MRI Quiz Imaging basics | QUESTIONS AND ANSWERS |
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Terms in this set (50)
What would the scan time be in a 3D volume acquisition D (3D scan time formula: TR x Phase
Matrix x NEX x # slices) as follows: TR 32 ms, TE 4 ms, Flip Angle 15°, FOV 18cm,
2mm slice thickness, 96 slices, 192 x 256 matrix, 1 NEX?
A. 4 min 28 sec B. 5 min 12 sec C. 8 min 42 sec D. 9
min 50 sec
Another name for a picture element is a: A. Voxel
B.
B Pixel C. Cubicle D. Filament
If a sequence with a matrix of 256 x 512 is D
adjusted to 512 x 512, A. The SNR will stay the
same B. The scan time will decrease C. The SNR
will increase and the scan time will decrease D.
The SNR will decrease and the scan time will
increase
Reducing the phase matrix from 256 to 192 D
will: A. Increase the signal-to-noise ratio B.
Decrease imaging time C. Decrease spatial
resolution D. All of the above
Reducing the number of lines filled in k-space A (Reducing the number of lines filled in k-space will produce an
will produce an image: A. With a decrease in image with a decrease in spatial resolution)
spatial resolution B. With an increase in spatial
resolution C. With an decrease in overall SNR D. A
and C
Choose the correct slice thickness to create B (An isotropic voxel has equal measurements in all three
an isotropic voxel for the following: TR 2000, dimensions (phase, frequency and slice direction) FOV/Matrix =
TE 90, Matrix 256 x 256, FOV 32cm. A. 0.75 mm 1.25mm)
B. 1.25 mm C. 2.00 mm D.
2.50 mm
, The timing of the RF pulses in an MRI pulse C
sequence controls: A. How long the procedure
takes B. Pixel size C. Image contrast D. Spatial
resolution
Water has a __________ T1 relaxation time and a B
________ T2 relaxation time. A. short; short B.
short; long C. long; short D. long; long
Calculate the voxel volume for the following B (To calculate voxel volume, first determine pixel area.
pulse sequence parameters: TR 450, TE 20, FOV/matrix x FOV/matrix = pixel area. Pixel area x slice thickness =
FOV 24cm, 320 x 320 matrix, 3mm slice voxel volume. 240/320 x 240/320 = 0.5625 mm2. 0.5625 x 3 =
thickness. A. 0.75mm3 B. 1.69mm3 1.69mm3)
C. 1.75mm3 D. 2.25mm3
All of the following would aid in reducing scan C
time EXCEPT: A. Utilizing the coarsest matrix
possible B. Reducing NEX C. Reducing TE D.
Increasing parallel imaging factor E. Setting TR to
shortest
All of the following affect acquisition time B
EXCEPT: A. TR B. TE C. NEX D. Matrix
Acquiring a bit more than half the phase k- D
space samples, then interpolating the data
with zeroes for the remaining half is a
technique known as: A. Half Fourier B. Zero fill C.
Fast spin echo D. A and/or B
Calculate the pixel area for the following B (FOV/matrix x FOV/matrix = pixel area. 280/304 x 280/304 = 0.85
sequence: TR 4000, TE 120, FOV 28cm, 304 x mm2.)
304 matrix, 2 NEX, ETL 12.
A. 0.76 mm2 B. 0.85 mm2 C. 0.92 mm2 D. 1.84 mm2
Calculate the pixel area for the following A (FOV/matrix x FOV/matrix = pixel area. 180/224 x 180/256 = 0.56
sequence: TR 450, TE 12, FOV 18cm, 224 x mm2)
256 matrix, 4 NEX. A. 0.56 mm2 B. 0.70 mm2 C.
0.80 mm2 D. 1.50 mm2
Calculate the voxel volume for the following D
pulse sequence: TR 2000, TE 85, FOV 28cm,
Matrix 272 x 320, 5mm slice thickness, 3 NSA.
A. 0.88 mm3 B. 1.03 mm3 C.
1.91mm3 D. 4.55 mm3
Assuming all other parameters are the same, A
an echo time of ms provides the best
Signal-to-Noise
Ratio. A. 15 B. 30 C. 80 D. 110
Assuming all other parameters are the same, a D
___________ms TR provides the best signal-to-
noise
ratio. A. 30 B. 200 C. 500 D. 800
Decreasing the TR will: A. Lower SNR B. D
Reduce scan time C. Increase SNR D. Both A and
B
LATEST UPDATE
Terms in this set (50)
What would the scan time be in a 3D volume acquisition D (3D scan time formula: TR x Phase
Matrix x NEX x # slices) as follows: TR 32 ms, TE 4 ms, Flip Angle 15°, FOV 18cm,
2mm slice thickness, 96 slices, 192 x 256 matrix, 1 NEX?
