Neurologists Exam Cerebrovascular Disease & Stroke 2

Question 1

Which neuroimaging modality has the highest sensitivity for detecting acute ischemic stroke within the first 6 hours of onset?

Accepted Answer

MRI diffusion-weighted imaging (DWI)

Answer

MRI DWI detects cytotoxic edema (restricted diffusion) within minutes of ischemic onset and has >95% sensitivity for acute ischemia, far exceeding CT which is primarily used to exclude hemorrhage.

Question 2

On non-contrast CT, acute intraparenchymal hemorrhage appears as:

Accepted Answer

A hyperdense (bright) region

Answer

Acute blood appears hyperdense (bright white) on non-contrast CT due to the high protein content of clotted hemoglobin, typically 55–90 Hounsfield units.

Question 3

The 'hyperdense MCA sign' on non-contrast CT in acute stroke represents:

Accepted Answer

Acute thrombus within the middle cerebral artery lumen

Answer

The hyperdense MCA sign reflects acute thrombus within the MCA lumen, which appears denser than surrounding brain tissue, and is an early CT indicator of large vessel occlusion.

Question 4

In acute stroke perfusion imaging, the 'penumbra' is defined as:

Accepted Answer

The ischemic but potentially salvageable tissue surrounding the infarct core

Answer

The ischemic penumbra is metabolically compromised but structurally intact tissue surrounding the infarct core; it remains viable temporarily and is the target of reperfusion therapy.

Question 5

Which cardiac condition is the most common identifiable cause of cardioembolic stroke?

Accepted Answer

Atrial fibrillation

Answer

Atrial fibrillation accounts for approximately 15–20% of all ischemic strokes and is the most common identified cardiac source of cerebral emboli, particularly in older patients.

Neurologists Exam Practice Test

Neurologists Exam Practice Test

Neurologists Exam Cerebrovascular Disease & Stroke 2