Hardware MRI Quiz

The purpose of shimming the magnet is to:
A. make the B0 field as homogenous as possible
B. make the B1 field as homogenous as possible
C. make the scan time as short as possible
D. correct for gradient slopes
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The purpose of shimming the magnet is to:
A. make the B0 field as homogenous as possible
B. make the B1 field as homogenous as possible
C. make the scan time as short as possible
D. correct for gradient slopes
A
The CPU used to plot and adjust slices in an MR sequence is located: A. Equipment room
B. Scan control room
C. Magnet room
D. Patient waiting room
B
The coil construction in an MR system, from the innermost aspect to the outer:
A. Radiofrequency coils, gradient coils, shim coils, main magnet
B. Main magnet, radiofrequency coils, gradient coils, shim coils
C. Shim coils, radiofrequency coils, gradient coils, main magnet
D. Gradient coils, radiofrequency coils, shim coils, main magnet
A
_________ would be used to contain the RF in an MR magnet room.
A. Steel
B. Lead
C. Aluminum
D. Copper
D
The duty cycle can be viewed as the:
A. MRI technologist job description
B. coil acceleration factor
C. active gradient time
D. measure of flip angle accuracy
C
The liquid cryogens most often used to maintain field strength in a super conducting MR system are:
A. Helium
B. Gadolinium
C. Hydrogen
D. Molybdenum
A
Doubling field strength will result in what impact on SAR potential, if any?
A. Half-SAR
B. No change
C. Double SAR
D. Quadruple SAR
D
Doubling the magnetic field strength will:
A. Increase the SNR factor by half
B. Decrease the SNR factor by half
C. Yield an increase of double the SNR
D. Yield a decrease of double the SNR
C
Active shielding can be defined as:
A. Steel lining in the walls of the scanner room
B. Superconducting windings within the MR scanner, reducing the fringe magnetic field
C. Performing robust prescan measurements for the purpose of field homogeneity
D. Monthly adjustments made to the magnetic field for the purpose of field uniformity
E. Copper lining in the walls of the scanner room
B
What is the daily/weekly QA/QC indicator testing for the accuracy of the magnetic field in determining coil tuning and consistent magnetic field strength?
A. Transmit gain
B. # of spokes
C. NSA
D. Center frequency
D
Transmit gain is a quality measure evaluating for? A. Geometric accuracy -- Z gradient B. Geometric accuracy -- X/Y gradients C. High contrast spatial resolution D. Low contrast spatial resolution E. Accuracy of flip anglesE___________ could be used to line the walls and/or floors of the MR magnet room to reduce the fringe field, and is defined as __________ shielding. A. Copper; active B. Steel; active C. Steel; passive D. Copper; passive E. Lead; passiveCReferring to SAR impact on the patient, all of the following parameter changes negatively impact pulse duty cycle EXCEPT: A. Presaturation slab employment B. Reduction in # slices C. Decreased TR D. Fat suppression selection E. Increased ETLBPassive shielding can be accomplished by lining the MR room with ___________. A. Lead B. Steel C. Copper D. AluminumBThe array processor is responsible for: A. Shimming the magnetic field B. Reconstructing the images using the Fourier transform C. Increasing scan speed using parallel coil elements D. Calculating Field of View measurements inside surface coilsBThe unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as: A. Ohm B. Volts C. Gauss D. TeslaCField strength at magnet isocenter is measured in units of: A. Ohm B. Volts C. Gauss D. TeslaDRadiofrequency (RF) shielding can be achieved by lining the scanner room walls with: A. Lead B. Aluminum C. Steel plates D. CopperDIn order for energy to be efficiently transferred between a transmitter and receiver, the two must be at the same: A. Charge B. Frequency C. Spin density D. Eye levelBWhat does the gradient system provide?ability to perform SPATIAL ENCODINGHow much higher is the 180 RF pulse than initial 90?4xWhat is SAR measured inWatts/kgSAR is proportional to the power of __ for the resonant frequency2What is CP coil?Quadrature coilCP (quadrature) coil has a ____ increase in SNR compared to linear coil.40%What gradient is used for SAG?XWhat plane is the X gradient?SAGWhat gradient is used for COR?YWhat plane is the Y gradient?CORWhat gradient is used for AX?ZWhat plane is the Z gradient?AXCables from RF coils and gating/trigger leads should be: A. Coiled, preferably into a figure "8" B. Nicely formed into loops in the magnet bore C. Resting on the patient's arm or leg to immobilize the cables D. Braided and positioned