ARMRIT Exam With 100% Correct And Verified Answers 2024, Exams of Advanced Education

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ARMRIT Exam With 100% Correct And

Verified Answers 2024

Electromagnetic energy is symbolized by a sine wave that has two components of measurements, they are: - Correct Answer-Wavelength and frequency Of the following techniques which one is applied to prevent "crosstalk" between multi- slices with little or no interslice "gap" - Correct Answer-Interleaving The artifact known as aliasing, wrap around or fold over will always show up in what gradient direction? - Correct Answer-Phase encoding Which of the following causes of artifacts on MR images is most commonly mistaken for a pathological signal? - Correct Answer-Chemical shift Substances which have magnetic properties of their own, such as, methemoglobin or gadolinium causes shortened T1 and T2 values for tissues in their vicinity are: - Correct Answer-Paramagnetic Currently, there is no evidence of a threat to fetal development from MRI exposure. - Correct Answer-True The formula that describes the relationship between the static magnetic field and the precessional frequency of the hydrogen protons is the _____ - Correct Answer-Larmor equation Employing an inversion recovery pulse sequence with a water suppression technique a normal intervertebral disc will appear dark - Correct Answer-True Of the following anatomical structure which is considered to be normally enhancing post gad injection? - Correct Answer-Choroids plexus Aliasing occurs due to tissue outside of the selected field of view (FOV) being : - Correct Answer-Undersampled The normal pituitary gland should appear bright following injection of a gadolinium enhancement agent - Correct Answer-True In conventional spin-echo imaging, each line of K-space is filled in each - Correct Answer-TR period As the M vector returns to equilibrium, the MR signal grows weaker, this is called: - Correct Answer-Free induction Decay

Gad enhancement agents will readily pass through the normal blood brain barrier - Correct Answer-False The temperature of the liquid helium in which the electromagnetic coil is immersed is approx: - Correct Answer--436 degrees F RF pulses are identified according to the _________ - Correct Answer-Flip angle MRI magnets that require cryogens to cool a substance to approximately 4 degrees Kelvin are: - Correct Answer-Superconducting ___ is the uniformity of the static magnetic field, expressed in terms of PPM (Parts per million) over a defined volume. - Correct Answer-Homogeniety In contrast to B0, B sub zero the Bsub one RF field is - Correct Answer-Rapidly rotating and always perpendicular to B sub zero The tissue property, in MRI, that is closely related to tissue state (solid, liquid) than any other tissue feature is: - Correct Answer-T1 effects Maximum exposure to gradient magnetic fields are set at a rate of: - Correct Answer- 6T/second The gradient that is turned on to sample the echo signal is: - Correct Answer-Phase encoding There are _ of __ serving the purpose of providing spatial information within the MR signal. - Correct Answer-Three pairs/gradient coils In general, parameter settings of TR and TE for attaining T1 and T2 images are as follows: - Correct Answer-T1: TR 100-1000 ms, TE 20-30 ms and T2: TR 1600-3000ms, TE 70-100 ms A resistive magnet requires liquid helium and liquid nitrogen in a dedicated cooling system - Correct Answer-False Following a 90 degree RF pulse, the signal that is created is called _____ - Correct Answer-free induction decay Passing from one compartment to another is the process of passing through the abnormal blood-brain-barrier. The compartments involved are the: - Correct Answer- Intravascular to interstitial The mathematical operation that converts a time varying RF signal to a graph that shows amplitude as a function of frequency and contains information about signal strength as a function of position is: - Correct Answer-2 dimensional Fourier Transform

MRI magnets that must have a dedicated special coding system due to heat produced by large currents (approx 100-150 amps) are - Correct Answer-Resistive Coils that superimpose small magnetic fields within the patient during the MRI process and allow for spatial encoding are - Correct Answer-Gradient coils Hydrogen nuclei have magnetic moment because they possess a property called _________ - Correct Answer-Spin In spatial localization, an efficient digital implementation of the mathematical method for converting a time-varying signal into its frequency and/or phase components that is actually performed by the MRI computer is known as: - Correct Answer-Fast Fourier transform Combining a metal ion with a ligand reduces their tendency to bind to proteins, enzymes, or membranes. The degree to which they dissociate is a measure of their _____________ - Correct Answer-Toxicity Magnetically sensitive objects such as credit cards, magnetic tapes and discs and EKG equipment should be kept beyond the ______ gauss line. - Correct Answer- Some fastened equipment such as pulse oxymeters, and electrodes have been reported to cause 3rd degree burns - Correct Answer-True Patients with cardiac pacemakers are only contraindicated for an MRI scan in main magnets of more than 0.5 T (>0.5T) - Correct Answer-False Of the following enhancement agents which is still investigational - Correct Answer-All Following the injection of a gadolinium enhancement agent, the pulse sequence most commonly employed is a - Correct Answer-T1 weighted MRI magnets that can range in weight from 26000-200000 lbs are: - Correct Answer- Permanent Using a conventional spin-echo multislice pulse sequence increasing the TE from 20 msec to 40 msec will __ the number of slices allowed - Correct Answer-Reduce In the environment of an MR main magnetic field most implants that cause a deflection are considered safe for imaging - Correct Answer-False TI is the characteristic time constant for ________ - Correct Answer-63% regrowth of longitudinal magnetization The field strength of an MR imaging magnet as measured within the bore is most typically expressed in terms of ________ - Correct Answer-Tesla

