MRI PHYSICS MATH FC
The smallest object that can be resolved in an image acquired with a 20cm FOV and a 224 x 224 matrix is
_________ mm. correct answers0.89
200 mm ÷ 224 = 0.892mm
The smallest object that can be resolved in an image acquired with a 24cm FOV and a 272 x 272 matrix is
_________ mm.
A. 0.76mm B. 0.88mm C. 0.93mm D. 1.13mm E. 1.24mm correct answers0.88.
240 ÷ 272=0.88MM
What would the scan time be in a 3D volume acquisition as follows: TR 32 ms, TE 4 ms, Flip Angle 15°,
FOV 18cm, 2mm slice thickness, 96 slices, 192 x 256 matrix? correct answers9 min 50 sec
3D scan time formula: TR x Phase Matrix x NEX x # slices
If the NEX is increased from 2 to 6, the signal-to-noise ratio increase would be: correct answers1.7
When increasing NEX/NSA, SNR (signal-to-noise ratio) increases by the square root (√) of the % increase.
For example, a sequence with 2 NEX, increased to 6 NEX (3times the total NEX) would have an increase
in SNR of √3, or 1.73 times more SNR than the original sequence.
Calculate the voxel volume for the following pulse sequence parameters: TR 450, TE 20, FOV 24cm, 320 x
320 matrix, 3mm slice thickness. correct answers1.69mm3
To calculate voxel volume, first determine pixel area. FOV/matrix x FOV/matrix = pixel area. Pixel area x
slice thickness = voxel volume. 240/320 x 240/320 = 0.5625 mm2. 0.5625 x 3 = 1.69mm3
Calculate the voxel volume for the following pulse sequence: TR 2000, TE 85, FOV 24cm, Matrix 272 x
320, 3mm slice thickness, 3 NSA. correct answers1.98mm3
To calculate voxel volume, first determine pixel area. FOV/matrix x FOV/matrix = pixel area. Pixel area x
slice thickness = voxel volume. 240/272 x 240/320 = 0.66 mm2 (pixel area). 0.66 x 3 = 1.98mm3
The smallest object that can be resolved in an image acquired with a 20cm FOV and a 224 x 224 matrix is
_________ mm. correct answers0.89
200 mm ÷ 224 = 0.892mm
The smallest object that can be resolved in an image acquired with a 24cm FOV and a 272 x 272 matrix is
_________ mm.
A. 0.76mm B. 0.88mm C. 0.93mm D. 1.13mm E. 1.24mm correct answers0.88.
240 ÷ 272=0.88MM
What would the scan time be in a 3D volume acquisition as follows: TR 32 ms, TE 4 ms, Flip Angle 15°,
FOV 18cm, 2mm slice thickness, 96 slices, 192 x 256 matrix? correct answers9 min 50 sec
3D scan time formula: TR x Phase Matrix x NEX x # slices
If the NEX is increased from 2 to 6, the signal-to-noise ratio increase would be: correct answers1.7
When increasing NEX/NSA, SNR (signal-to-noise ratio) increases by the square root (√) of the % increase.
For example, a sequence with 2 NEX, increased to 6 NEX (3times the total NEX) would have an increase
in SNR of √3, or 1.73 times more SNR than the original sequence.
Calculate the voxel volume for the following pulse sequence parameters: TR 450, TE 20, FOV 24cm, 320 x
320 matrix, 3mm slice thickness. correct answers1.69mm3
To calculate voxel volume, first determine pixel area. FOV/matrix x FOV/matrix = pixel area. Pixel area x
slice thickness = voxel volume. 240/320 x 240/320 = 0.5625 mm2. 0.5625 x 3 = 1.69mm3
Calculate the voxel volume for the following pulse sequence: TR 2000, TE 85, FOV 24cm, Matrix 272 x
320, 3mm slice thickness, 3 NSA. correct answers1.98mm3
To calculate voxel volume, first determine pixel area. FOV/matrix x FOV/matrix = pixel area. Pixel area x
slice thickness = voxel volume. 240/272 x 240/320 = 0.66 mm2 (pixel area). 0.66 x 3 = 1.98mm3
