ARMRIT EXAM QUESTIONS with Complete VERIFIED Solutions 2024/2025, Exams of Health sciences

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ARMRIT EXAM QUESTIONS with Complete VERIFIED Solutions 2024/2025 Different tissues that have signals that appear similar on an MR image are described as: A) hypointense B) hyperintense C) isointense D) isodense 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 A) precession B) resonance C) frequency D) angular momentum precession magnetic resonance imaging is derived from the process known as: A) magnetic resonance angiography B) magnetic relaxation imaging C) nuclear magnetic resonance D) nuclear resonance imaging nuclear magnetic resonance Once the nmv has moved away from equilibrium, the following will occur A) the longitudinal component will increase B) the transverse component will decrease C) the longitudinal component will stay the same D) the transverse component will increase the transverse component will increase In MR, substances respond to a specific radio frequency which is known as: A) magnetic frequency B) radio frequency C) gyro-magnetic frequency D) resonance frequency 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: A) intravascular to interstitial B) extracellular to intracellular C) hepatobiliary to renal D) extradural to renal intravascular to interstitial t2 is the measurement of time fot the transverse component of the NMV to decrease what percentage of its maximum value after the application of a 90 degree radio-frequency pulse A) 33% B) 63% C) 37% D) 67% 37% in the USA, the MRI system's magnetic field and vector that represents it is symbolized: A) B1 B) B2 C) B3 D) B0 B0 The resonance frequency of any substance in a magnetic field can be calculated by employing the A) damadian equation B) larmor equation C) faraday equation D) lauterbur equation Larmor equation C) 90 degrees D) 180 degrees 180 degrees of the following statements, which describes part of the basic MR imaging process: A) a patient is placed isocenter to ionizing radiation B) the patient is exposed to ionizing radiation C) the generated image contains hypersense and hypodense areas D) radio frequency signals interact with hydrogen protons radio frequency signals interact with hydrogen protons which type of electromagnetic coils correct inhomogeneities in the main magnetic field? A) gradient coils B) radio frequency coils C) shim coils shim coils immediately after an initial 90 degree radio frequency pulse is turned off, the hydrogen protons will begin to: A) Rephase B) Dephase C) Stay in the transverse plane D) Stay in phase Dephase tissues that are very efficient at spin-lattice interactions near the larmor frequency, such as fatty tissues should have: A) Low T1 values and produce hyperintense signals B) High T1 values and produce hyperintense signals C) High T1 values and produce hypointense signals D) Low T1 values and produce hypointense signals 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? A) 33% B) 63% C) 37% D) 67% 63% the tissue characteristic which depends more on the state (solid, liquid, gas) of a tissue than any other factor is: A) T1 effects B) T2 effects C) hydrogen concentration D) velocity effects T2 effects the basic process of MR signal generation contains 2 basic steps, they are: A) parallel alignment and anti-parallel alignment B) stimulation and relaxation C) magnetization and ionization D) magnetization and ionization stimulation and relaxation the T1 process is also known as: A) spin spin B) spin density C) spin lattice D) spin wrap spin lattice the T2 process is also known as: A) spin spin B) spin density C) spin lattice D) spin wrap spin spin once in the main magnetic field, a majority of hydrogen protons will align themselves A) anti-parallel to B0 B) Orthogonal to B0 C) Parallel to B0 D) Randomly to B0 Parallel to B0 the tissue characteristic that depend heavily on the relative content of fat molecules and free water is: A) T1 effects B) T2 effects C) hydrogen concentration D) velocity effects T1 effects which type of receiver radio frequency coil is placed close to a patient's body for the purpose of imaging superficial anatomic structures A) solenoid coils B) maxwell coils C) surface coils D) golay coils surface 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: A) larmor equation B) bloch equation C) phase shifts formula D) resonance frequency formula larmor equation which statement is true of the relaxation process? A) T2* effects slow down T2 decay B) without the effects of T2*, T2 decay continues C) T2* effects can not be corrected for D) T2* effects have no effect on T2 decay without 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 A) magnetic charge B) magnetic spin C) magnetic moment D) magnetic precession magnetic moment On a proton density image, 2 types of tissue that contain very low concentrations of hydrogen and