2434121
Pregunta 1
Pregunta
The scan time for a 3D acquisition is given by:
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TR X NEX X phase encodings X number of slices
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TR X NEX X phase encodings X slice thickness
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(TR X NEX X phase encodings)/echo train length
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TR X NEX X phase encodings
Pregunta 2
Pregunta
The scan time for a 2D acquisition is determined by:
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TR X NEX X phase encodings X FOV
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TR X NEX X phase encodings X number of slices
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TR X NEX X phase encodings X slice thickness
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TR X NEX X phase encodings
Pregunta 3
Pregunta
During a conventional spin echo exam, one line of k-space is filled each
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frequency encoding period
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TE period
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TR period
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TI period
Pregunta 4
Pregunta
Noise represents
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current induced in the phase encoding gradient
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frequencies that exist randomly in space and time
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frequencies that exist in a structured environment at a specific location
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Un-captured voltage potential
Pregunta 5
Pregunta
Changing the size of a voxel in the frequency direction will
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have no effect on the scan time
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double the scan time
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increase the scan time by a factor of 0.5
Pregunta 6
Pregunta
What is the slice thickness for an isotropic voxel with a 20 cm field of view and a 256 X 256 matrix
Respuesta
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13 cm
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0.8 mm
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3 cm
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1.3 mm
Pregunta 7
Pregunta
Where in a spin echo pulse sequence are pre-saturation pulses usually placed?
Respuesta
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after the excitation pulse
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after the 180 degree RF pulse
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between the 90 degree and 180 degree RF pulse
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prior to the excitation pulse
Pregunta 8
Pregunta
Which of the following TR parameters will provide the highest signal to noise?
Respuesta
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1800 ms
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400 ms
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2500 ms
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800 ms
Pregunta 9
Pregunta
Which of the following TE parameters will provide the highest signal to noise?
Respuesta
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120 ms
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20 ms
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40 ms
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80 ms
Pregunta 10
Pregunta
Which of the following flip angles will provide the highest signal to noise?
Respuesta
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45 degrees
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115 degrees
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90 degrees
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5 degrees
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