Neuroradiology Practice Questions

Q: What is true regarding Cerebrospinal Fluid (CSF) on Magnetic Resonance Imaging (MRI)?

CSF appears hyper-intense on T2-weighted images.. **Explanation:** In Magnetic Resonance Imaging (MRI), the appearance of tissues is determined by their relaxation times ($T1$ and $T2$). Cerebrospinal Fluid (CSF) is a simple fluid with a long $T1$ relaxation time and a long $T2$ relaxation time. * **Correct Answer (B):** On **T2-weighted images**, tissues with long relaxation times appear bright. Since CSF has a high water content, it appears **hyper-intense (white)**. This is a hallmark of T2 imaging, often referred to as the "H2O is bright on T2" rule. **Analysis of Incorrect Options:** * **Option A:** On **T1-weighted images**, fluids with long relaxation times appear **hypo-intense (dark)**. T1 is excellent for visualizing anatomy, where CSF provides a dark background against the grey and white matter. * **Option C:** **FLAIR (Fluid Attenuated Inversion Recovery)** is essentially a T2-weighted sequence where the signal from free-flowing water (CSF) is suppressed or "nulled." Therefore, CSF appears **dark** on FLAIR, allowing for better visualization of periventricular pathologies like Multiple Sclerosis plaques. * **Option D:** On **Diffusion-Weighted Imaging (DWI)**, CSF shows "restricted diffusion" only if it is highly viscous (like an abscess). Normal CSF allows free movement of water molecules and appears **hypo-intense (dark)** on DWI and bright on the corresponding ADC map. **High-Yield Clinical Pearls for NEET-PG:** * **T1 vs. T2:** Remember **T1 = Dark** fluid; **T2 = Bright** fluid. * **FLAIR:** Best for identifying edema or lesions near the ventricles (e.g., MS, infarcts). * **DWI:** The gold standard for diagnosing **Acute Ischemic Stroke** (appears hyper-intense due to cytotoxic edema). * **Pathology:** If CSF-like signal on T1/T2 does *not* suppress on FLAIR, consider an **Epidermoid cyst** rather than an Arachnoid cyst.

Q: Which imaging modality detects a brain infarct at the earliest?

Diffusion-weighted magnetic resonance imaging (DWI-MRI). **Explanation:** **Diffusion-Weighted Imaging (DWI)** is the most sensitive imaging modality for detecting an acute ischemic stroke. It can identify an infarct within **3–30 minutes** of onset. The underlying mechanism is **Cytotoxic Edema**. When blood flow is compromised, the failure of the ATP-dependent Na+/K+ pump causes sodium and water to shift into the intracellular space. This restricts the Brownian motion (random movement) of water molecules. DWI sequences are highly sensitive to this restriction, appearing as a **hyperintensity (bright signal)** on the scan. **Why other options are incorrect:** * **NCCT (Non-contrast CT):** While it is the initial investigation of choice to **rule out hemorrhage**, it is insensitive to early ischemic changes. Signs like the "Hyperdense MCA sign" or "Insular ribbon sign" usually take 6–12 hours to appear. * **CECT:** Contrast is generally avoided in acute stroke protocols as it can mask an underlying hemorrhage and does not improve the detection of early ischemia compared to NCCT. * **X-ray:** This modality has no role in the diagnosis of intracranial soft tissue pathologies like infarcts. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Stroke:** MRI with DWI is the gold standard for early diagnosis. * **DWI vs. ADC:** To confirm a true infarct and rule out "T2 shine-through," the hyperintensity on DWI must correspond to a **hypointensity (dark signal) on the ADC (Apparent Diffusion Coefficient) map.** * **Earliest CT sign:** Hyperdense MCA sign (represents a thrombus). * **Window Period:** For thrombolysis (IV Alteplase), the window is 4.5 hours; for mechanical thrombectomy, it can extend up to 24 hours based on perfusion imaging.

Q: Which of the following views is recommended for radiological examination of the maxillary sinus?

Water's view. ### Explanation **Correct Answer: A. Water’s View** **Water’s view (Occipitomental projection)** is the gold standard radiographic view for evaluating the **maxillary sinuses**. In this position, the patient’s chin is tilted up against the image receptor, which projects the dense petrous part of the temporal bone below the floor of the maxillary sinuses. This provides a clear, unobstructed view of the antrum, making it ideal for detecting sinusitis, air-fluid levels, and fractures of the orbital floor (blow-out fractures) or zygomatic arch. **Analysis of Incorrect Options:** * **B. Caldwell View (Occipitofrontal projection):** This view is best for visualizing the **frontal and ethmoid sinuses**. In this position, the petrous ridges are projected over the lower third of the orbits, obscuring the maxillary sinuses. * **C. Ferguson’s View:** This is a specialized view used in orthopedics to evaluate the **lumbosacral junction** (L5-S1) or to assess scoliosis. It is not used for paranasal sinus imaging. * **D. Skyline View:** This is a tangential view used to visualize the **patella** and the patellofemoral joint space. **High-Yield Clinical Pearls for NEET-PG:** * **Water’s View with Open Mouth:** This modification allows for the visualization of the **sphenoid sinus** through the open oral cavity. * **Submentovertex (SMV) View:** The preferred view for the **sphenoid sinus** and the base of the skull. * **Lateral View:** Best for assessing the **adenoids** and the anterior/posterior extent of the frontal sinuses. * **Gold Standard:** While X-rays are common screening tools, **Non-Contrast CT (NCCT) of the Paranasal Sinuses** is the investigation of choice for chronic sinusitis and preoperative planning.

