Module 1

Question 1

More powerful the External Magnetic Field

Answer 1

the more N.M.V. there are to manipulate.

Net Magnetization Vectors

Question 2

How is the field strength of the magnet displayed

Answer 2

in tesla represented as T

or Bo

Question 3

Path by which the Hydrogen Atoms follow.

Answer 3

Precessional Path:

Question 4

Hydrogen Atom Nucleus is rotating around its axis and the Proton or charged particle is also rotating which causes the hydrogen atom to have its own _____ _____

Answer 4

This causes the Hydrogen atom to contain its own Magnetic Field

Question 5

The sum of Protons and Neutrons in the nucleus

Answer 5

Atomic Mass

Question 6

Due to its odd number of Protons (one) in its nucleus. (hydrogen atom) start to proceed around causing a _____ _____.

Answer 6

Magnetic Moment that is relatively large

Question 7

To line up with the Magnetic Field, it takes more or less energy

Answer 7

Less energy

Question 8

MRI advantages

Answer 8

1. Non-ionizing radiation.
2. Spatial resolution (the ability to distinguish two points or structures as separate)
3. Contrast resolution
4. Multiplanar Imaging

Question 9

Hydrogen Nuclei spin on there own axis.

Once subjected to an External Magnetic Field they also start to wobble

Answer 9

This wobble is called its Precession

Question 10

With no external magnetic field, magnetic moments are randomly situated.

Once exposed to a Magnet Field M. M. start to_______with and against Magnetic field (North and South)

Answer 10

align

Question 11

Size and Direction of the magnetic moment in the Z plane.

has both magnitude and direction and is called a _____.

Answer 11

Vector

Question 12

This refers to three inividual forces: motion, magnetism and electrical charge.

If two of the three are present then the third will be induced

Answer 12

Faraday’s law of electromagnetic induction

Question 13

Disadvantage of MRI

Answer 13

Expensive

Long scan times

Audible noise (65-115dB or higher)

Isolation of patient (claustrophobia, monitoring of ill patients)

Exclusion of patients with conventional pacemakers and certain implants.

Question 14

This energy state aligns with the External Magnetic Field, termed Spin Up Nuclei.

Answer 14

Low energy state

Question 15

It takes more or less energy to fight against the direction of the Main Magnetic Field.

Answer 15

More energy

Question 16

Godfather of MRI

Answer 16

Felix Bloch

Question 17

Speed at which the Hydrogen Atoms spin we also call this wobble

Answer 17

Precessional Frequency:

Question 18

This is the sum of Protons in Nucleus

Answer 18

Atomic Number

Question 19

This is equal to the gyromagnetic Ratio of Hydrogen (42.57MHZ/Tesla) x the Magnetic Field Strength

Answer 19

The Precessional Frequency

Question 20

Precessional Frequency is represented

Answer 20

as f

or Wo

Question 21

This energy state aligns against the External Magnetic Field, termed Spin Down Nuclei.

Answer 21

High energy state

Question 22

The gyromagetic ratio is represented by

Answer 22

Greek gamma symbol

Question 23

Consists of central nucleus with one proton, no neutron, and one orbiting electrons

Answer 23

Hydrogen Atom

Question 24

3T images have _______ signal than 1.5T.

Answer 24

higher

Question 25

42.57 MHZ/T

Answer 25

Larmar equation ratio

Question 26

These are the winners or the remaining Vectors that now align with the external field… These are what will be manipulated by the external R.F. pulse to create M.R.I images.

Answer 26

Net Magnetization Vectors

Question 27

The third force of Faraday's law, magnetism, will be induced thus giving the hydrogen atom a magnetic moment allowing it to align with an external magnetic field.

Answer 27

hydrogen we have a positive charge and motion

Question 28

Battle between Spin Up and Spin Down Nuclei create a common ground. The result of this battle is the

Answer 28

N.M.V. w0 Net Magnetization Vector

Question 29

Images are created using 3 regions of the electromagnetic spectrum.

Answer 29

X-rays use transmitted x-rays Photographs use reflected visible light. MRI uses emitted radiofrequencies

Question 30

3 Types of Motion within the Hydrogen Atom

Answer 30

Electrons spinning on own axis Electrons orbiting the Nucleus The Nucleus itself spins on own axis

Question 31

The larger the field strength, the \_\_\_\_\_\_\_\_hydrogen will align in the spin up (low energy) state

Answer 31

more

Question 32

This is a test that uses a magnetic field and pulses of radio wave energy to make pictures of organs and structures inside the body

Answer 32

What is MRI

Question 33

Determines the Precessional Frequency

Answer 33

Larmor equation:

Question 34

This is direction of the North and South axis of a Magnet and the amplitude of the magnetic field

Answer 34

magnetic moment

Question 35

In a patient, the tissues that behave like tiny magnets themselves and are susceptible to an external magnetic field due to its magnetic moment

Answer 35

hydrogen nuclei

Question 36

The Hydrogen nuclei can have two types of energy states. What are they?

Answer 36

Low State High State