Part E

Question 1

In a 1 Tesla scanner, the precessional frequency of hydrogen is approximately:
a) 63.8MHz
b) 21.3MHz
c) 42.6MHz
d) 10.0 MHz

Answer 1

c) 42.6MHz

Question 2

The amount of energy necessary to produce a 90 degree flip angle is determined by:
a) the strength of the B1 magnetic field
b) The characteristics of the coil used
c) the amplitude and duration of the RF pulse
d) all of the above

Answer 2

c) the amplitude and duration of the RF pulse

Question 3

The _____________ nucleus is most commonly used in clinical imaging
a) Helium
b) Hydrogen
c) Nitrogen
d) Carbon

Answer 3

b) Hydrogen

Question 4

Using Faraday’s law of induction - A changing magnetic field causes the induction of an electric potential or voltage
a) true
b) false

Answer 4

a) true

Question 5

Distorted gradient waveforms due to Eddy Currents will cause spatial misregistration and spatial blurring
a) True
b) False

Answer 5

a) True

Question 6

In MRI the term FID is the abbreviation for
a) Federal Income Decay
b) Free Induction Decay
c) Free Inversion Decomposition

Answer 6

b) Free Induction Decay

Question 7

K space is an array of numbers whose Fourier Transform generates the MR image
a) true
b) false

Answer 7

a) true

Question 8

Each distinct point in K-Space relates to an individual pixel in the transformed image.
a) true
b) false

Answer 8

b) false

Question 9

The central portion of K-space contains the highest spatial frequencies
a) true
b) false

Answer 9

b) false

Question 10

If the frequency adjustment is inaccurate it will have an effect upon the spatial localisation within the image.
A) true
B) false

Answer 10

A) true

Question 11

Which of the following is not considered an intrinsic component of image contrast
a) tissue T1 and T2
b) proton density
c) Periodic physiological motion
d) TR

Answer 11

D) TR

Question 12

Cross talk refers to the interference between adjacent slices. One of the possible causes of this is due to non-rectangular RF pulses being used for slice selection
A) true
B) false

Answer 12

b) false

Question 13

The frequency encoding gradient used in a typical spin echo sequence is applied twice. It has a rephrasing and read out component
a) true
b) false

Answer 13

b) false

Question 14

The determination of SNR is total signal within a ROI divided by the standard deviation of the noise within a ROI.
A) true
B) false

Answer 14

a) true

Question 15

A patient presents for a lumbar spine examination - what options can you use to reduce the effect of physiological motion degrading your sagittal T1 image.
a) swap phase and frequency direction
b) employ pre saturation pulses anterior to the spine
c) use respiratory compensation or triggering
d) all of the above

Answer 15

b) employ pre saturation pulses anterior to the spine

Question 16

The chemical shift artefact occurs in the phase encoding direction. True or False

Answer 16

False, occurs in the frequency encoding direction

Question 17

Which of the following receiver bandwidths would produce the greatest amount of chemical shift.
a) 85Hz/pixel
b) 326 Hz/pixel
c) 55 Hz/pixel
d) all the same

Answer 17

c) 55Hz/pixel

Question 18

The Gyromagnetic ratio of a substance varies in different field strengths
a) false
b) true

Answer 18

a) false

Question 19

The resonant frequency type of chemical shift is related to the receive bandwidth used.
a) true
b) false

Answer 19

a) true

Question 20

A patient has a wire suture at the site of a laminectomy and you must perform a T1 weighted axial image. Which of the following will produce images with the least distortion due to this wire.
a) Conventional T1
b) Fast suppressed GRE
c) GRE
d) Fast SE T1

Answer 20

D) fast SE t1
FSE sequences = magnetic susceptibility artefacts decreased and motion artefact increases

Question 21

How much of an increase in RF power is needed to double the flip angle
a) 2 times
b) 4 times
c) 1.41 times
d) 3 times

Answer 21

a) 2 times

Question 22

Net magnetisation is transferred from the longitudinal plane to which plane after the 90 degree RF pulse
a) inverted 180
b) transverse
c) parasagittal
d) oblique

Answer 22

b) transverse

Question 23

T1 (longitudinal) relaxation is a _________ of magnetisation?
a) growth
b) decay
c) steady state
d) FID

Answer 23

a) growth

Question 24

Hydrogen nuclei have _____ spin states
a) 2
b) 4
c) 6
d) 8

Answer 24

a) 2

Question 25

An increase in the number of phase encoding steps is proportional to an increase in scan time

Answer 25

True

Question 26

In an MR system that uses shim coils, B0 homogeneity is adjusted by: a) changing current in the shim coils b) adding metal to different coils within the shim coil c) changing the temperature the shim coils d) turning the shim coils on and off rapidly

Answer 26

b) adding metal to different coils within the shim coils

Question 27

Which of the following tissues has the shortest T2 time. a) CSF b) grey matter c) fat d) flowing blood

Answer 27

c) fat

Question 28

The gradient coil oriented so as to produce a gradient magnetic field in the head - foot direction is known as the _______ direction? a) x b) y c) z d) axial

Answer 28

c) z direction

Question 29

When the TR is must shorter than the T1 and T2 of tissues, a condition known as ______ exists. a) saturation b) steady state c) equilibrium d) none of the above

Answer 29

b) steady state

Question 30

Complete saturation is a condition where ________ a) not enough time is given to allow T2 decay to complete b) The image becomes brighter c) longitudinal magnetisation is not allowed to recover between excitations d) proton density effects predominate

Answer 30

c) longitudinal magnetisation Is not allowed to recover between excitations