MRIQUIZ rapid fire

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WCUI MRI REGISTRY REVIEW
SESSION #5 – MR SAFETY & INSTRUMENTATION
Who should be screened before entering the MR scan room?
Identify the four zones of the MRI environment:
Define the following and describe the sticker associated with them:
MR safe:
MR conditional:
MR unsafe:
Identify Level 1 and Level 2 personnel:
Define fringe field:
SAR stands for ______________________________. What units is it measured in? ________
What are the FDA guidelines for SAR?

How can an MRI technologist manage the SAR effects?
Define magnetohydrodynamic effect and what does it cause?
What are the hazards of radiofrequencies?
How can an MRI technologist reduce the RF deposition?
Describe the effects of time-varying magnetic fields (TVMF) and the cause:
How should the cables and gating leads be positioned?
What happens during a quench? When should an MRI technologist quench the magnet?
List the primary safety concerns associated with cryogens:
The MRI scan room humidity should be ______%. The room temp should be ______%.

Diamagnetism:
Paramagentism:
Ferromagnetism:
1 Tesla = _______ gauss
Permanent magnet:
Resistive magnet:
Superconducting magnet:
What does the RF system do?
What does the RF amplifier do?
What does the gradient amplifier do?
Gradient strength or amplitude:
Rise time:
Slew rate:
Duty cycle:

______Active shimming a. Surrounds magnet with steel plates, used in high field systems
______Passive shimming b. Adjusts uniformity of field over specific body part
______Active shielding c. Uses metal discs/plates to reach optimal field homogeneity
______Passive shielding d. Solenoid electromagnets at each end of bore creating 5gauss line
Describe the following coils:
Receiver coil:
Volume coil:
Surface (linear) coil:
Phased array coil:
Define homogeneity:
____Theories of MRI a. Has magnitude and direction
____Hydrogen b. Secondary spin of proton
____Atomic number c. Primary MR signal
____Mass number d. Application of RF causing resonance to occur
____Free induction decay e. Number of protons in nucleus
____Vector f. Classical and quantum
____Precession g. Magnetic field induced around nucleus
____Magnetic moment h. Sum of protons and neutrons in nucleus
____Excitation i. Most abundant element in body, 1 proton
____ Net magnetization factor j. Number of H protons per unit volume
____ Proton density k. Excess of H protons aligned with magnetic field
Hydrogen has ______________________ because it is charged and ________________.
When atoms are in magnetic field, they will align ____________________________________.

Define:
Faraday’s Law of Induction:
Larmour equation:
Resonance:
Relaxation:
Gyro-magnetic ratio of hydrogen at 1 Tesla is ________________.
Define T1 relaxation:
Define T2 decay:
When does the slice selection occurs and what does it determine?
When does the phase encoding and frequency encoding occur?
Short axis of anatomy is normally the ___________encoding direction.
For small FOV in frequency direction, _________ frequency encoding gradient is applied.
Determine what gradient performs each function:
Plane Slice Selection Phase encoding Frequency encoding
Sagittal
Axial (body)
Axial (head)
Coronal

Define receive bandwidth:
Define transmit bandwidth:
K-space is defined as:
The center of K-space is responsible for _________________, whereas the outer portions are for
_________________. Phase encoding steps determines number of ______________________
that must be filled. Phase encoding gradient changes amplitude from _____________________
to encode a new line of data.
Name the different types of K-space filling

A ___ is a instrument that allows a patient to appoint an agent to make healt care decisions in the event that the primary individual is incapable of executing decisions

Health care proxy

This ___ weighted image axquire in the __ scan plane

t2, Sagittal

Reducing the flip angle yields images with what change in image contrast?

Less T1 information

Doubling field strength will result in what impact on SAR potential, if any?

Quadruple SAR

This is an example of a weighted sequence acquired in the scan plane

t2 , coronal

Normal Oxygen Sat levels should be between?

95-100%

Hemangiomas in the liver are typically bengin leisons, are best visualed with what

Delayed images

Isotropic voxel refers to a ___ voxel shape

Cubic

risk factors of MR exposure with reguards to SAR absorption include all the following except

Hypotension

In a contrast enhanced MR angiography of the abdomial arteries , the IV gadolinium would enhance in which order

Celiac, Superior mesenteric, renal, inferior mesenteric

Kienbock’s disease is a condition of osteomalacia in the Lunate bone of the wrist

Lunate bone of the wrist

The substances that bind to gadolinium ions are defined as

Chelates

Which colon is below the liver

Ascending colon

formula for effective TR( BPM question)

Effective TR=Heart Rate (bpm)/60​

What kind of pulse sequence is this

Gradient echo sequence. Due to small repeated excitation, and no 180

Best imaging view for spinal stenosis

sagittal

Which tendon torn the most in rotator cuff tear?

Supraspinatus

Primarily stemming from active RF coil, elements out side the scan FOV, ____ aritfacts can be fixed by de selecting the elements out side the scanning range

Annefact

what kind pulse sequence is this ?

Fast spin echo

Where does the common carotid artery bifurcate at?

C3-4 disc space

____ measures 20 feet long and is made of duodenum, jejunum, an dthe ileum

Small intestine

letter E is pointing at?

Supraspinatus tendon

What specifically is a SPGR sequence spoiling

Transverse magnetization

What parameter woild affect a cardiac function study

Heart rate

Most optimal veiw for evaluation of th eovaries is

Coronal

B is pointing to what?