Coils that can during the MRI process act as a transmitter receiver or both are: - Correct Answer-Radio frequency coils The MR signal is strongest when the precessing nuclei are _________ - Correct Answer-phase coherence Increasing the number of phase encoding steps will produce an image with: - Correct Answer-Higher resolution Increasing which parameter is considered the "best" technique for improving image quality? - Correct Answer-NEX The Inversion Time, in an inversion recovery pulse sequence, is the time interval between the - Correct Answer-180 degree and 90 degree pulses When the net magnetization in the XY plane has ceased to exist the condition of ___ has been reached. - Correct Answer-Equilibrium If a phase resolution of 256 is desired in conventional spin-echo imaging, then the TR must be repeated how many times? - Correct Answer- When undergoing T1 relaxation, the net magnetization vector will - Correct Answer- Realign with the Z axis What factor, in spatial localization, does the slope of the slice select gradient control? - Correct Answer-Slice thickness Which method for providing spatial localization is employed during a pulse sequence when selecting only one slice at a time? - Correct Answer-2DFT Spins aligned in the anti-parallel directions are in _______ - Correct Answer-A high energy state The individual hydrogen protons aligned in the parallel direction in excess of the number aligned in the anti-parallel direction, produce a ___- vector parallel to the main magnetic field - Correct Answer-Net magnetization In a 2DFT conventional spin-echo multislice pulse sequence, scan time is given by the following equation: - Correct Answer-TR x NEX x # of phase encoding steps An RF pulse transmitted with a strength and duration sufficient to flip the M vector from the Z axis to the XY plane is a ________ - Correct Answer-90 degree pulse In an Inversion recovery pulse sequence, the net magnetization vector is rotated to the physical negative Z axis by applying a: - Correct Answer-180 degree pulse

Nuclei in their natural environment (in the absence of a significant magnetic field) are aligned _____ - Correct Answer-Randomly Once MRI patient is comfortable and apparently has no problems with the overall procedure, its acceptable for the tech to leave the scanning area while a long scan is underway - Correct Answer-False A paramagnetic, rare earth substance, attached to a chelating ligand for MRI enhancement purposes is: - Correct Answer-Gadolinium Which pulse sequences do not use Fourier Transform? - Correct Answer-None of the above A magnetic field strength of 0.5 Tesla is equivalent to ___ gauss - Correct Answer- Spine lattice relaxation time is another term representing ______ - Correct Answer-T relaxation Cryogen levels should never fall below: - Correct Answer-30% The receive bandwidth is related to the slope of which gradient? - Correct Answer-Slice select The ___ is a level of dose below which no response will be elicited - Correct Answer- Threshold dose Magnetophosphenes are described as: - Correct Answer-Seeing flashes of light Spin-spin relaxation is another term for ____ - Correct Answer-T2 relaxation Coils that correct for inhomogeneities in the static (main) magnetic field are: - Correct Answer-Shim coils Guidelines excluding pregnant individuals from MRI is mainly to protect the individual from: - Correct Answer-Radiofrequency (RF) The actual MRI image as seen on your operators console monitor is made up of - Correct Answer-Pixels Following the excitation pulse the FID decays _________ - Correct Answer- Exponentially The measure of spin-spin interactions is: - Correct Answer-T2 relaxation Measured T1 values at 1.5T will be ___ at 0.5 T - Correct Answer-Greater than