Q: Medusa head appearance on MRI is seen in which of the following?

Venous angioma. **Explanation:** **Venous Angioma**, also known as **Developmental Venous Anomaly (DVA)**, is the most common intracranial vascular malformation. It consists of a cluster of small, radially arranged medullary veins that drain into a single, large collector vein. On MRI (especially post-gadolinium T1 or susceptibility-weighted imaging), this radial pattern resembles the snakes on the head of the mythical figure Medusa, hence the classic **"Caput Medusae"** or **"Medusa head"** appearance. **Analysis of Incorrect Options:** * **Arteriovenous Malformation (AVM):** Characterized by a "bag of worms" appearance due to a nidus of tangled vessels with high-flow shunting. It does not show the organized radial drainage pattern of a DVA. * **Cavernous Hemangioma (Cavernoma):** Classically described as having a **"Popcorn"** or "Mulberry" appearance on MRI, often with a peripheral rim of hemosiderin (hypointense on T2/GRE). * **Vein of Galen Malformation:** An arteriovenous fistula resulting in massive dilatation of the prosencephalic vein of Markowski. It typically presents in neonates with high-output heart failure. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** DVAs are usually asymptomatic "incidentalomas" and represent a variation of normal venous drainage. They should **not** be surgically removed, as doing so can lead to venous infarction of the brain territory they drain. * **Associations:** DVAs are frequently associated with **Cavernous Malformations** (up to 30% of cases). * **Imaging Gold Standard:** While MRI is excellent, Digital Subtraction Angiography (DSA) shows the "Medusa head" specifically during the **venous phase**.

Q: Humming bird sign on MRI is seen in which of the following conditions?

Progressive supranuclear palsy. The **Hummingbird sign** (also known as the **Penguin sign**) is a classic radiologic hallmark of **Progressive Supranuclear Palsy (PSP)**, a Parkinson-plus syndrome. ### 1. Why Progressive Supranuclear Palsy is Correct The sign is seen on **midsagittal T1-weighted MRI** images. It occurs due to profound **atrophy of the midbrain tegmentum** while the pons remains relatively preserved in size. This creates a silhouette resembling a hummingbird, where the thinned midbrain represents the bird's head/beak and the bulky pons represents the body. Another related finding is the **Mickey Mouse sign**, seen on axial sections due to the thinning of the midbrain peduncles. ### 2. Why Other Options are Incorrect * **Multiple Sclerosis:** Characterized by "Dawson’s Fingers" (periventricular demyelinating plaques perpendicular to the lateral ventricles) and the "Open Ring sign." * **Developmental Venous Anomaly (DVA):** A benign vascular variant characterized by the **"Caput Medusae" sign** (multiple small medullary veins draining into a single large collector vein). ### 3. High-Yield Clinical Pearls for NEET-PG * **Clinical Triad of PSP:** Supranuclear ophthalmoplegia (vertical gaze palsy), pseudobulbar palsy, and axial rigidity with frequent early falls. * **Mickey Mouse Sign:** Axial MRI showing midbrain atrophy in PSP. * **Hot Cross Bun Sign:** Seen in **MSA-C** (Multiple System Atrophy, Cerebellar type) due to degeneration of pontocerebellar fibers. * **Eye-of-the-Tiger Sign:** Seen in **NBIA** (Pantothenate Kinase-Associated Neurodegeneration) involving the globus pallidus.

Q: Which imaging modality is the primary test for extradural hemorrhage?

Non-contrast computed tomography (NCCT). **Explanation:** **Non-contrast computed tomography (NCCT) Head** is the gold standard and primary imaging modality for diagnosing Extradural Hemorrhage (EDH). In the acute trauma setting, NCCT is preferred because it is rapid, widely available, and highly sensitive to acute intracranial blood. On NCCT, an EDH typically appears as a **hyperdense, biconvex (lentiform) shape** that does not cross cranial sutures (as the dura is firmly attached at these points). **Why other options are incorrect:** * **Ultrasonography (USG):** While useful for FAST (Focused Assessment with Sonography for Trauma) in abdominal trauma, USG cannot penetrate the adult cranium to visualize intracranial bleeding. * **Doppler Ultrasonography:** This is used to evaluate blood flow velocity in vessels (e.g., carotid stenosis or DVT) and has no role in the primary diagnosis of acute intracranial hemorrhage. * **X-ray Pelvis:** This is part of the primary survey in trauma to rule out pelvic fractures but is irrelevant to head injuries. **Clinical Pearls for NEET-PG:** * **Source of Bleed:** The most common cause of EDH is a tear in the **Middle Meningeal Artery** (often associated with a fracture at the Pterion). * **Lucid Interval:** A classic clinical feature where the patient regains consciousness temporarily before deteriorating. * **Management:** If the hematoma volume is >30 cm³, thickness >15 mm, or midline shift >5 mm, urgent **Surgical Evacuation (Burr hole/Craniotomy)** is indicated. * **MRI:** While more sensitive for diffuse axonal injury, it is not the primary test for EDH due to the time required and incompatibility with metallic life-support equipment.