Calcaneus

what kind of artifact is this

Moire

The artifact indentified by the orange arrows in this image is a ___ artifact

FID Crushing

D is pointing to

Dorsal nerve root

An example of parenteral method of drug delivery is taking a drug by mouth

false

The yellows arrows point to what kind of artifact

Dielectric effects

What parameter combination will yield the best spatial res

3mm slice thickness, 256 × 256 matrix

The first major branch of the abdominal aorta is the celiac trunk, which branches into ___ arteries

Gastric, hepatic, and splenic

Standard dose for the adminstration of IV gad chelates is

0.1 mmol/kg

Which imaging plane would best display both the dorsal ventral nerve roots?

Axial

letter C is pointing to which cranial nerve

Trigeminal nerve ( CV V)

Letter F is pointing to

Middle cerebral artery

In an IR recovery sequence, the time interval between the 180 RF pulse and the 90 RF pulse is the

TI

Most optimal view for evalutation of the uterus is the

Sagittal

Remedy for Gibbs truncation artifact would be

Increase phase encodings

Depression in the base of the skull where the pituitary gland is located is called

Sella turcica

SNR does not increase with

Decreasing pixel sizeThe

timing of RF pulses controls

Image contrast

Who developed math equation to analyze the heat transfer between solid bodies

Joseph fourier

Letter B is pointing to

Infraspinatus muscle

C is pointing to

Coronoid process

Extracranial MRA exam is defined as MRA of the

Carotid arteries

Ernest angle can be defined as optimal ___ that yeilds the ____ signal for a particular spin the least amount of time

F/A, Maximum

In lumbar spine images through the intervertebral disc spaces, slices should be

Oblique

Metastic lesions enhance after injecting gado chelate b/c of

The breakdown in the blood brain barrier

When parallel imaging techniques are utilized, a low res ___ is acquired prior to the acquistion

Calibration

A sign that a pt may be in cardiac arrest might include

Not having a pulse

What can result in the highest SAR factor in an MR oulse sequence

Short RF transmit pulse ( vendor fast sequence )

With reguards to k-space, the data containing high res are located

The outer lines

What parameter adjustments reduce the overall SNR

Decrease TR, Reduce pixel size, Decrease FOV, Increase rBW, decrease NEX, and increase ETL

Technique used to supress fluids, utilizing a long echo time coupled w/ long inversion time is known as

FLAIR

The height of a peak on MR spectrum correlates to the __ of a substance that was detected

Amount

The ___ mag field poses risks to patients and staff, due to the torpedo effect when a ferromagnetic object becomes magnetized and attracts to the large magnet

Main Static

The major bifurcation of the abdominal aorta is the

Right and left iliac arteries

Mag field inhomogeneity is expressed in

PPM

Brain exam to evaluate crainal nerves VII & VIII due to pt symptoms of tinnutis

IAC exam

D is pointing to

Delotid muscle

This is an example of

Diffusion tensor imaging ( tractography)

The FDA set of mag field clinical use limits of for the entire population and over 1 month of age

4 T and 8 T

__ occurs when tissue outside FOV is undersampled, causing opposite side of anatomical location

Aliasing artifact, aka Wrap

J is pointing at

Fourth ventricle

This graph represents

TI ; inversion time ( look at RF)

The ___ is posterior to the vertebral body and consists of two pedicles and two laminae

Vertebral arch

Which MR technique assesses the mechanical properties of tissues

Magnetic resonance elastogrpahy ( MRE)

Readout gradient is usually turned on during the sampling or readout of the peak echo and during which other process

Frequency encoding

Array processor is responbile for

Reconstructing the images using the Fourier transform

Does gadolinium chelates readily pass the blood brain barrier

False

Letter B is pointing to

Septum

MR tech is permitted to administer how much oxygen to the pt in emergency

2L/min

D is pointing to what

Semicircular canal

For intracranial arterial blood flow sequence, a pre sat pulse would be applied where

Superior to slice group

Narrow receiver bandwidth

Increases susceptibility artifact

gradient moment nulling is used to compensate for what

First order motion, slow flowing vessels

FDA whole body SAR absorption rate

4 watts/ kg for 15 min

J is pointing to what

Proximal phalanx

Remedy for Gibbs truncation artifact is

Increase # of phase encodings

If this is a FSE, the number of lines of K space filled for each TR period would be

2 ( each 180 represents a line of k space )

The ___ to reduce chemical shift artifacts

rBW increased

____ is simply defined as the distance between echos

Echo spacing

Hemosiderin appears ___ to surrounding tissues on t2 weighted images

Hypointense

____ is a condition when blood sugar falls too low often occurring when diabetic patients take too much insuilin

Hypoglycemia

All of following artifacts except ___ occur along the phase encoding axi s

chemical shift

Letter C is pointing to

Head of 5th metacarpal

Reducing FOV by a factor of 2 will reduce the voxel volume by a factor

4

Hydrogen protons is the anti parallel state are referred to as

Spin down/ high energy spins

Active shielding can be defined as

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

____ discovered that when a magnet was moved inside a coil of copper wire, a tiny electric current flows through the wire

micheal faraday

What best describes a FSE sequence

A train of spin echos

____, —— gad compounds are considered the least likely to release the gad ion and hence the safest

Cyclical; ionic

On T2 image, edema appears bright because it has a ____-relaxation time

long t2

In FSE, acquired with a long TE, yielding t2 wieghted images, scan time can be reduced by

Using longer ETL

@ 1 T the freq difference between that of fat & water is approx

147hz

Regions of the body that don’t quickly dissipate thermal absorption from sar

Eyes and testicles