straight in the boreDThe ______________ is the speed rate of ascent or descent of a gradient from zero to its maximum amplitude, either positive or negative A. Slew rate B. Rise time C. Duty cycle D. Fringe fieldAWhich of the following's primary biological effects is tissue heating/deposition? A. Static magnetic fields B. Gravitational earth magnetic fields C. Time-varying magnetic fields (gradient) D. Oscillating magnetic fields (radiofrequency)DThe strength of the gradient magnetic fields are measured in: A. Gauss per centimeter B. Tesla per echo C. Watts per kilogram D. Millitesla per meter E. A and DEThe duty cycle is defined as the: A. Time it takes for the gradient to reach its full amplitude B. Time it takes longitudinal magnetization to regrow C. Time between TI and initial RF pulse D. Time the gradients are on during a TR periodDMagnetic field inhomogeneity is expressed in: A. Watts per kilogram B. Gauss per centimeter C. Tesla per meter D. Parts per millionDRF heating is more of a concern in ________ sequences. A. Gradient echo B. Inversion recovery C. Fast spin echo D. Time of flightCThe gradient slew rate is the: A. Time it takes for the gradient to reach its full amplitude B. Time it takes longitudinal magnetization to regrow C. Time between TI and initial RF pulse D. Rate of speed of ascent or descent of a gradient from zero to its maximum amplitudeDWhich of the following sequences would be more at risk for the effects that time varying magnetic fields can cause? A. SE B. FSE C. GE D. EPIDIf a sagittal slice plane has been selected, the __________ is enabled to alter the magnetic field around the patient's body. A. X gradient B. Y gradient C. Z gradient D. Shim coilsAThe orientation of the main magnetic field in a high field, superconducting, short bore magnet is: A. Vertical B. Cylindrical C. Horizontal D. AsymmetricalCA coil that is not properly tuned to the correct magnetic field strength will result in: A. Patient injury B. FID artifacts C. Signal loss D. Improvements in resolution capabilitiesCA 6 inch surface coil is able to receive signal: A. 6 inches deep into the patient B. 3 inches deep into the patient C. 2 inches deep into the patient D. 1 inch deep into the patientBThe effects of time varying magnetic fields can include all of the following EXCEPT: A. Peripheral nerve stimulation B. Magnetophosphenes C. Acoustic damage and/or hearing loss D. Warmth and/or increase in body temperatureDThe strength of the gradient over a specific distance is known as the: A. Slew rate B. Rise time C. Duty cycle D. Flux linesACurrent FDA limits on time varying magnetic fields are: A. 23T/sec B. 5G/cm C. 20G/cm D. Once the patient experiences peripheral nerve stimulationDUtilization of surface coils yields all of the following EXCEPT: A. Increased FOV capability B. Localized, smaller FOV capability C. Increased SNR D. Smaller slice thicknessAIf a coronal slice plane has been selected, the __________ is enabled to alter the magnetic field around the patient's body. A. X gradient B. Y gradient C. Z gradient D. Shim coilsBMultiple coil elements combined with multiple receiver channels make a: A. Surface coil B. Circularly polarized coil C. Quadrature coil D. Phased array coilDWhen going from a linear coil to a quadrature coil: A. Available FOV is reduced B. Parallel imaging is eliminated C. SNR is decreased by 40% D. SNR is increased by 40%DWhich of the following has been documented to cause muscle contractions, cardiac arrhythmias, mild cutaneous sensations and visual light flashes? A. Time varying magnetic fields (gradient) B. Static magnetic fields C. Oscillating magnetic fields (radiofrequency)AThe measurement of radiofrequency absorption is delineated as: A. Watts per pound B. dB/dT C. Volts per kilogram D. Watts per kilogramDThe gradient rise time is defined as the: A. Time it takes for the gradient to reach its full amplitude B. Time it takes longitudinal magnetization to regrow C. Time between TI and initial RF pulse D. Speed rate of ascent or descent of a gradient from zero to its maximum amplitudeARF (radiofrequency) energy is: A. Low energy non-ionizing radiation B. Low energy ionizing radiation C. High energy non-ionizing radiation D. High energy ionizing radiationAA technique utilized to reduce the MRI scan time which requires the use of an array coil is: A. Parallel imaging B. 1/2 NEX C. Rectangular field of view D. Phase encoding reduction techniqueAIf a transverse/axial slice plane has been selected, the __________ is enabled to alter the magnetic field around the patient's body. A. X gradient B. Y gradient C. Z gradient D. Shim coilsC