Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

ARMRIT ARRT > Medical Term - MR Glossary > Flashcards

Medical Term - MR Glossary Flashcards

1
Q

_____________ is a term describing the containment of the static magnetic field through the use of secondary coils attached around the MRI scanner.

A

Active shielding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

____________ is a term used to describe the adjustment of the current within the shim coils on a per patient or per sequence basis.

A

Active shimming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

__________ are reconstructed from diffusion weighted images with multiple b-values, and corresponds to the spatially distributed diffusion coefficients of the target tissues

A

ADC images

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

____________ occurs when tissue outside the Field of View is undersampled, causing a misregistration of anatomical location, in the phase direction, but on the opposite side of the anatomical location, also known as wrap-around artifact.

A

Aliasing artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The ____________ is part of the computer sysem that converts the analog acquired MR signal into a digital signal.

A

Analog-to-digital converter (ADC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

An ________ comprises a multiprocessor that is switched in sequence and in parallel while simultaneously performing a computing task.

A

Array processor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

An _____________ is one that has uneven measurements, with regards to the phase, frequency and slice thickness dimensions.

A

Anisotropic voxel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

____________ are signal misrepresentations that do not correspond to the spatial location of the specific tissue imaged

A

Artifacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

_______________ is defined as the range or spectrum of frequencies (minimum to maximum processed frequency)of a pulse sequence acquired by an RF system

A

Bandwidth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The ____________ is an integrated part of the magnet design that acts as its own transceiver coil, with large FOV capabilities, but lacking the high SNR of localized coils.

A

Body coil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The __________ is defined as a factor in diffusion weighted imaging; the higher the factor, the stronger the diffusion weighting.

A

B-value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The ___________ is defined as the static main magnetic field of an MR system.

A

B0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The __________ is the alternating magnetic field generated by the RF in a transceiver coil.

A

B1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

_____________ prevents or reduces motion artifacts in an MR image caused by the beating heart or pulsating blood flow and enables the images to be acquired synchronized to movement.

A

Cardiac triggering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

________________ is due to the difference in resonant frequencies between fat and water, causing a phase shift in voxels containing fat and water.

A

Chemical shift artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describing image display, the ________ function scrolls through the entire sequence’s images, giving the appearance of CSF flowing or cardiac movement, from the cycle of the images acquired.

A

Cine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

__________ can be defined as the signal strength differences between two adjacent tissue types.

A

Contrast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

_______________ utilizes the reduced T1 relaxation time of blood through the use of an intravenously injected Gadolinium contrast agent

A

CE MRA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

_______________ occurs when slices are positioned too close together, causing signals from adjacent slices to affect one another.

A

Cross talk artifact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

_________ occurs after initial RF application, causing phase differences to appear between precessing spins, resulting in decay of transverse magnetization.

A

Dephasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

___________ is an effect resulting in a slightly weakened magnetic field when a substance is introduced into it. This material is considered to have a negative magnetic susceptibility.

A

Diamagnetism

Diamagnetism is an effect resulting in a slightly weakened magnetic field when a substance is introduced into it. This material is considered to have a negative magnetic susceptibility

22
Q

An ________ is the MR signal generated by an RF or a gradient pulse.

A

Echo

An echo is the MR signal generated by an RF or a gradient pulse

23
Q

_________ is simply defined as the distance between echoes

A

Echo spacing

24
Q

The time between the excitation pulse of a sequence and the resulting echo used as the MR signal is known as:

A

Echo time

25
Q

A technique used to suppress fluids, utilizing a long echo time coupled with a long Inversion time is known as __________.

A

FLAIR

26
Q

__________ materials, such as iron, contain unpaired electrons, each with a small magnetic field of its own, that align readily with each other in response to an external magnetic field.

A

Ferromagnetic

27
Q

The mathematical process of converting raw data into an image suitable for display is known as _________.

A

Fourier transform

28
Q

The angle to which the longitudinal magnetization is tipped into the transverse plane, following the initial RF excitation pulse, is known as ________.

