MRI Physics Final Exam with all Correct & 100% Verified
Answers |Actual Complete Exam| Already Graded A+
As the B0 increases, SNR will ✔Correct Answer-Increase
The scan time can be determined by ✔Correct Answer-1. NEX
2. Number of phase encoding
The precessional difference between hydrogen in fat and hydrogen in water in a 1.5 T magnet is
✔Correct Answer-224 Hz
A chemical shift phenomenon that is useful to void signal from fat is known as ✔Correct Answer-
fat saturation
What effect does increasing TE have on SNR? ✔Correct Answer-decrease it
In a 1T magnet, fat and water will be "in phase" respectively at a TE of ____ msec. ✔Correct
Answer-6.7
A broad receiver bandwidth will contain less noise than a narrow bandwidth. ✔Correct Answer-
False
The precessional difference in ppm between hydrogen in fat and hydrogen in water is ✔Correct
Answer-3.5 ppm
Which of the following pulse sequence does not use a 180 degree refocusing RF pulse? ✔Correct
Answer-gradient echo
Doubling the NEX will increase the SNR by what factor? ✔Correct Answer-1. 1.41
3. SQR Root of 2
Increasing the slice thickness from 5mm to 10 mm will decrease SNR ✔Correct Answer-false
Increasing the TR will have what kind of affect on the image? ✔Correct Answer-1. decrease T1-
weighting contrast
3. Increase SNR
If NEX is doubled, scan time will be cut in half and the SNR will decrease by 41%. ✔Correct Answer-
False
Quadrature could provide a 41% increase in SNR over linear coils. ✔Correct Answer-True
Which of the following gradient oscillates between positive and negative amplitudes in EPI?
✔Correct Answer-frequency encoding gradient
Which of the following statements are true? ✔Correct Answer-2. Noise depends on the build of
the patient and the area under examination and the inherent noise of the system.
3. Noise occurs at all frequencies and is random in time
, What type of imaging uses the acronyms SENSE, GRAPPA, and iPAT? ✔Correct Answer-parallel
imaging
Which of the following factors determine the size of the voxel? ✔Correct Answer-the slice
thickness and the number of pixels
Echo planar imaging uses various schemes to fill the entire k-space or at least a large portion of space
in a single TR ✔Correct Answer-true
What effect does decreasing the receiver bandwidth have on SNR? ✔Correct Answer-increase it
The ratio of the amplitude of the signal received to the average amplitude of the noise is called ____
✔Correct Answer-SNR ratio
The difference in SNR between two adjacent tissues known as ___ ✔Correct Answer-CNR
SNR is a type of sequence that begins with a 180 RF inversion pulse that is applied at the specific
precessional frequency of hydrogen in fat. ✔Correct Answer-True
Which of the following sequence does not use inversion recovery technique? ✔Correct Answer-1.
