08) MRI: Tissue Properties, Contrast, Reactions
1.
The T1 relaxation time is the time required for the ________ magnetization to return to _____% of the thermal equilibrium magnetization.
A) Transverse, 63
B) Transverse, 37
C) Longitudinal,63
D) Longitudinal,37
E) Longitudinal,100
C) Longitudinal,63
if you want to understand where these numbers come from go to:
https://sites.google.com/site/neuroradiologyprimer/physics/mr-physics
2.
The T___ (spin-spin) relaxation time, is the time required for 63% of the _________ magnetization to decay.
A) 1, Transverse
B) 2, Transverse
C) 1, Longitudinal
D) 2, Longitudinal
E) 2, Net
B) 2, Transverse
if you want to understand where these numbers come from go to:
https://sites.google.com/site/neuroradiologyprimer/physics/mr-physics
3.
Inherent tissue properties that affect image contrast include all of the following EXCEPT
A) T1
B) T2
C) T2*
D) Hydrogen Spin Density
E) Tissue temperature
E) Tissue temperature
4.
What is the effect of positive contrast agents on the T1-relaxation times of biological tissue?
A) T1 increases after contrast agent administration
B) T1 decreases after contrast agent administration
C) T1 changes are dependent on the imaging sequence
D) T1 is unchanged
E) The change in T1 is dependent only on the field strength
B) T1 decreases after contrast agent administration
5.
Negative contrast agents cause ____-intensity on ___-weighted images
A) Hypo, T1
B) Hypo, T2,
C) Hyper, T1,
D) Hyper, T2,
E)
B) Hypo, T2,
6.
Which of the following contrast agents is ferromagnetic?
A) A)Gd2+
B) Iron
C) Magnetite Fe2O4
D) Dy3+
E)
B) Iron
7.
Gadolinium chelates commonly used as MRI contrast agents (e.g. Gd-DTPA) are:
A) Intracellular agents
B) Extracellular agents
C) 70% Extracellular and 30% Intracellular
D) 30% Extracellular and 70% Intracellular
E) Extracellular for the first 10 minutes post-administration, then intracellular
B) Extracellular agents
8.
Why is Gadolinium always chelated as a contrast agent?
A) Gd cannot be packaged as an independent element
B) The biological half-life of free Gd is too short for diagnostic purposes
C) Free Gd is toxic
D) Free Gd in non-paramagnetic
E)
C) Free Gd is toxic
9.
Gadolinium-based contrast agents increase the risk of nephrogenic systemic fibrosis (NSF) in patients with (Choose all that apply):
A) Acute or chronic severe renal insufficiency (glomerular filtration rate <30 mL/min/1.73m2)
B) Stage 2 chronic kidney failure
C) Acute kidney infarction
D) Gadolinium-based contrast agents no not increase the risk of NSF
A) Acute or chronic severe renal insufficiency (glomerular filtration rate <30 mL/min/1.73m2)
10.
The Mn2+ based contrast agent MnDPDP is clinically approved for imaging which of the following?
A) CNS
B) Heart
C) Body (excluding heart)
D) Liver
E) Extracranial/ Extraspinal Tissue
D) Liver
11.
Which of the following Is a non-Gadolinium based, clinically approved MRI contrast agent?
A) MultiHance
B) Teslascan
C) Magnevist
D) Omniscan
E)
B) Teslascan
12.
True of False: Gadolinium contrast agents do not normally cross the blood brain barrier.
A) True
B) False
A) True
13.
Gadolinium works as a contrast agent in MRI because
A) gadolinium has several unpaired valence electrons
B) of the composition of the nucleus of the gadolinium atom
C) it is chelated with DTPA
D) gadolinium is diamagnetic
A) gadolinium has several unpaired valence electrons
14.
In MRI, gadolinium contrast agents used at clinical concentrations
A) shorten both T1 and T2
B) Shorten T1 with no effect on T2
C) Lengthen both T1 and T2
D) Lengthen T1 with no effect on T2
E) Shorten T2 with no effect on T1
A) shorten both T1 and T2