MRI FINAL

What does a moving magnetic field induce in a conductor?

Increase magnetic field strength

Electrical current

Stronger magnetic field

Angular momentum

What parameters would you use to minimize T1 effects on a T2WI in a GRE?

short TR

long TR

short TE

long TE

short FA

long FA

Fe2O3 is a _____________ particle.

Diamagnetic

Paramagnetic

Superparamagnetic

Ferromagnetic

Once the net magnetization vector (NMV) has started to move away from equilibrium, the following will occur:

The longitudinal component start to increase.

The transverse component start to decrease.

The longitudinal component will stay the same.

The transverse component start to increase.

Which of the following is the primary MR signal resulting from a 90-degree excitation RF pulse?

Gradient echo rephasing

Spin echo generation

Free Induction Decay

Net Magnetization Vector

What better describes vector M right after a 90 degree flip angle

Rotating magnetic field in the B1 plane

Located at a right angle from the longitudinal axis

Protons precessing in phase

All answers are correct

What parameter combination would you select to produce a T2WI? select more than one answer

short TE

long TE

short TR

long TR

Materials with which of the following components have the highest degree of magnetic susceptibility

Diamagnetic

Paramagnetic

Superparamagnetic

Ferromagnetic

Which of the following conditions are necessary for resonance to occur?

Correct temperature and humidity

Matching chemical bonds

Equal number of protons and electrons

Energy applied at the precise frequency

Which of the following characteristics determines if an atom is suitable for use in MRI?

High atomic number

Full electron shell

Even mass number

Odd mass number

The direction perpendicular to the main magnetic field is designated as which direction?

X

Y

Z

XY

In MRI, substances respond to a specific radio frequency which is known as:

Magnetic frequency.

Radio frequency.

Gyro-magnetic frequency.

Resonance frequency.

What would be the effect of combining a very short TR (50 ms) with a long FA (90)? select more than one answer

Increase T1 effects

Increase T2 effects

Maximize saturation effects

Minimize T1 effects

What is the approximate precessional frequency of hydrogen in a 3.0 T magnet?

21 MHz/T

43 MHz/T

64 MHz/T

128 MHz/T

Which of the following conditions is necessary for energy to be the most efficiently transferred from one system to another?

Resonance

Precession

Alignment

Relaxation

In a gradient echo pulse sequence, what parameter combination would you use to produce a T1WI?

short TR

long TE

short TE

long FA

long TR

short FA

The magnetic field created by the nuclear alignment of hydrogen is known as which of the following?

Magnetic moment

Static magnetic field

Gradient magnetic field

Net Magnetization

The inversion time of a tissue ____________ as the magnetic field increases.

Increases

Decreases

It is not affected

Which of the following image parameters affects scan time?

Number of slices, matrix, number of excitations

Number of slices, matrix, time of repetition

Field of view, number of slices, matrix

Time of repetition, number of excitations, matrix

SAR is a major concern with ___________ pulse sequences

SE

FSE

GRE

EPI

Which of the following provides the greatest Signal to Noise Ratio?

Reverse gradient slopes

High speed gradient slopes

Steep gradients slopes

Shallow gradients slopes

In a 3D volumetric acquisition: What would be the scan time utilizing the following parameters?
TR 50 ms, PES 192, Slice 20, TE 25 ms, FES 256, ETL 1, FA 10, NEX 1, RBW 21 mHz

2.1 min

4.2 min

3.2 min

6.4 min

What TOF technique is more affected by the presence of slow flow in the blood vessels?

2D-TOF-MRA

3D-TOF-MRA

CE-MRA

PC-MRA

What parameters would you use to calculate the scan time in an FSE?

FES

TE

NEX

PES

TR

ETL

In a 2D acquisition: What would be the scan time using the following parameters?
TR 4000 ms, PES 192, Slice 20, TE 25 ms, FES 256, ETL 6, FA 90, NEX 2, RBW 21 mHz

2.1 min

4.2 min

6.6 min

8.4 min

Image construction in MRI is accomplished through which of the following mathematical processes?

Fast Fourier Transformation

Gradient reversal

Reverse Radio-Frequency Encoding

Pulse Sequence Manipulation

What imaging parameter affect the entry slice phenomenon?