appear very hypointense are A) Cerebral tissue and CSF B) fat and muscle C) medullary bone and kidney D) cortical bone and lung cerebral tissue and CSF in comparison to CT an advantage of MRI is: A) slower scan time B) higher cost of the MRI system to symbolize the flow and area of a magnetic field, lines are used which are called: A) gauss B) axes C) field or flux D) vector field or flux all chemical substances have an assigned constant known as the: A) gyro magnetic ratio B) larmor ratio C) precessional ratio D) angular momentum gyro magnetic ratio mri systmes require rooms that provide specific shielding requirements. these rooms are lined with what typer of material? A) stainless steel or titanium B) copper or galvanized steel C) lead D) iron oxide or neodymium copper or galvanized steel which type of MRI magnet requires no electricity to maintain its magnetic field and can weigh from 18,000 to 200,000 lb.? A) superconductive B) resistive C) permanent permanent which type of electromagnetic coils are employed as a transmitter, receiver, or both? A) gradient coils B) radio frequency coils C) shim coils radio frequency coils which type of MRI magnet requires a special cooling system to dissipate heat produced by very large currents? A) superconductive B) resistive C) permanent resistive tissues that are efficient in both T1 an T2 interactions have low (short) relaxation times, and therefore have: A) high T1 values B) high relaxation rates C) high T2 values D) low relaxation rate high relaxation rates because of only 10-15% variation in most tissues, the tissue characteristic that does not provide much contrast resolution is: A) T1 effects B) T2 effects C) hydrogen concentration D) velocity effects hydrogen concentration the tissue characteristics that is dependent on the strength of the main magnetic field and temperature is: A) T1 effects B) T2 effects C) hydrogen concentration D) velocity effects T1 effects the component Mz is most associated with: A) anti-parallel to B0; T2 relaxation; net magnetization B) transverse to B0; T2 relaxation; transverse magnetization C) parallel to B0; T1 relaxation; longitudinal magnetization D) perpendicular to B0; T2 decay; FID parallel to B0; T1 relaxation; longitudinal magnetization the component Mxy is most associated with: A) anti-parallel to B0; T1 relaxation; net magnetization B) transverse to B0; T2 relaxation; transverse magnetization C) parallel to B0; T1 relaxation; longitudinal magnetization D) perpendicular to B0; T2 decay; FID transverse to B0; T2 relaxation; transverse magnetization in the USA, MRI systems in clinical use have main magnetic field strengths that range from: A) 2T to 6T B) 0.06T to 3T C) 2 Gauss to 6 Gauss D) 0.006T to 0.03T 0.06T to 3T On a very basic level, the 3 basic components required to attain MR signals are: A) Magnetic field, proton, ionizing radiation B) magnetic field, electron, ionizing radiation C) magnetic field, electron, radio wave D) magnetic field, proton, radio wave magnetic field, proton, radio wave the main magnetic field of the MRI system is described as constant and always oriented in one set direction, either horizontal or vertical (dependent on the type of magnet). the transmitted radio frequency, in comparison, is described as: A) constant and always parallel to B0 B) oscillating and always parallel to B0 C) constant and always perpendicular to B0 D) oscillating and always perpendicular to B0 oscillating and always perpendicular to B0 which of the following parameters controls the amount of contrast seen in an image due to T2 relaxation A) T1 B) TE C) TR D) None of these TE a magnetic field strength of 0.5T is equivalent to: A) 1500 G B) 5000 G C) 1 G D) 10000 G 5000 G an example of a dipole is: A) a hydrogen nucleus B) a bar magnet C) the earth D) all of the above all of the above B) resistive C) permanent D) superconducting E) attach to a soft iron yoke resistive coils that super impose superimpose small magnetic fields within the patient during the MRI process and allow for spatial encoding are: A) shim coils B) radio frequency coils C) gradient coils D) resistive coils E) superconducting gradient coils a permanent magnet requires liquid helium and liquid nitrogen in a dedicated cooling system. A) True B) False False employing a pulse sequence with a long TR and long TE will result in tissues with a short T2 value appearing ___________ and tissues with a long T2 appearing __________on the resultant image A) dark/bright B) bright/bright C) bright/dark D) dark/dark dark/bright what factor, in spatial localization, does the slope of the slice select gradient control? A) slice thickness B) slice length C) slice angle D) how many slices in a scan E) FOV slice thickness increasing the # of phase encoding steps will produce an image with: A) lower resolution B) higher resolution C) increased voxel volume D) unchanged voxel volume