ABSIR
In a 2D imaging slice acquisition, scan time is given by which of the following equation? ✔Correct
Answer-TR x number of phase steps x NEX
Changing the number of phase encoding steps will directly affect which of the following? ✔Correct
Answer-scan time
Due to its high susceptibility to paramagnetic substances, which of the following sequence is
particularly useful to image hemorrhage? ✔Correct Answer-gradient echo
Gradient echo sequences produce a better SNR than spin echo sequences. ✔Correct Answer-False
Which of the following type of sequence can deliver up to four contrasts in one measurement in-
phase, out-of-phase, water and fat images? ✔Correct Answer-Dixon
In an IR pulse sequence, the time between initializing the 180 pulse and the 90 pulse is known as
✔Correct Answer-TI
void signal from fat ✔Correct Answer-STIR
recovery of longitudinal relaxation ✔Correct Answer-T1 relaxation
affected by magnetic field inhomogeneities ✔Correct Answer-T2* decay
void signal from fluid ✔Correct Answer-FLAIR
loss of transverse magnetization ✔Correct Answer-T2 relaxation
In GRE, the spine are mainly rephrased by the ___ to produce the signal (echo) ✔Correct Answer-
FEG
Answers |Actual Complete Exam| Already Graded A+
As the B0 increases, SNR will ✔Correct Answer-Increase
The scan time can be determined by ✔Correct Answer-1. NEX
2. Number of phase encoding
The precessional difference between hydrogen in fat and hydrogen in water in a 1.5 T magnet is
✔Correct Answer-224 Hz
A chemical shift phenomenon that is useful to void signal from fat is known as ✔Correct Answer-
fat saturation
What effect does increasing TE have on SNR? ✔Correct Answer-decrease it
In a 1T magnet, fat and water will be "in phase" respectively at a TE of ____ msec. ✔Correct
Answer-6.7
A broad receiver bandwidth will contain less noise than a narrow bandwidth. ✔Correct Answer-
False
The precessional difference in ppm between hydrogen in fat and hydrogen in water is ✔Correct
Answer-3.5 ppm
Which of the following pulse sequence does not use a 180 degree refocusing RF pulse? ✔Correct
Answer-gradient echo
Doubling the NEX will increase the SNR by what factor? ✔Correct Answer-1. 1.41
3. SQR Root of 2
Increasing the slice thickness from 5mm to 10 mm will decrease SNR ✔Correct Answer-false
Increasing the TR will have what kind of affect on the image? ✔Correct Answer-1. decrease T1-
weighting contrast
3. Increase SNR
If NEX is doubled, scan time will be cut in half and the SNR will decrease by 41%. ✔Correct Answer-
False
Quadrature could provide a 41% increase in SNR over linear coils. ✔Correct Answer-True
Which of the following gradient oscillates between positive and negative amplitudes in EPI?
✔Correct Answer-frequency encoding gradient
Which of the following statements are true? ✔Correct Answer-2. Noise depends on the build of
the patient and the area under examination and the inherent noise of the system.
3. Noise occurs at all frequencies and is random in time
, What type of imaging uses the acronyms SENSE, GRAPPA, and iPAT? ✔Correct Answer-parallel
imaging
Which of the following factors determine the size of the voxel? ✔Correct Answer-the slice
thickness and the number of pixels
Echo planar imaging uses various schemes to fill the entire k-space or at least a large portion of space
in a single TR ✔Correct Answer-true
What effect does decreasing the receiver bandwidth have on SNR? ✔Correct Answer-increase it
The ratio of the amplitude of the signal received to the average amplitude of the noise is called ____
✔Correct Answer-SNR ratio
The difference in SNR between two adjacent tissues known as ___ ✔Correct Answer-CNR
SNR is a type of sequence that begins with a 180 RF inversion pulse that is applied at the specific
precessional frequency of hydrogen in fat. ✔Correct Answer-True
Which of the following sequence does not use inversion recovery technique? ✔Correct Answer-1.
ABSIR
In a 2D imaging slice acquisition, scan time is given by which of the following equation? ✔Correct
Answer-TR x number of phase steps x NEX
Changing the number of phase encoding steps will directly affect which of the following? ✔Correct
Answer-scan time
Due to its high susceptibility to paramagnetic substances, which of the following sequence is
particularly useful to image hemorrhage? ✔Correct Answer-gradient echo
Gradient echo sequences produce a better SNR than spin echo sequences. ✔Correct Answer-False
Which of the following type of sequence can deliver up to four contrasts in one measurement in-
phase, out-of-phase, water and fat images? ✔Correct Answer-Dixon
In an IR pulse sequence, the time between initializing the 180 pulse and the 90 pulse is known as
✔Correct Answer-TI
void signal from fat ✔Correct Answer-STIR
recovery of longitudinal relaxation ✔Correct Answer-T1 relaxation
affected by magnetic field inhomogeneities ✔Correct Answer-T2* decay
void signal from fluid ✔Correct Answer-FLAIR
loss of transverse magnetization ✔Correct Answer-T2 relaxation
In GRE, the spine are mainly rephrased by the ___ to produce the signal (echo) ✔Correct Answer-
FEG
