MRI Quiz Hardware Control/Location

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. Yield an increase of double the SNR

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. Helium

In acquiring ACR QA data, Image 211 is used to evaluate for what quality measure?

A. Geometric accuracy — Z gradient

B. Geometric accuracy — X/Y gradient

C. High contrast spatial resolution

D. Low contrast spatial resolution

E. Accuracy of flip angles

B. Geometric accuracy — X/Y gradient

The location of the coils installed in the MRI scanner, from the inner point closest to the patient to the outer most edge, are:

A. Main magnet, gradient coils, shim coils, RF coils

B. Gradient coils, RF coils, shim coils, main magnet

C. Radiofrequency coils, shim coils, gradient coils, main magnet

D. Radiofrequency coils, gradient coils, shim coils, main magnet

D. Radiofrequency coils, gradient coils, shim coils, main magnet.

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. Radiofrequency coils, gradient coils, shim coils, main magnet

____ Would be used to contain the RF in an MR magnet room.

A. Steel

B. Lead

C. Aluminum

D. Copper

D. Copper

High field scanners typically have field strengths greater than or equal to:

A. 0.3 Tesla

B. 0.7 Tesla

C. 1.5 Tesla

D. 5 Gauss

C. 1.5 Tesla

The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as:

A. Ohm

B. Volts

C. Gauss

D. Tesla

C. Gauss

The local RF coil used to image a human brain is typically located/kept in the _________.

A. Equipment room

B. Scan control room

C. Magnet room

D. Patient waiting room

C. Magnet room

In acquiring ACR QA data, Image 212 is used to evaluate for what quality measure?

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 angles

A. Geometric accuracy — Z gradient

In acquiring ACR QA data, Image 213 is used in evaluating what quality measure?

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 angles

D. Low contrast spatial resolution

The direction of the magnetic field in Image 79 is:

A. Elliptical

B. Horizontal

C. Vertical

D. None of the above

B. Horizontal

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. Superconducting windings within the MR scanner, reducing the fringe magnetic field

In a cross sectional view of the MR magnet design, which coils are closest to the patient?

A. Active shim coils

B. Passive shim coils

C. Gradient coils

D. Radiofrequency coils

D. Radiofrequency coils

In acquiring ACR QA data, Image 210 is used to evaluate for what quality measure?

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 angles

C. High contrast spatial resolution

The ______ is located within an equipment room.

A. Magnetic shielding

B. RF power amplifier

C. Gradient coils

D. RF coils

B. RF power amplifier

Radiofrequency (RF) shielding can be achieved by lining the scanner room walls with:

A. Lead

B. Aluminum

C. Steel plates

D. Copper

D. Copper

Consistent room temperature of 65-75°F, humidity of 50-70%, and sufficient air flow in the MR scan room is recommended to:

A. Reduce the cryogen boil off rate

B. Minimize the risk of local surface coil burns

C. Make patients less vulnerable to the RF heating effects

D. Keep the shim and gradient coils from overheating.

C. Make patients less vulnerable to the RF heating effects

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 angles

E. Accuracy of flip angles

Image 79 is an example of which MR system?

A. Resistive magnet

B. Extremity magnet

C. Permanent magnet

D. Superconducting magnet

D. Superconducting magnet

The purpose of shimming the magnet is to:

A. Make the B0 field as homogenous as possible

B. Make the P1 field as homogenous as possible

C. Make the scan time as short as possible

D. Correct for gradient slopes

A. Make the B0 field as homogenous as possible

Which of the following is NOT a magnetic field associated with MR imaging?

A. Static magnetic fields

B. Oscillating magnetic fields (RF)

C. Time varying magnetic fields (gradient)

D. Gravitational earth magnetic fields

D. Gravitational earth magnetic fields

What type of magnet is used with most systems currently manufactured?

A. permanent

B. Superconducting

C. Resistive

D. Upright

B. Superconducting

The intensity limit for a static magnetic field in clinical use is limited by the Food and Drug Administration (FDA) to __________?

A. 1 Tesla

B. 3 Tesla

C. 4 Tesla

D. 7 Tesla

C. 4 Tesla

__________ Could be used to line the walls and/or floors of the MR magnet rooms to reduce the fringe field, and is defined as ______ shielding.

A. Copper; active

B. Steel; active

C. Steel; passive

D. Copper; passive

E. Lead; Passive

C. Steel; passive

In 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 level

B. Frequency

When acquiring ACR QA data, the slice correlating to Image 213 requires what visual discernment?

A. 4 holes in UL array

B. 10 visible spokes of 3 discs each

C. Laser-light accuracy

D. Phantom positioning accuracy

B. 10 Visible spokes of 3 discs each

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. Quadruple SAR

The liquid cryogens are cooled in a superconducting magnet at a temperature of ____?

A. 1° Celsius

B. 1° Fahrenheit

C. 4° Kelvin

D. 4° Celsius

C. 4°

Referring 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 ETL

B. Reduction in # of slices

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. Active gradient time

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. Center frequency

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. Scan control room