MRI Questions with All Correct & 100% Verified
Answers |Actual Complete Update| Already Graded A+
Fat has a ___ T1 and ____ T2 relaxation time ✔Correct Answer-Short. Short.
Water has a ___ T1 and T2 relaxation time. ✔Correct Answer-Long. Long.
If the repetition time is doubled, the scan time... ✔Correct Answer-Doubles.
^ FOV .. ___ SNR ✔Correct Answer-Increases
decrease pixel size does what to SNR ✔Correct Answer-Smaller pixel size is higher phase matrix
which leads to better resolution and DECREASED SNR
If you go from matrix of 256x512 to 512x512.. ✔Correct Answer-The SNR will decrease and the
scan time will increase
K space stats with signal and contrast info is located ✔Correct Answer-The central lines
If you change NEX what happens to resolution ✔Correct Answer-Nothing.
If NEX is inc from 2 to 6, the SNR ratio inc would be ✔Correct Answer-1.7 bc SNR inc by the square
root of the % inc. for example with 2 NEX inc to 6 NEX... (3 times the total NEX) would have inc in SNR
of square root of 3 which is 1.73 times more SNR than the original
How to find voxel volume ✔Correct Answer-Find pixel area (FOV *if cm add a zero* divided by
matrix X FOV/matrix = pixel area. That # X the slice thickness is the vox volume (mm3)
As # of phase encodings increases from 256 to 512, SNR ... ✔Correct Answer-Decreases
Dec NEX does what to SNR ✔Correct Answer-Dec. dec FOV dec SNR too
Reducing FOV only will result in ✔Correct Answer-Decreased SNR but increase in resolution
The smallest object that can be resolved in an image acquired with a 20cm FOV and a 224x224
matrix is ___mm ✔Correct Answer-0.89 because 200mm / 224 =0.89
Does TE affect scan time ? ✔Correct Answer-No it does not
Each line of k space is defined by the ✔Correct Answer-Phase encoding gradient
High amplitude signals are stored in the ✔Correct Answer-Center portion of k space
Acquiring a bit more than half the phase k space samples then interpolating the data with zeroes for
the remaining half is a technique known as ✔Correct Answer-Half Fourier or zero fill
Increasing NEX will ✔Correct Answer-Improve SNR
Decreased fov will result in ✔Correct Answer-Decrease SNR
, Reducing slice thickness will result in ✔Correct Answer-Decrease SNR but will decrease partial
volume averaging
The timing of the RF pulses in an MRI pulse sequence controls ✔Correct Answer-Image contrast
Method of reducing Mri scan time by not filling as many lines of kspace in the phase direction, while
maintaining resolution is known as ✔Correct Answer-Rectangular FOV
What can make an image with the most blurring ✔Correct Answer-The longer the ETL the more
chance of blurring
Reducing the number of lines filled in kspace will produce an image with ✔Correct Answer-A
decrease in spatial resolution
When only half the views of kspace are filled in the frequency axis is called ✔Correct Answer-
Partial or fractional echo. This is an acceleration technique used to shorten TR and TE
As the number of phase encodings are increased the SNR is ✔Correct Answer-Decreased
Two gradients applied at the same time during slice selection are utilized for ✔Correct Answer-
Encoding oblique slice planes. The slice selection gradient is the determinat of scan plane, slice
thickness; utilization of two gradients to perform this process allows for oblique slice orientation to
be acquired
The read out gradient is usually turned on during the sampling or readout of the peak echo and also
during which other process? ✔Correct Answer-Frequency encoding
What effect would decreasing the FOV have on spatial resolution of an image ✔Correct Answer-
Increase bc you reduce pixel size
What effect would using a steep slice select slope and or narrow bandwidth have on slice thickness
✔Correct Answer-Slices will be thin
An isotopic voxel refers to a ___ shaped voxel ✔Correct Answer-Cubic
Formula for slice coverage ✔Correct Answer-Slice thickness + (inter slice gap x #slices) ???
The process that digitizes the mr signals is known as ✔Correct Answer-Fourier transform
Defined as a small change in the mag field along a particular axis ✔Correct Answer-A gradient
In order to generate an mr image, the slice select gradient must be turned on during ✔Correct
Answer-RF energy absorption
Decreasing the slice selection gradient strength will ___ of the resulting slice ✔Correct Answer-
Change the slice thickness
Who discovered that tumors and normal tissue can be distinguished by NMR bc of their relaxation
times ✔Correct Answer-Damadian
Answers |Actual Complete Update| Already Graded A+
Fat has a ___ T1 and ____ T2 relaxation time ✔Correct Answer-Short. Short.