TE

TR

TI

All answers are correct

What can be the artifact resulting from using a narrow receive bandwidth?

Aliasing

Truncation

Susceptibility

Chemical shift

To prevent in-plane flow saturation on a TOF-MRA, the slices should be positioned __________ to the blood vessels.

Parallel

At 45 degrees

Perpendicular

The position of the slices does not prevent in-plane flow effects.

The steady state is the phenomenon that result from ____ shorter that the ___ relaxation times of the tissues?

TR / T1 & T2

TE / T1 & T2*

TI / TE & TR

TR / TE & T1

What technique is more effective to reduce intra-voxel dephasing?

Long TE

Short TR

Gradient moment nulling

No-phase wrap

What pulse sequence would be the most susceptible to in-homogeneities of the magnetic field?

SE

FSE

IR-FSE

GRE

What combination will reduce the most the effects of magnetic susceptibility?

FSE 24 ETL/Matrix 512/RBW 64 Hz

FSE 24 ETL/Matrix 512/RBW 32 Hz

FSE 12 ETL/Matrix 512/RBW 64 Hz

FSE 24 ETL/Matrix 256/RBW 64 Hz
38

To maintain the entry slice in a TOF-MRA, how should the slice be acquired?

with a very short TR

with a very short TE

co-current

counter -current

If FOV is increased from 20 to 40, SNR will increases by a factor of

1

2

3

4

Using narrow receive bandwidth can result in an:

Increase SNR

Increase chemical shift artifacts

Increase of the minimum TE

All of the above

When increasing the FOV: (Select best two)

Increase scan time

Increase the chances of chemical shift

Increase spatial resolution

Increas SNR

Increasing the NEX will have a direct impact on the following:

Image contrast

SNR

Scan Time

Spatial Resolution

What is the TOF-MRA technique more effective in areas of rapid flow?

2D

3D

4D

The velocity of the flow does not affect TOF =-MRA

Doubling the PES: (Select two)

SNR drops to 50%

Spatial resolution drops to 50%

Scan time doubles

Chances of chemical shift increases

As phase encoding steps increase, the spatial resolution will increase due to which of the following?

Signal-to-noise ratio decreases

Field-of-view increase

Voxel increase in size

Voxel decrease in size

Please match the parameter with its possible effect.

TR :

Receive bandwidth

Slice Thickness :

TE :

Flowing blood will appear dark on spin-echo pulse sequences due to the following:

Time of Flight Phenomenon

There are no hydrogen protons in blood

Intra-voxel dephasing

All of the above

Which of the following parameters has a direct effect on scanning times?

Echo Time

Slice thickness

Time to echo (TE)

Repetition Time (TR)

As slice thickness increases, spatial resolution decreases due to corresponding increases in which of the following?

Gibbs artifacts

Chemical shift artifacts

Signal-to- noise ratio

Partial volume effects

a TOF-MRA technique, flowing blood becomes saturated when a slice runs parallel to a blood vessel. What name is used to describe this phenomenon?

Time of Flight

Entry slice

Intra-voxel dephasing

In-plane flow

What TOF technique is more affected by the slow flow?

3D-TOF-MRA

CE-MRA

PC-MRA

All of the above

To increase spatial resolution without affecting scan time, an MRI technologist can do which of the following?

Decrease frequency encoding steps

Increase phase encoding steps

Increase number of signal averages

Decrease the field-of- view

When increasing the image matrix to improve the spatial resolution, it increases which of the following:

SNR

T1 Weihgted

T2 Weighted

Scan Time

Per FDA use of gadolinium-based contrast agents should be avoided for patients with a glomerular filtration rate of

<30 ml/min/1.73 m2

<40 ml/min/1.73 m2

>30 ml/min/1.73 m2

<15 ml/min/1.73 m2

In an emergency, an MRI technologist should take one of the following actions?

Open magnet doors and patient areas to responders

Lock the main magnet room door and shut down the magnet

Quench the magnet

Implement department policies and procedures

At a minimum, during the exam, patient monitoring includes which of the following?

Continual verbal contact with the patient to ensure he/she is not having difficult

EKG monitoring of all patients over the age of 70 years

Making periodic physical checks on the patient in the magnet room

Use a pulse

Which of the following terms refers to the type of measurement the FDA uses to monitor the amount of RF energy deposited into a patient's body for each pulse sequence?

