Practice Set (2) - Basic Principles

With the exception of hydrogen, all matter is composed of three components.
They are

The negatively charged component of an atom is called the

The positively charged component of an atom is called the

The neutral component of an atom is called the

The nucleus of the hydrogen atom is made up of one

Materials reach their highest magnetic potential when their atoms are grouped in areas known as

Material that is weakly attracted to a magnetic field is said to be

Material that is strongly attracted to a magnetic field is said to be

Material that is slightly repelled from a magnetic field is said to be

Three types offerromagnetic material are

To exist, magnets must have two poles, therefore they are commonly called

The lines that represent the field of a magnet are known as

The strength of a magnet is measured by its

The strength of an MRI magnet is most commonly represented by a unit of
measurement called

10,000 gauss is equal to

15,000 gauss is equal to

The law that is used in MRI to describe how a magnetic field is induced by
flowing current is known as

Which of the following is an advantage of a permanent magnet MRI
system?

What type of molecule makes up 500/0 to 90% of a person's total body
weight?

Clinical MRl is based on the generation of signal from the nucleus of which
atom?

The nucleus of the hydrogen atom carries what type of charge?

The spin of the proton of the hydrogen atom is known as

Because the nucleus of the hydrogen atom acts much like a bar magnet it is
said to have a

Because the spinning nucleus of the hydrogen atom has both a North and
South pole it is commonly called a

When placed in an external magnetic field, hydrogen nuclei

After being placed in an external magnetic field, high energy hydrogen nuclei
point in which direction?

After being placed in an external magnetic field, low energy hydrogen nuclei
point in which direction?

When placed in an external magnetic field, the hydrogen nuclei that are of
clinical interest are

When a patient is placed in an external magnetic field, the number of
unmatched hydrogen protons usually equals

The sum of all of the unmatched parallel protons in an external magnetic field
makes up what is called the

The type of rotation that is displayed by hydrogen nuclei in an external
magnetic field is known as

Within a perfect magnetic field all protons rotate at

The speed at which protons rotate in an external magnetic field is known as

The ratio that describes the constant at which any magnetic nucleus will
precess in a 1 tesla magnet is known as

The precessional frequency of magnetic nuclei is determined by which of the
following?

The equation that is used to determine the precessional frequency of magnetic
nuclei is known as

The stronger the magnetic field the ________ the precessional frequency

Which of the following is the equation that is used to determine precessional
frequencies?

Alignment of the net magnetic vector in the direction of the external
magnetic field is known as

Magnetization in the XY plane is known as

When the proper radio frequency is applied, the precessing hydrogen nuclei
begin to

The RF pulse used to move nuclei into a higher energy state is at a frequency
known as

Hydrogen nuclei begin to precess in phase when which of the following
occurs?

When the radio frequency is turned off, precessing nuclei begin to

Another name for transverse relaxation is

Another name for Tl relaxation is

The return of longitudinal magnetization to equilibrium is known as

Dephasing of the net vector in the transverse plane is known as

The time it takes for a tissue's bulk longitudinal magnetization to return to
63% of its original value is known as

The time it takes for transverse magnetization to decay to 37% of its original
value is known as

Dephasing ofthe net vector in the transverse plane is caused by two factors, imperfections in the external magnetic field and

Magnetization in the transverse plane can also be known as

Magnetization in the longitudinal plane can also be known as

MRI signals can only be detected in which ofthe following planes

~~ The signal created after applying a 90 degree RF pulse is known as a

The signal produced after the 180 degree RF pulse is applied is known as a

A 180 degree RF pulse is used to ________ the dephasing net vector in the transverse plane

The larger the net magnetic vector in the transverse plane the _______  the signal that is produced

The smaller the net magnetic vector in the transverse plane the signal that is produced

The letters FID in an Fill signal stand for

The type of signal that is created after a gradient is used to refocus the dephasing net vector is known as

The time between two successive 90 degree RF pulses is known as

The time between the 90 degree RF pulse and the spin echo signal in a spin echo pulse sequence is known as

In an inversion recovery pulse sequence, the time between the 180 degree RF pulse and the 90 degree RF pulse is known as