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Decreasing the receiver bandwidth (utilizing a narrow BW):
A. Increases susceptibility artifact
B. Decreases susceptibility artifact
C. Does not affect susceptibility artifact
D. Decreases SNR
E. A and D only
F. B and D only
A. Increases susceptibility artifact
B. Decreases susceptibility artifact
C. Does not affect susceptibility artifact
D. Decreases SNR
E. A and D only
F. B and D only
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Question
Which is FALSE regarding the use of a narrow receiver bandwidth?
A. generates lower SNR images
B. should be applied in anatomical regions that contain high fat and water
C. utilized with a high readout gradient amplitude
D. All of the above
A. generates lower SNR images
B. should be applied in anatomical regions that contain high fat and water
C. utilized with a high readout gradient amplitude
D. All of the above
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MRI image formation
MRI image
| Question | Answer |
|---|---|
| Decreasing the receiver bandwidth (utilizing a narrow BW): A. Increases susceptibility artifact B. Decreases susceptibility artifact C. Does not affect susceptibility artifact D. Decreases SNR E. A and D only F. B and D only | Increases susceptibility artifact |
| Which is FALSE regarding the use of a narrow receiver bandwidth? A. generates lower SNR images B. should be applied in anatomical regions that contain high fat and water C. utilized with a high readout gradient amplitude D. All of the above | All of the above |
| If 24 4mm slices are planned with a gap of 1mm, the total anatomic coverage is _______ cm. A. 10 B. 12 C. 15 D. 120 | 12 |
| Gradient echo sequences use flip angles: A. To control saturation effects B. After the 180º pulse C. Between the 90º and the 180º pulses D. To control SAR in bariatric patients | To control saturation effects |
| Gradient echo sequences use flip angles: A. To control saturation effects B. After the 180º pulse C. Between the 90º and the 180º pulses D. To control SAR in bariatric patients | To control saturation effects |
| Two gradients applied at the same time during slice selection are utilized for: A. Reducing the cryogen boil off rate B. Encoding oblique slice planes C. Eliminating residual transverse magnetization for steady state D. Encoding 3D volumes for MRA | B. Encoding oblique slice planes |
| The presaturation pulses typically are found: A. Between the 90º and the 180º pulses B. Prior to the TE C. Following the 180º pulse D. Prior to the excitation pulse E. A and D only | Prior to the excitation pulse |
| Decreasing the receiver bandwidth (utilizing a narrow BW): A. Reduces readout time B. Increases readout time C. Does not affect the readout time D. Increases SNR E. A and D only F. B and D only | B and D only |
| If the radiologist requires 3mm slices axially acquired through the IAC, with a slice gap of 0.5mm, and requires 4.2cm total coverage, how many slices must be selected? A. 6 B. 9 C. 12 D. 15 | 12 |
| Reducing the TE: A. Increases the contrast based on T1 tissue relaxation times B. Reduces saturation effects C. Decreases the contrast based on T2 tissue relaxation times D. Increases fat suppression E. Increases signal from fluids | Decreases the contrast based on T2 tissue relaxation times |
| As the TR is increased, I. SNR is increased II. Available number of slices is increased III. T2 information is maximized A. I and II B. I, II and III C. I and III D. None of the above | I and II |
| In order to generate an MR image, the slice select gradient must be turned on during: A. T1 relaxation B. Collection of the echo C. Patient positioning D. RF energy application | RF energy application |
| The signal produced immediately following an RF pulse is: A. Ham radio signal B. Gradient echo C. FID D. MIP | FID |
| The time during which the frequency encoding gradient is on A. Increases with a reduction in receiver bandwidth B. Decreases with a reduction in receiver bandwidth C. not affected by a reduction in receiver bandwidth D. limited by the inverse of | Increases with a reduction in receiver bandwidth |
| As the flip angle is increased, SNR(signal to noise ratio): A. Decreases until it reaches the Ernst angle B. Increases to a point called the Ernst angle C. Reduces to the Minimum Allowable Tesla (MAT) D. Is unaffected | Increases to a point called the Ernst angle |
| What effect would decreasing the FOV have on the spatial resolution of an image? A. None B. Increase C. Decrease D. K space filled faster | Increase |