E) higher SNR higher resolution on T1 weighted images sub-acute hemorrhage will appear bright. True or False True substances which have magnetic properties of their own, such as Methemoglobin or Gadolinium, cause shortened T1 and T2 values for tissues in their vicinity are: A) non magnetic B) paramagnetic C) superparamagnetic D) ferromagnetic E) diamagnetic paramagnetic the maximum exposure of the head and trunk to the main magnetic field (B0) is: A) no more than 8 w/kg B) no more than 3.2 w/kg C) no more than 0.4 w/kg D) a maximum spatial peak of 8 w/kg no more than 3.2 w/kg currently, there is evidence of a threat to fetal development from MRI exposure: true or false False some older implanted ferromagnetic neuro-aneurysm clips, suture materials, and surgical clips will experience a force of _____________, as the material is passed through a strong magnetic field. A) deceleration B) torque C) acceleration D) inertia torque the factor, which determines the calculated SAR averages is: A) field strength B) the patients weight in kilograms C) an average calculation of heat per milisecond D) heat dissipated over time the patients weight in kilograms the receive bandwidth is related to the slope of which gradient? A) slice select B) phase encoding C) frequency encoding D) 90 degree RF pulse E) 180 degree RF pulse slice select in an inversion recovery pulse sequence, the NMV is rotated to the physical negative Z axis by applying a: A) 60 degree pulse B) 90 degree pulse C) 180 degree pulse D) 270 degree pulse E) 90 degree pulse pair 180 degree pulse which of the following setting descriptions for the parameters TR and TE best describes a proton density image? A) short TR/ short TE B) long TR/ long TE C) short TR/ long TE D) long TR/ short TE E) long TR/ short TI long TR/short TE the inversion time, in an inversion recovery pulse sequence, is the time interval between the: A) 90 and 180 pulses B) 90 degree pulse and the echo signal C) 180 degree pulse and the echo signal D) 90 and 90 degree pulses E) 180 and 90 degree pulses 180 and 90 degree pulses in general, parameter settings of TR and TE for attaining T1 and T2 images are as follows: A) T1; TR 1600-3000ms, TE 70-100ms / T2; TR 100-100ms, TE 20-30ms B) T1; TR 100-1000ms, TE 70-100ms / T2; TR 1600-3000ms, TE 20-30ms C) T1; TR 100-1000ms, TE 20-30ms / T2; TR 1600-3000ms, TE 70-100ms D) T1; TR 1600-3000ms, TE 20-30ms / T2; TR 100-1000ms, TE 70-100ms T1; TR 100-1000ms, TE 20-30ms / T2; TR 1600-3000ms, TE 70-100ms the pulse sequence that replaces the second RF pulse with a magnetic field gradient to rephase the transverse vector and produce the echo signal is: A) spin echo for MRI magnets, the specification for field homogeneity that is considered acceptable is: A) 5-10ppm B) 10-15ppm C) 20-30ppm D) 40-50ppm 20-30ppm the primary factor of an inversion recovery pulse sequence is which of the following parameters? A) TR B) TE C) TI D) FSE E) MRA TI of the different types of coils used in MRI, which type(s) are found only in the housing of the main magnet? A) surface coils B) radio frequency coils C) Heimholtz coils D) shim/gradient coils E) all shim/gradient coils which of the following causes of artifacts on MR images is most commonly mistaken for a pathological signal? A) eddy currents B) magnetic susceptibility C) chemical shift D) untuned RF coils E) ferromagnetic object chemical shift of the following anatomical structures, which is considered to be normally enhancing post gadolinium injection? A) cerebellum B) choroid plexus C) intervertebral disc D) auditory nerves E) corpus callosum choroid plexus cryogen levels should never fall below: A) 23% B) 30% C) 50% D) 66% E) 80% 50% the electromagnetic coil responsible for producing the strong magnetic field of a superconducting magnet is embedded in a _____________ which serves as an insulator from heat in the even of a quench. A) niobium-titanium matrix B) lead matrix C) carbon composite matrix D) steel matrix E) copper matrix copper matrix there are ____________ of _____________ serving the purpose of providing spatial information within the MR signal A) 3 pairs/ gradient coils B) 2 pairs/ shim coils C) 2 pairs/ RF amplifiers D) 6 pairs/ solenoid coils 3 pairs/ gradient coils the temperature of the liquid helium in which the electromagnetic coil is immersed is appoximately: A) 32 degree F B) 0 degree k C) -40 degree C D) -436 degree F E) -4 degree C -436 degree F cooling the electromagnetic coil windings to the point of supeconductivity and then inducing an electric current from an external power supply until the magnet is a full power is called: A) ramping up B) resistance load C) quench D) boot E) topping off ramping up Following the injection of a gadolinium enhancement agent, the pulse sequence most commonly employed is a: A) T2 weighted B) gradient echo C) T1 weighted D) proton density E) inversion recovery T1 