Computed Tomography Test Computed Tomography (CT Brain) 3

Question 1

On CT brain, the normal Hounsfield unit (HU) range for white matter is approximately:

Accepted Answer

20–30 HU

Answer

White matter typically measures 20–30 HU, slightly lower than gray matter (30–40 HU) due to its higher myelin lipid content.

Question 2

A ring-enhancing lesion in the brain on post-contrast CT with surrounding edema in an immunocompromised patient most likely represents:

Accepted Answer

Toxoplasma abscess

Answer

Toxoplasmosis is the most common ring-enhancing lesion in immunocompromised (HIV/AIDS) patients, presenting as multiple ring-enhancing lesions.

Question 3

Which type of brain herniation is characterized by downward displacement of the cerebellar tonsils through the foramen magnum on CT?

Accepted Answer

Tonsillar herniation

Answer

Tonsillar herniation occurs when increased posterior fossa pressure drives the cerebellar tonsils through the foramen magnum, compressing the brainstem.

Question 4

On CT brain, 'sulcal effacement' in one hemisphere most likely indicates:

Accepted Answer

Cerebral edema causing compression of sulci

Answer

Sulcal effacement occurs when edema or a mass expands the brain hemisphere, compressing and obliterating normal cortical sulci.

Question 5

A CT of the head shows enlargement of all four ventricles with periventricular hypodensity. The most likely diagnosis is:

Accepted Answer

Communicating hydrocephalus with transependymal edema

Answer

Communicating hydrocephalus causes symmetric dilation of all ventricles and periventricular hypodensity from transependymal CSF migration.

Computed Tomography Test Practice Test

Computed Tomography Test Practice Test

Computed Tomography Test Computed Tomography (CT Brain) 3