Random Flashcards
The Sag T2, demonstrates a post stenotic jet in which region?
Aqueduct of Sylvius
What is the artefact in this image caused by?
RF leak
What is the artefact in this image caused by?
Metallic implant
Use FSE to try and reduce artefacts from metal implants
In half NEX imaging, it is necessary to acquire what percentage of the phase?
A little more than 50% (55%)
A PD sequence using a wider rBW will result in?
Decreased sampling rate
Which of the following occurs when the rBW is increased?
A) increased SNR
B) reduced chemical shift
C) reduced sampling rate
D) decreased sampling rate
B) reduced chemical shift
What does the 180-degree refocusing pulse in a SE sequence correct for?
Precessional differences between fat and water
In a FSE sequence with long effective TE, scan time can be reduced by the selection of:
A) large FOV
B) longer ETL
C) shorter ETL
D) there are no ETL changes that could affect scan time
B) Longer ETL
Increasing the number of slices (or partitions) in a 3D acquisition from 32 to 128 will increase the SNR by a factor of….
A) 2
B) 4
C) 6
D) square root of 2
D) square root of 2
What will using a zero-fill or interpolation technique to reduce scan time also reduce?
A) SNR
B) Reconstructed voxel size
C) flow artifacts
D) FOV
A) SNR
The attractive force of an object will experience at 2 metres from isocentre is not dependent on what?
A) the mass of the object
B) the ferromagnetic properties of the object
C) the field strength of the machine
D) slew rate of the machine
D) slew rate of the machine
Which of the following are important in an MRA sequences to minimise the loss of signal due to dephasing within a voxel?
A) long TR
B) low frequency matrix
C) long TE
D) small voxels
C) Long TE
In magnetic resonance angiography (MRA), TE stands for Echo Time, a term referring to the time from the application of the radiofrequency pulse to the peak of the echo signal in MRI. A shorter TE time (short TE) helps reduce signal loss because it minimizes the period during which dephasing can occur within a voxel, thus preserving more of the signal.
In a TOF sequence, flowing blood is hyperintense relative to stationary tissue because of the…?
A) T2 effect
B) coil being used
C) saturation pulse being used
D) flow related signal
D) flow related signal
When referring to a half NEX or partial Fourier sequence, which of the following is true?
A) spatial resolution remains the same
B) SNR is increased
C) less susceptible to periodic motion
D) increase in scan time
C) Less susceptible to periodic motion
K space is an array of numbers, what process generates the MR image?
A) Fourier transform
B) synthetic transform
C) compress sensing
D) parallel imaging
A) Fourier transform
In which directions do pulsatile motion artefacts occur in?
A) both phase and frequency
B) frequency
C) phase
D) can be in any direction depending on the TR used
C) phase
What is the artefact demonstrated in Image 12 known as?
A) wrap
B) zipper
C) truncation
D) flow
A) wrap
In this image, what direction would the phase direction be in?
A) A->P
B) R->L
C) superior to inferior
D) cannot determine
A) A->P
Increasing the FOV by a factor of 2, the SNR will increase by what factor?
A) square root of 3
B) 2
C) 8
D) 4
A) square root of 3?
At what point is phase encoding performed?
A) prior to frequency encoding
B) in place of frequency encoding
C) during frequency encoding
D) after frequency encoding
A) prior to frequency encoding
What is the gradient that is on during the echo called?
Frequency encoding/readout gradient
To keep scan time to a minimum, what is diffusion imaging typically performed with?
Single shot EPI acquisition
The white paper on MRI states that MRI centres should be separated into how many zones?
4
RF heating is more of a concern during which sequence?
GRE
The effect of RF absorption is limited to an increase in core temp of?
0.5 celsius
What type of structure is labelled A in this image
Ligament
What is letter G?
Pituitary gland
Identify the anatomical region labelled A
Genu of the corpus callosum
What would the structure labelled C on this image present as on a T2 image
Hyper intense to white matter
What two planes are best for imaging the orbits?
Coronal and Axial
What is the best B value for imaging with DWI in the brain clinically?
B = 1000 s/mm^2
What sequence was this image acquired with
T1FS
In this image, what letter is pointing to the quadregeminal plate?
Letter I
Name the region B
Left frontal horn of the lateral ventricle
In a solenoid superconducting magnet, what does the direction of flow affect?
Direction of the magnetic field
The MR system component that provides a means for alignment is known as the?
Main magnet
Name the fluid filled structure named H
Pancreatic duct
What arrow is pointing to the aorta?
G
What is pointing to the aqueduct of Sylvius?
E
Which arrow is pointing to the medulla oblongata?
C
What arrow is pointing to the cerebellar vermis?
K
What does the lentiform nucleus consist of?
Globus Pallidus and Putamen
In a superconducting magnet, the magnetic field is increased by increasing what?
Number of wire turns
To maintain the magnetic field of a resistive magnet, which of the following should be applied to the magnet coils?
A) water
B) heat
C) current
D) cooling
C) current
Most modern superconducting magnets have a helium boil off rate per month of what percentage?
Approx 5% per month
What is the temperature of the liquid helium used in superconducting magnets?
-270 degrees celsius
What are gradient magnetic field used to do?
Spatial encoding
What does a bucket handle tear involve?
The mensicii
What muscle inserts into the lesser tubercle of the humerus and is the major contributor to humeral medial rotation?
Subscapularis muscle
In this image, what arrow is pointing to the deltoid muscle?
Arrow F