weighted all FDA approved gadolinium enhancement agents for MRI are administered at the same dose, it is: A) 0.1mmols/kg B) 0.01mmols/kg C) .001mmols/kg D) 1.0mmols/kg E) 10.0mmols/kg 0.1mmols/kg on mri images, an acute hemorrhage will have a bright signal intensity in a T2 weighted pulse sequence? True or False True employing an inversion recovery pulse sequence with a water suppression technique a normal intervertebral disc will appear dark. true or false true a T2 weighted pulse sequence of the brain results in the white matter appearing brighter than the gray matter. true or false false when describing overall image quality, which best describes the difference in signal intensity between 2 adjacent structures divided by noise: A) resolution B) signal to noise ration C) signal averaging D) 5T e) 6T 3T the maximum exposure of extremities to the main magnetic field (B0) is: A) 2T B) 3T C) 4T D) 5T e) 6T 5T exposure to gradient magnetic fields are based on the premise that the fields should be too weak to cause neuromuscular stimulation by at least a factor of 3. true or false true maximum exposure to gradient magnetic fields are set at a rate of A) 3T/ second B) 4T/ second C) 5T/ second D) 6T/ second 6T/ second the maximum exposure of RF averaged over the whole body is: A) no more than 8 w/kg B) no more than 3.2 w/kg C) no more than 0.4 w/kg D) a maximum spatial peak of 8 w/kg no more than 0.4 w/kg the maximum exposure of RF in one gram of tissue is: A) no more than 8 w/kg B) no more than 3.2 w/kg C) no more than 0.4 w/kg D) a maximum spatial peak of 8 w/kg a maximum spatial peak of 8 w/kg in regards to RF the concern is that there should not be an increase in body core temperature of: A) 1 degree F B) 1 degree C C) 2 degrees F D) 2 degrees C E) 3 degree K 1 degree C currently, patients and personnel are excluded from exposure to MRI for the 1st trimester of pregnancy true or false true guidelines excluding pregnant individuals from MRI is mainly to protect the individual from: A) main magnetic field B) Radio frequency C) gradient magnetic fields D) cryogen boil off radio frequency of the following categories of patients, the one that would not present any special safety considerations is: A) patient with cardiac pacemaker B) patient on life support systems C) patients with previous arthroscopic knee surgery D) patients with a history of employment as a metal worker patients with previous arthroscopic knee surgery the _____________ is a level of dose below which no response will be elicited A) Specific absorption dose B) dose equivalent C) threshold dose D)dose response curve threshold dose local exposures to the RF are: less than 38 degrees C in the head, less than 39 degrees C in the trunk, less than 40 degree C in the extremities true or false true patients with cardiac pacemakers are only contraindicated for an MRI scan in main magnets of more than 0.5T. true or false false magnetophosphenes are described as: A) phosphorous levels in the body increase B) palpitations C) seeing flashes of light D) 2nd degree burn seeing flashes of light magnetically sensitive objects such as credit cards, magnetic tapes and discs, and EKG equipment should be kept beyond the ________gauss line A) 5 B) 10 C) 15 D) 30 E) 50 5 some fastened equipment such as pulse oximeters and electrodes have reported to cause 3rd degree burns true and false true being a relatively new field in medicine, the radio-biological questions about MRI, including delayed response concerns, are still unanswered. true and false true in the enviornment of an MR main magnetic field, most implants that cause a deflection are considered safe for imaging. true and false false once the MRI patient is comfortable and apparently has no problem with the overall procedure, it is acceptable for the technologist to leave the scanning area while a long scan is underway. true or false false to avoid any possibility for a ferromagnetic object becoming a projectile, it would be advisable and safer to have the patient remove all metal objects from their person prior to the scan true or false true given tissue sample containing 10^23 mobile hydrogen protons, it can be safety assumed that approximately __________of those protons will __________ to the static magnetic field A) 10^23/ align antiparallel B) 10^17/align parallel C) 10^6/ precess perpendicular D) 10^12/ align parallel the NMV will generate a stronger MR signal if the alignment is at: A) 180 degrees B) 120 degrees C) 90 degrees D) 360 degrees 90 degrees The __________ and ___________ are the terms which indicate the amount the macroscopic magnetization vector is rotated by RF pulse with respect to the static magnetic field A) flip angle/nutration angle B) T1/T2 relaxation C) Lannor/resonance frequency D) Tesla/gauss flip angle/nutration angle nuclei having an _________ of nucleons (neutrons and protons) will tend to