysms?

Accepted Answer

Angiography

Answer

CT scan

Answer

MRI scan

Answer

PET scan

Question 10

J-Shaped sella turica is seen in which condition?

Accepted Answer

Hurler's disease

Answer

Multiple myeloma

Answer

Pinealoma

Answer

All the above

Neuroradiology — MCQs

Neuroradiology — MCQs

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