MRI - PPT

Question 1

Who discovered the properties of MRI?

Answer 1

1940s

Bloch & Purcell

Question 2

Who produced 1st MRI image of a human being?

Answer 2

1977

Damadian

Question 3

Who awarded Nobel Prize in Physiology for discoveries in MRI?

Answer 3

2003

Lauterbur & Mansfield

Question 4

Who produced 1st MRI image of an object?

Answer 4

1973

Lauterbur

Question 5

When was 1st MRI equipment became available for

installation?

Answer 5

1980s

Question 6

MRI depends of

Answer 6

The properties of the nucleus of an atom

Question 7

Hydrogen is used since

Answer 7

It is the most abundant element in the body

Question 8

Hydrogen with a single proton in its nucleus is

Answer 8

The strongest nuclear magnet, therefore creating the strongest MRI signal

Question 9

RF (radiofrequency) coils are

Answer 9

“antenna” of the MRI system that broadcasts the RF signal to the patient and/or receives the return signal
(Received signals & send feedback)

Question 10

Gradient coils are used to

Answer 10

• Produce deliberatevariations in the main magnetic field (Bo).
• There are usually three sets of gradient coils, one for each direction (x, y, z axes)

Question 11

Resistive magnets

Answer 11

• Simple, large electromagnets

- Limited field strength (no more than 0.6 T)

Question 12

Superconductive (cryogenic) magnets

Answer 12

• Electromagnets that use liquid helium for cooling

- Permits higher magnet strengths than resistive magnets

Question 13

Permanent magnets

Answer 13

• Does not require electricity or cooling
• Heavy, massive
• Smaller fringe field

Question 14

Clinical MRI uses

Answer 14

Superconductive (cryogenic) magnets

Question 15

Magnetic field strength is measured in

Answer 15

tesla (T) or gauss (G)

1 T = 10,000 G

Question 16

Earth’s natural magnetic field is

Answer 16

0.5 G

Question 17

Low-field magnets range is

Answer 17

0.2 T – 1.0T

Question 18

High-field magnets range is

Answer 18

1.5T and higher

Question 19

FDA has approved up to ………………….. magnets for clinical imaging of babies and up to 8T for clinical imaging of adults and children

Answer 19

4T

Question 20

Outside the U.S., up to ……………. can be used

Answer 20

15T

China 27T

Question 21

Patient Table is

Answer 21

Hydraulically or mechanically driven

Magnetically safe and contain no metal parts

Question 22

Patient Table Must allow for

Answer 22

attachment of coils and immobilization devices

Question 23

Patient Table Weight limits range from

Answer 23

300 – 660 lbs

Question 24

T1‐weighted image is Used to evaluate

Answer 24

• Anatomy (structure)

• Characterized by bright fat & dark water

Question 25

T2‐weighted image is Used to evaluate

Answer 25

- Pathology | • Characterized by bright water & dark fat

Question 26

2 Types of Contrast Media

Answer 26

1. Gadolinium compounds | 2. Iron oxide mixtures

Question 27

Gadolinium compounds also called

Answer 27

Paramagnetic substance | T1 agent

Question 28

Gadolinium compounds is

Answer 28

- Most commonly used - Lower toxicity and fewer side effects than iodinated IV contrast - Used in the evaluation of the CNS and for tumor detection

Question 29

Iron oxide mixtures also called

Answer 29

Superparamagnetic substance | T2 agent

Question 30

Iron oxide mixtures is used to

Answer 30

Detect and diagnose liver lesions

Question 31

MRI Safety: 4 Basic Areas of Concern

Answer 31

* Thermal injuries * Acoustic noise * Projectiles * Nephrogenic Systemic Fibrosis

Question 32

Thermal Injuries

Answer 32

Burns can result when: • Cables from coils are in contact with the patient’s skin • Metals, wires, medication skin patches with foil, and ferromagnetic inks from tattoos are present in the scanner

Question 33

Acoustic Noise

Answer 33

- MRI can produce noise up to 130 dB | - Ear plugs can reduce the noise by 10-30 dB

Question 34

Projectiles

Answer 34

The missile effect the force with which projectiles are pulled towards a magnetic field is proportional to: • the strength of the magnet • the distance from the magnet • the mass of the object • the material that the object is made of

Question 35

Ferromagnetic metal object can reach a terminal velocity of ...................when pulled into a ............................ magnet

Answer 35

40 mph | 1.5T

Question 36

MRI offers

Answer 36

superior imaging of soft-tissue structures

Question 37

MRI does NOT use

Answer 37

ionizing radiation

Question 38

MRI Contrast material is better tolerated compared to

Answer 38

Radiography and CT

Question 39

Proper patient screening is

Answer 39

utmost importance

Question 40

the magnet is ALWAYS

Answer 40

ON