Random

Question 1

Center of K space contains …

Answer 1

Lower spatial frequencies - info about spatial contrast (what is bright versus dark)

Question 2

Periphery of K space contains …

Answer 2

Higher spatial frequencies - fine details of image (borders of structures) *undersampling can lead to truncation artifact i.e. Gibbs

Question 3

How can you reduce susceptibility artifact from metallic hardware?

Answer 3

• Increase bandwidth
• Orient frequency encoding direction parallel to long access of the hardware
• Increase FOV
• Decrease voxel size
• Decrease slice thickness
• Decrease echo time
• Maximize echo train length

Question 4

Effect of decreasing bandwith

Answer 4

improved signal to noise

more metal artifact, more chemical shift artifact

Question 5

Alpha decay results in the release of ___

Answer 5

Alpha particle - 2 neutrons and 2 protons (same as He)

• heavy, least penetrating (“alpha males”) but higher linear energy transfer compared to beta and gamma
• for these reasons not used in clinical imaging

Question 6

Formula for Lamour frequency

Answer 6

ω₀ = γ · B₀ (with ω₀ being Larmor frequency, γ being the gyromagnetic ratio for element being imaged, and B₀ being the strength of the magnetic field)

Can be further modulated by local interactions (chemical shift)