MRI Physics Final Exam 2024/2025(Questions With 100% Correct Answers)A+ Graded Verified
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Course
MRI Physics
Institution
MRI Physics
As the B0 increases, SNR will - ANSWER Increase
The scan time can be determined by - 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 - ANSWER 224 Hz
MRI Physics Final Exam 2024/2025(Questions With
100% Correct Answers)A+ Graded Verified
As the B0 increases, SNR will - ANSWER Increase
The scan time can be determined by - 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
- ANSWER 224 Hz
A chemical shift phenomenon that is useful to void signal from fat is known as - ANSWER fat
saturation
What effect does increasing TE have on SNR? - ANSWER decrease it
In a 1T magnet, fat and water will be "in phase" respectively at a TE of ____ msec. -
ANSWER 6.7
A broad receiver bandwidth will contain less noise than a narrow bandwidth. - ANSWER
False
The precessional difference in ppm between hydrogen in fat and hydrogen in water is -
ANSWER 3.5 ppm
Which of the following pulse sequence does not use a 180 degree refocusing RF pulse? -
ANSWER gradient echo
Doubling the NEX will increase the SNR by what factor? - ANSWER 1. 1.41
3. SQR Root of 2
Increasing the slice thickness from 5mm to 10 mm will decrease SNR - ANSWER false
Increasing the TR will have what kind of affect on the image? - 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%. - ANSWER
False
Quadrature could provide a 41% increase in SNR over linear coils. - ANSWER True
, Which of the following gradient oscillates between positive and negative amplitudes in EPI? -
ANSWER frequency encoding gradient
Which of the following statements are true? - 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? - ANSWER parallel
imaging
Which of the following factors determine the size of the voxel? - 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 - ANSWER true
What effect does decreasing the receiver bandwidth have on SNR? - ANSWER increase it
The ratio of the amplitude of the signal received to the average amplitude of the noise is called
____ - ANSWER SNR ratio
The difference in SNR between two adjacent tissues known as ___ - 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. - ANSWER True
Which of the following sequence does not use inversion recovery technique? - ANSWER 1.
ABSIR
In a 2D imaging slice acquisition, scan time is given by which of the following equation? -
ANSWER TR x number of phase steps x NEX
Changing the number of phase encoding steps will directly affect which of the following? -
ANSWER scan time
Due to its high susceptibility to paramagnetic substances, which of the following sequence is
particularly useful to image hemorrhage? - ANSWER gradient echo
Gradient echo sequences produce a better SNR than spin echo sequences. - 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? - ANSWER Dixon
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