Neuroradiology Practice Questions

Q: Which sequence of MRI is used to detect microhemorrhages?

SWI. **Explanation:** The correct answer is **SWI (Susceptibility Weighted Imaging)**. **1. Why SWI is the Correct Answer:** SWI is a high-spatial-resolution 3D gradient-echo sequence that is extremely sensitive to substances that cause "magnetic susceptibility" effects, such as **hemosiderin** (from old blood) and **calcium**. * **Mechanism:** When microhemorrhages occur, hemoglobin breaks down into paramagnetic hemosiderin. This creates local magnetic field distortions, leading to a loss of signal. On SWI, these appear as small, dark "blooming" spots (the **Blooming Effect**). SWI is significantly more sensitive than conventional T2* Gradient Echo (GRE) for detecting tiny punctate hemorrhages. **2. Why Other Options are Incorrect:** * **T1WI (T1 Weighted Imaging):** Primarily used for anatomy. While acute/subacute blood can appear bright (hyperintense) on T1, it lacks the sensitivity to detect chronic microhemorrhages. * **T2WI (T2 Weighted Imaging):** Standard T2 sequences are poor at detecting microbleeds as they do not emphasize magnetic susceptibility. * **DWI (Diffusion Weighted Imaging):** This sequence measures the random motion of water molecules. It is the "Gold Standard" for detecting **Hyperacute Ischemic Stroke** (cytotoxic edema), not microhemorrhages. **3. High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis for Microhemorrhages:** 1. **Hypertensive Microbleeds:** Usually located in the basal ganglia, thalamus, and pons. 2. **Cerebral Amyloid Angiopathy (CAA):** Characteristically located in the **peripheral/lobar** cortical-subcortical junctions. 3. **Diffuse Axonal Injury (DAI):** Microhemorrhages at the grey-white matter junction, corpus callosum, or brainstem following trauma. * **Mnemonic:** "SWI for Blood and Bone (Calcium)." * **Comparison:** If both GRE and SWI are in options, **SWI** is the superior choice for microhemorrhage detection.

Q: What is the earliest sign of raised intracranial tension on a skull X-ray in infants?

Sutural diastasis. **Explanation:** In infants and young children (typically under the age of 2), the cranial sutures are not yet fused. When intracranial pressure (ICP) rises, the skull expands to accommodate the volume. **Sutural diastasis** (widening of the sutures) is the **earliest and most sensitive sign** of raised ICP in this age group. A suture width of >2 mm is generally considered abnormal. **Analysis of Options:** * **A. Sutural diastasis (Correct):** Because the infant skull is compliant, the sutures separate before any bony erosion occurs. This is the pediatric equivalent of the "erosion of dorsum sellae" seen in adults. * **B. Erosion of the dorsum sellae:** This is the **most common** and earliest sign of raised ICP in **adults**. In infants, the sutures give way first, making this a later or less common sign. * **C. Pineal gland displacement:** This indicates a midline shift due to a space-occupying lesion (e.g., tumor or hematoma). While it suggests increased pressure, it is a sign of mass effect rather than a generalized early sign of raised ICP. Furthermore, the pineal gland is rarely calcified (and thus not visible) in infants. * **D. Copper beaten appearance (Silver beaten skull):** This refers to prominent gyral impressions on the inner table of the skull. While associated with chronic raised ICP (like craniosynostosis), it can be a **normal finding** in healthy children during periods of rapid brain growth (ages 4–10) and is therefore not a reliable early sign. **High-Yield Clinical Pearls for NEET-PG:** * **Adults:** Earliest sign on X-ray is erosion of the **dorsum sellae**. * **Infants:** Earliest sign is **sutural diastasis**. * **Gold Standard:** While X-ray shows chronic changes, **Non-Contrast CT (NCCT)** is the investigation of choice for acute raised ICP to look for midline shift and effacement of sulci.

Q: Which condition is characterized by the MRI finding of "tectal beaking"?