A. 4 min 28 sec B. 5 min 12 sec C. 8 min 42 sec D. 9
min 50 sec
Another name for a picture element is a: A. Voxel
B.
B Pixel C. Cubicle D. Filament
If a sequence with a matrix of 256 x 512 is D
adjusted to 512 x 512, A. The SNR will stay the
same B. The scan time will decrease C. The SNR
will increase and the scan time will decrease D.
The SNR will decrease and the scan time will
increase
Reducing the phase matrix from 256 to 192 D
will: A. Increase the signal-to-noise ratio B.
Decrease imaging time C. Decrease spatial
resolution D. All of the above
Reducing the number of lines filled in k-space A (Reducing the number of lines filled in k-space will produce an
will produce an image: A. With a decrease in image with a decrease in spatial resolution)
spatial resolution B. With an increase in spatial
resolution C. With an decrease in overall SNR D. A
and C
Choose the correct slice thickness to create B (An isotropic voxel has equal measurements in all three
an isotropic voxel for the following: TR 2000, dimensions (phase, frequency and slice direction) FOV/Matrix =
TE 90, Matrix 256 x 256, FOV 32cm. A. 0.75 mm 1.25mm)
B. 1.25 mm C. 2.00 mm D.
2.50 mm
, The timing of the RF pulses in an MRI pulse C
sequence controls: A. How long the procedure
takes B. Pixel size C. Image contrast D. Spatial
resolution
Water has a __________ T1 relaxation time and a B
________ T2 relaxation time. A. short; short B.
short; long C. long; short D. long; long
Calculate the voxel volume for the following B (To calculate voxel volume, first determine pixel area.
pulse sequence parameters: TR 450, TE 20, FOV/matrix x FOV/matrix = pixel area. Pixel area x slice thickness =
FOV 24cm, 320 x 320 matrix, 3mm slice voxel volume. 240/320 x 240/320 = 0.5625 mm2. 0.5625 x 3 =
thickness. A. 0.75mm3 B. 1.69mm3 1.69mm3)
C. 1.75mm3 D. 2.25mm3
All of the following would aid in reducing scan C
time EXCEPT: A. Utilizing the coarsest matrix
possible B. Reducing NEX C. Reducing TE D.
Increasing parallel imaging factor E. Setting TR to
shortest
All of the following affect acquisition time B
EXCEPT: A. TR B. TE C. NEX D. Matrix
Acquiring a bit more than half the phase k- D
space samples, then interpolating the data
with zeroes for the remaining half is a
technique known as: A. Half Fourier B. Zero fill C.
Fast spin echo D. A and/or B
Calculate the pixel area for the following B (FOV/matrix x FOV/matrix = pixel area. 280/304 x 280/304 = 0.85
sequence: TR 4000, TE 120, FOV 28cm, 304 x mm2.)
304 matrix, 2 NEX, ETL 12.
A. 0.76 mm2 B. 0.85 mm2 C. 0.92 mm2 D. 1.84 mm2
Calculate the pixel area for the following A (FOV/matrix x FOV/matrix = pixel area. 180/224 x 180/256 = 0.56
sequence: TR 450, TE 12, FOV 18cm, 224 x mm2)
256 matrix, 4 NEX. A. 0.56 mm2 B. 0.70 mm2 C.
0.80 mm2 D. 1.50 mm2
Calculate the voxel volume for the following D
pulse sequence: TR 2000, TE 85, FOV 28cm,
Matrix 272 x 320, 5mm slice thickness, 3 NSA.
A. 0.88 mm3 B. 1.03 mm3 C.
1.91mm3 D. 4.55 mm3
Assuming all other parameters are the same, A
an echo time of ms provides the best
Signal-to-Noise
Ratio. A. 15 B. 30 C. 80 D. 110
Assuming all other parameters are the same, a D
___________ms TR provides the best signal-to-
noise
ratio. A. 30 B. 200 C. 500 D. 800
Decreasing the TR will: A. Lower SNR B. D
Reduce scan time C. Increase SNR D. Both A and
B
