1
Q
is the process of creating diagnostic images through the use of magnetic fields and radiowaves to obtain a mathematically reconstructed image
A
magnetic resonance imaging
2
Q
most important particle
A
protons
3
Q
heavies particle
A
neutrons
4
Q
lightest particle
A
electrons
5
Q
spin of each particle induces magnetic field also known as
A
magnetic moments
6
Q
if an element has ___ atomic number, it possesses a nuclear net spin and considered as an MR active nuclei
A
odd
7
Q
has the highest nuclei magnetization due to its nuclear net spin based from its atomic mass
A
hydrogen
8
Q
60% of the human body is composed of
A
h2o/water
9
Q
80% of h20 is sourced from ____
A
hydrogen
10
Q
3 naturally occurring isotopes of hydrogen
A
protium
deuterium
tritium
11
Q
scattered magnetic field, can turn off cardiac pacemaker
A
fringe fields
12
Q
deadly MR phenomenon which MRI safe materials forms into a deadly projectile
A
missile effect
13
Q
emergent phenomenon in MR scanning in which the cryogenic gases are being released from cryostat
px is at high risk for asphyxiation/suffocation
A
quench
14
Q
gold standard pulse sequence
A
conventional spin echo
15
Q
signals from px
A
free induction decay
16
Q
electron spinning on its own axis also called as _______
A
little bar magnets
17
Q
hydrogen inside human body is _____ aligned
A
randomly
18
Q
small pockets, has consistently and uniform alignment of atoms such as metals
A
magnetic domain
19
Q
MXY
A
transverse magnetization - X and Y
20
Q
MZ
A
longitudinal magnetization - Z
21
Q
hydrogen of px when in bore
A
vector alignment
22
Q
sum of all hydrogen nuclei that has energy and direction
A
net magnetization vector
23
Q
2 theories describes alignment
A
quantum theory
classical theory
24
Q
in ____ theory, it has direction and energy
anti parallel = high energy
A
quantum theory
25
in ____ theory, it has direction only
up = parallel
down = anti parallel
classical theory
26
is the phenomenon which net magnetization vector is formed
anti parallel and parallel cancellation
px is also part of big magnetic system
polarization
27
is the wobbling type of motion that occurs in spinning hydrogen atoms
caused by interaction of Bo with the spinning hydrogen atoms
precession
28
is a mathematical formula that is used to calculate the speed of precession and its frequency
larmor equation
29
LF of 1.0 T / hydrogen
42.57 MHz
30
refers to the position of magnetic moments of spins on their precessional path at any moment in time
also called as phase coherence
precessional phase
31
different position and direction of spins
occurs in relaxation and de-excitation
also called as magnetic phase
out of phase/incoherent phase
32
same position and direction of spins
occurs in resonance
in phase/coherent phase
33
occurs when the natural frequency of an object or system matches the external energy
resonance
34
de-excitation of hydrogen atoms
release of energy (FID signal)
relaxation
35
releasing of energy to environment
T1 relaxation time
or
spin - lattice
36
releasing of energy to neighbouring hydrogen atom and is first to happen in relaxation
T2 relaxation time
or
spin - spin
37
happens after stopping RF
loss of phase coherence
release of energy to neighbouring hydrogen atom
dephasing
38
is the MR signal that is released from the de-excitation of the hydrogen protons
free induction decay
39
parameters cannot be altered or controlled
T1 and T2 recovery and proton density
intrinsic
40
parameters can be altered or controlled
repetition time, time to echo, flip angle and turbo factor
extrinsic
41
extrinsic parameter that is the time of application of one RF to the next
controls relaxation time
repetition time
42
extrinsic parameter that is the time between an RF excitation pulse and collection of signal
controls relaxation time and peak signal received
also known as listening time
time to echo
43
extrinsic parameter that is an angle formed by the rotation of the nuclear magnetization vector
flip angle
44
extrinsic parameter that is the succession of rephasing pulses in TSE
also called as rapid acquisition relaxation enhancement or RARE
turbo factor
45
intrinsic parameter that is the time it takes for the 63% of the NMV to recover/return into equilibrium (balance)
controlled by TR
fat = white
h20 = black
T1 recovery
46
it takes shorter time to recover towards equilibrium
it takes shorter time in losing phase coherence
fat
47
it takes longer time to recover towards equilibrium
it takes longer time in losing phase coherence
water
48
intrinsic parameter that the time it takes for the 37% of the NMV to maintain their phase coherence
controlled by TE
water = white
fat = black
T2 recovery
49
intrinsic parameter that is the number of hydrogen atoms present in the area being sampled is the basis for image contrast formation
proton density
50
process in MR imaging in which the characteristics of a certain recovery image appears more pronounced
image weighting
51
series of grouping of one or more RF pulses
pulse sequences
52
2 types of RF pulse
90 degree excitation pulse
180 degree rephasing pulse
53
a gold standard pulse sequence that uses a 90-180 pulse sequence to form an image
capable of producing T1, T2 and PD weighted images
spin echo pulse sequence
or
CSE - conventional spin echo
54
pulse sequence that uses a 90 RF pulse and a series of 180 RF rephasing pulse to form an image
fast spin echo pulse sequence
55
pulse sequence mainly used for stroke and perfusion imaging
diffusion weighted imaging
56
2 types of inversion recovery pulse sequence
STIR - short T1 inversion recovery
or
FLAIR - fluid attenuated inversion recovery
57
point that is voiding either fat or h2o FID signals
null point
58
2 types of stroke
ischemic and hemorrhagic
59
stroke that occurs when there is a blockage of blood supply to a certain region of brain that leads to tissue necrosis