Water has a ___ T1 and T2 relaxation time. ✔Correct Answer-Long. Long.
If the repetition time is doubled, the scan time... ✔Correct Answer-Doubles.
^ FOV .. ___ SNR ✔Correct Answer-Increases
decrease pixel size does what to SNR ✔Correct Answer-Smaller pixel size is higher phase matrix
which leads to better resolution and DECREASED SNR
If you go from matrix of 256x512 to 512x512.. ✔Correct Answer-The SNR will decrease and the
scan time will increase
K space stats with signal and contrast info is located ✔Correct Answer-The central lines
If you change NEX what happens to resolution ✔Correct Answer-Nothing.
If NEX is inc from 2 to 6, the SNR ratio inc would be ✔Correct Answer-1.7 bc SNR inc by the square
root of the % inc. for example with 2 NEX inc to 6 NEX... (3 times the total NEX) would have inc in SNR
of square root of 3 which is 1.73 times more SNR than the original
How to find voxel volume ✔Correct Answer-Find pixel area (FOV *if cm add a zero* divided by
matrix X FOV/matrix = pixel area. That # X the slice thickness is the vox volume (mm3)
As # of phase encodings increases from 256 to 512, SNR ... ✔Correct Answer-Decreases
Dec NEX does what to SNR ✔Correct Answer-Dec. dec FOV dec SNR too
Reducing FOV only will result in ✔Correct Answer-Decreased SNR but increase in resolution
The smallest object that can be resolved in an image acquired with a 20cm FOV and a 224x224
matrix is ___mm ✔Correct Answer-0.89 because 200mm / 224 =0.89
Does TE affect scan time ? ✔Correct Answer-No it does not
Each line of k space is defined by the ✔Correct Answer-Phase encoding gradient
High amplitude signals are stored in the ✔Correct Answer-Center portion of k space
Acquiring a bit more than half the phase k space samples then interpolating the data with zeroes for
the remaining half is a technique known as ✔Correct Answer-Half Fourier or zero fill
Increasing NEX will ✔Correct Answer-Improve SNR
Decreased fov will result in ✔Correct Answer-Decrease SNR
, Reducing slice thickness will result in ✔Correct Answer-Decrease SNR but will decrease partial
volume averaging
The timing of the RF pulses in an MRI pulse sequence controls ✔Correct Answer-Image contrast
Method of reducing Mri scan time by not filling as many lines of kspace in the phase direction, while
maintaining resolution is known as ✔Correct Answer-Rectangular FOV
What can make an image with the most blurring ✔Correct Answer-The longer the ETL the more
chance of blurring
Reducing the number of lines filled in kspace will produce an image with ✔Correct Answer-A
decrease in spatial resolution
When only half the views of kspace are filled in the frequency axis is called ✔Correct Answer-
Partial or fractional echo. This is an acceleration technique used to shorten TR and TE
As the number of phase encodings are increased the SNR is ✔Correct Answer-Decreased
Two gradients applied at the same time during slice selection are utilized for ✔Correct Answer-
Encoding oblique slice planes. The slice selection gradient is the determinat of scan plane, slice
thickness; utilization of two gradients to perform this process allows for oblique slice orientation to
be acquired
The read out gradient is usually turned on during the sampling or readout of the peak echo and also
during which other process? ✔Correct Answer-Frequency encoding
What effect would decreasing the FOV have on spatial resolution of an image ✔Correct Answer-
Increase bc you reduce pixel size
What effect would using a steep slice select slope and or narrow bandwidth have on slice thickness
✔Correct Answer-Slices will be thin
An isotopic voxel refers to a ___ shaped voxel ✔Correct Answer-Cubic
Formula for slice coverage ✔Correct Answer-Slice thickness + (inter slice gap x #slices) ???
The process that digitizes the mr signals is known as ✔Correct Answer-Fourier transform
Defined as a small change in the mag field along a particular axis ✔Correct Answer-A gradient
In order to generate an mr image, the slice select gradient must be turned on during ✔Correct
Answer-RF energy absorption
Decreasing the slice selection gradient strength will ___ of the resulting slice ✔Correct Answer-
Change the slice thickness
Who discovered that tumors and normal tissue can be distinguished by NMR bc of their relaxation
times ✔Correct Answer-Damadian
