Physics Chapter 7 - Parameters and Trade-offs exam 2024/2025 with 100% correct answers
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Course
Physics Chapter 7 - Parameters and Trade-offs
Institution
Physics Chapter 7 - Parameters And Trade-offs
MRI Protocol is defined as ____________ correct answers-Set of rules
- These rules in MRI are described as different pulse sequences within one exam that contain a variety of parameters.
- An average MRI protocol can have around 5 to 10 pulse sequences (ex: knee injury - two PD weighted sagit...
MRI Protocol is defined as ____________ correct answers-Set of rules
- These rules in MRI are described as different pulse sequences within one exam that contain a variety of
parameters.
- An average MRI protocol can have around 5 to 10 pulse sequences (ex: knee injury - two PD weighted
sagittal and coronal, two T2 weighted sagittal and coronal, and one T2 axial which are 5 different
sequences)
Name the 7 different parameters. correct answers-TR
-TE
-Flip Angle
-NEX
-Received Bandwidth
-FOV (field of view)
-Matrix
What is a trade-off? (or consequence) correct answersGiving up one thing for another
In MRI.... when we change a parameter to make another better, we sacrifice something or affect another
characteristic in some way. Trade-offs can be a positive effect or a negative effect.
(Ex: increasing NEX to get more SNR)
What is SNR? correct answersSignal to Noise Ratio
,It is the signal amplitude divided by the amplitude of noise.
What is the signal part in SNR? correct answersSignal is the amount of voltage induced in the coil at the
time the echo is collected (TE)
What is the noise part in SNR? correct answersNoise represents frequencies of RF energy that exist
randomly in time and space.
There is information there but not enough signal to tell what it is. Example: when you get too far from
the broadcasting source of a radio station.
Regarding SNR, anything that raises the signal will __________ the SNR?
A. raise
B. lower correct answersA. raise
Regarding SNR, anything that raises the noise will _____________ the SNR?
A. raise
B. lower correct answersB. lower
Regarding SNR, anything that lowers the noise will __________ the SNR?
A. raise
B. lower correct answersA. raise
Regarding SNR, anything that lowers the signal will ___________ the SNR?
A. raise
B. lower correct answersB. lower
, Signal is cumulative and predictable.
True or False? correct answersTrue
Noise is also predictable and is detected by the whole coil volume.
True or False? correct answersFalse - Noise is not predictable. It is, however, detected by the whole coil
volume.
The purpose of optimizing SNR is to make the contribution from __________ larger than that from
_____________.
A. noise/signal
B. signal/noise correct answersB. signal/noise
Noise is generated by the presence of the patient in the magnet, and the background electrical noise of
the system.
True or False? correct answersTrue
Noise is constant for the patient and depends on 3 things. What are they? correct answers1. Build of
patient
2. Area under examination
3. Inherent noise of the system
Noise occurs randomly at every frequency.
True or False? correct answersTrue
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