Chapter 2 Flashcards
Image weighting & contrast
The T1 process is also known as:
a. Spin-spin
b. Spin density
c. Spin-lattice
d. Spin-warp
c. Spin-lattice
The T2 process is also known as:
a. Spin-spin
b. Spin density
c. Spin-lattice
d. Spin-warp
a. Spin-spin
T1 relaxation time is defined as:
a. 37% of the longitudinal magnetization has regrown
b. 63% of the transverse magnetization has decayed
c. 37% of the transverse magnetization has decayed
d. 63% of the longitudinal magnetization has regrown
d. 63% of the longitudinal magnetization has regrown
Repetition time is the parameter that is manipulated to control what relaxation?
a. T2
b. T2*
c. T1
d. PD
c. T1
Tissues with long T1 times regain their longitudinal magnetization:
a. Completely
b. Partially
c. Quickly
d. Slowly
d. Slowly
The rate of regrowth of the net magnetization along the longitudinal direction is known as:
a. T2*
b. resonance
c. T1
d. repetition time
c. T1
The decay of magnetization from the x-y plane is known as:
a. Spin-spin Relaxation
b. Spin-lattice Relaxation
c. Longitudinal relaxation
d. T1 relaxation
a. Spin-spin Relaxation
The phenomenon in which the transverse magnetization decays is called:
a. T1 Relaxation
b. precession
c. T2 Relaxation
d. resonance
c. T2 Relaxation
The phenomenon in which one proton transfers energy to another is called:
a. Rephasing
b. Precession
c. Dephasing
d. Spin-spin interaction
d. Spin-spin interaction
MTC saturation band is used to:
a. Diminish partial volume averaging
b. Improve spatial resolution
c. Saturate free protons
d. Saturate bound protons
d. Saturate bound protons
Bound protons tend to have shorter T1 and T2 relaxation times than free protons.
a. True
b. False
a. True
Which of the following parameters control the amount of contrast seen in an image due to T2 relaxation?
a. TE
b. TR
c. TI
d. None of these
a. TE
What type of contrast would result from combining a long TR and a long TE?
a. T1 contrast
b. T2 contrast
c. Proton Density contrast
d. None of these
b. T2 contrast
On a T2 weighted image, CSF appears bright since it has a:
a. short T2 relaxation time
b. short T1 relaxation time
c. long T2 relaxation time
d. long T1 relaxation time
c. long T2 relaxation time
What type of contrast would result from combining a short TR and a short TE:
a. T1 contrast
b. T2 contrast
c. Proton Density
d. None of these
a. T1 contrast
Full saturation results when:
a. The signal relaxes to 90 degrees
b. The NMV is pushed to 180 degrees
c. A variable flip angle is used
d. None of these
b. The NMV is pushed to 180 degrees
Partial saturation occurs:
a. After the excitation pulse
b. After the rephasing pulse
c. Before the TE is received
d. With a flip angle larger than 90 degrees
d. With a flip angle larger than 90 degrees
Flip angles are affected by:
a. Strength and duration of the RF pulse
b. T1 & T2 parameters of the receiving signal
c. Proton Density
d. Echo time
a. Strength and duration of the RF pulse
With a proton density weighted study:
a. Low density tissues appear bright
b. High density tissues appear bright
c. High density tissues appear dark
d. Low density tissues induce a large signal in the coil
b. High density tissues appear bright
A long TR and a short TE results in:
a. A T1 weighted image
b. A PD weighted image
c. A T2 weighted image
d. A gradient image
b. A PD weighted image
Tissues efficient at both T1 and T2 interactions and have low (short) relaxation times, therefore have:
a. High T1 values
b. High relaxation rates
c. High T2 values
d. Low relaxation rates
b. High relaxation rates
As the NMV precesses within the transverse plane, it induces an electrical current in a:
a. Gradient coil
b. Shim coil
c. B0
d. Radio-frequency coil
d. Radio-frequency coil
Once the NMV has moved away from equilibrium, the following will occur:
a. The longitudinal component will increase
b. The transverse component will decrease
c. The longitudinal component will stay the same
d. The transverse component will increase
d. The transverse component will increase
__________ contrast parameters are those that cannot be changed because they are inherent to the body’s tissues.
a. Extrinsic
b. TR
c. Intrinsic
d. TE
c. Intrinsic
Fat molecules consist of large molecules, closely packed together, called:
a. Histidines
b. Lipids
c. Glycines
d. Steroids
b. Lipids
Images characterized by bright fat and dark water are:
a. T1 weighted
b. T2 weighted
c. Proton density weighted
d. Nuclear density weighted
a. T1 weighted
The intrinsic contrast mechanism with regard to fMRI is:
a. Faraday’s law of induction
b. chemical shift
c. flow-related enhancement
d. the BOLD effect
d. the BOLD effect
Abnormal tissue has a high ADC (restricted diffusion) and high signal.
a. True
b. false
b. false
Blood oxygenation level ________ (BOLD) produces MR signal intensity changes between stimulus and rest.
a. dependent
b. dosage
c. diffusion
d. data
a. dependent
Which of the following would result in an image with the greatest amount of diffusion weighting?
a. b-value 750
b. b-value 450
c. b-value 825
d. b-value 1100
d. b-value 1100
The main purpose of producing an ADC map is to:
a. reduce the contribution from diffusion effects
b. eliminate T2 shine-through
c. increase SNR
d. reduce T1 weighting
b. eliminate T2 shine-through
Changing the b-value alters the:
a. amplitude, timing and/or duration of the diffusion gradients
b. amplitude of the phase encoding gradient
c. length of the readout gradient
d. spatial resolution
a. amplitude, timing and/or duration of the diffusion gradients
The term used to describe the movement of molecules in the extra-cellular space due to random thermal motion is:
a. transference
b. osmosis
c. diffusion
d. perfusion
c. diffusion
In a spin echo pulse sequence by decreasing the TR from 2000 ms to 600 ms, which of the following is the end result?
a. a stronger MRI signal
b. few protons would experience spin-spin interaction
c. better tissue contrast based on the tissue T2 characteristics
d. better tissue contrast based on the tissue T1 characteristics
d. better tissue contrast based on the tissue T1 characteristics
The most serious risk of GBCA’s is
a. extravasation
b. nephrogenic systemic fibrosis
c. adverse reaction
d. allergic reaction
b. nephrogenic systemic fibrosis
Nephrogenic systemic fibrosis has been reported only in patients with
a. normal kidney function
b. diabetes
c. serious decreased renal function
d. high blood pressure
c. serious decreased renal function
The mechanism of T2 contrast enhancements agents is to:
a. Increase T2 relaxation time, therefore producing low signal
b. decrease T2 relaxation time, therefore producing low signal
c. increase T2 relaxation time, therefore producing high signal
d. decrease T2 relaxation time, therefore producing high signal
b. decrease T2 relaxation time, therefore producing low signal
The mechanism of T1 contrast enhancements agents is to:
a. increase T1 relaxation time, therefore producing low signal
b. decrease T1 relaxation time, therefore producing low signal
c. increase T1 relaxation time, therefore producing high signal
d. decrease T1 relaxation time, therefore producing high signal
d. decrease T1 relaxation time, therefore producing high signal
Gadolinium is a rare earth metal (lanthanide), more commonly known as a _______ metal.
a. base
b. heavy
c. noble
d. precious
b. heavy
Extrinsic contrast parameters include all expect:
a. TR
b. Flow
c. TE
d. b value
b. Flow