| Which of the following can be considered an advantage of selecting a 3D acquisition as opposed to a 2D acquisition? A. The slices have a greater SNR B. No crosstalk C. Longer repetition times D. All of the above E. A & B only | A & B only |
| The readout gradient is usually turned on during the sampling or readout of the peak echo and also during which other process? A. Slice selection B. Phase encoding C. Frequency encoding D. None of the above | Frequency encoding |
| The range of transmitted frequencies at each slice position must _____ to maintain slice thickness. A. Remain constant B. Increase with each slice C. Decrease with each slice D. Disable, then re-enable | Remain constant |
| Increasing the TE: A. Increases the contrast based on T1 tissue relaxation times B. Decreases the SNR of the image C. Decreases the contrast based on T2 tissue relaxation times D. Increases the contrast based on T2 relaxation times | B and D only |
| When gradient moment nulling is used as an imaging option in MR sequences: A. SNR is degraded B. The minimum TE is increased C. The minimum TE is decreased D. More slices are available per TR | The minimum TE is increased |
| Decreasing the receiver bandwidth (narrow rBW): A. Increases the contrast based on T1 tissue relaxation times B. Decreases the SNR of the image C. Increases the SNR of the image D. Inverts the SNR of the image E. Does not affect the SNR of the i | Increases the SNR of the image |
| __________ is defined as a small change in the magnetic field along a particular axis. A. Analog to digital converter B. K-space C. Fourier transform D. A gradient | A gradient |
| Which set of scan parameters below would yield the best spatial resolution? A. 270 mm FOV, 192 x 512 matrix, 5mm slice thickness, 8 NEX B. 200 mm FOV, 512 x 512 matrix, 3mm slice thickness, 4 NEX | 200 mm FOV, 512 x 512 matrix, 3mm slice thickness, 4 NEX |
| Which factors affect the flip angle? A. Gradient slew rate and the magnetic field strength B. Duty cycle and RF field C. Strength and duration of the RF field D. Static magnetic field and gradient rise time | Strength and duration of the RF field |
| Multiplanar reconstructions are typically utilized in 3D pulse sequences because: A. 2D slices are too thick to reformat B. 2D slice groups are too long C. There are gaps between 2D slices D. A & C only E. B & C only | A & C only |
| A ______________ is defined as a picture element and has _________ characteristics. A. Pixel, two-dimensional B. Pixel, three-dimensional C. Voxel, two-dimensional D. Voxel, three-dimensional | Pixel, two-dimensional |
| Complete saturation is a condition where: B. The signal from fluid is inverted from a long TI C. Transverse magnetization is not allowed to recover between excitations D. Longitudinal magnetization is not allowed to recover between excitations | Longitudinal magnetization is not allowed to recover between excitations |
| If the receiver bandwidth (rBW) is decreased, the sampling rate: A. Increases B. Decreases C. Increases by the square root of 2 D. Does not change | Decreases |
| Decreasing the slice selection gradient strength will ________ of the resulting slice. A. Change the orientation B. Change the slice thickness C. Invert the phase and frequency sampling directions D. Alter the field of view | Change the slice thickness |
| Reducing the TR: A. Increases the SNR of the image B. Decreases the SNR of the image C. Decreases the contrast based on the T2 relaxation time D. Increases saturation effects | B and D only |
| Applying two gradients simultaneously during slice selection would: A. Produce an artifact B. Produce an oblique slice C. Produce partial volume averaging D. Result in an equipment fault | Produce an oblique slice |
| Increasing the field of view (FOV) would have what effect? A. Decrease spatial resolution B. Increase spatial resolution C. Decrease temporal resolution D. Increase temporal resolution | Decrease spatial resolution |
| _________ is a file on the computer where the collected echoes are stored prior to being processed into an image by the Fourier Transform. A. Analog to digital converter B. Raw data C. K-space D. A gradient | Raw data |
| Increasing the receiver bandwidth (rBW): A. Increases chemical shift artifacts B. Decreases chemical shift artifacts C. Decreases slice thickness D. Increases slice thickness | Decreases chemical shift artifacts |
