Computed Tomography Test Computed Tomography (CT Brain) 2 — Questions and Answers
Question 1: On a non-contrast CT brain, a hyperdense (bright) lesion within the basal ganglia most likely represents:
- Acute hemorrhage (Correct answer)
- Subacute infarction
- Metastatic lesion
- Demyelinating plaque
Correct answer: Acute hemorrhage
Acute blood is hyperdense on non-contrast CT due to the high protein content of clotted hemoglobin.
Question 2: Which CT finding is most characteristic of a subdural hematoma compared to an epidural hematoma?
- Crescent-shaped collection that crosses suture lines (Correct answer)
- Biconvex lenticular hyperdense collection
- Midline hyperdense lesion
- Rim-enhancing lesion after contrast
Correct answer: Crescent-shaped collection that crosses suture lines
Subdural hematomas form a crescent shape and follow the brain contour, crossing suture lines, unlike the lenticular epidural hematoma.
Question 3: A CT brain shows a hypodense wedge-shaped area in the right MCA territory that does not enhance. This pattern is most consistent with:
- Subacute ischemic infarction (Correct answer)
- Glioblastoma multiforme
- Cerebral abscess
- Arteriovenous malformation
Correct answer: Subacute ischemic infarction
A wedge-shaped hypodensity in a vascular territory without enhancement is classic for subacute ischemic infarction following blood-brain barrier breakdown.
Question 4: The 'hyperdense MCA sign' on non-contrast CT brain indicates:
- Acute thrombus within the middle cerebral artery (Correct answer)
- Calcification of the MCA wall
- Arteriovenous malformation involving the MCA
- Contrast material within the MCA from prior study
Correct answer: Acute thrombus within the middle cerebral artery
The hyperdense MCA sign reflects acute thrombus in the proximal MCA lumen, an early sign of large-vessel occlusion.
Question 5: On CT brain, which structure normally appears hyperdense (bright) without contrast administration?
- Choroid plexus (Correct answer)
- White matter
- Cortical gray matter
- CSF in ventricles
Correct answer: Choroid plexus
The choroid plexus is normally hyperdense due to its highly vascular nature and calcification in adults.
Question 6: A patient presents with thunderclap headache. CT brain shows hyperdense material in the basal cisterns. The most likely diagnosis is:
- Subarachnoid hemorrhage (Correct answer)
- Basilar meningitis
- Bilateral subdural hematomas
- Cerebral venous thrombosis
Correct answer: Subarachnoid hemorrhage
Subarachnoid hemorrhage classically presents with thunderclap headache and appears as hyperdensity filling the basal cisterns on CT.
Question 7: Which window setting is most appropriate for evaluating brain parenchyma on CT?
- Window width 80 HU, level 40 HU (Correct answer)
- Window width 400 HU, level 40 HU
- Window width 2000 HU, level 600 HU
- Window width 1500 HU, level -600 HU
Correct answer: Window width 80 HU, level 40 HU
A narrow window (80 HU width) centered at 40 HU maximizes contrast between gray matter, white matter, and CSF for brain evaluation.
Computed Tomography Test Computed Tomography (CT Brain) 2
On a non-contrast CT brain, a hyperdense (bright) lesion within the basal ganglia most likely represents: