week 3 CT

Question 1

What determines how much of the object included in the reconstructible FOV in CT?

Answer 1

Fan beam angle.

Question 2

What is ct detectors measuring?

Answer 2

Attenuation coefficients of XR beams

Question 3

What is the minimum data set to reconstruct images in CT

Answer 3

180 degrees of data.

Question 4

whats the problem of back projection picture

Answer 4

Blurry

Question 5

What is reconstruction kernel?

Answer 5

High pass filter to remove noise.
Hard kernel for high contrast anatomy.
Soft kernel for low contrast anatomy.

Question 6

Risk of CT IV contrast

Answer 6

1. Patient adverse reaction
2. nephropathy
3. thyrotoxicosis

Question 7

time for circulation of IV contrast?
1. Pulmonary artery
2. aorta
3. portal system
4. IVC

Answer 7

1. ~10 secs
2. ~20 secs
3. ~60 secs
4. ~100 secs

Question 8

ways to determine contrast media arrival time

Answer 8

Test Bolus & Bolus tracking.

Question 9

strength of CT

Answer 9

fast and efficient.
High contrast.
Eliminate superimposition of XR.
Limited limitation of applications.

Question 10

Limitation of using CT

Answer 10

Exposure to ionising radiation.
Risk of tissue effects or stochastic effects
increased dependency
increased cost of health sectors

Question 11

Dual source Ct type

Answer 11

Dual source
ultra fast KV switching
sandwich detector

Question 12

What is infract core in CT

Answer 12

Prolonged MTT or Tmax in Ct perfusion. as a result of reduction of CBF and CBV

Question 13

Ischaemic penumbra

Answer 13

MTT prolonged.
CBF moderated reduced.
CBV normal or slightly increased.

Question 14

Benefits of PCCT

Answer 14

Higher spatial resolution, improved CNR, lower radiation dose.