A

Flip angle

The angle to which the longitudinal magnetization is tipped into the transverse plane, following the initial RF excitation pulse, is known as the flip angle.

29
Q

_________ is defined as the number of times that a periodic function or vibration repeats itself in a specified time. It is usually measured in hertz (Hz).

A

Frequency

Frequency – the number of times that a periodic function or vibration repeats itself in a specified time. It is usually measured in hertz (Hz).

30
Q

The timing the collection of MR data to physiological motion in order to minimize motion artifacts is known as:

A

Gating

31
Q

The linear increased or decreased change in the magnetic field of a certain orientation is defined as a _________.

A

Gradient

32
Q

________ is defined as the ratio of the magnetic moment (field strength) of a rotating charged particle, such as an electron, to its angular momentum (frequency).

A

Gyromagnetic ratio

Gyromagnetic ratio – the ratio of the magnetic moment (field strength) of a rotating charged particle, such as an electron, to its angular momentum (frequency).

33
Q

What is the term for the echo generated by switching a pair of dephasing and rephasing gradients, without the use of a 180° refocusing pulse?

A

Gradient echo

34
Q

An MR sequence that begins with 180º RF inverting pulse followed by 90º RF excitation pulse, then 180º RF refocusing pulse is known as

A

Inversion recovery

35
Q

_________ is known as the specific frequency at which magnetic resonance in a nucleus can be excited and detected, and varies directly with magnetic field strength.

A

Larmor frequency

Larmor frequency – the specific frequency at which magnetic resonance in a nucleus can be excited and detected, and varies directly with magnetic field strength.

36
Q

_________ is the magnetic and thermal environment through which nuclei exchange energy in longitudinal (T1) relaxation.

A

Lattice

Lattice – the magnetic and thermal environment through which nuclei exchange energy in longitudinal (T1) relaxation

37
Q

___________ is defined as the Z component of the net magnetization vector in the direction of the static magnetic field.

A

Longitudinal magnetization

Longitudinal magnetization – The Z component of the net magnetization vector in the direction of the static magnetic field. Following RF excitation, this vector returns to its equilibrium value at a rate characterized by the time constant T1.

38
Q

MR technique utilized to image flowing blood and specific vasculature structures:

A

Magnetic resonance angiography (MRA)

39
Q

MR technique which quantitatively assesses the mechanical properties of tissues, based on the propagation of shear waves:

A

Magnetic resonance elastography (MRE)

40
Q

MR technique generating a spectrum of metabolites in a specific volume of interest:

A

Magnetic resonance spectroscopy (MRS)

41
Q

__________ is defined as the magnitude and direction of the magnetization resulting from the collection of atomic nuclei.

A

Net magnetization vector

42
Q

What is an uncharged neutral particle located in the nucleus of most atoms which serves as a stabilizer?

A

Neutron

43
Q

_________ is defined as a loss of resolution due to excessively large voxels, typically caused by slices that are too thick

A

Partial volume averaging

44
Q

An artificial object that can be imaged to test the performance and quality of a magnetic resonance system would be:

A

Phantom

45
Q

________ is comprised of the components of the magnetization in the imaging object after excitation, sampled from the receiver coil signal and stored as a function of time during the data acquisition of an MR imaging sequence

A

Raw data

46
Q

_________ gradient – magnetic field gradient applied during the moment when the echo is formed

A

Readout

47
Q

_________ is defined as an event in a superconducting MR system causing a loss of superconductivity, a rapid loss of the magnet cryogens

A

Quench

48
Q

Short TI Inversion Recovery: a version of the Inversion Recovery pulse sequence where the inversion time (TI) is set to ______ times the T1 of fat, nulling the signal from fat at the specific field strength in which it’s being acquired

A

0.69

49
Q

MRA technique relying on flow related enhancement to distinguish between stationary spins and flowing spins:

A

Time of flight

50
Q

_________ is defined as a volume element with 3-Dimensional characteristics

A

Voxel

ARMRIT ARRT (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions