MRI Final Exam with all Correct & 100% Verified
Answers |Latest Update| Guaranteed to Pass
T1 ✔Correct Answer-Time it takes for 63% of NMV to "grow back" to longitudinal plane.
Longitudinal relaxation - spin lattice - the return of longitudinal NMV.
White matter: short (bright)
Gray matter somewhat longer
CSF: long (dark)
T2 ✔Correct Answer-Time it takes for 37% of transverse magnetization to be lost (decay).
Dephasing -transverse relaxation - spin-spin - the decrease of the transverse NMV after RF is turned
off.
White matter: short (dark)
Gray matter: somewhat longer
CSF: long - dephases slower (bright)
T2* ✔Correct Answer--Due to dephasing effects in gradient echo images, true T2 contrast did not
used to be possible
-So T2* is the type of contrast that is T2 weighted but also contains contributions from magnetic
susceptibility and from fat/water interfaces
-Small flip angle
-Long TR
-Long TE
PD ✔Correct Answer-When an MRI sequence is set to produce a PD-weighted image, it is the
tissues with the higher concentration or density of protons (hydrogen atoms) which produce the
strongest signals and appear the brightest on the image. Proton density weighted sequence
produces contrast mainly by minimizing the impact of T1 and T2 differences with long TR (2000-
5000ms) and short TE (10-20).
White matter: darker than bright gray
Gray matter: bright gray
CSF: bright
GE ✔Correct Answer--Gradient Recalled Echo
-Field echo pulse - uses a short flip angle, and therefore shorter echo time.
-Two types:
1. Spoiled GRE
2. Steady State GRE
What is spoiled GRE? ✔Correct Answer-Disturbance of longitudinal NMV by flip angle of less than
90, gradient rephrasing occurs and a gradient echo will be formed at the TE.
Spoiler pulse is sent in to spoil residual transverse magnetization following the gradient echo
collection, so that is does not contribute to echo.
What is steady state GRE? ✔Correct Answer--Identical to spoiled GRE except at gradient echo
formation
-Steady state rephases and maximizes residual transverse magnetization after the echo to include in
the echo
Answers |Latest Update| Guaranteed to Pass
T1 ✔Correct Answer-Time it takes for 63% of NMV to "grow back" to longitudinal plane.
Longitudinal relaxation - spin lattice - the return of longitudinal NMV.
White matter: short (bright)
Gray matter somewhat longer
CSF: long (dark)
T2 ✔Correct Answer-Time it takes for 37% of transverse magnetization to be lost (decay).
Dephasing -transverse relaxation - spin-spin - the decrease of the transverse NMV after RF is turned
off.
White matter: short (dark)
Gray matter: somewhat longer
CSF: long - dephases slower (bright)
T2* ✔Correct Answer--Due to dephasing effects in gradient echo images, true T2 contrast did not
used to be possible
-So T2* is the type of contrast that is T2 weighted but also contains contributions from magnetic
susceptibility and from fat/water interfaces
-Small flip angle
-Long TR
-Long TE
PD ✔Correct Answer-When an MRI sequence is set to produce a PD-weighted image, it is the
tissues with the higher concentration or density of protons (hydrogen atoms) which produce the
strongest signals and appear the brightest on the image. Proton density weighted sequence
produces contrast mainly by minimizing the impact of T1 and T2 differences with long TR (2000-
5000ms) and short TE (10-20).
White matter: darker than bright gray
Gray matter: bright gray
CSF: bright
GE ✔Correct Answer--Gradient Recalled Echo
-Field echo pulse - uses a short flip angle, and therefore shorter echo time.
-Two types:
1. Spoiled GRE
2. Steady State GRE
What is spoiled GRE? ✔Correct Answer-Disturbance of longitudinal NMV by flip angle of less than
90, gradient rephrasing occurs and a gradient echo will be formed at the TE.
Spoiler pulse is sent in to spoil residual transverse magnetization following the gradient echo
collection, so that is does not contribute to echo.
What is steady state GRE? ✔Correct Answer--Identical to spoiled GRE except at gradient echo
formation
-Steady state rephases and maximizes residual transverse magnetization after the echo to include in
the echo