Sensitivity Average Rate

Specific Annual Range

Sensitivity Area Range

Specific Absorption Rate

In the MRI environment, which of the following provides the greatest risk of spreading infectious disease?

Human hands

Insect bites

Food

Objects

Which of the following contrast agents is most commonly used in MRI?

Non-specific extracellular agents

Oral contrast agents

Blood pool agents

Hepatocyte-specific agents

A patient indicates having a metallic implant. What are the necessary steps prior to entering the magnet room?

Consult with the radiologist to schedule a different test

Proceed with the scan if the implant is medically necessary

Confirm MRI safety using the facility's establishing safety processes

Cancel the study and contact referring physician

Compared to iodined contrast agents used in radiography and CT, the incidence of adverse reactions from MRI-used gadolinium-based contrast agents is:

Significantly lower

Generally the same

Significantly higher

Indeterminable given vast differences in molecular composition of different agents

In MRI, Specific Absorption Rate (SAR) is calculated using one of the following units of measurement?

Watts per gram

Watts per Kilogram

Megawatts per Kilogram

Kilowatts per Kilogram

Anaphylaxis refers to which of the following conditions?

Dizziness

Allergic reaction

Shortness of breath

Dysphagia

When is it safe to administer a gadolinium injection to a pregnant patient?

Gadolinium injections are not safe during pregnancy

During the first trimester

During the third trimester

During the second trimester

Which of the following protocols would be included in an emergency plan for an outpatient MRI facility?

Leaving the scanning area while waiting for the first responders

Quenching the magnet, locking all the doors, and waiting for emergency crews to arrive

Contacting supervisor to ask how to proceed

Advanced agreement with outside emergency personnel

Hazards to cryogens in the MRI environment do NOT include which of the following?

Radio frequency burns

Explosion

Frost bite

Asphyxiation

Why administering a gadolinium-based contrast agent to a pregnant patient is considered to be a risk?

Kidney filtration of the contrast agent is decreased in pegnant patients

The contrast agents crosses the placenta to the fetus

Vasodilation is common in developing fetuses

Pregnant patients have increases risk of adverse reactions

What blood test results are necessary prior to administer contrast?

Chemistry panel and complete blood count

Creatinine

Hemoglobin A1 c

Glucose

At a minimum, during the exam, patient monitoring includes which of the following?

Use a pulse oximeter

Making periodic physical checks on the patient in the magnet room

Continual verbal contact with the patient to ensure he/she is not having difficult

EKG monitoring of all patients over the age of 70 years

Which type of patient may be left unattended during the MRI procedure?

Pediatric

Stable adult

Geriatric

None

When is it safe to administer a gadolinium injection to a pregnant patient?

During the first trimester

During the second trimester

Gadolinium injections are not safe during pregnancy

During the third trimester

Patient screening forms are to be completed and reviewed by the operating MRI technologist before a patient enters one of the following zones?

Zone 4

Zone 1

Zone 2

Zone 3

To form a chelate, a gadolinium ion is chemically bonded with which of the following?

Ligand

Unpaired electron

Water molecule

Hydrogen ion

Per the FDA, peripheral nerve stimulation is categorized as what type of concern?

Patient comfort

Safety

Specific absorption Rate

Acoustic noise

Which type of patient may be left unattended during the MRI procedure?

Geriatric

None

Stable adult

Pediatric

IV contrast agents use which of the following types of ions as the primary contrast mechanism in MRI?

Hydrogen

Iron

Gadolinium

Tin

A patient develops hives after gadolinium contrast administration. Which of the following medications should the radiologist use to treat this reaction?

Iodine

Calcium blockers

Antihistaminics

Antibiotics

What blood test results are necessary prior to administer contrast?

Chemistry panel and complete blood count

Creatinine

Hemoglobin A1 c

Glucose

Which of the following is NOT an advantage of the superconductive magnets?

No resistance to the flowing electrical current

Large fringe field

High magnetic field strength

Low power consumption

How is the homogeneity of the main magnetic field measured?

MilliTesla per meter (mT/m)

Gaus (G)

Tesla per meter per second (T/m/s)

Parts per million (ppm)

Conductive copper windings that alter the main magnetic field along a strict coordinate are known as which of the following?

