mri Module 2

Question 1

MRI ability to encode within the mr signal the location of each anatomical area of the patient is called

Answer 1

spatial localization

Question 2

____________ refers to the rate that vector travels around the Bo

Answer 2

Frequency

Question 3

____________ refers to vectors traveling along the precessional path, weather or not they are synchronized with each other.

Answer 3

phase

Question 4

is it possible for frequency to be the same and there be a phase differeance?

Answer 4

yes. just like a clock makes a complete turn in 24 hrs but the time may not be the same.

Question 5

Is it possible for the frequency of two systems remains constant and therefore the phase system between the two also remain constant?

Answer 5

Yes. just think of the clock.

Question 6

If the frequency between two systems is different, what happens to the phase difference over time?

Answer 6

phase difference increases linearly (more and more) over time

Question 7

What would happen to phase if there is a positive change in frequency along with an equal negative change in frequency?

Answer 7

will have no net effect on phase

Question 8

Independently from the direction of the magnetic system what are the patients coordinates?

Answer 8

Z
X
Y

Question 9

___- axis is the same direction as the Bo, it travels along the long axis of the human body

Answer 9

Z-axis (head to feet)

Question 10

_____ axis extend from left to right side of the patient.

Answer 10

X-axis

Question 11

_____ axis extends from the anterior to the posterior of the pt.

Answer 11

Y- axis

Question 12

Since we only want to look at one slice from a specific plane, we need to make sure we use a

Answer 12

RF pulse that only excites one slice

Question 13

The selection of slice plane is made possible through the use of

Answer 13

magnetic field gradients

Question 14

________________________ are hardwear component of the mri sysytem, which consist of many coils of wire which, when current is passed through them, they are capable of varying the main magnetic field.

Answer 14

magnetic field gradients

Question 15

In a magnetic field gradient, the center of the magnetic field is called the ____________________. If you diviate from the center and you go inone direction or to the oppisite direction the magnetic field will _______________ or ________________.

Answer 15

isocentre

increase or decrease