Computed Tomography Test Computed Tomography Knowledge Questions and An 4

Question 1

What is the primary safety concern when scanning a patient with a pacemaker using CT?

Accepted Answer

Potential image artifacts affecting diagnostic quality

Answer

While CT does not emit RF waves that affect pacemaker function, metallic pacemaker components cause streak artifacts that can limit evaluation of surrounding cardiac and mediastinal structures.

Question 2

What is meant by 'isotropic voxels' in CT imaging?

Accepted Answer

Voxels with equal dimensions in all three spatial planes (x, y, z)

Answer

Isotropic voxels have equal length, width, and height, enabling high-quality multiplanar and 3D reconstructions without resolution loss in any plane.

Question 3

A technologist notes that a CT image has a mottled, grainy appearance. Which adjustment would most directly improve this?

Accepted Answer

Increase mAs

Answer

Increasing mAs increases X-ray photon flux, reducing quantum (photon) noise and improving the signal-to-noise ratio of the image.

Question 4

Which structure should be visible in a CT scan performed at the level of the carina?

Accepted Answer

Bifurcation of the trachea into the left and right main bronchi

Answer

The carina is the cartilaginous ridge at the inferior end of the trachea marking its bifurcation into the left and right main bronchi, located at approximately T4–T5.

Question 5

What is the role of iterative reconstruction (IR) in modern CT imaging?

Accepted Answer

To reduce image noise at lower radiation doses compared to filtered back projection

Answer

Iterative reconstruction algorithms model the acquisition process and iteratively correct image data, enabling diagnostic image quality at significantly reduced radiation doses.

Computed Tomography Test Practice Test

Computed Tomography Test Practice Test

Computed Tomography Test Computed Tomography Knowledge Questions and An 4