Part V Flashcards
phase encoding main gradient coil [..]
y-axis
phase encoding [purpose]
support flipping M to x and y plane, give pulse/extra energy to enhance gradient coil @ left and right side
[RF ENRGY?] Phase Encoding
NONE, during PE if RF is introduced, it will not follow Bo
frequency encoding main gradient coil [..]
x-axis
frequency encoding [purpose]
SPATIAL DOMAIN -initial appearance and readable app. is in TRAPEZOIDAL
[component] convert signal to readable signal [process]
Fourier Transformer
Twisting of Form
[RF ENERGY?] Frequency Encoding
YES, include FID -energy transmitted from H atoms
time to give another sequence from first to second
TR repetition time
time b/w application of the RF excitation pulse and the peak of the signal induced in the coil
TE echo time
most impo plane in spin echo
TRANSVERSE - where most energy comes from
Spin echo with multiple 180 deg corresponding pulses
Fast Spin Echo
Fast Spin Echo [purpose]
lengthen exposure H to RF
Refocusing Pulse [purpose]
Give 180 degrees pulse to refocus H, make sure precession is same for increase FID
command it to go back - Rabbit and Turtle Principle
time you suppress signal of a certain poi
TI - Inversion time
[reason] signal starts after 90 degrees in inversion recovery sequence
only used to remove any signal coming from POI
[characteristics] T1-W Imaging
short TR and short TE
(less signal - increase intensity b/w x and y)
[dark-hypointense T1-W Imaging (E.T.H.I.C)
Edema
Tumor
Hemorrhage (hyperacute, chronic)
Infection/Inflamm
Calcifications
[bright-hyperintense] T1-W Imaging (F.F.S.M.P.P)
Fat
Flowing blood (slow)
Subacute Hemorrhage, Melanin
Protein-rich fluid
Paramagnetic substances (Ga, Cu, Manganese)
[characteristic] T2-W Imaging
long TR ang long TE
prolong relaxation = higher signal=brighter
[dark-hypointense] T2-W Imaging (Ca.Fi.P.-PV)
Calcification
Fibrous Tissue
Paramagnetic Substances (Deoxyhemoglobin, Ferritin, Melanin)
Protein-rich fluid
Flow Void