The conversion formula for magnetic field strength is expressed as ________ - Correct Answer-1 Tesla= 10,000 gauss On T2 or T1 weighted images cortical bone will appear: - Correct Answer-Signal void Currently, patients and personnel are excluded from exposure to MRI for the 1st trimester of pregnancy - Correct Answer-True Following the RF excitation, as transverse magnetization (Mxy) decays to zero, the MR signal _________ - Correct Answer-Increases exponentially Due to the normal signal decay and the effects of B sub zero, inhomogeneities, techniques have been developed to lengthen the RF signal and the disappearance of transverse magnetization. The most commonly employed technique today is: - Correct Answer-Gradient echo Of the following categories of patients, the one that would not present any special safety consideration is: - Correct Answer-Patients with previous arthroscopic knee surgery Of the different types of coils used in MRI, which types are found only in the housing of the main magnet. - Correct Answer-Shim/gradient coils All FDA approved gad enhancement agents for MRI are administered at the same dose it is: - Correct Answer-0.01 mmols/kg or 0.1 mm In terms of time, the least expensive parameter to incrase, of those that affect time when attempting to improve image quality is: - Correct Answer-TR SAR (specific absorption rate) set by the FDA, is the rate that RF energy is introduced to body tissue, measured in watts per kilogram - Correct Answer-True MRI magnets know for safe relatively low fringe fields and no electrical requirements are: - Correct Answer-Permanent __ is the accepted symbol used in MR to identify a magnetic component of the RF pulse which is introduced to stimulate the hydrogen protons into resonance. - Correct Answer- B sub zero Measurement of the magnetic field strength outside the bore of the MR imaging is most typically expressed in units of ______ - Correct Answer-Gauss Being relatively new field in medicine, the radio-biological questions about MRI including delayed response concerns are still unanswered. - Correct Answer-True MRI magnets that have been described as giant versions of toy (horseshoe or home fridge) magnets are: - Correct Answer-Permanent

The spinning nuclei begin to move out of the XY plane and realign toward the Z axis - Correct Answer-As a spin-lattice occurs TR is defined as - Correct Answer-Time interval between 90 degree pulses In 1990 Lauffer described two types of enhancement media, the mechanism of the T agent is to - Correct Answer-increase T2 relaxation time therefore emitting low signal n 1990, Lauffer described two types of enhancement media the mechanism of the T agent is to - Correct Answer-Increase T1 relaxation therefore emitting high signal TE is defined as: - Correct Answer-Time interval between 90 degree pulse and echo signal A T2 weighted pulse sequence of the brain results in the white matter appearing brighter than the gray matter - Correct Answer-False Which characteristic of tissue in MRI is the result of fast transition phenomenon and/or entry phenomenon - Correct Answer-Flow/velocity effects T2 relaxation time is defined as when ___ of the ___ magnetization has decayed. - Correct Answer-63%/transverse During 2DFT, spin-echo pulse sequences, fast flowing blood usually appears - Correct Answer-Hypointense During 2DFT spin echo pulse sequences, slow flowing blood usually appears: - Correct Answer-Hyperintense A maximum spatial peak of 8w/kg - Correct Answer-RF in one gram of tissue Fatty tissues have a molecular structure that is very efficient at spin-lattic interactions at the Larmor Frequency, so fatty tissue should - Correct Answer-Have short T1 values and appear hyperintense Raw data (digitized echos) is loaded into the array processor in a 2D data acquisition matrix, commonly referred to as _______ - Correct Answer-K space On MRI images, an acute hemorrhage will have a bright signal intensity in a T2 seighted pulse sequence - Correct Answer-False On T1 weighted images subacute hemorrhage will appear bright - Correct Answer-True The _____ and _____ are the terms which indicate the amount of macroscopic magnetization vector is rotated by an RF pulse with respect to the static magnetic field - Correct Answer-Flip angle/mutation angle

Enhancement can be demonstrated on which of the following pulse sequences post gad injection - Correct Answer-ALL In regards to radiofrequency (RF) the concern is that there should not be an increase in body core temp of: - Correct Answer-1 degree C Local exposures to the radiofrequency are less than 38 degree C in the head, less than 39 degrees C in the trunk, less htan 40 degrees C in extremities - Correct Answer-True T2 is the characteristic time constant for ______ - Correct Answer-37% loss of magnetization in the transverse plane Of the following MRI enhancement agents, which are FDA approved for clinical use - Correct Answer-ALL Given a tissue sample containing 10 (23) mobile hydrogen protons, it can be safely assumed that approximately _____ of those protons will _____ to the static magnetic field - Correct Answer-10(17) align parallel The Larmor precessional or resonate frequency of hydrogen protons in a static magnetic field of 1.0T is approximately _____ - Correct Answer-42.576 MHz RF average over the head - Correct Answer-No more than 3.2 w/kg RF average over whole body is - Correct Answer-No more than 0.4 w/kg B subzero extremities absorption rate is - Correct Answer-5 Tesla B subzero head and trunk absorption rate is - Correct Answer-3 Tesla Because of a variation of only 10-15% in most tissue which tissue characteristic does not allow for much contrast resolution on MR images? - Correct Answer-Bound water If the M vector lies between the longitudinal and transverse axes, what will the magnitudes of M for the longitudinal component M2 and the transverse component Mxy be? - Correct Answer-Longitudinal; larger than zero Transverse larger than zero The maximum exposure of the head and neck to the main magnetic field B subzero is: - Correct Answer-4T In spatial localization phase encoding is performed: - Correct Answer-Prior to frequency encoding