possess magnetic properties A) even number B) isotropic number C) excess number D) odd number odd number the tendency of a substance to become magnetized or to distort an applied magnetic field is ___________. A) ferromagnetic B) magnetic susceptibility C) diamagnetic D) superconducting magnetic susceptibility ______________ is the uniformity of the static magnetic field, expressed in terms of PPM (parts per million) over a defined volume. A) hertz B) homogeneity C) shim D) B0 homogeneity ____________ is the property of most substances having paired orbital electrons resulting in these substances being weakly repelled by the applied magnetic field A) paramagnetic B) ferromagnetic C) superparamagetic D) diamagnetic diamagnetic as spin lattice occurs, ___________. A) the spinning nuclei begin to align randomly B) the spinning nuclei begin to dephase C) the precessional frequency of the spinning nuclei begins to increase exponentially D) the spinning nuclei begin to move out of the XY plane and realign toward the Z axis the spinning nuclei begin to move out of the XY plane and realign toward the Z axis ___________ occurs when the frequency of the intermittent magnetic field, the RF pulse, matched the frequency of the precessing nuclei- the nuclei absorbing the energy of the RF pulse and flipping the nuclei at some alpha angle away from the Z axis and into the XY plane. A) saturation B) resonance C) dephasing D) relaxation resonance raw data (digitized echoes) is loaded into the array processor in a 2D data acquisition matrix, commonly referred to as ____________. A) data acquisition board B) host interface board C) matrix memory storage D) k space k space in MR, spatial resolution is determined by _______ & _____________. A) field strength/receiver coil B) flip angle/TE C) slice thickness/pixel size D) TR/NEX slice thickness/pixel size TR is defined as: A) the time interval between 90 degree pulses B) the time interval between the 90 degree and the 180 degree pulses C) the time interval between the 180 degree and the 90 degree pulses D) time of rephasing the time interval between 90 degree pulses TE is defined as: A) the time interval between 90 degree pulses B) the time interval between the 90 degree and echo signal C) the time interval between the 180 degree and the 90 degree pulses D) time of encoding the time interval between the 90 degree and echo signal During 2DFT, spin echo pulse sequences, fast flowing blood usually appear: A) hyperintense B) isointense C) hypointense D) enhanced hypointense During 2DFT, spin echo pulse sequences, slow flowing blood usually appear: A) hyperintense B) isointense C) hypointense D) void hyperintense the measure of spin-spin interactions is: A) T2 relaxation B) T2* relaxation C) T1 relaxation D) inversion recovery E) Proton density T2 relaxation TI is defined as: A) the time interval between 90 degree pulses B) the time interval between the 90 degree and the 180 degree pulses C) the time interval between the 180 degree and the 90 degree pulses D) the time interval between the 90 degree and echo signal the time interval between the 180 degree and the 90 degree pulses which pulse sequences do not use Fourier transform? A) gradient echo, spin echo, inversion recovery B) inversion recovery, fast spin-echo, gradient echo C) fast spin-echo, gradient echo, time-of flight D) none of the above none of the above due to the normal signal decay and the effects of B0 inhomogeneities, techniques have been developed to lengthen the RF signal and the disappearance of transverse magnetization. the most commonly employed technique today is: A) inversion recovery B) gradient echo C) spin-echo D) partial saturation E) saturation recovery spin-echo as the M vector returns to equilibrium, the MR signal grows weaker, this is called: A) free fourier transform B) free fourier decay C) free induction decay D) free induction transform free induction decay without the effects of T2* on the FID signal, signal decay still takes place true or false true fatty tissues have a molecular structure that is very efficient at spin lattice interactions at the Larmor frequency, so fatty tissues should: A) have short T1 values and appear hyperintense B) have long T1 values and appear hyperintense C) have short T1 values and appear hypointense D) have long T1 values and appear isointense E) have long T1 values and appearhypointense have short T1 values and appear hyperintense CSF contains more free water, making it less efficient at spin spin interactions. CSF should: A) have short T2 values and appear hyperintense B) have long T2 values and appear hyperintense C) have short T2 values and appear hypointense D) have long T2 values and appear isointense E) have long T2 values and appear hypointense have long T2 values and appear hyperintense of the following size molecules, which molecules will precess closer to the Larmor