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ARMRIT (Ronizzle) Questions with Solutions
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Exam of 16 pages for the course ARMRIT at ARMRIT (ARMRIT (Ronizzle))
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ARMRIT (Ronizzle)Different tissues that have signals that appear similar on an MR image are described
as: - answer isointense
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
magnetic resonance imaging is derived from the process known as: - answer nuclear
magnetic resonance
Once the nmv (Net Magnetization Vector) has moved away from equilibrium, the
following will occur. - answer the transverse component will increase
In MR, substances respond to a specific radio frequency which is known as: - answer
resonance frequency
the introduction of gadolinium-based contrast enhancement agents by intravenous
injection can involve passing through an abnormal blood brain barrier. the tissue
compartments involved are the: - answer intravascular to interstitial
T2 is the measurement of time for the transverse component of the NMV to decrease
what percentage of its maximum value after the application of a 90 degree radio-
frequency pulse - answer37%
in the USA, the MRI system's magnetic field and vector that represents it is symbolized:
- answerB0
The resonance frequency of any substance in a magnetic field can be calculated by
employing the - answerLarmor equation
in a pulse sequence, transmitting an initial 90 degree radio-frequency pulse will cause
the NMV to: - answershift in both size and direction
Which type of electromagnetic coils are designed to stimulate and detect an MR signal?
- answerradio frequency coils
tissues that are less efficient at spin-spin interactions because they contain more free
water, such as CSF, should have - answerHigh T2 values and produce hyperintense
signals
,magnetism can be defined as the ability of certain substances to attract: - answerIron,
cobalt, nickel
the purpose of magnetic resonance angiography is to image the: - answerblood flow
the strength of very large magnetic fields like those employed in MRI systems, the SI
unit most commonly used is: - answerTesla
the larmor frequency of hydrogen protons in a 1.5 tesla magnetic field is: - answer63.9
MHz/Tesla
In MR imaging, for chemical substance to be affected by the main magnetic field and
the radio-wave it must contain an: - answerOdd number of total protons and neutrons
A 1.5T magnetic field is equal to: - answer15,000 gauss
the components of the gyromagnetic ratio are: - answermagnetic moment to angular
momentum
fast transition phenomenon and entry phenomenon are theories that explain which of
the following characterisitics: - answerVelocity effects
the effects of main magnetic field inhomogeneities on the FID signal are corrected for in
the spin echo sequence by applying a second radio frequency pulse. the flip angle of
this radio frequency pulse is: - answer180 degrees
of the following statements, which describes part of the basic MR imaging process: -
answerradio frequency signals interact with hydrogen protons
which type of electromagnetic coils correct inhomogeneities in the main magnetic field?
- answershim coils
immediately after an initial 90 degree radio frequency pulse is turned off, the hydrogen
protons will begin to: - answerDephase
tissues that are very efficient at spin-lattice interactions near the larmor frequency, such
as fatty tissues should have: - answerLow T1 values and produce hyperintense signals
T1 is the measurement of time for the longitudinal component of the NMV to recover
what percentage of its original value after the application of a 90 degree radio frequency
pulse? - answer63%
the tissue characteristic which depends more on the state (solid, liquid, gas) of a tissue
than any other factor is: - answerT2 effects
, the basic process of MR signal generation contains 2 basic steps, they are: -
answerstimulation and relaxation
the T1 process is also known as: - answerspin lattice
the T2 process is also known as: - answerspin spin
once in the main magnetic field, a majority of hydrogen protons will align themselves -
answerParallel to B0
the tissue characteristic that depend heavily on the relative content of fat molecules and
free water is: - answerT1 effects
which type of receiver radio frequency coil is placed close to a patient's body for the
purpose of imaging superficial anatomic structures - answersurface coils
an equation derived to predict the MR signal intensity of a particular tissue as the result
of a spin echo pulse sequence is the: - answerlarmor equation
which statement is true of the relaxation process? - answerwithout the effects of T2*, T2
decay continues
because of the spinning motion of the hydrogen proton it has the same properties as a
bar magnent. the hydrogen protons spinning motion gives it a - answermagnetic
moment
On a proton density image, 2 types of tissue that contain very low concentrations of
hydrogen and appear very hypointense are - answercerebral tissue and CSF
in comparison to CT an advantage of MRI is: - answersuperior soft tissue contrast
resolution
in a loop of conductor in which an electric current is introduced and maintained a
magnetic field will be produced in the center perpendicular to the flow of the electric
current. this is called: - answerFaraday's Law
which type of MRI magnet has attainable field strengths of 0.35T to 3T for clinical use in
the USA and higher strengths elsewhere and in research? - answersuperconductive
the process of relaxation begins when: - answerB1 is turned off
a sinewave is a symbol used to measure electromagnetic energy. A sinewave's 2
components of measurement are: - answerwavelength and frequency
magnetic fields have direction which are usually designated as north and south
therefore magnetic fields are described as: - answerdipoles
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