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 precessio...
ARMRIT Test 3 Questions With Correct Answers 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 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 intra-venous 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 - Answer 37%
in the USA, the MRI system's magnetic field and vector that represents it is symbolized: - Answer B0
The resonance frequency of any substance in a magnetic field can be calculated by employing the: - Answer Larmor equation
in a pulse sequence, transmitting an initial 90 degree radio-frequency pulse will cause the NMV to: - Answer shift in both size and direction
Which type of electromagnetic coils are designed to stimulate and detect an MR signal - Answer radio-
frequency
tissues that are less efficient at spin-spin interactions because they contain more free water, such as CSF, should have - Answer High T2 values and produce hyperintense signals
magnetism can be defined as the ability of certain substances to attract: - Answer Iron, cobalt, nickel
the purpose of magnetic resonance angiography is to image the: - Answer blood flow
the strength of very large magnetic fields like those employed in MRI systems, the SI unit most commonly used is: - Answer Tesla
the larmor frequency of hydrogen protons in a 1.5 tesla magnetic field is: - Answer 63.9 MHz/Tesla
In MR imaging, for chemical substance to be affected by the main magnetic field and the radio-wave it must contain an: - Answer Odd number of total protons and neutrons
A 1.5T magnetic field is equal to: - Answer 15,000 gauss
the components of the gyromagnetic ratio are: - Answer magnetic moment to angular momentum
fast transition phenomenon and entry phenomenon are theories that explain which of the following characterisitics: - Answer Velocity 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: - Answer 180 degrees of the following statements, which describes part of the basic MR imaging process: - Answer radio frequency signals interact with hydrogen protons
which type of electromagnetic coils correct inhomogeneities in the main magnetic field: - Answer shim coils
immediately after an initial 90 degree radio frequency pulse is turned off, the hydrogen protons will begin to: - Answer Dephase
tissues that are very efficient at spin-lattice interactions near the larmor frequency, such as fatty tissues should have: - Answer Low 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? - Answer 63%
the tissue characteristic which depends more on the state (solid, liquid, gas) of a tissue than any other factor is: - Answer T2 effects
the basic process of MR signal generation contains 2 basic steps, they are: - Answer stimulation and relaxation
the T1 process is also known as: - Answer spin lattice
the T2 process is also known as: - Answer spin spin
once in the main magnetic field, a majority of hydrogen protons will align themselves - Answer Parallel to
B0
the tissue characteristic that depend heavily on the relative content of fat molecules and free water is: - Answer T1 effects
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