Gradients Flashcards
In a pulse sequence diagram, “Gy” refers to the gradient perfoming:
Phase Encoding
In a pulse sequence diagram, “Gz” refers to the gradient performing:
Slice Excitation
The type of gradients that are used to denote specific functions on a pulse sequence are referred to as ______ gradients.
Logical
a gradient coil is what type of magnet?
A. Electro
B. Both Electro & Resistive
C. Resistive
B. Both Electro & Resistive
Which of the following is not at an advantage of higher performance gradients?
A. Shorter minimum TR’s.
B. Longer Minimum TE’s
C. Shorter Echo spacing times
D. Thinner minimum slice thickness
B. Longer minimum TE’s
The measurement of mili-tesla/meter (mT/m) is the measurement of a gradient’s:
amplitude
What are the 3 main functions of MRI gradients?
Slice excitation
Phase encoding,
frequency encoding
The person credited with the concept and development of MRI gradient fields is:
Paul Lauterbur
True or false:
A gradient field can only be created in the X and Y directions.
False
If Electrical current is run in the same direction of the main magnet field, the gradients included magnetic field __________ to/from the main magnetic field.
(adds or subtracts?)
adds
How many gradient coils are in an MRI system?
6
True/False:
A gradient with a higher peak amplitude always out performs a gradient with a lower peak amplitude
False
The slope of the gradient that derives from a combination of the rise & amplitude is known as its:
slew rate
The time interval from a gradient’s minimum to maximum field difference is known as its:
Rise time
the measurement of a gradients minimum to maximum field difference is known as its:
amplitude