Q: Tram line calcification seen in skull X-ray are characteristic of:

Sturge Weber Syndrome. **Explanation:** **Sturge-Weber Syndrome (SWS)**, also known as encephalotrigeminal angiomatosis, is the correct answer. The characteristic "tram-line" or "railroad track" calcifications seen on a skull X-ray (and more clearly on CT) represent **gyriform cortical calcifications**. These occur due to chronic ischemia and venous stasis caused by the underlying leptomeningeal angioma, leading to calcium deposition in the second and third layers of the cerebral cortex. These calcifications typically follow the convolutions of the brain, creating the parallel-line appearance. **Analysis of Incorrect Options:** * **Congenital CMV:** Characterized by **periventricular calcifications** (around the ventricles). * **Congenital Toxoplasmosis:** Characterized by **diffuse, scattered intracranial calcifications** throughout the brain parenchyma. * **Craniopharyngioma:** Shows **suprasellar calcifications** (curvilinear or nodular), most commonly seen in the adamantinomatous subtype in children. **High-Yield Clinical Pearls for NEET-PG:** * **SWS Triad:** 1. Port-wine stain (Nevus flammeus) in the V1/V2 distribution of the trigeminal nerve; 2. Leptomeningeal angioma (ipsilateral to the skin lesion); 3. Glaucoma. * **Imaging Gold Standard:** Contrast-enhanced **MRI** is the most sensitive investigation to detect leptomeningeal enhancement ("pial angiomatosis"). * **Skull X-ray finding:** Calcifications are usually not visible until after 2 years of age. * **Genetics:** Associated with a somatic mutation in the **GNAQ gene**.

Question 1

What is true regarding Cerebrospinal Fluid (CSF) on Magnetic Resonance Imaging (MRI)?

Accepted Answer

CSF appears hyper-intense on T2-weighted images.

Answer

CSF appears hyper-intense on T1-weighted images.

Answer

CSF appears hyper-intense on FLAIR images.

Answer

CSF appears hyper-intense on Diffusion-Weighted Images (DWI).

Question 2

Which of the following is not a MRI feature of Mesial temporal sclerosis?

Accepted Answer

Blurring of grey-white matter junction of ipsilateral temporal lobe

Answer

Atrophy of mammillary body

Answer

Atrophy of fornix

Answer

Atrophy of hippocampus

Question 3

Which imaging modality detects a brain infarct at the earliest?

Accepted Answer

Diffusion-weighted magnetic resonance imaging (DWI-MRI)

Answer

Non-contrast computed tomography (NCCT)

Answer

Contrast-enhanced computed tomography (CECT)

Answer

X-ray

Question 4

Which of the following views is recommended for radiological examination of the maxillary sinus?

Accepted Answer

Water's view

Answer

Caldwell view

Answer

Ferguson's view

Answer

Skyline view

Question 5

Medusa head appearance on MRI is seen in which of the following?

Accepted Answer

Venous angioma

Answer

Arteriovenous malformation

Answer

Cavernous hemangioma

Answer

Vein of Galen malformation

Question 6

Humming bird sign on MRI is seen in which of the following conditions?

Accepted Answer

Progressive supranuclear palsy

Answer

Multiple sclerosis

Answer

Developmental venous anomaly

Answer

All of the above

Question 7

A 9-year-old child presents with scoliosis, a hairy tuft in the skin of the back, and neurological deficit. Plain X-rays reveal multiple vertebral anomalies and a vertical bony spur overlying the lumbar spine on AP view. What is the most probable diagnosis?

Accepted Answer

Diastometamyelia

Answer

Dorsal dermal sinus

Answer

Tight filum terminale

Answer

Caudal regression syndrome

Question 8

Which imaging modality is the primary test for extradural hemorrhage?

Accepted Answer

Non-contrast computed tomography (NCCT)

Answer

Ultrasonography (USG)

Answer

Doppler ultrasonography

Answer

X-ray pelvis

Question 9

Computed tomography (CT) is useful in the formulation of a treatment plan of blow-out fractures because:

Accepted Answer

CT can fairly accurately determine the size of the fracture and its relationship to the orbital soft tissues.

Answer

It is the only way to diagnose an orbital fracture.

Answer

Coexistent sinus disease can be evaluated.

Answer

Magnetic resonance imaging is superior to CT in the evaluation of orbital fractures.

Question 10

Tram line calcification seen in skull X-ray are characteristic of:

Accepted Answer

Sturge Weber Syndrome

Answer

Congenital cytomegalovirus infection

Answer

Congenital toxoplasmosis

Answer

Craniopharyngioma

Neuroradiology — MCQs

Neuroradiology — MCQs

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