The tissue characteristic that provides more tissue contrast and pathological information is: -
ANSWER T2 effects
The basic process of MR signal generation contains two basic steps, they are: - ANSWER
Stimulation & Relaxation
Which statement is true of the relaxation process? - ANSWER Without the effects of T2*
(star), T2 decay continues
Which type of MRI magnet requires cryogen to cool magnetic coils to 4 degrees Kelvin? -
ANSWER Superconductive
Tissues that are very efficient at spin-lattice interactions near the Larmor frequency, such as
fatty tissues, should have - ANSWER Low T1 values and produces hyperintense signals
Which type of electromagnetic coils are employed as a transmitter, receiver or both? -
ANSWER Radio-frequency coils
The process of relaxation begins when: - ANSWER B1 is turned off
To symbolize the flow and area of a magnetic field, lines are used which are called: -
ANSWER Field or flux
Which molecule precesses closer to the Larmor frequency? - ANSWER Fat
1
, Which cryogenic material can produce temperature as low as 4 degrees Kelvin? -
ANSWER Liquid helium
Magnetism can be defined as the ability of certain substances to attract: - ANSWER Iron
Cobalt
Nickel
In a large main magnetic field such as those employed in MRI, the motion of a hydrogen
proton has been described as wobbling like a spinning top. This motion is called: -
ANSWER Precession
In comparison to Computed Axial Tomography, a disadvantage of MRI is: - ANSWER
Special and costly site planning & shielding
The tissue characteristic which depends more on the state (solid, liquid, gas) of a tissue than
any other factor is: - ANSWER T2 effects
The T1 process is also known as: - ANSWER Spin-Lattice
To describe the uniformity of the MRI system's main magnetic field, the term employed is: -
ANSWER Homogeneity
The main magnetic field of MRI systems in clinical use must meet an acceptable specification
of: - ANSWER 20-30 PPM
PPM: parts-per-million
A 90 degree radio-frequency pulse will alter the net magnetization vector. Another effect is: -
ANSWER The hydrogen protons will have phase coherence
2