Arnold-Chiari malformation. ### Explanation **Correct Answer: B. Arnold-Chiari malformation** **Tectal beaking** is a classic neuroimaging sign specifically associated with **Chiari II malformation**. It refers to the fusion and posterior pointing (beaking) of the colliculi of the midbrain. This occurs because the small posterior fossa and the downward displacement of the hindbrain structures cause the midbrain to be pulled inferiorly and squeezed, resulting in the characteristic "beaked" appearance of the tectal plate on sagittal MRI. **Analysis of Incorrect Options:** * **A. Dandy-Walker malformation:** Characterized by the triad of cystic dilatation of the fourth ventricle, cerebellar vermis hypoplasia, and an enlarged posterior fossa. It does not involve tectal plate distortion. * **C. Aqueductal stenosis:** While it causes obstructive hydrocephalus and can lead to thinning of the corpus callosum, it typically presents with a normal or "bulging" tectum rather than a fused, beaked one. * **D. Third ventricular tumor:** These (e.g., colloid cysts) cause obstructive hydrocephalus and pressure symptoms but do not result in the structural hindbrain herniation required to produce tectal beaking. **High-Yield Clinical Pearls for NEET-PG:** * **Chiari II Malformation Triad:** Tectal beaking, downward displacement of the cerebellar tonsils/vermis/medulla, and association with **myelomeningocele** (nearly 100%). * **Other Chiari II Signs:** "Towering cerebellum" (upward herniation through the tentorium) and "Luckenschadel skull" (lacunar skull). * **Chiari I:** Only cerebellar tonsillar herniation (>5mm); usually asymptomatic until adulthood and associated with **syringomyelia**.

Q: The "Eye of the Tiger" appearance in MRI is seen in which of the following conditions?

Hallervorden-Spatz syndrome. **Explanation:** The **"Eye of the Tiger"** sign is a classic radiological hallmark seen on **T2-weighted MRI** of the brain. It is pathognomonic for **Hallervorden-Spatz syndrome**, now more commonly known as **Pantothenate Kinase-Associated Neurodegeneration (PKAN)**, a type of Neurodegeneration with Brain Iron Accumulation (NBIA). **Pathophysiology:** The sign consists of a central area of **hyperintensity** (high signal) surrounded by a rim of **hypointensity** (low signal) in the **Globus Pallidus**. * **Hypointensity:** Caused by excessive iron deposition (paramagnetic effect). * **Hyperintensity:** Represents gliosis, vacuolization, and axonal swelling (spheroid bodies). **Analysis of Options:** * **Option D (Correct):** Hallervorden-Spatz syndrome (PKAN) is the primary condition associated with this sign due to the specific pattern of iron and gliosis in the globus pallidus. * **Option A:** **Wilson’s Disease** typically shows the **"Face of the Giant Panda"** sign in the midbrain (high signal in tegmentum with preserved normal signal in red nuclei and superior colliculi). * **Option B:** While PKAN involves iron accumulation, "Neuronal accumulation of iron" is a broad category. The "Eye of the Tiger" is specifically linked to the PKAN subtype of NBIA. * **Option C:** **Alzheimer’s Disease** is characterized by generalized cortical atrophy and hippocampal atrophy, not specific basal ganglia iron patterns. **NEET-PG High-Yield Pearls:** 1. **Gene Mutation:** PKAN is caused by a mutation in the **PANK2 gene** (Chromosome 20p). 2. **Clinical Triad:** Extrapyramidal symptoms (dystonia, rigidity), pigmentary retinopathy, and cognitive decline. 3. **MRI Sequence:** The sign is best visualized on **T2-weighted** or **SWI** (Susceptibility Weighted Imaging) sequences.

Q: An X-ray film of the skull is provided. What is the diagnosis?