Gradients coils

Interference coils

Surface coils

Shim coils

Why does a 3.0 tesla magnet have inherently higher SNR than a 1.5 tesla magnet?

More hydrogens protons contributing to the net magnetization vector

3.0 tesla magnets have higher performing gradients

3.0 surface coils are more efficient

Larger physical magnet bore

Superconducting magnets coils exhibit what type of resistance when operating at or below critical temperature?

High resistance

Low resistance

Zero resistance

Variable resistance

Which of the following best describes gradient slew rate?

Speed and amplitude of a gradient measured in mT/m/s

Peak amplitude of a gradient measured in mT/m or G/cm

Percentage of time a gradient can work

Time for a gradient to reach maximum amplitude measure in ms

When using a receiver-only surface coil, or multichannel coil, which of the following transmits the RF pulse to the patient's body?

Body coil

Gradient coil

Volume coil

Head coil

What is the cryogen in a superconductive magnet?

Gaseous helium

Liquid helium

Liquid nitrogen

Liquid oxygen

In a permanent magnet design, which of the following best describes the direction of the main magnetic field?

Rotates about the long axis of a body in the magnet

Along a diagonal to the long axis of the body in the magnet

Parallel to the long axis of a body in the magnet

Perpendicular to the longitudinal axis of a body in the magnet

What is the cryogen in a superconductive magnet?

Liquid helium

Liquid oxygen

Gaseous helium

Liquid nitrogen

Superconducting magnets coils exhibit what type of resistance when operating at or below critical temperature?

High resistance

Low resistance

Zero resistance

Variable resistance

In a permanent magnet design, which of the following best describes the direction of the main magnetic field?

Rotates about the long axis of a body in the magnet

Along a diagonal to the long axis of the body in the magnet

Perpendicular to the longitudinal axis of a body in the magnet

Parallel to the long axis of a body in the magnet

Which type of RF coil uses several small surface coils linked together to provide improved SNR and a large area of coverage?

Linear surface coil

Volume coil

Phase-array coil

Saddle coil

A phased-array surface coil is a receiver system that utilizes several individual coils, which are connected directly to a dedicate

Transmit channel

Surface coil

Receiver

Quadrature coil

Gradient coils are best described as which of the following?

Independent electromagnets that switch on and off

Devices placed on or near the region of interest to be imaged before scanning

Shim coils that correct for homogeneity

Useful for field service engineers when ramping up a magnetic field

Which of the following is NOT an advantage of permanent magnets?

No power supply requeriments

low operating cost

Small fringe fileds

Quick turn off capability

The primary objective of the MRI receiver system is to convert analog signals into which of the following?

B1 maps

Digital signals

Radiofrequency transmit signals

Bo maps

Which of the following is NOT an advantage of permanent magnets?

Quick turn off capability

No power supply requeriments

Small fringe fileds

low operating cost

What would be the best slice position and order (direction) when performing a TOF-MRA of the intracranial circulation?

Coronal

Foot to head

Sagittal

Anterior to posterior

Head to foot

Axial

What image will result from the following description?
1. The coverage must include the entire eyeball from inferior to superior.
2. The FOV should include the optic chiasm posteriorly and the eyeball anterior.
3. Slices should be aligned parallel to both optic nerves.


Axial orbits

Sagittal pituitary

Coronal orbits

Coronal IAC

What pulse sequence is the best to detect an acute ischemic event in the brain?

SWI

DWI

STIR

FLAIR

What pulse sequence is the best to detect hemorrhagic blood?

DWI

PWI

FLAIR

SWI

Which of the following are indications for an MRI of the orbits?>

Proptosis

Microadenoma

CPA mass

Diplopia

What protocol would you use on a patient that has an MRI of the brain order looking for a vestibular schwannoma?

Brain Temporal lobe

Brain Sella

Brain IAC

Brain Orbits

What would be the correct protocol to run in a patient that comes for an MRI of the brain and the indication is acromegaly?

Brain IAC

Brain Sella

Brain Orbits

Brain Temporal lobe

Which of the following are primary brain tumors?

Astrocytoma

Hepatocellular carcinoma

Schwannomas

Renal Cell carcinoma