ischemic stroke
60
stroke that occurs when there is a rupture of blood vessel/artery in which causes the leaking of blood in the brain
hemorrhagic stroke
61
tissue oxygenation and exchange of nutrients and waste products vie blood supply
tissue perfusion
62
movement of particle/solute from high concentration to low concentration
diffusion
63
uses strong magnetic fields and RF to measure the rate of diffusion
ADC - apparent diffusion coefficient
64
magnets that emits or creates Bo
primary magnets
65
type of primary magnets
permanent magnets
electromagnets
66
type of secondary magnets
shim coils
gradient coils
RF coils
67
type of primary magnet that uses natural magnet (Ferrite)
for claustrophobic and obese patients
vertical orientation of magnetic field
Bo cannot turned off
permanent magnet
68
type of primary magnet that uses electricity to generate Bo
electromagnets
69
less expensive type of electromagnet MRI machine
high electric consumption
uses electromagnets: aluminum strips that are spirally arranged in thousands of layers
resistive MRI machine
70
allows the flow of electricity without any resistance which occurs at near absolute zero
modern and most common MRI magnet machine
uses superconductivity
superconductive MRI machine
71
contains the NbTi and cryogens found inside the MR machine
cryostat
72
container of cryogens for safe handling and transport
dewars
73
cryogens composed of:
liquid helium (4k)
liquid nitrogen (77k)
74
unforeseen event when the superconducting magnets warms and the electromagnetic coil become resistive
liquid helium evaporates
quench
75
secondary magnets that are responsible for the maintaining magnetic field homogeneity
shimming coils
76
process of maintaining magnetic field homogeneity
shimming
77
secondary magnets that has broad and thick copper conducting bands that varies the external magnetic field strength
X, Y and Z coils
gradient coils
78
is the rate of turning on and turning off the gradient coils
slew rate
79
is the force that is felt by the charged object when it moves through a magnetic or electric field
act of energizing or activating gradient coil
Lorentzian force
80
is an important part of MRI system that helps in localization of free induction decay signals and slice selection
gradient coils
81
it is the changing values of magnetic fields particularly upward and downward
magnetic gradient
82
creation of spatial map
encoding
83
measurement of phase shifts
the variation of phase coherence of individual hydrogen atoms
in between RF and FID production
phase encoding
84
measurement of frequency shifts
the variation of precessional frequency of individual hydrogen atoms
after the FID is received "Read Out Gradient"
frequency encoding
85
range of FID signals that is going to be used in an image
transmit bandwidth
86
is an array processor in the computer systems which temporarily stores data until the scan is finished
K-space
87
is a mathematical function that is used in MR imaging to transform/process the data stored in the K-space into a meaningful image
fourier transformation
88
secondary magnet that has a main function of transmitting and receiving signals
radiofrequency coils
89
RF coils that are placed directly to the specific part or anatomy of interest
surface coils
90
RF coils that built in the MR system which aims to cover a large volume of anatomy such as spine, head and neck, abdomen and extremities
volume coils
91
artifact that occurs when the scanning field contains anatomy that has slight difference in resonance frequencies
more apparent in superconductive MRI
chemical shift
92
artifact that occurs due to the uncontrolled voluntary and involuntary motion of the patient
blurred in appearance
ghosting artifact
93
artifact that occurs when a ferromagnetic material/objects are inside a diamagnetic material
appears as bright and dark areas of surrounding anatomy or signal distortion
magnetic susceptibility artifact
94
artifact that occurs when there is an under sampling of digital frequencies in K-space
appears as bright/dark lines that are parallel to the borders of abrupt intensity changes
also known as Gibbs artifact
truncation artifact
95
artifact that occurs when the slice thickness selection or wide transmit bandwidth
causes the signals to encompassed into a single voxel
partial volume artifact
96
3 states of magnetic susceptibility
diamagnetic
paramagnetic
ferromagnetic
97
magnetic susceptibility that opposes the direction of the applied magnetic force
weakly repelled
decreases the local magnetic field
glass, plastic, wood
diamagnetic
98
magnetic susceptibility that aligns to the direction of the applied magnetic force
weakly attracted
increases/enhances the local magnetic field
Gd - DTPA
paramagnetic
99
magnetic susceptibility that strongly attracted to the applied magnetic force
retains alignment without the applied magnetic field
increases/enhances the local magnetic field
Al, Ni, Co
ferromagnetic
100
paramagnetic cm that is used routine in MR imaging
shorten/enhances the T1 relaxation time
T1 tissue extreme appears brighter in the scan
gadolinium
101
superparamagnetic cm that is used routine in MR imaging
shorten/enhances the T2 relaxation time
T1 tissue extreme appears darker in the scan
iron oxide
RC
flashcards
Decks in class (26)
# Cards
-
RAD PRODUCTION - D278
-
RAD PRODUCTION - D155
-
RAD PRODUCTION - D365
-
ANAPHY - D1107
-
RAD BIOLOGY81
-
RAD PROTECTION100
-
IMAGING SCIENCE80
-
POI - D173
-
POI - D249
-
FILM SCREEN - D130
-
FILM SCREEN - D269
-
FILM SCREEN - D317
-
QAQC81
-
POSI - UPPER EXT.52
-
POSI - LOWER EXT.74
-
POSI - SKULL55
-
MAMMO & DENTAL48
-
RAD CONTRAST - D177
-
RAD CONTRAST - D290
-
RAD CONTRAST - D339
-
PHARMACOLOGY & VENIPUNCTURE134
-
CT SCAN134
-
MRI101
-
ETHICS108
-
NUCLEAR MEDICINE96
-
ULTRASOUND110
