MRI - PRELIM L2

Question 1

The dense, central core of an atom, containing nearly all
of its mass.

Answer 1

Atomic Nucleus

Question 2

Fill in the blanks with their corresponding charges:

Protons:
Neutrons:
Electrons:

Answer 2

Protons: Positive Electric Charge

Neutrons: Neutral Charges

Electrons: Negative Electric Charges

Question 2

The Nucleus is made up of ______ and ______, held together by the ______

Answer 2

1. Protons
2. Neutrons
3. Strong Nuclear Force

Question 2

Electrons orbit the nucleus in regions called _______

Answer 2

Electron Shells / Orbitals

Question 3

Many of the electron spins align in the same direction, creating a stronger overall magnetic field such as in magnetic materials like _____

Answer 3

Iron

Question 3

TRUE OR FALSE

Electrons balance the positive charge of protons, keeping the atom electrically neutral

Answer 3

TRUE

Question 3

In most materials, the magnetic fields of individual atoms cancel out because they point in _________

Answer 3

Random Directions

Question 3

This comes from the motion of charged particles
(especially electrons) inside atoms.

Answer 3

Magnetism

Question 4

Electrons have a property called _______ which generates tiny magnetic fields

Answer 4

Spin

Question 4

The proton has a spin of

Answer 4

1/2

Question 5

Proton Spin is a _______ that does not correspond to literal spinning in space but rather to a form of _______

Answer 5

1. Quantum Mechanical Property
2. Intrinsic Angular Momentum

Question 5

Refers to a fundamental property of protons (and other elementary particles) related to their intrinsic angular momentum

Answer 5

Proton Spin

Question 5

It provides a mathematical way to determine the frequency at which a charged particle precesses in a magnetic field

Answer 5

Larmor Relationship

Question 5

TRUE OR FALSE

When subjected to a strong magnetic field, electrons in the body align and then release energy when they return to their original alignment, which is detected to form images.

Answer 5

FALSE

When subjected to a strong magnetic field, PROTONS in the body align and then release energy when they return to their original alignment, which is detected to form images.

Question 6

The time it takes for protons to return to their original alignment
with the magnetic field after being disturbed by an RF pulse by the interaction energy with their surrounding environment

Answer 6

T1 Relaxation Time

Question 6

The motion of protons as they wobble around the magnetic field after being disturbed by the RF pulse.

Answer 6

Precession

Question 7

The wave character of
electromagnetic radiation but it is basically equivalent to the
wavelength since the wavelength is just the speed divided by the frequency and the speed of light is a constant.

Answer 7

Radiofrequency

Question 7

Motion of nuclear spins in a magnetic field when there is no external influence, such as a radiofrequency (RF) pulse, acting on them

Answer 7

Free Precession

Question 7

Frequency of precession is called as ________

Answer 7

Larmor Frequency

Question 7

The uniformity and synchronization of the precessional
motion of protons (or other nuclei) in response to an applied magnetic field

Answer 7

Phase Coherent

Question 8

MRI images are made with RF in the range from _________

Answer 8

Approximately 10 to 300 MHz

Question 8

After the protons align with the magnetic field, short RF pulse (a burst of electromagnetic energy) is applied at a specific frequency, this is hence the ________

Answer 8

Larmor Frequency

Question 9

When all protons are precessing in phase, the signal they emit is _______ and ______ to detect.

Answer 9

Stronger and Easier

Question 10

The time constant that describes when a signal decreases with
time as the proton spins begin to lose phase coherence or diphase

Answer 10

Relaxation Time

Question 11

The Relaxation Time is the period it takes for protons to return to their _______ after being disturbed by an RF pulse

Answer 11

Equilibrium State

Question 12

The time it takes for protons to lose phase coherence in the transverse plane after the RF pulse is turned off.

Answer 12

T2 Relaxation Time

Question 13

T1 is important for creating contrast between tissues in T1-weighted images, where tissues with a shorter T1 (like fat) show up _______ and tissues with Longer T1 (like Water) show up ______

Answer 13

Shorter T1 = Brighter Longer T1 = Darker

Question 14

T1 Relaxation Time may also be known as _______ or ______

Answer 14

1. Spin-Lattice Relaxation Time 2. Longitudinal Relaxation Time

Question 15

T2 is crucial for creating contrast in T2-weighted images, where tissues like water (which has a longer T2) appear _______, and tissues like fat (which have a shorter T2) appear _______

Answer 15

Shorter T2 = Darker Longer T2 = Brighter

Question 16

T2 Relaxation Time may be also called as _______ or _______

Answer 16

1. Spin-Spin Relaxation Time 2. Transverse Relaxation Time

Question 17

RELAXATION SPEED T1 is ________ than T2 whereas T2 is _______ than T1

Answer 17

1. Generally Slower 2. Generally Faster

Question 17

T1 is important for showing ______ vs _____

Answer 17

Fat vs Water

Question 18

Tissues like muscle (which has a relatively high _____ ) will appear _____.

Answer 18

1. Proton Density 2. Darker

Question 19

The concentration of magnetic nuclei (typically protons) that are available to contribute to the MR signal. Essentially, it refers to the number of protons in a given tissue volume that can be detected during an MRI scan

Answer 19

Spin Density

Question 19

T2 is important for showing ______ or ______

Answer 19

Edema or Inflammation

Question 20

Fat or bone (which has a _____ proton density) will appear _______

Answer 20

1. Lower 2. Darker