Computed Tomography Test Computed Tomography 2

Question 1

Which CT artifact is caused by two high-density objects lying in the same scan plane?

Accepted Answer

Beam hardening artifact

Answer

Beam hardening occurs when polychromatic X-rays are differentially absorbed, causing dark streaks between dense structures like metal implants or dense bone.

Question 2

What does the term 'pitch' refer to in helical CT scanning?

Accepted Answer

The table distance traveled per gantry rotation divided by beam collimation

Answer

Pitch is calculated as table feed per rotation divided by total beam collimation width; a pitch of 1 means the table moves exactly one beam width per rotation.

Question 3

Which window setting is most appropriate for evaluating pulmonary nodules?

Accepted Answer

Lung window (WW 1500, WL -600)

Answer

The lung window uses a wide window width and low window level to optimize contrast between air-filled lung parenchyma and soft tissue nodules.

Question 4

What is the primary purpose of a bow-tie filter in a CT scanner?

Accepted Answer

To shape the X-ray beam and reduce dose to peripheral tissues

Answer

A bow-tie (wedge) filter is thicker at the edges to attenuate X-rays where the patient cross-section is thinner, reducing peripheral skin dose and detector saturation.

Question 5

A patient with a creatinine level of 2.8 mg/dL is scheduled for contrast-enhanced CT. What is the most appropriate next step?

Accepted Answer

Consult with the ordering physician regarding contrast risk and alternatives

Answer

Elevated creatinine indicates reduced renal function and significant risk of contrast-induced nephropathy; the ordering physician must be consulted to weigh risk versus benefit.

Computed Tomography Test Practice Test

Computed Tomography Test Practice Test

Computed Tomography Test Computed Tomography 2