frequency when placed within a large static magnetic field A) small (water) B) medium (fat) C) large (protein) D) all E) none small (water) MRI magnets that have been described as giant versions of toy (horseshoe or home refrigerator) magnets are: A) superconducting B) resistive C) permanent D) hybrid E) horizontal field permanent MRI magnets known for safe, relatively low fringe fields and no electrical requirements are: A) superconducting B) resistive C) permanent D) high field E) vertical field permanent which gradient axis direction is typically (for educational purposes) designated as the slice selection gradient? A) physical X gradient B) physical Z gradient C) logical Z gradient D) logical Y gradient E) logical X gradient physical Z gradient in spatial localization, phase encoding is performed: A) after frequency encoding B) prior to frequency encoding C) in place of frequency encoding D) during echo sampling prior to frequency encoding if a phase resolution of 256 is desired in conventional spin echo imaging, then the TR must be repeated how many times? A) 512 B) 256 C) 192 D) 160 E) 128 256 one direction in K space represents phase while the other direction represents: A) intensity B) contrast C) resolution D) frequency E) slice select frequency in conventional spin echo imaging, each line of K space is filled in each: A) TE period B) phase encoding period C) TR period D) frequency encoding period E) TI period TR period increasing the FOV will increase the SNR true or false true the gradient that is turned on to sample the echo signal is: A) phase encoding B) slice select C) frequency encoding D) secondary slice select E) gradient echo phase encoding the actual MRI image, as seen on your operators console monitor, is made up of A) pixels B) voxels C) wessels D) volume elements E) all pixels a pulse sequence where only 90 degree RF pulses are used is called: A) spin echo B1 the tissue characteristic that provides more tissue contrast and pathological information is: A) T1 effects B) T2 effects C) hydrogen concentration D) velocity effects T2 effects what is the gyro magnetic ration of hydrogen? A) 17.23 MHz B) 11.26 MHz C) 42.58 MHz D) 40.05MHz 42.58 MHz which type of MRI magnet is made up of naturally ferromagnetic material? A) superconductive B) resistive C) permanent permanent once the patient's area pf interest is placed in the main magnetic field of the MRI system, the hydrogen protons will: A) precess parallel to B1 B) precess parallel to B0 C) precess orthogonal to B0 D) precess randomly in B0 precess parallel to B0 1 millilter of H2O contains how many hydrogen protons? A) 6x10^22 B) 6x10^23 C) 6x10^17 D) 6x10^18 6x10^22 an inversion recovery pulse sequence can be which of the following A) T1 weighted B) water suppressed C) fat suppressed D) all all in a horizontal field magnet, what is the primary Gs for an axial slice? A) Gx B) Gy C) Gz Gz increasing FOV will: A) increase SNR B) decrease SNR C) decrease Matrix increase SNR which of the following statements is true for gadolinium MRI IV enhancement products? A) does not promote transmissions B) produces randomly fluctuating magnetic fields in its immediate environment C) does not have a rapid molecular tumbling in solution D) does not have a large magnetic moment produces randomly fluctuating magnetic fields in its immediate environment decreasing NEX will: A) increase SNR B) decrease SNR C) increase scan time D) has no effect on scan time decrease SNR Decreasing TE will: A) decrease the # of allowable slices B) increase the # of allowable slices C) increase scan time D) decrease scan time increase the # of allowable slices information acquired when you increase or decrease the frequency of the RF pulse of the Gs, causing the center of the excited plane to change with the center of the Gs RF pulse is: A) slice plane B) slice interval C) slice position D) slice number slice position in an inversion recovery pulse sequence, what T1 will produce a STIR fat suppressed pulsesequence? A) 80-120 B) 180-300 C) 300-500 D) 500-800 80-120 increasing FOV, TE, and slicce interval will: A) increase scan time B) decrease scan time C) not affect scan time not affect scan time the purpose of the 1st use of metal ions in MRI enhancement like gadolinium is to: A) increase relaxation time for H in tissue B) decrease relaxation time for H in tissue C) increase signal on T2 images D) decrease signal on T1 images decrease relaxation time for H in tissue what year was the 1st MRI enhancement agent approved for clinical use? A) 1988 B) 1946 C) 1973 D) 1981 1988 decreasing slice thickness will: A) increase SNR B) decrease SNR C) increase matrix decrease SNR increasing NEX will: A) decrease SNR B) increase SNR C) decrease scan time D) have no effect on scan time increase SNR decreasing matrix will: A) increase pixel size B) decrease pixel size C) have no effect on pixel size