ARMRIT

Question 1

On a T1 weighted image, edema appears dark because

Answer 1

It has a Long T1 relaxation time

Question 2

Gibbs Truncation

Answer 2

caused by under sampling, corrected by increasing phase matrix or reducing FOV

Question 3

magnetic susceptibility

Answer 3

artifact caused by metal, to reduce effects use smaller voxels, shorter TE, and increased bandwidth.

Question 4

How to correct for Metal artifact

Answer 4

Use FSE/SE, the additional 180 pulses help with inhomogeneities, do not use parallel imaging, this requires gradients, use high TSE factors/ Long ETL, wide rBW, thin slices, STIR’s over Fat supressio, good SNR and high NEX

Question 5

Chemical shift artifact

Answer 5

Occurs because fat and water precess at different frequencies.

Question 6

how do you correct chemical shift artifact

Answer 6

If you increase the receiver bandwidth you get a shorter sampling time and less time for artifact to enter the slice the sacrifice here is SNR

Question 7

Flow artifact

Answer 7

Can be corrected by applying Gradient moment nulling or flow comp.

Question 8

Gradient moment Nulling/flow comp

Answer 8

minimizes phase shift obtained by transverse magnetization of excited nuclei moving along the gradients, (only works for first-order motion such as small vessels CSF)

Question 9

zipper artifact

Answer 9

a leak in RF shielding, ensure door suction and all doors are closed in scan room to minimize or correct.

Question 10

Partial volume averaging artifact

Answer 10

occurs when multiple tissue types are contained within a single voxel, generally happens with thicker slices

Question 11

How to correct for partial volume averaging artifact

Answer 11

best way is to decrease in voxel volume or thinner slices

Question 12

Moire/Fringe Field artifact

Answer 12

caused by interference of aliased signals at different phases

Question 13

Magic angle artifact

Answer 13

occurs when a tendon or ligament is positioned at 55 degrees in the direction of the main magnetic field and a short TE is used.

Question 14

how to correct for magic angle artifact

Answer 14

long TE,

Question 15

Best method to evaluate cardiac infarction is

Answer 15

Perfusion cardiac imaging

Question 16

Trigger delay

Answer 16

delay after system detects the R wave before transmitting RF to intended slice

Question 17

Purpose of trigger delay

Answer 17

To postpone slice acquisition until the heart is diastolic (relaxation period of heart beat)

Question 18

Trigger window

Answer 18

waiting period before each R wave and is expressed as % of R-R interval

Question 19

Mitral Valve

Answer 19

bicuspid, Left AV valve

Question 20

Tricuspid

Answer 20

Right AV valve

Question 21

Aortic Valve

Answer 21

Located between Left Ventricle and ascending aorta, semilunar valve

Question 22

pulmonary valve

Answer 22

lies between pulmonary artery and the right ventricle

Question 23

P wave

Answer 23

atrial muscle contraction (systole)

Question 24

QRS complex

Answer 24

Ventricular Systole (muscle contraction) some might say this is the R-T interval

Question 25

T Wave

Answer 25

Ventricular Diastole (muscle relaxation) or T-R interval (

Question 26

The coils in a magnet from the innermost to the outermost are

Answer 26

bore, rf, gradient, main magnet (revise)

Question 27

____ discovered that a charged particle such as a proton spinning on its own axis has a magnetic field known as a magnetic momentum

Answer 27

Felix Bloch

Question 28

____ developed the equation showing precession of nuclear spins being proportional to magnetic field strength

Answer 28

Sir Joseph Larmor

Question 29

in 1975 _______ introduced 2D NMR using phase and frequency encoding and the fourier transform

Answer 29

Richard Ernst

Question 30

In the year _____ Scherings _____ IV Gadolinium contrast gets the first approval by FDA

Answer 30

1988, Magnevist

Question 31

When was function mri developed

Answer 31

1991

Question 32

_____ and ____ won the 2003 nobel prize in medicine or their work in the 1970's developing MR imaging techniques and capabilities

Answer 32

Lauterbur and Mansfield

Question 33

_____ coined the work "electricity" and was the first to realize the earth is a giant magnet

Answer 33

william gilbert

Question 34

_____developed the mathematical equation to analyze heat transfer between solid bodies, later becoming the basis for the rapid processing of phase and frequency signals in MRI

Answer 34

Joseph Fourier

Question 35

______discovered that a current flowing through a wire could produce a magnetic field

Answer 35

Hans Christian Oersted

Question 36

Shielding of the magnet does what to the field

Answer 36

decreases the size of the fringe field and increases the MSG

Question 37

How does shielding within the magnet housing affect the system spatial gradient

Answer 37

It increases the systems spatial gradient, because it decreases the size of the fringe field forcing lines of flux together

Question 38

frequency encoding gradient being right to left means this is the ____ gradient

Answer 38

X gradient

Question 39

when did michael colimbini die

Answer 39

2001

Question 40

decreasing TE will do what to SNR

Answer 40

increase

Question 41

partial echo

Answer 41

is a fast imaging technique that only acquires part of the MRI signal during the frequeny encoding process

Question 42

partial fourier

Answer 42

is a technique used to fill k-space by only recording a portion of all of the phase encoding steps and leveraging the conjugate symmetry of k space

Question 43

saturation occurs when the __

Answer 43

TR is SHORTER than the T1 of the tissue

Question 44

passive shielding

Answer 44

the process of using ferromagnetic materials placed in the scanner bore to improve the homogeneity of the main magnetic field