Osteoma. ***Osteoma*** - Classic skull X-ray appearance shows a **dense, well-circumscribed, homogeneous ivory-like bony protrusion**, typically on the **frontal bone** or **paranasal sinuses**. - **Benign bone tumor** with characteristic **sclerotic appearance** and **smooth, round contours** without soft tissue involvement. *Osteoblastoma* - Appears as a **mixed lytic-sclerotic lesion** with **irregular borders** and possible **expansion** of bone cortex. - Typically larger than **2 cm** and shows **heterogeneous density** rather than the homogeneous ivory appearance of osteoma. *Sinusitis* - X-ray shows **fluid levels** or **opacification** within the **paranasal sinuses**, not solid bony masses. - May demonstrate **mucosal thickening** and **air-fluid levels** but lacks the dense bony protrusion seen here. *Multiple myeloma* - Characteristic **punched-out lytic lesions** with **no sclerotic margins** throughout the skull ("raindrop skull"). - Shows **multiple round radiolucent areas** without the dense, ivory-like appearance of osteoma.

Q: Extensive involvement of deep white matter with hyperdense thalamic lesion on non-contrast CT scan of the brain is seen in which of the following conditions?

Krabbe disease. ### Explanation The correct answer is **Krabbe disease** (Globoid Cell Leukodystrophy). **1. Why Krabbe Disease is Correct:** Krabbe disease is an autosomal recessive lysosomal storage disorder caused by a deficiency of the enzyme **galactocerebrosidase**. This leads to the accumulation of psychosine, which is toxic to oligodendrocytes. * **Radiological Hallmark:** On a non-contrast CT (NCCT), Krabbe disease characteristically shows **hyperdensity in the thalami**, caudate nuclei, and posterior limb of the internal capsule. This is attributed to the presence of dense "globoid cells" and calcification. * **White Matter Involvement:** It involves extensive symmetric demyelination of the deep white matter, often starting posteriorly (parieto-occipital) and spreading anteriorly. **2. Why Other Options are Incorrect:** * **Alexander Disease:** Characterized by **frontal lobe** predominance of white matter changes. A key finding is "Rosenthal fibers" on pathology and macrocephaly clinically. * **Metachromatic Leukodystrophy (MLD):** The most common leukodystrophy. It shows a characteristic **"tigroid" or "leopard skin" pattern** (sparing of perivenular myelin) on MRI. It typically does *not* show hyperdense thalami on CT. * **Canavan Disease:** Characterized by diffuse white matter involvement with a hallmark of **elevated N-acetylaspartate (NAA) peak** on MR spectroscopy and macrocephaly. **3. High-Yield Clinical Pearls for NEET-PG:** * **Hyperdense Thalami on CT:** Think Krabbe disease or GM1 Gangliosidosis. * **Macrocephaly + Leukodystrophy:** Think Alexander disease or Canavan disease. * **Tigroid Pattern:** Pathognomonic for MLD. * **Parieto-occipital Predominance:** Seen in Krabbe and X-linked Adrenoleukodystrophy (ALD).

Q: A 12-year-old boy presents with seizures. His mother reports multiple previous hospitalizations for difficult-to-control seizures. A CT scan was performed. What is the diagnosis?

Tuberous sclerosis. ***Tuberous sclerosis*** - Characterized by **subependymal calcified nodules** and **cortical tubers** on CT, which are pathognomonic findings in children with refractory seizures. - Classic presentation includes **difficult-to-control seizures** in childhood, often associated with **developmental delay** and **autism spectrum disorders**. *Sturge Weber Syndrome* - CT typically shows **pial angiomatosis** with **gyriform calcifications** in the occipital and parietal regions, not subependymal nodules. - Associated with **port-wine stain** facial birthmark and **glaucoma**, which are not mentioned in this case. *Neurofibromatosis* - CT findings include **neurofibromas** and **optic gliomas**, not the calcified nodules seen in tuberous sclerosis. - Typically presents with **café-au-lait spots** and **neurofibromas** rather than primarily seizure disorders. *Von Hippel Lindau Syndrome* - CT shows **cerebellar hemangioblastomas** and **retinal angiomas**, not cortical tubers or subependymal nodules. - Primarily affects **young adults** rather than children and rarely presents with seizures as the main symptom.