| To increase the voxel volume, which parameters would be adjusted? A. Slice thickness and interslice gap B. Matrix, slice thickness and slice gap C. FOV, slice gap and matrix D. FOV, slice thickness and matrix | FOV, slice thickness and matrix |
| A technique that reduces scan time by not filling as many lines of k-space in the phase direction, while maintaining spatial resolution, is known as: A. Rectangular FOV B. Parallel imaging C. Partial saturation D. Dual inversion recovery | Rectangular FOV |
| The process that digitizes the MR signals is known as: A. Hahn echos B. Faraday's law C. Gyromagnetic reconstruction D. Fourier transform | D. Fourier transform |
| In a gradient echo sequence, reducing the flip angle while maintaining the TR reduces: A. Scan time B. T2* contrast C. Inversion delay D. Saturation | Saturation |
| The Ernst angle can be defined as the optimal ___________ that yields the ____________ signal for a particular spin in the least amount of time. A. NSA; minimum B. TR; maximum C. Flip angle; minimum D. Flip angle; maximum | Flip angle; maximum |
| What effect would using a steep slice select slope and/or narrow bandwidth have on slice thickness? A. Partial volume averaging will occur B. Slices will be thin C. Slices will be thick D. Slices will cross-talk | Slices will be thin |
| Signal to Noise Ratio (SNR) would increase in a 3D volume acquisition with an increase in: A. TE B. Slices C. Field of view D. All of the above E. B and/or C only | B and/or C only |
| To obtain a thin slice thickness: B. A shallow gradient is applied with the receiver bandwidth at the Larmor frequency of H C. A steep gradient is applied with the transmit bandwidth at the Larmor frequency of H | A steep gradient is applied with the transmit bandwidth at the Larmor frequency of H |
| Which of the following is NOT a result of reducing the FOV? A. Improved spatial resolution B. Decreased signal-to-noise C. Anatomical structures are displayed smaller in the image D. The pixel size becomes smaller | Anatomical structures are displayed smaller in the image |
| Decreasing the receiver bandwidth (utilizing a narrow BW): A. Increases the number of slices available B. Decreases the number of slices available C. Does not change the number of slices available D. Decreases SNR E. A and D only F. B and D on | A. Increases the number of slices available |
| Presaturation pulses are often used to: A. Improve spatial resolution B. Improve temporal resolution C. Reduce scan time D. Reduce flow artifacts E. Enable bright signal from flowing blood | Reduce flow artifacts |
| A narrow receiver bandwidth: A. Decreases susceptibility artifact B. Increases susceptibility artifact C. Lowers SNR D. Should be used in the presence of metal implants | Increases susceptibility artifact |
| 2D acquisitions usually require: A. Flow compensation B. Presaturation slabs C. Fat suppression D. An interslice gap | An interslice gap |
| All of the following are true mechanisms of saturation EXCEPT: A. A saturation pulse excites hydrogen protons to a frequency that gives no signal on the image B. Partial saturation yields T1 weighting; occurs when NMV >90° C. Partial saturation yiel | Partial saturation yields T1 weighting; occurs when NMV is 180° |
| Creating additional images in various planes from a 3D data set is accomplished by a technique known as: A. Maximum intensity projection (MIP) B. Multi-Planar reconstruction (MPR) C. Region of interest calculation(ROI) D. Subtraction | Multi-Planar reconstruction (MPR) |
| An isotropic voxel refers to a __________ shaped voxel. A. Circular B. Rectangular C. Cubic D. Oval | C. Cubic |
| Gradient moment nulling is used to compensate for: I. First order motion II. Second order motion III. Slow flowing vessels IV. Fast flowing vessels | I and III |
| The maximum intensity projection algorithm: Projects the high intensity pixels which represent blood vessels/ducts into one image | Projects the high intensity pixels which represent blood vessels/ducts into one image |
| Slice ___________ is determined by the slice selection process. A. Position B. Orientation C. Thickness D. All of the above | All of the above |
| If the maximum slices in a set TR is 10, and the necessary number of slices for a given sequence's anatomical coverage is 26, how many acquisitions (packages) will be required? A. 1 B. 2 C. 3 D. 4 | 3 |
| Decreasing rBW (receiver bandwidth)by a factor of two: A. Decreases SNR by 2 B. Increases SNR by 2 C. Decreases SNR by √2 D. Increases SNR by √2 E. Increases SNR by 4 F. Decreases SNR by 4 | Increases SNR by √2 |
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zach1710