Q: The MRI finding shown in the image is characteristic of which of the following pathologies?

Multiple Sclerosis. ***Multiple Sclerosis*** - **Periventricular white matter lesions** (Dawson's fingers) on **FLAIR MRI** are pathognomonic for multiple sclerosis, showing demyelinating plaques perpendicular to ventricles. - The **finger-like projections** extending from ventricles represent perivenular inflammation and demyelination characteristic of MS pathophysiology. *Sturge-Weber syndrome* - Typically shows **tram-track calcifications** in the cortex on CT imaging, not periventricular white matter lesions. - Associated with **leptomeningeal angiomatosis** and cortical atrophy, distinctly different from the shown MRI pattern. *Neurofibromatosis* - MRI findings include **schwannomas**, **optic gliomas**, and **café-au-lait spots**, not periventricular white matter lesions. - **Neurofibromas** along nerve pathways and **sphenoid wing dysplasia** are characteristic imaging features, absent in this case. *Tuberous Sclerosis* - Characteristic findings include **cortical tubers**, **subependymal nodules**, and **candle-guttering calcifications** on imaging. - **Subependymal giant cell astrocytomas** near the foramen of Monro are typical, not the periventricular pattern shown.

Question 1

Which sequence of MRI is used to detect microhemorrhages?

Accepted Answer

SWI

Answer

T1WI

Answer

T2WI

Answer

DWI

Question 2

What is the earliest sign of raised intracranial tension on a skull X-ray in infants?

Accepted Answer

Sutural diastasis

Answer

Erosion of the dorsum sellae

Answer

Pineal gland displacement

Answer

Copper beaten appearance

Question 3

Which condition is characterized by the MRI finding of "tectal beaking"?

Accepted Answer

Arnold-Chiari malformation

Answer

Dandy-Walker malformation

Answer

Aqueductal stenosis

Answer

Third ventricular tumor

Question 4

The "Eye of the Tiger" appearance in MRI is seen in which of the following conditions?

Accepted Answer

Hallervorden-Spatz syndrome

Answer

Wilson's disease

Answer

Neuronal accumulation of iron

Answer

Alzheimer's disease

Question 5

Which of the following is a characteristic radiological finding of an epidermoid cyst?

Accepted Answer

High signal on diffusion-weighted MRI

Answer

Low signal on diffusion-weighted MRI

Answer

High signal on FLAIR MRI

Answer

High signal on STIR MRI

Question 6

An X-ray film of the skull is provided. What is the diagnosis?

Accepted Answer

Osteoma

Answer

Osteoblastoma

Answer

Sinusitis

Answer

Multiple myeloma

Question 7

Extensive involvement of deep white matter with hyperdense thalamic lesion on non-contrast CT scan of the brain is seen in which of the following conditions?

Accepted Answer

Krabbe disease

Answer

Alexander disease

Answer

Metachromatic leukodystrophy

Answer

Canavan disease

Question 8

A 12-year-old boy presents with seizures. His mother reports multiple previous hospitalizations for difficult-to-control seizures. A CT scan was performed. What is the diagnosis?

Accepted Answer

Tuberous sclerosis

Answer

Sturge Weber Syndrome

Answer

Neurofibromatosis

Answer

Von Hippel Lindau Syndrome

Question 9

The MRI finding shown in the image is characteristic of which of the following pathologies?

Accepted Answer

Multiple Sclerosis

Answer

Sturge-Weber syndrome

Answer

Neurofibromatosis

Answer

Tuberous Sclerosis

Question 10

Which of the following imaging sequences is most useful in differentiating between an arachnoid cyst and an epidermoid cyst?

Accepted Answer

FLAIR

Answer

T1 weighted MRI

Answer

Smooth margin

Answer

Contrast enhancement

Neuroradiology — MCQs

Neuroradiology — MCQs

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